Response to neoadjuvant chemoradiation in rectal cancer: Experience from the national cancer institute of Peru.

Abstract

e15157 Background: Preoperative Chemoradiation (CRT) in rectal cancer has benefit in local control. 50 - 60% of cases are down-staged and 20% achieve a pathologic complete response (pCR). Despite the fact that there is no a clear benefit in long-term outcomes, response to preoperative treatment could have a prognostic value. Our objectives were to determine the pCR and down-staging (DS) rates after neoadjuvant CRT, as well as disease free survival (DFS), overall survival (OS) and prognostic factors associated with these outcomes Methods: Patients with rectal cancer treated with preoperativefluoropyrimidine based CRT at the National Cancer Institute of Peru (INEN) from 2007 to 2012 were evaluated. OS and DFS were calculated according to Kaplan-Meyer method. The survival curves were compared using the Log-rank or Breslow test. Multivariate analysis was performed with Cox regression Results: 282 patients were included, median age was 62 years (range 18-93), female: male ratio (1:1). Clinical stages were as follows: I, 13.8%; II, 32.3% and III, 52.9%. Median follow up was 5 years. Patients received capecitabine and 5-FU during radiotherapy in 75.5% and 24.5% of cases respectively. Sphincter preserving surgery was possible in 46% of cases. In patients who underwent surgery, DS and pCR rates were 52% and 10.8%, respectively. Patients who achieved pCR were predominant female and had CEA less of 5 ng/mL. In multivariate analysis, clinical stage, DS, type of fluoropyrimidine (capecitabine) and surgery were associated with OS. 5 year DFS and OS was 54.9% and 60.5% respectively in patient that underwent surgery Conclusions: DS rate achieved at our institution is within the range reported by the literature and is associated with an improvement in OS. Our pCR rate was lower than what has been reported, this might be related to great proportion of patients with advanced clinical stage (EC III) in our study. This patient could have benefit with totally neoadjuvant Chemoradiation.