International Journal of Radiation Oncology*Biology*Physics
Clinical InvestigationsPreoperative radiotherapy in esophageal carcinoma: a meta-analysis using individual patient data (oesophageal cancer collaborative group)
Introduction
Surgical resection is standard therapy for patients with carcinoma of the esophagus (5), but the prognosis for these patients remains poor, with 5-year survival of approximately 10% (4). Local recurrences are frequent even after intended curative resection. Following the results of numerous uncontrolled historical studies [reviewed (8)] there has been interest in the use of preoperative radiotherapy as a possible means of reducing local spread, thereby, improving survival. By downstaging the tumor, it may also increase resectability and perhaps alleviate symptoms.
Five prospective randomized controlled trials have investigated the effects of preoperative radiotherapy. Although pathological responses were reported in four of these trials 3, 8, 10, 15, resectability appeared to be unaffected in all trials and a conventionally significant survival benefit was detected in only the most recent (11). All but one of these trials involved fewer than 250 patients, and they were, therefore, too small to detect moderate treatment effects. However, combining the results of these trials quantitatively in a meta-analysis of updated individual patient data, increases the statistical power to detect such differences and is the most reliable and unbiased way to evaluate the evidence (12) from these trials.
Such a meta-analysis was therefore suggested by the Medical Research Council (MRC) Oesophageal Cancer Working Party, initiated by the MRC Cancer Trials Office, Cambridge and carried out on behalf of the Oesophageal Cancer Collaborative Group.
Section snippets
Methods and materials
The general methods for the meta-analysis were outlined prospectively in a protocol.
Results
The meta-analysis is based on five trials including 1147 patients. This represents 98.5% of patients from all known randomized trials, because data were not available for 17 patients in one (10) of the five trials. All trials included patients with potentially resectable cancer of the thoracic esophagus and with the exception of one (3), restricted entry to patients with squamous carcinoma. Trials included both men and women of most age groups. In general, the majority of patients in the
Discussion
This meta-analysis was based on five trials comparing preoperative radiotherapy with no preoperative radiotherapy. It included 1147 patients representing 98.5% of patients from all confirmed eligible randomized trials. Most of the survival data for these trials were updated for the meta-analysis, many years after the publication of the results and up to 20 years after recruitment had stopped. Therefore, currently, the meta-analysis provides the most comprehensive and reliable assessment of the
Acknowledgements
This meta-analysis and collaborators meeting was supported by the British Medical Research Council (MRC). We would like to thank all those patients who took part in the trials and contributed to this research. The meta-analysis would not have been possible without their help or without the collaborating institutions who kindly supplied their trial data.
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