Abstract
Objectives: To explore racial differences in stage of diagnosis and survival among oral and pharyngeal cancer patients over the past three decades.
Methods: We obtained 1981–2010 cancer patient data for anatomic sites of the oral and pharyngeal structure from the Florida Cancer Data System. These cancers were grouped into oral cavity (lip, tongue, salivary, floor of mouth, palate, and other oral cavity) and pharynx (base of tongue, tonsil, hypopharynx, oropharynx, nasopharynx, and other pharynx). Percentage of diagnoses at the late (regional and distant) and localized stages were computed for each of the time periods: 1981–1990, 1991–2000, and 2001–2010. In survival analysis, survival time (in month) was computed as the time between date of diagnosis and date of death. Kaplan-Meier survival curves were generated and compared using the Wilcoxon test.
Results: For oral cavity, a higher percentage of Blacks were diagnosed at the late stage than Whites at each of the three time periods (59.1%, 57.9%, and 49.4% for Blacks and 35.1%, 37.1%, and 39.5% for Whites). Blacks had significantly poorer survival than Whites for cancer of the oral cavity diagnosed at the late stage (Wilcoxon Chi-square=13.3, p<0.001) as well as for survival of oral cavity cancer diagnosed at the localized stage (Wilcoxon Chi-square=14.0, p<0.001). For late-stage oral cavity cancer, the mean survival time (MST) was 17.9 (SE=1.0) months for Blacks and 24.2 (SE=0.6) months for Whites. For localized-stage oral cavity cancer, the MST was 32.9 (SE=3.94) months for Blacks and 42.1 (SE=1.04) months for Whites. For pharyngeal cancer, the percentage of Whites diagnosed at the late stage increased in the past three decades. By the time period of 2001–2010, no significant racial difference in late stage diagnosis of pharyngeal cancer was observed, with 71.6% of Blacks and 68.5% of Whites being diagnosed at the late stage. Of note, Blacks had poorer survival for late-stage pharyngeal cancer than Whites (Wilcoxon Chi-square=49.6, p<0.001). The MST was 18.5 (SE=1.1) for Blacks and 22.8 (SE=0.5) months for Whites. No difference in survival was observed for pharyngeal cancer diagnosed at the localized stage (Wilcoxon Chi-square=0.49, p=0.49). The MST was 29.8 (SE=4.20) months for Blacks and 33.6 (SE=1.26) months for Whites.
Conclusions: The racial disparity in stage of diagnosis in oral cavity cancer is larger than that in pharynx cancer. For pharyngeal cancer, both Whites and Blacks are more likely to be diagnosed at the late rather than the localized stage. Whites became increasingly more likely to be diagnosed at the late stage for pharyngeal cancer across time. By 2001–2010, Blacks and Whites had comparable rates of late-stage diagnosis. Overall, Blacks had poorer survival than Whites except that, for localized pharynx cancer, Whites and Blacks had comparable survival. The mean survival time for pharyngeal cancer is significantly lower than that for oral cavity cancer. Future research is needed to identify putative reasons behind the larger racial disparity in stage of diagnosis and survival for oral cavity cancer. We speculate that access to dentists, a primary source of oral cancer screenings is lower for Blacks than Whites, making early detection of oral cancer less likely for Blacks.
Citation Format: Yi Guo, Henrietta Logan. Racial disparity in stage of diagnosis and survival among oral and pharyngeal cancer patients. [abstract]. In: Proceedings of the Sixth AACR Conference: The Science of Cancer Health Disparities; Dec 6–9, 2013; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2014;23(11 Suppl):Abstract nr A88. doi:10.1158/1538-7755.DISP13-A88
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