Long-term outcomes of endoscopic or surgical resection in T1 colorectal cancer patients: a retrospective cohort study

The personalized treatments of T1 colorectal cancer (CRC) remains controversial. We compared the long-term outcomes of T1 CRC patients after endoscopic resection (ER) and surgery, and evaluated the risk factors for the long-term prognosis.

T1 CRCs after resection at the Cancer Hospital, Chines Academy of Medical Sciences from June 2011 to November 2021 were reviewed. High-risk factors included positive resection margin, poor differentiation, deep submucosal invasion (DSI ≥ 1000 μm), lymphovascular invasion and intermediate/high tumor budding. Comparative analyses were conducted based on three treatment methods: follow-up after ER (Group A), additional surgery after ER (Group B) and initial surgery (Group C). The primary endpoints included recurrence-free survival (RFS) and overall survival (OS). Cox proportional hazard regression models were constructed to identify risk factors for RFS and OS.

A total of 528 patients were enrolled (173 patients in Group A, 102 patients in Group B, 253 patients in Group C). The 3-year RFS, 5-year RFS, 3-year OS, and 5-year OS rates were 96.7%, 94.7%, 99.1%, and 97.8%, respectively. In the absence of other high-risk factors, RFS (P = 0.321) and OS (P = 0.155) of patients with DSI after ER were not inferior to those after surgery. Multivariate analyses identified sex (HR 0.379; 95% CI 0.160–0.894), Charlson comorbidities index (CCI) (HR 3.330; 95% CI 1.571–7.062), margin (HR 8.212; 95% CI 2.325–29.006), and budding (HR 3.794; 95% CI 1.686–8.541) as independent predictive factors of RFS, and identified CCI (HR 10.266; 95% CI 2.856–36.899) as an independent predictive factor of OS.

The long-term outcomes of ER are comparable to those of surgery in T1 CRC patients with DSI when other high-risk factors are negative. Resection margin, tumor budding, sex, and CCI may be the most important long-term prognostic factors for T1 CRC patients.