The aim of this overview was to investigate whether adjuvant chemotherapy has a favourable effect on the outcome of patients with rectal cancer who had preoperative (chemo)radiotherapy.
A review of randomised clinical trials that allocated patients between fluorouracil-based and observation or between fluorouracil-based and oxaliplatin-based adjuvant chemotherapy after preoperative (chemo)radiotherapy was carried out, including their corresponding meta-analyses.
None of the five randomised trials has shown a significant benefit of fluorouracil-based adjuvant chemotherapy for overall survival or disease-free survival. Also, the three corresponding meta-analyses failed to show a benefit of adjuvant treatment. Of three randomised trials – two phase III and one phase II with a 3-year disease-free survival end point – two showed a small benefit of adding oxaliplatin to fluorouracil, one failed. The corresponding meta-analyses showed that the pooled difference was not significant.
In conclusion, the use of postoperative 5-fluorouracil-based chemotherapy with or without oxaliplatin in patients with rectal cancer after preoperative (chemo)radiotherapy is not scientifically proven.