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

Abstract

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. 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). 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%. 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.