This study evaluates the clinical characteristics of head and neck cancer cases according to race and suggests that after matching for smoking dose and age, and adjusting for socioeconomic status and insurance status, oral cavity and larynx cases with self-defined African ancestry are more likely to be diagnosed with advanced stage disease. Since primary risk factors for head and neck cancer are tobacco and alcohol 23-27
, all of the cases included in this study were matched on smoking dose, in order to account for the effect of smoking in the study design. Alcohol use was similarly distributed between Black and White patients. The analysis was also adjusted for socioeconomic status and access to care by using insurance status as a surrogate. Therefore, none of these factors should have significantly contributed to the observed differences in stage with race. Shiboski, et al. reported somewhat similar findings; African-Americans were diagnosed with a significantly higher proportion of tongue cancer compared to Whites, which had spread to a regional node or to a distant site; these data however were not adjusted for socioeconomic and insurance status or smoking11
. In our study Black cases with oral cavity tumors were more likely to present with advanced stage disease, but did not have an increased likelihood of nodal involvement. T
his suggests that the increased likelihood of advanced stage disease observed for Blacks with oral cavity tumors may not necessarily be attributed to differences in behavioral risk factors, poor socioeconomic status or access to care.
In contrast to the oral cavity,
Black and White cases diagnosed with pharynx or larynx tumors did not significantly differ in the disease stage or
nodal involvement; yet, Black patients were significantly more likely than Whites to develop laryngeal cancers. Studies have reported that Blacks are less likely to stop smoking and are more likely to smoke mentholated cigarettes compared to Whites 28,29
. Smoking mentholated cigarettes result in deeper and longer inhalations 30,31
which would allow tobacco smoke to reach the larynx. This may also help to explain the reason why Black cases are more likely to develop larynx cancers compared to Whites. Nevertheless, we cannot rule out the possibility that host factors related to tobacco metabolism may also
play a role in the observed tumor site-specific risk
between Blacks and Whites.
Arbes et al. evaluated disease-specific survival for 1,165 Blacks and 7,338 Whites diagnosed with either oral cavity or pharynx cancer 5
. After adjusting for age, geographic area, socioeconomic status, stage and treatment the study reported no significant difference according to race (HR = 1.1, 95% CI = 0.9-1.4). Our study reported similar results after additional adjustments for smoking and insurance status. In addition, we report that
the risk of recurrence, second primary or metastasis was almost two-fold for Blacks compared to Whites. Differences in treatment modalities between Blacks and Whites may explain the increased risk of recurrence, second primary or metastasis among Black cases. Murdock, et al. examined differences in treatment modalities for HNSCC in 54 African-American and 52 Whites, and showed higher incidence of surgical intervention amongst Whites
compared to Blacks 8
, but did not evaluate relapse-free survival. We observed a higher incidence of surgical intervention among Whites; and relapse-free survival was independently associated with treatment by radiation and/or chemotherapy only and was not associated with socioeconomic status or a lack of health insurance.
While tobacco and alcohol use are primary risk factors for all head and neck tumors, HPV is also thought to be an independent risk factor for most pharynx tumors 32-34
. In a previous study, we reported that patients with HPV-positive tumors have an improved survival and are less likely to develop recurrent tumors; and the improved survival and recurrence, second primary, or metastasis rate was restricted to tumors diagnosed in the pharynx 35
. A recent
study by Chen et. al. reported that among oropharynx cancer patients, African-Americans and Hispanics had lower overall survival compared to White patients but this study did not include or adjust for socioeconomic or access to care in the analysis, nor evaluate the role of HPV 36
. In our study the contribution of HPV involvement could not be evaluated as well, and this was a limitation. Nevertheless, after adjusting for the covariates in the model there was no difference in the risk of death or recurrence, second primary, or metastasis for Black patients diagnosed with oral cavity or pharynx tumors, compared to White patients. Further research of overall survival and relapse-free survival that include both HPV status and socio-demographic variables are needed to further evaluate racial disparities in head and neck cancer outcomes.
Although differences in disease outcome according to race may be attributed to a combination of tumor stage, socioeconomic status and access to health care, our findings suggest that the disparity still exists after adjusting for these factors. The inclusion of biological markers such as Human Papillomavirus status, and the extension of the study to a larger sample of Black patients are needed to further evaluate racial disparities in head and neck cancer outcomes.