Role of adjuvant chemotherapy in patients with locally advanced rectal carcinoma after preoperative chemoradiotherapy: Single center experience

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Background: Various national guidance provide different approaches in adjuvant chemotherapy for locally advanced rectal carcinoma initially treated with preoperative chemoradiotherapy. We evaluated the efficacy of adjuvant chemotherapy depending on the clinical stage of disease (prior to chemoradiotherapy) and yp stage (after surgery). Methods: Preoperative chemoradiotherapy was administered in 457 patients with locally advanced rectal carcinoma. Radiotherapy was performed in pts receiving capecitabine (64%), intravenous administration of 5-FU (16%) or combination fluoropyrimidines with oxaliplatin (20%). Adjuvant chemotherapy was administered in 98 patients (21%) (fluoropyrimidines alone (20%) or in combination with oxaliplatin (80% patients). Overall survival (OS) was the primary endpoint. Statistical analysis was performed in IBM SPSS statistics v.20 software package. Results: the mean age of patients was 56.6 years, male - 56%. Median of follow up was 42 months (2-141). Adjuvant chemotherapy did not result to better OS in any of clinical stage (p = 0.6 HR 1.1, 95% CI 0.6-2.1). However adjuvant chemotherapy tended to improve disease free survival (DFS) in stage ypT0-4N1-2M0 (р=0.1, HR=0.6, 95%CI 0.4-1.1). Subanalysis showed significant improvement of DFS in patients with ypT1-4N2M0: median of DFS in patients with adjuvant chemotherapy was 62 months, in patients from group of surveillance – 16 months (р<0.01, HR=0.3, 95%CI 0.14-0.7) and a tendency to improvement of OS (table). Conclusions: Our retrospective data confirmed the results of ADORE prospective trial, and showed that adjuvant chemotherapy for locally advanced rectal carcinoma after chemoradiotherapy should be administered only in patients with residual positive lymph nodes (yp stage III). [Table: see text]