Objective: This study seeks to determine whether lower survival of black versus white oral and pharyngeal cancer patients is due to, or differs by, stage at diagnosis.
Methods: Subjects identified through the North Carolina Central Cancer Registry included all black and white North Carolina residents diagnosed from 1987 to 1990 with malignant squamous cell carcinoma of the oral cavity or pharynx. Proportional hazards regression models were used to calculate hazard ratios for all-cause mortality during the first 18 months after diagnosis, adjusting for age, reported histologic grade, site, and several time-dependent interactions.
Results: Within the first two months after diagnosis, the black/white hazard ratio for mortality among those with localized disease was 11.8 (95% CI = 3.7, 37.5), compared to 6.4 (95% CI = 2.6, 15.8) for those with advanced disease. During months 3 to 18 after diagnosis, black/white hazard ratios were 2.07 (95% CI = 1.03, 4.18) among those with localized disease and 1.12 (95% CI = 0.85, 1.47) for those with advanced disease.
Conclusions: In the first 18 months after diagnosis, blacks with oral and pharyngeal cancer have higher all-cause mortality than whites diagnosed at the same stage of disease. Racial differences are greater among those with localized disease than for those with more advanced conditions.