Risk of second primary malignancy after esophagectomy for squamous cell carcinoma of the thoracic esophagus.

PURPOSE To assess the risk of subsequent malignancies after esophagectomy for squamous cell carcinoma of the thoracic esophagus for the establishment of an adequate follow-up program. PATIENTS AND METHODS We statistically analyzed clinical factors in 114 cases of second malignancy after esophagectomy that developed in 94 of 679 patients who underwent curative resection. The cancer incidence rates in the general population estimated by the Research Group for Population-Based Cancer Registration in Japan were used as standards for comparison. RESULTS The 10-year cumulative risk of second malignancy was 34.5%, and the overall relative risk (RR) was 2.98 (95% CI, 2.41 to 3.65). The risk of head and neck cancer was markedly elevated (RR, 34.9; 95% CI, 24.3 to 48.6), followed by the risks of lung cancer (RR, 3.24; 95% CI, 1.89 to 5.19) and stomach cancer (RR, 2.00; 95% CI, 1.17 to 3.21). Multifactor analysis demonstrated that independent factors affecting the risk of subsequent malignancies were presence of other malignancies detected before esophagectomy and any of the following factors: masculine sex, alcohol consumption, and smoking. The 5-year survival rate after detection of subsequent malignancy was 45%. The outcome in patients with subsequent head and neck cancer was significantly less favorable as a result of difficulty in early detection. CONCLUSION Patients had a remarkably high risk of subsequent cancer of the upper aerodigestive tract after esophagectomy, in particular, head and neck cancer. Minute postoperative surveillance is strongly recommended, especially in patients with a history of malignancies before esophagectomy. Early detection of second malignancies allowed less invasive treatment with favorable outcome.