Association of Adjuvant Chemoradiotherapy vs Radiotherapy Alone With Survival in Patients With Resected Major Salivary Gland Carcinoma Data From the National Cancer Data Base

IMPORTANCE Data on adjuvant concurrent chemoradiotherapy (CRT) after resection of salivary gland carcinomas (SGCs) are limited. OBJECTIVE To examine overall survival (OS) outcomes of patients who receive CRT vs radiotherapy (RT) alone after resection of SGCs. DESIGN, SETTING, AND PARTICIPANTS The National Cancer Data Base (NCDB), a hospital-based registry that represents 70% of all cancer cases in the United States, was queried for patients who underwent resection of major SGCs with at least 1 high-risk feature (T3-T4 stage, N1-N3 stage, or positive margins). Included patients had histologic findings for malignant SGC with grades 2 to 3 disease and at least 1 high-risk feature. All patients underwent resection with postoperative CRT or RT alone. Patients were treated from 1998 to 2011. Data were analyzed from January to March 2016. EXPOSURES Patients received CRT, defined as chemotherapy start within 14 days of RT initiation, or RT alone. MAIN OUTCOMES AND MEASURES Univariate, multivariate, and propensity score-matched analyses were performed to compare OS for patients undergoing CRT vs RT alone. RESULTS Analyses included 2210 eligible patients (1372 men [62.1%] and 838 women [37.9%]; median age [range], 63 [18-90] years); of these, 1842 (83.3%) received RT alone and 368 (16.7%) received CRT. Median follow-up was 39 (range, 2-188) months. Most of the resected major SGCs occurred at the parotid gland (1852 [83.8%]), followed by the submandibular gland (276 [12.5%]), major gland not otherwise specified (66 [3.0%]), and sublingual gland (16 [0.7%]). Unadjusted 2-year OS was worse with adjuvant CRT vs RT alone (71.3% vs 80.2%), as was 5-year OS (38.5% vs 54.2%) (hazard ratio [HR], 1.51; 95% CI, 1.29-1.76; P < .001). Overall survival was inferior with adjuvant CRT on multivariate analysis (HR, 1.22; 95% CI, 1.03-1.44; P = .02) and propensity score-matched analysis (HR, 1.20; 95% CI, 0.98-1.47; P = .08) compared with RT alone. Subgroup analyses by age, comorbidity score, primary site, histologic type, grade, T stage, N stage, margin status, and chemotherapy (single agent vs multiagent) demonstrated equivalent or shorter OS with the addition of chemotherapy to RT. CONCLUSIONS AND RELEVANCE This large analysis compared survival outcomes between postoperative CRT and RT alone in patients undergoing resection of high-risk major SGCs using a nationally representative database. The addition of concurrent chemotherapy to RT in patients with high-risk major SGCs did not offer an advantage in OS.