EP1005 - Incidence and Pathology of Rectal Strictures in Rectal Cancer Patients Following Total Neoadjuvant Therapy

Purpose/Background: Following total neoadjuvant therapy (TNT), some rectal cancer patients have residual strictures or develop new strictures at the site of the original rectal cancer. These patients are not considered to have a complete clinical response and are recommended to undergo surgical resection. Some of these patients have a complete pathologic response. Rectal strictures refer to a narrowing of the rectal lumen and are typically classified by severity: mild, moderate or severe. Strictures can also be evaluated endoscopically. A stricture is considered clinically significant if it is non-negotiable by endoscope, indicating a high-grade obstruction.

This study aims to evaluate the incidence and pathological characteristics of rectal strictures in rectal cancer patients treated with TNT, with the goal of providing more objective data to support patient-centered surgical decision-making.

Methods/Interventions: A retrospective review of the database at a single institution from January 1, 2023, to December 31, 2024 was performed. Included were patients diagnosed with locally advanced rectal cancer who completed total neoadjuvant therapy.

Rectal cancer patients with residual rectal strictures and those who developed a stricture at the cancer site endoscopically following TNT were identified. Data collected included patient demographics (age, sex), cancer staging (clinical and pathological), final surgical pathology, dates of treatment, dates of surveillance endoscopy, whether chemotherapy or radiation was performed first, time from completion TNT to the diagnosis of the stricture, time from completion of radiation therapy to the diagnosis of the stricture, and MRI findings post-treatment. Descriptive statistics were used to assess the incidence of rectal strictures and the presence of residual malignancy in resected specimens. All data analysis was performed using IBM® SPSS® Statistics, Version 29.

Results/Outcomes: A total of 119 patients diagnosed with rectal cancer underwent TNT during the study period. Among these, 8 patients (6.7%) were found to have rectal strictures on post-TNT surveillance endoscopy. Of these, 7 (87.5%) were found to have residual cancer on final pathology. 6 of the 8 patients had undergone chemoradiation followed by consolidated chemotherapy, and 2 had induction chemotherapy followed by chemoradiation. 5 of the patients with rectal strictures had pathologic stage T3 N0/1 on the final surgical specimen, 2 had T0 N0/1, and 1 had T2 N0.

Conclusion/Discussion: This study highlights a significant incidence of rectal strictures following total neoadjuvant therapy (TNT) in rectal cancer patients with locally advanced rectal cancer. Among the 119 patients treated with TNT, 6.7% developed a stricture detectable on surveillance endoscopy. 87.5% of those who underwent surgical resection of the strictures were found to have residual malignancy on final pathology.

These findings corroborate the high risk nature of rectal strictures for residual neoplasia following TNT for locally advanced rectal cancer. The high rate of residual cancer in this cohort underscores the importance of thorough evaluation and shared decision-making for surgery when strictures are identified.