Esophageal cancer treated with radiotherapy: impact of total treatment time and fractionation.

Abstract

Local control rate and survival rate of esophageal cancer treated with radical radiation therapy (RT) were analyzed with special respect to total treatment time and fractionation. Between 1979 and 1992, 88 patients with Stages I-III esophageal cancer were treated radically with RT at Kyoto University Hospital and Wakayama Red Cross Hospital. Of the 88 patients, 52 patients were treated with conventional fractionation (1.7-2.0 Gy/day, five times/week), and the remaining 36 patients were treated with accelerated hyperfractionation (AHF). In 1989, we started AHF regimen for esophageal cancer. Daily fractionations were 2.0 Gy and 1.2 Gy (field-in-field), or 1.5 Gy and 1.5 Gy at 5- to 6-h interval. Most of the patients treated with AHF received the total radiation dose of 64-68 Gy. Twenty-seven patients were treated with intraluminal brachytherapy (IBT) as boost therapy following external RT. Fourteen patients were treated with IBT following AHF. The median of treatment time of AHF was approximately 2 weeks shorter than that of conventional fractionation. Local control rate at 1 year were 47% for AHF, which was significantly higher than that for conventional fractionation (22%, p < 0.05). The improvement of local control by AHF was responsible for a trend to an improved cause-specific survival (p = 0.07). Local control rates at 1 year were plotted as a function of total treatment time. The slope of the linear regression line was -2.3 +/- 0.5% per day (p < 0.025) for patients treated with external RT alone, indicating a 2.3% per day loss in local control. Pretreatment and treatment parameters were evaluated in a multivariate analysis for the end point of local control. T stage (T1, 2 vs. T3, 4; p = 0.003) and fractionation schedule (p = 0.03) were independent of prognostic significance. Patients could tolerate the AHF well, although esophageal stenosis was noted frequently as a late toxicity. Accelerated hyperfractionation was the most important treatment-related variable in this patient population. Total treatment time may have a significant impact on the treatment outcome for esophageal cancer.