抄録
Two hundred and thirty eight patients with squamous cell carcinoma of the esophagus treated with irradiation in the multicenter of a research group of JASTRO were analyzed retrospectively. One hundred and fifteen patients were treated with external radiation therapy (ERT) alone, 70 with ERT and high dose rate intracavitary radiation therapy (HDR), and 53 with ERT and low dose rate intracavitary radiation therapy (LDR). In most patients the field size of ERT was defined by primary tumor the margin of which was sometimes marked with clips using endoscopy. Five-year overall survival rate and 5-year local control rate were 71%, 46% in ERT alone group, 51%, 42% in HDR group, and 73%, 43% in LDR group, respectively. In all groups there was no significant difference in the local control rate by total dose levels. Five-year local control rate of 55 mucosal tumors the depth of which was confirmed by echogram was 70%, and that of 101 submucosal tumors was 65%. Complications of ERT alone group and LDR group were mild, but sometimes fatal in patients treated with a fraction size of 5 Gy or more by HDR. The complication rate was more correlated with the fraction size of intracavitary radiation therapy (ICRT) than the total dose of irradiation in ICRT group. Although the local control rate of LDR group was worst, five recurrences of the group were observed after five years later. There was no significant difference in the incidence of metastasis among the three groups. Patients died rather from the other reasons than from their primary esophageal cancers. From the analysis of local control rate and complications, the following treatment methods for superficial esophageal cancer are considered to be reasonable and permissible, that is, a total dose of 60 to 70 Gy in 30 to 35 fractions by ERT for ERT alone group, a total dose of 50 Gy in 25 fractions by ERT followed by 16 Gy in 4 fractions by HDR-ICRT or a total dose of 60 Gy in 30 fractions by ERT followed by 8 Gy in 2 fractions by HDR-ICRT for HDR group, and a total dose of 60 Gy in 30 fractions by ERT followed by 16 Gy in 4 fractions by LDR-ICRT for LDR group. Although fraction size of 4 Gy by twice a week is usually used in HDR-ICRT, fraction size of 2 Gy by five times a week is employed as an option of HDR-ICRT.
We recommended a radiation treatment method for superficial esophageal cancer from a retrospective analysis. To obtain a final optimal treatment method, a further prospective study is needed.
