Challenges of Surveillance in Implementing Nonoperative Management for Rectal Cancer.

Importance: Close surveillance for detection of local tumor regrowth is critical for patients opting for nonoperative management after neoadjuvant therapy for rectal cancer. However, there are minimal data regarding the feasibility and adherence to National Comprehensive Cancer Network (NCCN) surveillance guidelines for these patients. Objective: To determine adherence rates to NCCN-recommended surveillance in patients undergoing nonoperative management for rectal cancer. Design, Setting, and Participants: This retrospective cohort study included patients treated at a single academic center (University of Rochester, Rochester, New York) from 2012 to 2023, with analysis completed from March through May 2024. Patients with clinical stage I to III rectal cancer who underwent treatment with neoadjuvant therapy, achieved a clinical complete response (or initially near complete clinical response), and elected for nonoperative management were enrolled. Exposure: Achievement of recommended surveillance. Main Outcomes and Measures: The primary outcome was adherence to surveillance guidelines for patients undergoing nonoperative management for rectal cancer. Secondary outcomes included assessment of oncologic outcomes stratified by adherence to surveillance. Results: Eighty-five patients (54 male [63.5%]; median [IQR] age, 63.0 [54.0-73.0] years) were managed nonoperatively and followed for a median of 4.04 years (95% CI, 3.17-4.58 years). The 5-year overall survival was 82.3% (95% CI, 71.8%-94.5%), the 5-year disease-specific survival was 95.1% (95% CI, 89.6%-100.0%), the rate of local regrowth was 24.7% (21 patients), and the rate of distant metastases was 12.9% (11 patients). Among the 77 patients with more than 6 months of follow-up in their first year of surveillance, only 39.0% of patients (30 patients) achieved NCCN-recommended surveillance in the first year, and this decreased to 15.0% (3 patients) by year 5. However, the time to local regrowth and distant metastasis were similar regardless of the level of surveillance. Conclusions and Relevance: In this cohort study of patients with rectal cancer undergoing surveillance after nonoperative management, most did not achieve NCCN-recommended guidelines, although outcomes were not associated with surveillance intensity. This highlights the need for prospective evaluation of a surveillance regimen that is both feasible for patients and health care systems increasingly using nonoperative management. In addition, studies are warranted to explore patient preferences in rectal cancer care and to identify barriers to optimal surveillance.