Locoregional failure was analyzed in a total of 34 esophageal carcinoma patients treated with postoperative prophylactic irradiation following curative surgery. All patients had squamous cell carcinoma and no prior treatment. Twelve patients had subsequent lymph node metastasis in the follow-up period. In the 12 patients with node metastasis, there were 5 instances of supraclavicular node metastasis, 7 instances of thoracic inlet node (uppermost part of mediastinum) metastasis, and 3 instances of mediastinal node metastasis. Three patients had 2 metastatic nodes and 9 patients had 1 metastatic node. Intervals between surgery and recurrence were a median of 12 months for mediastinal nodes, 19 months for thoracic inlet nodes, and 26 months for supraclavicular nodes. Ten (52.6%) of the 19 patients treated by using a 12-MeV electron beam had metastatic involvement at the supraclavicular and thoracic inlet nodes. On the other hand, 2 (13.3%) of the 15 patients had the above-described lymph node metastases when treated by using 15-MeV electron, 18-MeV electron, or 10-MV photon beams. The difference in the metastatic rate between these two groups was statistically significant at the level of p < 0.05 (chi-square test); this seems to be attributable mainly to the dose level at deep region. Doses of over 50 Gy to the thoracic inlet and supraclavicular nodes at deep location were necessary to reduce metastasis.