Prognostic impact of tumor location after abdominoperineal resection of rectal cancer: A single-center propensity score matching analysis based on 1806 cases.

BACKGROUND

Randomized controlled trials have revealed that abdominoperineal resection leads to inferior oncological outcomes compared with low anterior resection, especially regarding local recurrence rates (LRRs). While neoadjuvant chemoradiotherapy can lower LRRs, it is linked to potential short- and long-term radiation-induced adverse effects. Consequently, meticulous patient selection for neoadjuvant chemoradiotherapy is imperative to balance benefits and risks.

METHODS

This research encompassed individuals with rectal cancer (RC) who underwent abdominoperineal resection (APR) from January 2006 to December 2017. The cohort was categorized into two cohorts on the basis of tumor location: the anterior cohort and the nonanterior cohort. Propensity score matching (PSM) was employed to mitigate selection bias, and this resulted in 767 patients in both cohorts. The primary endpoint assessed was survival without local recurrence (LR).

RESULTS

Of the 2025 cases examined, 1806 were deemed eligible for inclusion. In the entire cohort, the incidence of LR was 9.9% (178/1806); the anterior cohort exhibited a higher rate of LR (15.2% versus 5.9%, p < 0.001). Multivariate examination revealed that anterior location was an independent risk factor (IRF) for LR (hazard ratio [HR] = 2.503, p < 0.001). In patients with stage II/III or T3/4, anterior location persisted as a predictor of increased LR. Neoadjuvant chemoradiotherapy for stage II and III tumors diminished the LR rate in anterior tumor locations (p = 0.017) but not in nonanterior locations (p = 0.390).

CONCLUSION

Anterior tumor location is an IRF for LR in RC patients. Tumor location can serve as a criterion for patient selection in neoadjuvant chemoradiotherapy.

TRIAL REGISTRATION

The studies involving human participants were reviewed and approved by the National Cancer Center's Institute Research Medical Ethics Committee (23/180-3922, 11 May 2023). A copy of the written consent is available for review by the Editor-in-Chief of this journal on request.