Clinical stage T2N0M0 rectal adenocarcinoma: Is radical resection associated with improved overall survival in patients with low-risk histology?

ABSTRACT

BACKGROUND: Prior studies evaluating the efficacy of local excision compared to radical resection in the treatment of rectal adenocarcinoma lacked sufficient power to identify differences in outcomes for patients with cT2 disease but low-risk histopathology. We compared the outcomes of local excision and radical resection for low-risk histopathology and high-risk histology of patients with cT2N0M0 rectal adenocarcinoma to assess their outcomes. METHODS: We queried the National Cancer Database for patients presenting with cT2N0M0 rectal adenocarcinoma between 2004 and 2019 and categorized them as low-risk histopathology or high-risk histology. We used the Cox proportional hazards model to identify factors associated with the risk of all-cause mortality. We 11 propensity-matched patients who underwent local excision to patients who underwent radical resection and used the Kaplan-Meier method to compare overall survival for matched cohorts. RESULTS: Of the 4,446 patients selected, we classified 1,206 (27%) as high-risk histology and 3,240 (73%) as low-risk histopathology. Among the patients with high-risk histology, 121 (10%) underwent local excision and 1,085 (90%) underwent radical resection. Among the patients with low-risk histopathology, 340 (10%) underwent local excision and 2,900 (90%) radical resections. Whereas radical resection was associated with decreased risk of all-cause mortality and increased overall survival for patients with high-risk histology, it was not for patients with low-risk histopathology. CONCLUSION: The overall survival of patients with low-risk histopathology with cT2N0M0 rectal adenocarcinoma who undergo local excision is similar to those of patients with low-risk histopathology who undergo radical resection, suggesting local excision is a reasonable approach for these patients. In contrast, radical resection provides a significant survival advantage for patients with high-risk histology and should remain their treatment of choice.