Curative radiotherapy with high-dose-rate brachytherapy boost for localized esophageal carcinoma: dose-effect relationship of brachytherapy with the balloon type applicator system.

BACKGROUND AND PURPOSE: This study analyzed the feasibility, local control and toxicity in potentially curable patients with esophageal carcinoma treated with a combination of external irradiation and high-dose-rate (HDR) brachytherapy using a balloon type applicator system to minimize hot spots on the mucosa. MATERIALS AND METHODS: During the 9 years, 124 patients with esophageal carcinoma and no apparent extraesophageal spread were treated with 40-60 Gy of external irradiation followed by 8-24 Gy of HDR brachytherapy. The fraction size of brachytherapy was 4-6 Gy. We developed a new applicator with 15 mm external diameter inflatable balloons. The reference point was a point 12.5 mm depth from the mid source. The study end points were local control, late toxicity and palliative effect. RESULTS: All 124 patients completed the planned radiotherapy. Local control rate was 69/124 (56%). There was a trend toward better local control rate for T1 lesions with increasing dose via brachytherapy. Of 69 patients with local control, treatment-related ulcers occurred in 28 patients, leading to death in four. The incidence of ulcers increased with increasing brachytherapy dose; 1/6 with 12 Gy, 16/43 with 16 Gy, 6/ 12 with 20 Gy, 4/5 with 24 Gy. Esophageal benign strictures occurred in ten patients and in all cases developed from ulcers. The incidence of freedom from dysphagia was not dose-dependent. CONCLUSION: A combination of external irradiation and HDR brachytherapy with the balloon type applicator was feasible and well tolerated. Although better local control was achieved by a higher dose of brachytherapy, the higher dose caused more severe esophageal injury.