Racial and Ethnic Disparities in Salivary Gland Cancer Survival.

IMPORTANCE

Several recent US studies have documented racial disparities in head and neck cancer outcomes, but few have investigated racial and ethnic differences in salivary gland cancer (SGCA) survival.

OBJECTIVE

To determine whether patient race or ethnicity affects SGCA survival.

DESIGN, SETTING, AND PARTICIPANTS: Retrospective survival analysis of all patients with SGCA from 1988 through 2010 in the Surveillance, Epidemiology, and End Results database.

MAIN OUTCOMES AND MEASURES

Disease-specific survival according to race and ethnicity. End points assessed included age at diagnosis, sex, tumor grade, tumor size at diagnosis, extension at diagnosis, lymph node involvement at diagnosis, and treatment. Results were further analyzed by histologic subtype of SGCA.

RESULTS

Of 11,007 patients with SGCA, 1073 (9.7%) were black, and 1068 (9.7%), Hispanic. Whites' mean age at diagnosis was 63 years vs 53 and 52 years for blacks and Hispanics, respectively (P < .001). Twenty-year disease-specific survival rates for all SGCA histologic subtypes combined for whites, blacks, and Hispanics were 78%, 79%, and 81%, respectively. Unadjusted survival curves showed no significant difference between blacks and whites and an apparent advantage for Hispanics. However, multivariable Cox regression models controlling for patient, tumor, and treatment characteristics showed poorer disease-specific survival vs whites for blacks (hazard ratio [HR], 1.22 [95% CI, 1.03-1.46]; P = .03) but not for Hispanics (HR, 0.97 [0.79-1.19]; P = .77). The overall disease-specific survival disparity was due to poorer disease-specific survival for blacks vs whites with mucoepidermoid (P = .03) and squamous cell carcinomas (P = .05). Less surgical treatment for blacks than whites (57.26% vs 76.94%; P < .001) was a source of the survival disparity for squamous cell but not mucoepidermoid SGCA.

CONCLUSIONS AND RELEVANCE

Black race is a risk factor for poorer disease-specific survival for patients with mucoepidermoid or squamous cell carcinoma, whereas Hispanic ethnicity has no effect. Differing treatment between black and white patients affects survival in squamous cell but not mucoepidermoid SGCA. Differences in chemotherapy treatment, comorbidities, socioeconomic status, tumor genetic factors, and environmental exposures are potential but unproven additional sources of the racial survival disparities for mucoepidermoid and squamous cell SGCA.