Local-regional recurrence after surgery without postoperative irradiation for carcinomas of the major salivary glands: Implications for adjuvant therapy

Purpose: To determine factors predictive of local-regional recurrence (LRR) after surgery alone for carcinomas of the major salivary glands in an attempt to evaluate the potential role of postoperative radiation therapy. Methods and Materials: Between 1960 and 2004, 207 patients with carcinomas of the major salivary glands were treated with definitive surgery without postoperative radiation therapy. Histology was: 67 mucoepidermoid (32%), 50 adenoid cystic (24%), 34 acinic cell (16%), 23 malignant mixed (11%), 16 adenocarcinoma (8%), 6 oncocytic (3%), 6 myoepithelial (3%), and 5 other (2%). Distribution of pathologic T-stage was: 54 T1 (26%), 83 T2 (40%), 46 T3 (22%), and 24 T4 (12%). Sixty patients (29%) had microscopically positive margins. Median follow-up was 6.1 years (range, 0.5-18.7 years). Results: The 5-year and 10-year estimates of local-regional control were 86% and 74%, respectively. A Cox proportional hazard model identified pathologic lymph node metastasis (hazard ratio [HR], 4.8; p = 0.001), high histologic grade (HR, 4.2; p = 0.003), positive margins (HR, 2.6; p = 0.03), and T3-4 disease (HR, 2.0; p = 0.04) as independent predictors of LRR. The presence of any one of these factors was associated with 10-year local-regional control rates of 37% to 63%. Conclusion: Lymph node metastasis, high tumor grade, positive margins, and T3-4 stage predict for significant rates of LRR after surgery for carcinomas of the major salivary glands. Postoperative radiation therapy should be considered for patients with these disease characteristics.