Trends and survival of malignant mesothelioma across racial groups between 2000-2019: A real-world study.

Abstract

e20539 Background: Malignant mesothelioma of the pleura (MMP) is a rare and aggressive malignancy and predominantly affects patients of White race in the U.S. Despite treatment advancements, the 5-year survival rate remains between 5% and 10%. Studies assessing racial disparities in MMP are lacking. We conducted a retrospective study to evaluate prevalence, survival and mortality trends among racial groups. Methods: We used the SEER database to determine the racial prevalence of all histological subtypes of MMP between 2000 and 2019. We calculated racial and histological subtype survival Cox proportional hazard ratios while controlling for age, gender, ethnicity, surgery, chemotherapy, and radiation use. Second, we used the CDC WONDER database to identify all mesothelioma deaths for the same period. Age-adjusted mortality (AAM) rates per 100,000 persons were standardized to 2000 US census data and stratified by race. Results: A total of 12791 patients were identified, mostly White (95%), followed by Blacks (%5) and Asians (0.4%). The percentages of patients with epithelioid, sarcomatoid and biphasic histologies were as follows: Whites (67.6%, 19.2%, 13.2%), Blacks (70.4%, 19.4%, 10.1%), and Asians (64.4%, 23.6%, 11.9%). As demonstrated in Table 1, compared to Whites, regardless of stage, survival was worse for Blacks (HR 1.16) and Asians (HR 1.14). As expected, survival was inferior for pts with sarcomatoid MMP followed by biphasic. Epithelioid MMP had the most favorable prognosis. Lastly, using the CDC WONDER database over the same period, there were 47,323 White, 2,068 Black, and 541 Asian MMP deaths. AAM was 0.8, 0.3, and 0.2 per 100,000 persons for White, Black, and Asian patients, respectively. AAM declined from 2000 to 2019 by 22% (0.9 to 0.7) in White, 50% (0.4 to 0.2) in Black, and 33% (0.3 to 0.2) in Asian. Conclusions: This is one of the largest population-based studies analyzing MMP racial disparities and histologic subtypes. Mortality analysis revealed declines across all racial groups, with the greatest decline among Blacks, which is two-fold that of Whites. However, a survival gap between races and histological subtypes persists. Despite no differences in the prevalence of histologic subtypes, mortality was 16% higher for Black patients when compared to Whites. Asian patients also had a higher risk of death of 14%, though the aggressive sarcomatoid subtype was more prevalent in this racial group. Social determinants of health and biological differences, could be responsible. Further studies are needed. [Table: see text]