Radiation therapy for carcinoma of the major salivary glands. Results of conventional irradiation technique.

From January 1967 through November 1991, a total of 135 patients with carcinoma of the major salivary glands (parotid: 95; submandibular: 39; sublingual: 1) were treated at our department. 40 patients had adenocarcinoma, 29 adenoid cystic carcinoma, 24 mucoepidermoid carcinoma and 16 squamous cell carcinoma. 100 patients were irradiated postoperatively and the remaining 35 were treated with radiation alone. Total radiation doses delivered were 50 Gy for the postoperative group and 50 to 66 Gy for the group receiving only radiation using a 60Co single portal with or without wedged paired or single electron portal boost. Actuarial five-year survivals after radiation therapy were 55% for the postoperative group and 26% for radiation only group (p = 0.0004). The local control rates for the postoperative group were 83% for adenocarcinoma, 81% for adenoid cystic carcinoma, 83% for mucoepidermoid carcinoma and 62% for squamous cell carcinoma. Corresponding figures for the radiation only group were 40% for adenocarcinoma, 38% for adenoid cystic carcinoma and 33% for mucoepidermoid carcinoma. Conventional irradiation techniques continue to play an important role because they offer superior local control for postoperative patients with carcinoma of the major salivary glands. However, the local control rates for the radiation only group were only 30 to 40%, so that new irradiation modalities such as provided by a high LET machine are needed for these patients.