非切除食道癌の放射線治療成績　「食道癌の放射線治療基準」の問題点

The aim of this retrospective study was to evaluate the efficacy of “the criteria of radiation therapy for carcinoma of the esophagus” published by the committee of the Japanese association for Radiotherapy Systems in 1987. This study involved 96 patients treated by radiotherapy alone using megavoltage equipment between January 1978 and February 1989 at the Cancer Institute Hospital. Most patients had locally advanced disease in intra-thoracic or abdominal esophageal carcinoma: 41 patients (43%) were T3, and 45 (47%) were T4. Nineteen patients (20%) were NO, 46 (48%) were N1, and 31 (32%) were Nx. At the time of analysis, mean follow-up time was 83 months (range 8-141). Overall actuarial survival at 5 years was 3.6%. The patients were divided into curable and non-curable groups according to pretreatment indication of the criteria. The curable group demonstrated significantly longer median survival time (MST) than the non-curable group (7 months vs 5 months). Evaluation after radiotherapy was divided into 4 groups in terms of radiation dose and response. Median survival time was 14 months for the absolutely curative irradiation group, 7 months for the relatively curative group, 9 months for the relatively non-curative group and 4 months for the absolutely non-curative group. In the deeply invasive group (A3), the survival rate of patients with tortuous or bulky lesions was higher than that in the group with penetrated or perforated lesions (MST: 6 months vs 5 months), however the difference was not significant. Their survival was similar to that of the intermediate group (A 1, 2). Esophagram alone was insufficient to evaluate responses to radiotherapy. Other diagnostic modality such as computed tomography, which can directly detect the volume of residual mass, should be included. Multivariate analysis revealed exclusively, among 10 prognostic factors, the importance of vertical extension of tumor for estimating prognosis. The factors in the criteria, such as the depth of tumor lesion, pretreatment intent and post-radiotherapy evaluation, were not significant. In conclusion “the criteria” should be used more generally and further revised in the near future.