Chemotherapy for carcinoma of the esophagus: A comparison of evidence from meta-analyses of randomized trials and of historical control studies

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Abstract
Chemotherapy (CT) has been used as an adjunct to local treatment (surgery or radiotherapy) in esophageal carcinoma. A meta-analysis of all published randomized clinical trials and historical control studies which have used cisplatinum-based combination CT was carried out to asses the effect of chemotherapy on survival for esophageal cancer. A computer-based literature search was performed for the period from January 1988 to March 1995 using the index terms ‘Esophageal neoplasms’ and ‘Chemotherapy’. The frame of reference was further narrowed to include only cisplatinum-based combination chemotherapy. Twelve randomized clinical trials (RCT) and eight historical control (HC) studies were included in the meta-analysis. In the overview of HC studies a highly significant reduction in odds of death with CT was observed (68% ±8% OR =0.32, 95% CI 0.24–0.42). On the other hand, the over view of RCTs showed a relative reduction in odds of death for the CT group of 4.2% ± 23.7% (OR = 0.96, 95% CI 0.75–1.22). There was a gross overestimation of treatment effect in the studies using HC as compared to RCTs, despite the use of cisplatinum-based chemotherapy in both groups. The meta-analysis of RCTs reveal no significant survival benefit from cisplatinum-based adjuvant/neoadjuvant chemotherapy in esophageal cancer.