Black Patients With Salivary Gland Mucoepidermoid or Squamous Cell Carcinoma Have Poorer Disease-Specific Survival Than White Patients
In a retrospective study of salivary gland cancer survival reported in JAMA Otolaryngology Head & Neck Surgery, Russell et al found black patients with mucoepidermoid or squamous cell carcinoma have poorer disease-specific survival than white patients, with no difference being observed between white and Hispanic patients in any histologic subtype.
Study Details
The study involved survival data from all white, black, and Hispanic patients with a diagnosis of salivary gland cancer from 1988 to 2010 in the Surveillance, Epidemiology, and End Results (SEER) database.
Among 11,007 patients, 8,866 (80.6%) were white, 1,073 (9.7%) were black, and 1,068 (9.7%) were Hispanic. The mean age at diagnosis was 63 years in white patients vs 53 and 52 years for blacks and Hispanics (P < .001). White patients were more likely (P < .05 for trend for all) to be male, have high tumor grade, smaller tumor size, and lymph node involvement, and to have received radiotherapy. There were also significant differences among the three groups in tumor extension (eg, highest extraglandular rate in whites), histologic subtypes (eg, mucoepidermoid carcinoma more common in blacks and Hispanics, squamous cell carcinoma more common in whites), and years of diagnosis.
Survival Differences
The 20-year disease-specific survival rates for all patients were 78% for whites, 79% for blacks, and 81% for Hispanics, with unadjusted survival analysis showing no difference among the groups. However, multivariable Cox regression models adjusting for patient, tumor, and treatment characteristics showed significantly poorer disease-specific survival vs whites for blacks (hazard ratio [HR] = 1.22, P = .03) but not for Hispanics (HR = 0.97, P = .77).
The overall disease-specific survival disparity was due to poorer disease-specific survival for blacks vs whites with mucoepidermoid carcinoma (HR = 1.56, P = .03) and squamous cell carcinoma (HR = 1.58, P = .05). The lower rate of surgical treatment for blacks vs whites with squamous cell carcinoma (57% vs 77%, P < .001) was a factor in the survival difference in this subtype.
The investigators concluded, “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 [salivary gland cancer]. 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 [salivary gland cancer].
Vicente A. Resto, MD, PhD, of The University of Texas Medical Branch at Galveston, is the corresponding author for the JAMA Otolaryngology Head & Neck Surgery article.
The study authors declared no potential conflicts of interest.
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