Effects of clinical information on the treatment decisions for good responders to neoadjuvant chemoradiotherapy among rectal cancer patients

Eon Bin Kim; In Ja Park; Hwa Jung Kim; Jong Keon Jang; Seong Ho Park; Young Il Kim; Min Hyun Kim; Jong Lyul Lee; Chan Wook Kim; Yong Sik Yoon; Seok-Byung Lim; Chang Sik Yu

doi:10.3393/ac.2024.00276.0039

Articles

Page Path: HOME > Ann Coloproctol > Volume 41(5); 2025 > Article

Original Article Colorectal cancer Effects of clinical information on the treatment decisions for good responders to neoadjuvant chemoradiotherapy among rectal cancer patients: Eon Bin Kim¹, In Ja Park², Hwa Jung Kim³, Jong Keon Jang⁴, Seong Ho Park⁴, Young Il Kim², Min Hyun Kim², Jong Lyul Lee², Chan Wook Kim², Yong Sik Yoon², Seok-Byung Lim², Chang Sik Yu²; Annals of Coloproctology 2025;41(5):473-482.
DOI: https://doi.org/10.3393/ac.2024.00276.0039
Published online: July 10, 2025

¹Department of Surgery, Dongguk University Ilsan Hospital, Dongguk University College of Medicine, Goyang, Korea

²Division of Colon and Rectal Surgery, Department of Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea

³Department of Clinical Epidemiology and Biostatistics, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea

⁴Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea

Correspondence to: In Ja Park, MD, PhD Division of Colon and Rectal Surgery, Department of Surgery, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Korea Email: ipark@amc.seoul.kr

• Received: May 1, 2024 • Revised: June 10, 2024 • Accepted: June 16, 2024

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

prev next

1,418 Views
31 Download
1 Crossref

Full Article

Download PDF

Abstract
INTRODUCTION
METHODS
RESULTS
DISCUSSION
ARTICLE INFORMATION
SUPPLEMENTARY MATERIALS
REFERENCES

Abstract

Purpose
The decision for treatment after neoadjuvant chemoradiotherapy (nCRT) in rectal cancer is intricately linked to tumor response and clinical parameters. This study was designed to elucidate determinants influencing treatment decisions for good responders to nCRT, while concurrently evaluating the ramifications of modifications in magnetic resonance imaging (MRI) tumor response evaluation protocols.
Methods
A survey was constructed with 5 cases of good responder after nCRT based on the magnetic resonance–based tumor regression grade (mrTRG) criteria. A total of 35 colorectal surgeons in Korea participated in the survey via email, and they were introduced to 2 discrete MRI-based tumor response evaluation methodologies: the conventional mrTRG and an emergent complete response (CR)/non-CR classification system. Surgeons were directed to select between total mesorectal excision, local excision, or a watch and wait strategy.
Results
Treatment decisions varied significantly (P<0.01), as gradually more clinical information was provided with mrTRG. The paradigm shift from mrTRG to CR/non-CR evaluation criterion instigated the highest alteration in decision (P<0.01). Even comparing with other sets of information, decision change with different tumor response assessment (i.e., mrTRG vs. CR/non-CR) was statistically significant (P<0.01). Three particular cases consistently displayed a declining predilection for total mesorectal excision, favoring a more pronounced inclination towards watch and wait strategy or local excision. Nonetheless, the magnitude of these decisional shifts oscillated depending on the specific endoscopic imagery present.
Conclusion
Our current findings underscore the significant role of tumor response assessment methods in shaping treatment decisions for rectal cancer patients who respond well to nCRT. This highlights the need for clear and accurate tools to interpret MRI results.
Keywords: Chemoradiotherapy; Complete response; Treatment decision; Tumor regression grade; Rectal neoplasms

INTRODUCTION

Rectal cancer patients demonstrate diverse tumor responses following neoadjuvant chemoradiotherapy (nCRT) [1]. These varied responses critically influence on subsequent treatment choices. In cases where a complete response (CR) is anticipated, treatment alternatives might extend to local excision (LE) or even a watch and wait (WW) approach, as opposed to the traditional total mesorectal excision (TME) [1–8]. Given the association of pathologic CR with favorable oncological outcomes [2, 6, 9], emphasis has predominantly centered on its prediction to optimize treatment plans.

Recent data indicates an uptick in good responders when there is an elongated interval between nCRT completion and response evaluation [10]. Clinical responses appear enhanced in the context of total neoadjuvant therapy. In these prolonged intervals, repetitive response assessments become imperative. Consequently, basing treatment decisions on clinical response evaluation is deemed pragmatic.

In clinical settings, the magnetic resonance–based tumor regression grade (mrTRG) has been instrumental in treatment planning, gauging viable tumor versus fibrosis proportions [1, 11–13]. However, the congruence between mrTRG and pathologic TRG hovers around 60% to 70% [12, 14, 15]. Using an assessment tool with this level of agreement to identify complete responders might inadvertently overlook residual tumors. Mitigating this, an enhanced magnetic resonance imaging (MRI) interpretation approach has been introduced, incorporating diffusion-weighted images (DWI) alongside T2-weighted images (T2WI) [12, 16, 17]. Jang et al. [18] presented a refined approach to discern CR, simplifying the indication process. Complementary efforts are underway to amplify treatment decisions by assimilating diverse clinical data, including digital rectal exam findings, initial tumor attributes, endoscopic responses, and tumor positioning [17, 19]. Additionally, based on the information gathered, a multidisciplinary team approach for colorectal patients has been a standard approach which has proven to be helpful [20].

The degree to which such comprehensive clinical data steers treatment choices remain underexplored, however. This study aimed to quantify the influence of varied MRI-based response criteria on treatment alterations and evaluate the clinical determinants of treatment decisions for robust nCRT responders in rectal cancer.

METHODS

Ethics statement

The study was approved by the Institutional Review Board of Asan Medical Center, with a waiver of informed consent (No. 2017-1114).

Survey development and administration

A survey was designed using data from patients diagnosed with advanced low rectal cancer who underwent nCRT. Five patients, randomly chosen from this group, displayed favorable responses to nCRT with an mrTRG grade of either 1 or 2. We collected clinical information such as age, sex, and tumor location, denoted as the distance from the anal verge (AV).

Tumor responses were evaluated using 2 distinct MRI-based methodologies. The first, mrTRG, uses a 5-tier grading system derived from T2WI. In contrast, the CR/non-CR method is a 2-tier classification, formulated by integrating both T2WI and DWI interpretations [18]. Patients deemed to be approaching or achieving a CR were classified under the CR category. These 2 evaluation techniques were applied independently [21].

Surgeons were presented with the survey, which gradually disclosed increasing amounts of patient information, prompting them to select among 3 treatment strategies: TME, LE, or WW. The survey encompassed 25 questions, segmented into 5 sets corresponding to the 5 patients. The first question set provided a post-nCRT endoscopic image and the patient's mrTRG grade. The subsequent set presented the same endoscopic image, now accompanied by a CR/non-CR grade. Sets 3 to 5 supplemented the first dataset with additional patient particulars: age and sex, tumor location (as distance from the AV), and the initial endoscopic image, respectively. The endoscopic images were presented without descriptive text, whereas the mrTRG and CR/non-CR grades were conveyed exclusively in textual format, devoid of accompanying images. Tumor distances from the AV were determined via MRI (Fig. 1). The characteristics of the selected patients remained well-balanced despite the random selection process (Table 1, Supplementary Fig. 1).

The survey was administered to colorectal surgeons who has specialty in colorectal surgery and experience of longer than 3 years across secondary and tertiary healthcare facilities from November 11 to 25, 2022, via personalized email communications.

Treatment and response assessment

Patients incorporated into the survey underwent an extended course of nCRT, which included 25 to 28 radiation therapy sessions, delivering a cumulative dose ranging from 45 to 50.4 Gy. The concurrent chemotherapy was either a combination of fluoropyrimidine (42.5 mg/m²/day) and leucovorin (20 mg/m²/day) administered during the initial and final weeks of radiation therapy, or capecitabine, with a dosage of 850 mg/m² given orally twice daily throughout the radiation therapy period. In accordance with our institutional protocol, the post-nCRT response evaluation took place 4 to 6 weeks post nCRT completion. Clinical responses to nCRT were assessed using digital rectal examinations, endoscopy, and MRI.

Statistical analysis

We analyzed the treatment decision data using both the GLIMMIX and the generalized estimating equations (GEE) methods. The GEE method effectively managed repeated measures since we gathered data through repeated surveys based on consistent cases across surgeons. This method accounted for intrasubject correlations and yielded unbiased regression coefficient estimates. Moreover, using the GLIMMIX technique, we fitted generalized linear mixed models that incorporated both fixed and random effects within a unified framework.

We performed statistical analyses with IBM SPSS ver. 24.0 (IBM Corp) and MedCalc ver. 13.3 (MedCalc Software). We considered a P-value of <0.05 as statistically significant.

RESULTS

Influence of clinical information on treatment decisions

From the 37 surveys sent out, 35 responses were received; 82% of the respondents were male surgeons. In total, we collected 175 responses for the survey's 5 consecutive questions.

In set 1, where both the post-nCRT endoscopic image and the mrTRG grade were provided, treatment choices shifted as additional information was sequentially included: by 9.1% for set 3 (adding age and sex to set 1), 20.6% for set 4 (adding tumor location to set 3), and 22.3% for set 5 (adding pre-nCRT endoscopic image to set 4). The change was statistically significant (P=0.002), though not in a stepwise manner corresponding to the increase in clinical information. When categorizing the treatment decision into nonoperative management (WW) and operative management (LE and TME), decisions significantly varied with the volume of clinical information (P=0.010) (Table 2).

The least apparent change in treatment decisions occurred in set 3 when supplementary details, specifically age and sex, were incorporated into the initial question. TME preference rose when male sex information was provided (from 58.9% to 64.5%), yet it exhibited minimal alteration when female sex data was introduced (from 72.9% to 71.4%). In set 4, disclosing the distance from the AV influenced choices: for cases less than 5 cm from the AV, WW dropped from 5.7% to 4.3% and TME decreased from 78.6% to 71.4%, while LE surged from 15.7% to 24.3%. Conversely, for cases more than 5 cm from the AV, the TME preference rose from 59.8% to 73.3%, WW had a slight uptick from 11.2% to 12.4%, and only LE decreased, from 29.0% to 14.3%. Upon the availability of prior endoscopic images, TME dropped from 72.6% to 61%, whereas both WW and LE saw increases, moving from 9.1% to 16.4% and 18.3% to 22.6%, respectively, across all 5 cases.

Influence of the MRI-based response assessment method on treatment decisions

When the MRI-based tumor response assessment method was adjusted, treatment decisions were altered, even when the same post-nCRT endoscopy image was provided. Altering the tumor response assessment from the mrTRG method to the CR/non-CR method resulted in a 33.7% change in treatment decisions among TME, LE, and WW (P<0.001). Choices favoring WW changed by 11.4% upon transitioning to the CR/non-CR method from the mrTRG method (P=0.007) (Table 2).

Interestingly, even when there was concordance between mrTRG and CR/non-CR—specifically, when mrTRG2 aligned with non-CR— the answers changed by 25.7%. Conversely, the change in responses increased to 35.7% when there was a discrepancy between the 2 methods (P<0.01). When comparing nonoperative management (WW) with operative management (LE and TME), the difference in decisions was no longer statistically significant (P=0.45) (Table 3).

We performed statistical analysis to explore the potential influence of sequentially added clinical data on decision-making. We also sought to ascertain whether these alterations held significance in comparison to changes in MRI response assessment. Initially, we gauged the variances in sets 2, 3, 4, and 5 against set 1. Subsequently, we used the variation from set 2 relative to set 1 as a baseline. With this foundation, we juxtaposed the variance observed in each of sets 3, 4, and 5 against set 1. Our findings highlighted that alterations in decision-making were statistically significant throughout all response sets (Fig. 2A). However, when the analysis was limited exclusively to decisions pertaining to WW, only the data from sets 3 and 5 exhibited significant disparities (Fig. 2B).

Decision changes in patients with discordant MRI assessments

In 3 distinct cases, lesions were categorized as mrTRG2 but subsequently transitioned to CR upon MRI response assessment. A consistent trend emerged in these patients: a decline in the selection of TME and an uptick in the preference for WW. The degree of this shift was influenced by the post-nCRT endoscopy images presented in the survey (Fig. 3). For instance, in case 1, where the endoscopy revealed an almost completely resolved tumor with only scar tissue remaining, there was a marked rise in the preference for WW, while TME selections diminished. In contrast, for cases 2 and 3, where endoscopic images displayed ulcerative lesions, there was an increased inclination toward LE, corresponding to a drop in TME selections.

While many respondents adjusted their decisions based on the information presented, 5 surgeons consistently provided the same response throughout the survey. Among these 5, 4 (representing 80%) had over 2 decades of clinical practice. Four consistently favored TME across all questions, while the 5th surgeon consistently opted for WW.

DISCUSSION

From the findings of this study, it became evident that MRI response assessments play a critical role in guiding treatment choices for rectal cancer patients who respond well to nCRT. Treatment decision changes ranging from 9% to 34% were evident as we presented more clinical data. In that regard, more treatment decisions were changed when tumor location information was added compared with sex and age demographics, but few changes were observed when preoperative endoscopy imaging was included. Treatment planning alterations were also higher when the MRI-based assessments changed compared with the addition of clinical information. These insights highlighted the meticulous attention surgeons pay to each piece of information when mapping out a treatment plan for a cancer patient.

We here utilized an MRI-based CR/non-CR as a response assessment tool after nCRT as an alternative to mrTRG. We used this simpler assessment method to investigate whether it could better streamline the information conveyed to surgeons and thereby assist in their decision-making processes. This same approach was also described at the 2016 European Society of Gastrointestinal and Abdominal Radiology (ESGAR) meeting, which developed a structured MRI report template for restaging after a neoadjuvant treatment has been constructed from a 3-tier level categorization [22]. This purposed template was developed by consensus meeting to improve the quality of MRI reporting and the satisfaction levels from surgeons who have received the referrals.

Our current findings revealed somewhat different results however that the intended reduction in categorization. Even though the highest rates of change in treatment decisions were evident when the tumor response assessment had changed, our further analysis indicated no significant changes from nonoperative management under this circumstance. Based on these results, while there was significant variation of decision when the surgeons select among 3 decisions, its change did not reach to nonoperative management. This trend was also observed when we analyzed only the changes in responses for WW (Fig. 2B), where set 5 showed the most significant variation and set 3 had the least. Considering that set 2 had the highest overall response variation, its change in terms of a WW management choice appeared relatively modest.

WW can be considered as a viable therapeutic option for good responders and there has been increased interest in this approach among clinicians after an nCRT intervention for rectal cancer. The paradigm shift toward WW was also stimulated by intensifying multimodal neoadjuvant treatment, such as precision medicine [23]. Notably, however, the number of patients who would be treated using WW strategies did not approach the actual proportion of cases that achieved pathologic CR after nCRT. According to our institutional data, there were 446 rectal cancer patients designated with ≤ycT2 stage from 2008 to 2016, and only 34 (7.6%) were managed using WW [24]. Also, among this cohort, out of the 73 patients who demonstrated clinical CR, 13 cases (17.3%) underwent WW. From a prior survey conducted among various Asian countries including Korea, 7.4% of respondents indicated they would choose a WW approach in cases of clinical CR [25]. In our present study, the proportion of WW cases varied depending on the type and amount of information provided, ranging from as low as 9.0% to as high as 16.4%. This trend aligns with the values observed in previous studies. One of the reasons for such limited choice preference of WW could be found in a recent case report [26]. Even if a good clinical response was observed and LE was done, the report suggested the possibility of recurrence even after 5 years.

Even though MRI response assessments seem to play the most significant role in determining the direction of treatment for rectal cancer, there has been some criticism around the reliability of MRI imaging interpretation and additional information is therefore needed by the treating clinicians. We observed a consistent trend in the aforementioned survey targeting Asian countries in which 77.8% of participants responded that WW could be selectively used as a treatment option [25]. Notably, the most cited reason for not choosing the WW approach was the perceived inaccuracy of imaging (67.9%). To address limitations in response assessments, a prior report has described assessing digital rectal exam results and endoscopic findings together, defined as a complete endoscopic response [27]. Those authors used the endoscopic response to define the clinical CR, in conjunction with the mrTRG. Although the survey responses in our present study did not provide information on digital rectal exams, we could find similar trends. We compared 3 different cases where the MRI-based assessments had not been concordant (mrTRG2 and CR). For all 3 patients, the selection shifted in the same direction: an increase in WW and LE choices and a decrease in TME choices. However, the extent of these changes was found to be associated with the severity of the lesions observed on endoscopic images. Hence, while an MRI response assessment has a significant impact on the posttreatment decisions for rectal cancer patients, they are also influenced by other information, particularly endoscopic image findings. It is known in this regard that surgeons do not rely solely on MRI assessments when determining the treatment direction for their cancer patients. A prior study has described a similar correlation between endoscopic findings and the pathologic T category after nCRT [28]. That study reported that endoscopy may be used to select lesions for LE i.e., ypT2 or deeper lesion. Hence, when post-nCRT findings and the mrTRG are not concordant, pre-nCRT colonofiberscope has a role in treatment decision-making in rectal cancer.

Our present findings indicated the lowest variation in treatment responses when age and sex were provided. Surprisingly, this observation contrasts with those of previous reports. Regardless of the country in question, a significant portion of surgeons—around 80%— will chose to selectively apply WW to elderly patients or to cases with medical comorbidities when they achieve clinical CR after nCRT [25]. Another study has compared the radical resection rates of rectal cancer between the elderly population, defined as 80 years and above, and the nonelderly population, defined as between 65 and 75 years [29]. The authors reported a 57.1% surgical rate in the elderly group and 71.7% in the nonelderly group. From our own institutional data also, the average age of the rectal cancer patients who underwent radical resection was 58.66 years, while that for WW cases was 62.91 years [24]. There was no observed variation in rectal cancer incidence based on sex in cases where surgery or WW were performed. Hence, the appropriate choice of surgery or WW could not be based on sex considerations. One possible reason for the discrepancy in our present findings and prior data, even though the age range of our study cases was comparable at between 54 and 76 years, could be the limited sample size in our current analyses.

Our present study had several limitations of note. First, when mrTRG and CR/non-CR interpretations were provided, only text descriptions without the MRI images were provided. Additionally, evaluation regarding the regression of lymph nodes were omitted, focusing solely on the main tumor. Although manual rectal exams are among the most important sources of information to determine treatment, this information could not be provided due to its subjective nature. The study's limitations include a survey based on only 5 specific cases and participation from only 35 surgeons, making it difficult to generalize the findings. This small and narrowly focused sample size may not adequately reflect the full diversity of cases in actual clinical practice. A larger sample size and a variety of patient characteristics are necessary for more generalizable results. Moreover, the study focuses on short-term treatment decisions without assessing long-term patient outcomes, leaving the impact of the proposed evaluation method on actual patient survival and recurrence rates unknown. Data collection through surveys heavily relies on the subjective judgments of respondents, which may reduce the reliability of decision changes that are not verified through objective clinical data. Additionally, there may have been potential biases as all of our cases were from Korea, and thus subject to treatment under the same national health insurance system. The interpretation of tumor response via MRI can also vary; surgeons with less experience in MRI interpretation might have differing assessments based on the criteria used.

Despite these limitations however, we have still objectively demonstrated the importance of an MRI response assessment in determining the optimal treatment approach for rectal cancer patients who have undergone nCRT. There is a real need therefore for objective indicators to help develop and quantify endoscopic image evaluations, as they can also influence the decision-making process. Further research is thus needed to develop a standardized and quantified assessment protocol for endoscopic data.

In conclusion, MRI response assessments have the most influence on the choice of treatment modality for rectal cancer patients who respond well to nCRT. More accurate and objective indicators are thus needed to better interpret MRI image information. Further research will be required to develop an imaging analysis technique that can be qualified post-nCRT response assessment.

ARTICLE INFORMATION

Conflict of interest

In Ja Park is the Editor-in-Chief of this journal, but was not involved in the reviewing or decision process of this manuscript. No other potential conflict of interest relevant to this article was reported.

Funding

None.

Author contributions

Conceptualization: IJP; Data curation: JKJ, SHP; Formal analysis: HJK; Investigation: EBK; Methodology: IJP, HJK; Project administration: IJP; Resources: JKJ, SHP, YIK, MHK, JLL, CWK, YSY, SBL, CSY; Software: HJK; Supervision: IJP; Validation: IJP; Visualization: EBK, HJK; Writing–original draft: EBK; Writing–review & editing: all authors. All authors read and approved the final manuscript.

SUPPLEMENTARY MATERIALS

Supplementary Fig. 1.

Clinical data of all 5 cases in the survey.

ac-2024-00276-0039-Supplementary-Fig-1.pdf

Supplementary materials are available from https://doi.org/10.3393/ac.2024.00276.0039.

Fig. 1.

Example of a survey for surgeons. The first dataset includes a post-neoadjuvant chemoradiotherapy (post-nCRT) endoscopic image and the patient's magnetic resonance tumor regression grade (mrTRG). The subsequent sets add a complete response (CR)/non-CR grade, patient demographics (age and sex), tumor location (distance from the anal verge [AV]), and the initial endoscopic image, respectively. Post-endoscopy, post-nCRT endoscopic image; MRI, magnetic resonance imaging; Pre-endoscopy, pre-nCRT endoscopic image; WW, watch and wait; LE, local excision; TME, total mesorectal excision.

Fig. 2.

Changes in treatment decisions in accordance with different given information. Set 2, post-neoadjuvant chemoradiationtherapy (post-nCRT) endoscopic image + complete response (CR)/non-CR; set 3, post-nCRT endoscopic image + magnetic resonance tumor regression grade (mrTRG) + age and sex; set 4, post-nCRT endoscopic image + mrTRG + age/sex + tumor location (from the anal verge); set 5, post-nCRT endoscopic image + mrTRG + age/sex + tumor location (from the anal verge) + pre-nCRT endoscopic image. (A) Difference between the changes in decision according to given sets of information. The incorporation of clinical information led to a gradual evolution in treatment decisions. The tradition from the mrTRG method to the CR/non-CR assessment had the most significant impact on altering these decisions. (B) Difference between the changes in watch and wait (WW) decisions according to given sets of information. The decision to WW approach is most influenced by the addition of the pre-nCRT endoscopic image.

Fig. 3.

Decision changes with equivalent magnetic resonance imaging response assessments. (A, B) Case 1. (C, D) Case 2. (E, F) Case 3. (A, C, E) Post-neoadjuvant chemoradiotherapy endoscopy images. (B, D, F) Impact of endoscopy image on decision making. WW, watch and wait; LE, local excision; TME, total mesorectal excision; mrTRG, magnetic resonance tumor regression grade; CR, complete response.

Table 1.

Distribution of the patients’ characteristics in the survey (n=5)

Given information	No. of patients (%)
mrTRG
mrTRG1	1 (20)
mrTRG2	4 (80)
CR/non-CR
CR	3 (60)
Non-CR	2 (40)
Sex
Male	3 (60)
Female	2 (40)
Age (yr)
≥65	2 (40)
<65	3 (60)
Tumor location (distance from AV) (cm)
≥5	3 (60)
<5	2 (40)

mrTRG, magnetic resonance tumor regression grade; CR, complete response; AV, anal verge.

Table 2.

Changes in treatment decision for watch and wait according to given information (n=175)

Given information	Change in decision (%)	P-value	Change in NOM (%)^a	P-value
Set 1. Post-endoscopy + mrTRG	Reference	-	Reference	-
Set 3. Post-endoscopy + mrTRG + age/sex	9.1	0.002^b	3.4	0.010^b
Set 4. Post-endoscopy + mrTRG + age/sex + tumor location	20.6		9.1
Set 5. Post-endoscopy + mrTRG + age/sex + tumor location + pre-endoscopy	22.3		13.1
Set 2. Post-endoscopy + CR/non-CR criteria	33.7	<0.001	11.4	0.007

Post-endoscopy, post-nCRT endoscopic image. Pre-endoscopy, pre-nCRT endoscopic image.

NOM, nonoperative management (watch and wait); mrTRG, magnetic resonance tumor regression grade; CR, complete response; nCRT, neoadjuvant chemoradiotherapy.

^aVersus local excision + total mesorectal excision.

^bStatistical difference between sets 3, 4, and 5.

Table 3.

Changes in treatment decision on diverse MRI response assessment (n=175)

Agreement of MRI response assessment	Change in decision		Change in NOM^a
Agreement of MRI response assessment	No. of responses (%)	P-value	No. of responses (%)	P-value
mrTRG = CR/non-CR^b (n=35)	9 (25.7)	<0.01	4 (11.4)	0.45
mrTRG ≠ CR/non-CR^c (n=140)	50 (35.7)		25 (17.8)

MRI, magnetic resonance imaging; NOM, nonoperative management (watch and wait); mrTRG, magnetic resonance tumor regression grade; CR, complete response.

^aVersus local excision + total mesorectal excision.

^bmrTRG2 with non-CR.

^cmrTRG1 with non-CR or mrTRG2 with CR.

REFERENCES

1. van der Valk MJ, Hilling DE, Bastiaannet E, Meershoek-Klein Kranenbarg E, Beets GL, Figueiredo NL, et al. Long-term outcomes of clinical complete responders after neoadjuvant treatment for rectal cancer in the International Watch & Wait Database (IWWD): an international multicentre registry study. Lancet 2018;391:2537–45.Article PubMed
2. Dattani M, Heald RJ, Goussous G, Broadhurst J, São Julião GP, Habr-Gama A, et al. Oncological and survival outcomes in watch and wait patients with a clinical complete response after neoadjuvant chemoradiotherapy for rectal cancer: a systematic review and pooled analysis. Ann Surg 2018;268:955–67.Article PubMed
3. Kim CH. The risk-benefit trade-off in local excision of early rectal cancer. Ann Coloproctol 2022;38:95–6.Article PubMed PMC PDF
4. Bach SP, Hill J, Monson JR, Simson JN, Lane L, Merrie A, et al. A predictive model for local recurrence after transanal endoscopic microsurgery for rectal cancer. Br J Surg 2009;96:280–90.Article PubMed PDF
5. Hallam S, Messenger DE, Thomas MG. A systematic review of local excision after neoadjuvant therapy for rectal cancer: are ypT0 tumors the limit? Dis Colon Rectum 2016;59:984–97.Article PubMed
6. Renehan AG, Malcomson L, Emsley R, Gollins S, Maw A, Myint AS, et al. Watch-and-wait approach versus surgical resection after chemoradiotherapy for patients with rectal cancer (the OnCoRe project): a propensity-score matched cohort analysis. Lancet Oncol 2016;17:174–83.Article PubMed
7. Son GM. Organ preservation for early rectal cancer using preoperative chemoradiotherapy. Ann Coloproctol 2023;39:191–2.Article PubMed PMC PDF
8. Varela C, Kim NK. Surgical treatment of low-lying rectal cancer: updates. Ann Coloproctol 2021;37:395–424.Article PubMed PMC PDF
9. Park MY, Yu CS, Kim TW, Kim JH, Park JH, Lee JL, et al. Efficacy of preoperative chemoradiotherapy in patients with cT2N0 distal rectal cancer. Ann Coloproctol 2023;39:250–9.Article PubMed PDF
10. Probst CP, Becerra AZ, Aquina CT, Tejani MA, Wexner SD, Garcia-Aguilar J, et al. Extended intervals after neoadjuvant therapy in locally advanced rectal cancer: the key to improved tumor response and potential organ preservation. J Am Coll Surg 2015;221:430–40.Article PubMed PMC
11. Siddiqui MR, Gormly KL, Bhoday J, Balyansikova S, Battersby NJ, Chand M, et al. Interobserver agreement of radiologists assessing the response of rectal cancers to preoperative chemoradiation using the MRI tumour regression grading (mrTRG). Clin Radiol 2016;71:854–62.Article PubMed
12. Park SH, Cho SH, Choi SH, Jang JK, Kim MJ, Kim SH, et al. MRI assessment of complete response to preoperative chemoradiation therapy for rectal cancer: 2020 guide for practice from the Korean Society of Abdominal Radiology. Korean J Radiol 2020;21:812–28.Article PMC PDF
13. Lambregts DM, Boellaard TN, Beets-Tan RG. Response evaluation after neoadjuvant treatment for rectal cancer using modern MR imaging: a pictorial review. Insights Imaging 2019;10:15. Article PMC PDF
14. Jang JK, Choi SH, Park SH, Kim KW, Kim HJ, Lee JS, et al. MR tumor regression grade for pathological complete response in rectal cancer post neoadjuvant chemoradiotherapy: a systematic review and meta-analysis for accuracy. Eur Radiol 2020;30:2312–23.Article PDF
15. Sclafani F, Brown G, Cunningham D, Wotherspoon A, Mendes LS, Balyasnikova S, et al. Comparison between MRI and pathology in the assessment of tumour regression grade in rectal cancer. Br J Cancer 2017;117:1478–85.Article PubMed PMC PDF
16. Yoen H, Park HE, Kim SH, Yoon JH, Hur BY, Bae JS, et al. Prognostic value of tumor regression grade on MR in rectal cancer: a large-scale, single-center experience. Korean J Radiol 2020;21:1065–76.Article PubMed PMC PDF
17. Lambregts DM, Vandecaveye V, Barbaro B, Bakers FC, Lambrecht M, Maas M, et al. Diffusion-weighted MRI for selection of complete responders after chemoradiation for locally advanced rectal cancer: a multicenter study. Ann Surg Oncol 2011;18:2224–31.Article PubMed PMC
18. Jang JK, Lee CM, Park SH, Kim JH, Kim J, Lim SB, et al. How to combine diffusion-weighted and T2-weighted imaging for MRI assessment of pathologic complete response to neoadjuvant chemoradiotherapy in patients with rectal cancer? Korean J Radiol 2021;22:1451–61.Article PMC PDF
19. Horvat N, Veeraraghavan H, Khan M, Blazic I, Zheng J, Capanu M, et al. MR imaging of rectal cancer: radiomics analysis to assess treatment response after neoadjuvant therapy. Radiology 2018;287:833–43.Article PubMed
20. Park KJ. Against all odds: why surgeons need to be more aggressive in the era of the multidisciplinary team approach to colorectal cancer. Ann Coloproctol 2022;38:393–7.Article PubMed PMC PDF
21. Gormly KL. High-resolution T2-weighted MRI to evaluate rectal cancer: why variations matter. Korean J Radiol 2021;22:1475–80.Article PubMed PMC PDF
22. Beets-Tan RG, Lambregts DM, Maas M, Bipat S, Barbaro B, Curvo-Semedo L, et al. Magnetic resonance imaging for clinical management of rectal cancer: updated recommendations from the 2016 European Society of Gastrointestinal and Abdominal Radiology (ESGAR) consensus meeting. Eur Radiol 2018;28:1465–75.Article PubMed PDF
23. Park IJ. Precision medicine for primary rectal cancer will become a reality. Ann Coloproctol 2022;38:281–2.Article PubMed PMC PDF
24. Lee C, Park IJ, Lim SB, Yu CS, Kim JC. The watch-and-wait strategy versus radical resection for rectal cancer patients with a good response (≤ycT2) after neoadjuvant chemoradiotherapy. Ann Surg Treat Res 2022;103:350–9.Article PubMed PMC PDF
25. Huh JW, Maeda K, Liu Z, Wang X, Roslani AC, Lee WY. Current status of "watch-and-wait" rectal cancer treatment in Asia-Pacific countries. Ann Coloproctol 2020;36:70–7.Article PMC PDF
26. Han JS, Lim SB, Park JH, Hong YS. Late recurrence in a rectal cancer patient who underwent preoperative chemoradiotherapy followed by local excision: a case report. Ann Coloproctol 2021;37:S24–7.Article PubMed PMC PDF
27. Beard BW, Rettig RL, Ryoo JJ, Parker RA, McLemore EC, Attaluri V. Watch-and-wait compared to operation for patients with complete response to neoadjuvant therapy for rectal cancer. J Am Coll Surg 2020;231:681–92.Article PubMed
28. Han KS, Sohn DK, Kim DY, Kim BC, Hong CW, Chang HJ, et al. Endoscopic criteria for evaluating tumor stage after preoperative chemoradiation therapy in locally advanced rectal cancer. Cancer Res Treat 2016;48:567–73.Article PubMed PDF
29. Shulman K, Musallam S, Epelbaum R, Haim N, Ben-Yosef R, Kaidar-Person O. The older adults with rectal cancer: does age matter?: a single-center experience. Am J Clin Oncol 2020;43:861–4.Article PubMed

Figure & Data

References

Citations

Citations to this article as recorded by

Clinical implications of radiologic criteria and prognostic factors for lateral lymph node metastasis in low rectal cancer
Gyung Mo Son
Annals of Coloproctology.2025; 41(6): 489. CrossRef

Cite this Article

Cite this Article: export Copy Download Format; Close

Download Citation

Download a citation file in RIS format that can be imported by all major citation management software, including EndNote, ProCite, RefWorks, and Reference Manager.

Format:

RIS — For EndNote, ProCite, RefWorks, and most other reference management software
BibTeX — For JabRef, BibDesk, and other BibTeX-specific software

Include:

Citation for the content below
Citation and abstract for the content below

Effects of clinical information on the treatment decisions for good responders to neoadjuvant chemoradiotherapy among rectal cancer patients

Ann Coloproctol. 2025;41(5):473-482. Published online July 10, 2025

DOI: https://doi.org/10.3393/ac.2024.00276.0039

XML Download

Figure

Related articles

Effects of clinical information on the treatment decisions for good responders to neoadjuvant chemoradiotherapy among rectal cancer patients

Fig. 1. Example of a survey for surgeons. The first dataset includes a post-neoadjuvant chemoradiotherapy (post-nCRT) endoscopic image and the patient's magnetic resonance tumor regression grade (mrTRG). The subsequent sets add a complete response (CR)/non-CR grade, patient demographics (age and sex), tumor location (distance from the anal verge [AV]), and the initial endoscopic image, respectively. Post-endoscopy, post-nCRT endoscopic image; MRI, magnetic resonance imaging; Pre-endoscopy, pre-nCRT endoscopic image; WW, watch and wait; LE, local excision; TME, total mesorectal excision.

Fig. 2. Changes in treatment decisions in accordance with different given information. Set 2, post-neoadjuvant chemoradiationtherapy (post-nCRT) endoscopic image + complete response (CR)/non-CR; set 3, post-nCRT endoscopic image + magnetic resonance tumor regression grade (mrTRG) + age and sex; set 4, post-nCRT endoscopic image + mrTRG + age/sex + tumor location (from the anal verge); set 5, post-nCRT endoscopic image + mrTRG + age/sex + tumor location (from the anal verge) + pre-nCRT endoscopic image. (A) Difference between the changes in decision according to given sets of information. The incorporation of clinical information led to a gradual evolution in treatment decisions. The tradition from the mrTRG method to the CR/non-CR assessment had the most significant impact on altering these decisions. (B) Difference between the changes in watch and wait (WW) decisions according to given sets of information. The decision to WW approach is most influenced by the addition of the pre-nCRT endoscopic image.

Fig. 3. Decision changes with equivalent magnetic resonance imaging response assessments. (A, B) Case 1. (C, D) Case 2. (E, F) Case 3. (A, C, E) Post-neoadjuvant chemoradiotherapy endoscopy images. (B, D, F) Impact of endoscopy image on decision making. WW, watch and wait; LE, local excision; TME, total mesorectal excision; mrTRG, magnetic resonance tumor regression grade; CR, complete response.

Fig. 1.

Fig. 2.

Fig. 3.

Effects of clinical information on the treatment decisions for good responders to neoadjuvant chemoradiotherapy among rectal cancer patients

Given information	No. of patients (%)
mrTRG
mrTRG1	1 (20)
mrTRG2	4 (80)
CR/non-CR
CR	3 (60)
Non-CR	2 (40)
Sex
Male	3 (60)
Female	2 (40)
Age (yr)
≥65	2 (40)
<65	3 (60)
Tumor location (distance from AV) (cm)
≥5	3 (60)
<5	2 (40)

Given information	Change in decision (%)	P-value	Change in NOM (%)^a	P-value
Set 1. Post-endoscopy + mrTRG	Reference	-	Reference	-
Set 3. Post-endoscopy + mrTRG + age/sex	9.1	0.002^b	3.4	0.010^b
Set 4. Post-endoscopy + mrTRG + age/sex + tumor location	20.6		9.1
Set 5. Post-endoscopy + mrTRG + age/sex + tumor location + pre-endoscopy	22.3		13.1
Set 2. Post-endoscopy + CR/non-CR criteria	33.7	<0.001	11.4	0.007

Agreement of MRI response assessment	Change in decision		Change in NOM^a
Agreement of MRI response assessment	No. of responses (%)	P-value	No. of responses (%)	P-value
mrTRG = CR/non-CR^b (n=35)	9 (25.7)	<0.01	4 (11.4)	0.45
mrTRG ≠ CR/non-CR^c (n=140)	50 (35.7)		25 (17.8)

Table 1. Distribution of the patients’ characteristics in the survey (n=5)

mrTRG, magnetic resonance tumor regression grade; CR, complete response; AV, anal verge.

Table 2. Changes in treatment decision for watch and wait according to given information (n=175)

Post-endoscopy, post-nCRT endoscopic image. Pre-endoscopy, pre-nCRT endoscopic image.

NOM, nonoperative management (watch and wait); mrTRG, magnetic resonance tumor regression grade; CR, complete response; nCRT, neoadjuvant chemoradiotherapy.

Versus local excision + total mesorectal excision.

Statistical difference between sets 3, 4, and 5.

Table 3. Changes in treatment decision on diverse MRI response assessment (n=175)

MRI, magnetic resonance imaging; NOM, nonoperative management (watch and wait); mrTRG, magnetic resonance tumor regression grade; CR, complete response.

Versus local excision + total mesorectal excision.

mrTRG2 with non-CR.

mrTRG1 with non-CR or mrTRG2 with CR.