Postoperative irradiation of minor salivary gland malignancies of the headand neck

Objectives: (1) To review the Stanford experience with postoperative radiot herapy for minor salivary gland carcinomas of the head and neck. (2) To ide ntify patterns of failure and prognostic factors for these tumors. Materials and methods: Fifty-four patients with localized tumors were treat ed with curative intent at Stanford University between 1966 and 1995. The 1 992 AJCC staging for squamous cell carcinomas was used to retrospectively s tage these patients. Thirteen percent had stage I, 22% stage II, 26% stage III, and 39% stage IV neoplasms. Thirty-two patients (59%) had adenoid cyst ic carcinoma, 15 (28%) had adenocarcinoma, and seven (13%) had mucoepidermo id carcinoma. Thirty (55%) had positive surgical margins and seven (13%) ha d cervical lymph node involvement at diagnosis. The median follow-up for al ive patients was 7.8 years (range: 25 months-28.9 years). Results: The 5- and 10-year actuarial local control rates were 91 and 88%, respectively. Advanced T-stage (T3-4), involved surgical margins, adenocarc inoma histology, and sinonasal and oropharyngeal primaries were associated with poorer local control. The 5- and 10-year actuarial freedom from distan t metastasis were 86 and 81%, respectively. Advanced T-stage (T3-4), lymph node involvement at diagnosis, adenoid cystic and high-grade mucoepidermoid histology were associated with a higher risk of distant metastases. The 10 -year cause-specific survival (CSS) and overall survival (OS) were 81% and 63%, respectively. On multivariate analysis, prognostic factors affecting s urvival were T-stage (favoring T1-2), and N-stage (favoring NO). When T- an d N-stage were combined to form the AJCC stage, the latter became the most significant factor for survival. The 10-year OS was 86% for stage I-II vs. 52% for stage III-IV tumors. Late treatment-related toxicity was low (3/54) ; most complications were mild and no cranial nerve damage was noted. Conclusions: Surgical resection and carefully planned post-operative radiat ion therapy for minor salivary gland tumors is well tolerated and effective with high local control rates. AJCC stage was the most significant predict or for survival and should be used for staging minor salivary gland carcino mas. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.