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

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.