Total neoadjuvant therapy vs standard therapy in locally advanced rectal cancer: A single-center, real-world study in Mexico.

72 Background: Total neoadjuvant therapy (TNT) has emerged as a pivotal treatment approach for locally advanced rectal cancer (LARC). Despite its importance, there is a significant lack of comparative research examining the outcomes of chemoradiotherapy followed by surgery and adjuvant therapy (CRT) in comparison to TNT within the Mexican population. Methods: We retrospectively analyzed data of 183 patients with LARC from January 2018 to December 2022. We aimed to determine the differences in Recurrence Free Survival (RFS), Overall Survival (OS) and Pathological Complete Response by RYAN (PCR) between patients receiving TNT vs CRT though Chi square, Kaplan-Meier Meier and Cox regression methods. Results: Median age was 57 years; 55.7% of cases were male. Lower rectum was affected in 72.7%, middle in 20.2% and 7.1% in lower rectum. TNT therapy was administered in 111 cases (60.7%) an CRT in 72 cases (39.3%). Adverse Events were present in 41% in the TNT group and 33.3% in the CRT group (p 0.009). Mean RFS between CRT and TNT groups was not significant (70 months vs 63 months, p=0.323). In multivariate analyses, TNT was an independent predictor for OS (B – 1.507; HR 0.222, IC 95% 0.070-0.7; p=0.026) and PCR by RYAN was also shown to be an independent predictor of survival (p = 0.001). Conclusions: Patients who underwent TNT demonstrated enhanced OS. In our cohort, PCR by RYAN appears to serve as a surrogate marker for OS and RFS. It is imperative to carefully select patients to ensure complete therapeutic responses while avoiding overtreatment, which may result in significant toxicity. Multivariate analyses for overall survival (Cox regression). B SE Wald df Sig. Exp(B) 95.0% CI Exp(B) Inferior Superior Neoadjuvant therapy -1.507 .587 6.590 1 .010 .222 .070 .700 RYAN 20.845 3 .000 RYAN 0 -4.345 1.198 13.152 1 .000 .013 .001 .136 RYAN 1 -.570 .655 .758 1 .384 .566 .157 2.041 RYAN 2 -2.253 .643 12.260 1 .000 .105 .030 .371 Age .038 .025 2.331 1 .127 1.039 .989 1.091 Lymph node negative -1.045 .718 2.122 1 .145 .352 .086 1.435 Grade 2.941 2 .230