Short term results of neoadjuvant chemoradiotherapy with fluoropyrimidine alone or in combination with oxaliplatin in locally advanced rectal cancer: A meta analysis

Background: Oxaliplatin (OX), in combination with fluoropyrimidine (5-fluorouracil or Capecitabine, FU)-based regimens and radiation, has been expected to both enhance primary tumour shrinkage and reduce micrometastases at distant sites in the neoadjuvant chemoradiotherapy (CRT) for locally advanced rectal cancer (LARC). However, results in terms of pathologic complete response (pCR) and toxicities were inconsistent. The aim of this meta analysis was to evaluate the short term efficacy and toxicities of adding OX to FU in CRT for LARC. Methods: We searched PubMed, EMBASE, ISI databases, Chinese Biomedical Literature Database and the Cochrane library before December, 2011. Additionally, abstracts presented at American Society of Clinical Oncology conferences held between January, 2000, and July, 2011, were searched to identify relevant clinical trials. Only randomised studies with an analysis by an intention-to-treat principle were included, and searches were restricted to those databases citing articles in English. Summary incidence rates and 95% confidence intervals (CIs) were calculated using a fixed-effects or random-effects model, depending on the heterogeneity of the included studies. Four randomised clinical trials comparing OX/FU versus FU alone regimens in CRT for LARC met our search criteria and were assessed. A total of 3863 patients (FU, n = 1937; OX/FU, n = 1926) were included in the analysis. Findings: The addition of OX to FU significantly improved pathologic complete response (pCR), and reduced peri-operative metastases (including intra-abdominal metastases) with an odd ratios (OR) for OX/FU compared with FU of 1.20 (95% CI, 1.01-1.42; P = 0.04) and 0.51 (95% CI, 0.34-0.77; P = 0.001), respectively. The grade 3/4 toxicity rate was significantly higher for OX/FU versus FU alone with an OR of 2.29 (95% CI, 1.31-4.00; P = 0.004). There was no difference in the rates of positive circumferential resection margin, permanent stoma, surgical complication and death within 60 d between the OX/FU and FU alone patients. The OR for the proportion of patients completing full-dose radiotherapy and completing full-dose chemotherapy were 0.32 (95% CI, 0.15-0.69; P = 0.004), and 0.71 (95% CI, 0.35-1.42; P = 0.33), respectively. Interpretation: Adding weekly OX to FU in neoadjuvant CRT of LARC appeared to modestly increase the pCR rate and reduced the rate of intra-abdominal or peri-operative metastases in this meta analysis. Although OX/FU significantly increased grade 3/4 toxicity, it did not result in more surgical complications or postoperative deaths within 60 d. The concept of combination of OX and FU in the pre-operative setting for LARC still seems promising, either with a modified schedule, or as induction therapy prior to CRT or after CRT, prior to surgery.