Neoadjuvant treatment in a Mexican cohort of patients with locally advanced rectal cancer: Oncologic outcomes and prognostic factors.

Abstract

704 Background: Preoperative chemoradiotherapy (CRT) followed by total mesorectal excision (TME) and adjuvant chemotherapy (CT) is the standard of care for locally advanced rectal cancer (LARC). Total neoadjuvant therapy (TNT) consists of induction CT followed by CRT prior to surgery. This is an alternative strategy recommended in guidelines. Objective: To describe neoadjuvant strategies, oncologic outcomes and prognostic factors in a cohort of patients (pts) with LARC treated at a referral center in Mexico City. Methods: We retrospectively reviewed medical records from pts with LARC (T3-T4 or N+) treated with any neoadjuvant strategy at Instituto Nacional de Ciencias Médicas y Nutrición “Salvador Zubirán” from January 2010 to December 2015. Clinical and pathological information was registered. Survival was estimated by Kaplan-Meier method. Univariate analysis for prognostic factors was performed and survival was compared by the log rank test. Results: 43 pts were included. Median age was 62 y/o (19-83), 51% were female. Clinical stage (CS) II 9% and CS III 91%. 36 pts were T3-4 and N+(86%). Localization was lower third 30%, middle third 56% and upper third 12%. 63% were moderately differentiated adenocarcinoma. 84% had TNT: induction CT with FOLFOX-4 regimen for 3 months followed by CRT (50.4 Gy in 28 fractions concurrently with fluoropyrimidines) and TME. Surgery: ultra-low anterior resection (AR) 48%, low AR 28% and abdominoperineal resection 24%. One patient did not accept surgery. Of the 32 pts with ultra-low and low AR, 94% had protective ileostomy. The pathologic complete response (pCR) ypT0ypN0 rate was 45% (19/42). Median follow-up was 48 months. There were 8/42 recurrences (19%): local-only 2.3%, systemic only 12% and both 5%. None of the pts with pCR recurred. All pts with residual nodal disease recurred (5/5). The 5-year relapse-free survival rate was 73%. There were 6 deaths, one patient died without disease. The 5-year overall survival rate was 83%. Conclusions: In pts with LARC the TNT is associated with high rates of pCR and favorable oncological outcomes. pCR and residual nodal disease after neoadjuvant therapy were strongly associated with recurrence and survival.