Treatment of superficial esophageal cancer by external radiation therapy alone: results of a multi-institutional experience

Abstract

Purpose: To assess the effectiveness and toxicity of external radiation therapy for superficial esophageal cancer. Methods and Materials: During the period from March 1979 to November 1996, 78 patients with superficial esophageal cancer received radiation therapy without intracavitary irradiation at nine radiotherapy institutions in Japan. All patients had histologically-proven squamous cell carcinoma. Endoscopic ultrasonography was performed in 34 patients to discriminate mucosal from submucosal cancer. Most of the patients had received radiation therapy using conventional fractionation at an average dose of 65.5 Gy. Results: The survival rates at 1, 2, and 5 years were 88%, 73%, and 45%, respectively. The local control rates at 1, 2, and 5 years were 85%, 79%, and 66%, respectively. Although the difference was not significant, the survival rate of cancer patients with a tumor invading the submucosa was lower than that of the other patients. In 6 mucosal cancer patients, local recurrence was observed in 1 patient with extensive cancer. Regional lymph node recurrence and distant failure were not observed in mucosal cancer patients, while in 28 submucosal cancer patients, the 5-year survival rate and relapse free rate were only 49% and 43%, respectively. Univariate and multivariate analysis identified age as the only significant prognostic factor. Severe late injury, such as esophageal ulcer, perforation, and bleeding, was not observed. Conclusion: External radiation therapy is effective for mucosal cancer. However, further investigation is needed to establish a better standard treatment protocol for submucosal cancer.