The impact of aspirin use on pathological outcomes in locally advanced rectal cancer patients undergoing total neoadjuvant therapy: Real-world data from the Ankara University Colorectal Cancer study group.

Abstract

e15657 Background: Total neoadjuvant therapy (TNT) in locally advanced rectal cancer (LARC) has become standard of care, but predictors of pCR and ideal patient selection are not well-defined. There is now increasing evidence that common cardiometabolic agents, including aspirin, may confer an oncological benefit; however, their impact in the TNT setting remains unclear. Methods: We performed a single-center retrospective cohort study of 117 patients with locally advanced rectal adenocarcinoma treated with TNT. Aspirin exposure was defined as continuous use of 100 mg aspirin throughout the treatment course. pCR was defined as ypT0N0 (absence of viable tumor cells in the resected specimen). Downstaging was defined as post-TNT clinical stage regression from stage III to stage II or from stage II to stage I. Associations were assessed using univariable analyses and multivariable logistic regression. Results: pCR was achieved in 40/117 (34.2%) patients. Those with pCR had a higher rate of aspirin use than those without (47.5% vs 22.1%, P = 0.006). Aspirin use remained an independent predictor of pCR in the final multivariable model (adjusted OR 3.25; 95% CI, 1.33–7.96; P = 0.010), and clinical T-stage was also retained (adjusted OR 3.12; 95% CI, 1.14–8.54; P = 0.027). Downstaging was observed in 96/117 patients (82.1%), and aspirin use was a correlate of downstaging on univariable analysis (35.4% vs 9.5%, p = 0.020). In the final multivariable model for downstaging, aspirin demonstrated a strong positive association that did not reach conventional statistical significance (adjusted OR 5.15; 95% CI, 0.92–28.92; P = 0.063). Conclusions: In this TNT-treated LARC cohort, continuous 100 mg aspirin use throughout therapy independently predicted pCR, supporting aspirin as a pragmatic adjunct candidate to intensify treatment response. These data warrant prospective confirmation of aspirin’s role as an adjunct to TNT, particularly for maximizing complete response.