Carcinoma of the major salivary glands treated by surgery or surgery plus postoperative radiotherapy.

From 1975 to 1987, 87 patients with carcinomas of the major salivary glands (70 parotid and 17 submandibular) were treated at our institution by either surgery or surgery followed by postoperative radiotherapy (RT). Surgical procedures included superficial (24%) or total (56%) parotidectomies and submandibular gland resection (20%). Postoperative RT usually began 2 to 4 weeks following surgery. Using 4 MV photons or, infrequently, 60Co, the majority of patients received 6000 cGy in 6 weeks to the parotid region (ranged from 4500 to 7000 cGy). Determinant actuarial survival was 74% at 5 years and 71% at 10 years. For patients with previously untreated disease, 5 of 19 (26%) treated by surgery alone experienced local recurrence, whereas only 2 of 50 (4%) recurred locally following surgery plus postoperative RT (p = 0.01). For patients presenting with recurrent disease, 4/4 (100%) failed locally following surgery as opposed to 3/14 (21%) following surgery plus postoperative RT (p = 0.01). The determinant 5-year actuarial survival for patients receiving postoperative RT was 75% versus 59% for surgery alone. Results were analyzed by multivariate methods using determinant survival or recurrence as endpoints. Five important prognostic factors were identified. (a) Facial nerve paresis was predictive of poor outcome (p less than 0.001) with 3-year relapse free survival of 13%. (b) Undifferentiated histology was associated with decreased survival (p = 0.002). (c) Male sex was associated with poor outcome (p = 0.008). (d) Skin invasion resulted in decreased survival (p = 0.012). (e) Radiotherapy was associated with improved survival (p = 0.014). In addition, postoperative RT was effective in preventing local recurrence (p less than 0.001). The data demonstrate the efficacy of postoperative RT in improving survival and local control for patients with carcinomas of the major salivary glands.