Neoadjuvant or adjuvant therapy for resectable esophageal cancer: a systematic review and meta-analysis

BACKGROUND: Carcinoma of the esophagus is an aggressive malignancy with an increasing incidence. Its virulence, in terms of symptoms and mortality, justifies a continued search for optimal therapy. The large and growing number of patients affected, the high mortality rates, the worldwide geographic variation in practice, and the large body of good quality research warrants a systematic review with meta-analysis. METHODS: A systematic review and meta-analysis investigating the impact of neoadjuvant or adjuvant therapy on resectable thoracic esophageal cancer to inform evidence-based practice was produced. MEDLINE, CANCERLIT, Cochrane Library, EMBASE, and abstracts from the American Society of Clinical Oncology and the American Society for Therapeutic Radiology and Oncology were searched for trial reports. Included were randomized trials or meta-analyses of neoadjuvant or adjuvant treatments compared with surgery alone or other treatments in patients with resectable thoracic esophageal cancer. Outcomes of interest were survival, adverse effects, and quality of life. Either one- or three-year mortality data were pooled and reported as relative risk ratios. RESULTS: Thirty-four randomized controlled trials and six meta-analyses were obtained and grouped into 13 basic treatment approaches. Single randomized controlled trials detected no differences in mortality between treatments for the following comparisons: - Preoperative radiotherapy versus postoperative radiotherapy. - Preoperative and postoperative radiotherapy versus postoperative radiotherapy. Preoperative and postoperative radiotherapy was associated with a significantly higher mortality rate. - Postoperative chemotherapy versus postoperative radiotherapy. - Postoperative radiotherapy versus postoperative radiotherapy plus protein-bound polysaccharide versus chemoradiation versus chemoradiation plus protein-bound polysaccharide. Pooling one-year mortality detected no statistically significant differences in mortality between treatments for the following comparisons: - Preoperative radiotherapy compared with surgery alone (five randomized trials). - Postoperative radiotherapy compared with surgery alone (five randomized trials). - Preoperative chemotherapy versus surgery alone (six randomized trials). - Preoperative and postoperative chemotherapy versus surgery alone (two randomized trials). - Preoperative chemoradiation therapy versus surgery alone (six randomized trials). Single randomized controlled trials detected differences in mortality between treatments for the following comparison: - Preoperative hyperthermia and chemoradiotherapy versus preoperative chemoradiotherapy in favour of hyperthermia. Pooling three-year mortality detected no statistically significant difference in mortality between treatments for the following comparison: - Postoperative chemotherapy compared with surgery alone (two randomized trials). Pooling three-year mortality detected statistically significant differences between treatments for the following comparisons: - Preoperative chemoradiation therapy versus surgery alone (six randomized trials) in favour of preoperative chemoradiation with surgery. - Preoperative chemotherapy compared with preoperative radiotherapy (one randomized trial) in favour of preoperative radiotherapy. CONCLUSION: For adult patients with resectable thoracic esophageal cancer for whom surgery is considered appropriate, surgery alone (i.e., without neoadjuvant or adjuvant therapy) is recommended as the standard practice.