Is adjuvant chemotherapy justified in rectal cancer patients after radiochemotherapy and radical resection?

Abstract

Recommendations for the application of post-operative adjuvant chemotherapy in patients who received preope­rative radio-chemotherapy are not consistent. Some of them advise post-operative chemotherapy, whilst others follow-up without any adjuvant treatment. The objective of this paper is to undertake an overview of the randomised studies evaluating whether the administration of adjuvant chemotherapy can be justified with clinical evidence. A systematic overview of the publications shows 5 randomised trials in which only the patients after pre-operative radio-chemotherapy were enrolled, whilst randomisation concerned adjuvant therapy vs follow-up without adjuvant therapy. None of the studies showed any improvement after post-operative chemotherapy with regards to both the overall survival and disease-free survival rate. Moreover, 3 randomised studies were found in which post-operative chemotherapy with fluoropyrimidine was compared with post-operative chemotherapy with fluoropyrimidine with the addition of oxaliplatin. One of these studies showed an improvement in the overall survival rate after the use of post-operative chemotherapy, whereas in two others the difference was statistically insignificant. Two studies showed a slight improvement after chemotherapy with regards to disease-free survival rates, whilst no such effect was observed in the third. A meta-analysis of the studies comparing the results after the administration of post-ope­rative chemotherapy with the results after the chemotherapy-free follow-up did not demonstrate any positive effect of the chemotherapy on the overall and disease-free survival rate. A meta-analysis of randomised studies in which post-operative chemotherapy with fluoropyrimidine was compared with post-operative chemotherapy with fluoro­pyrimidine with the addition of oxaliplatin did not show any improvement in disease-free survival rates in patients receiving oxaliplatin. The overall survival was not analysed because of the lack of appropriate data at the moment the meta-analysis was made. The above overview of the randomised trials points to a lack of any strong evidence justifying the administration of post-operative chemotherapy.