[Predictive factors of tumour response after neoadjuvant chemoradiation for locally advanced rectal cancer and correlation of these factors with survival]

Abstract

Purpose: Neoadjuvant chemoradiation followed by surgery is the standard of care for locally advanced rectal cancer. The aim of this study was to correlate tumour response to survival and to identify predictive factors for tumour response after chemoradiation.

Patients and methods: From 1998 to 2008, 168 patients with histologically-proven locally advanced adenocarcinoma treated by preoperative chemoradiation before total mesorectal excision were retrospectively studied. They received a radiation dose of 45 Gy with a concomitant 5-fluoro-uracil-based chemotherapy. Analysis of tumour response was based on the lowering of T stage between pre-treatment endorectal ultrasound and pathologic specimens. Overall and progression-free survival was correlated with tumour response. Tumour response was analysed with predictive factors.

Results: The median follow-up was 34 months. Five-year disease-free survival and overall survival were respectively of 44.4% and 74.5% in the whole population, 83.4% and 83.4% in patients with pathological complete response, 38.6% and 71.9% in patients with tumour downstaging, 29.1% and 58.9% in patients with absence of response. A pre-treatment concentration of carcinoembryonnic antigen below 5 ng/mL was significantly associated with tumour downstaging and significantly independently associated with pathologic complete tumour response (P = 0.019).

Conclusion: Downstaging and complete response after chemoradiation improved progression-free survival and overall survival of locally advanced rectal adenocarcinoma. In multivariate analysis, a pre-treatment concentration of carcinoembryonnic antigen below 5 ng/mL was associated with complete tumour response, hence with tumour downstaging.