Survival Advantage of Asian Metastatic Prostate Cancer Patients Treated with External Beam Radiotherapy over Other Races/ethnicities - Beyond the Abstract

The purpose of our SEER analysis was to analyze potential differences in cancer-specific mortality (CSM) between races/ethnicities in metastatic prostate cancer treated with external beam radiotherapy to the prostate. Propensity score matching (3:1) accounted for patient age, prostate-specific antigen, clinical T and N stages, Gleason Grade Groups, and M1 substages between the largest reference group (Caucasians) vs the remaining races/ethnicities: African-Americans, Hispanic/Latinos, and Asians. Other-cause mortality (OCM) adjusted multivariable analyses (competing risks analyses) tested for differences in CSM.

We highlighted a significant advantage for Asian race/ethnicity over other remaining examined races/ethnicities (Caucasian, African-American, Hispanic/Latino) that were confirmed also after propensity score matching and multivariable adjustment that also accounted for other-cause mortality (HR of 0.66 (CI 0.52-0.83, p<0.001). For example, after 3:1 propensity score matching, Asians exhibited lower CSM at 60 and 120 months (48.2 and 60.0%, respectively) compared to Caucasians (66.7 and 79.4%, respectively, p < 0.001). The remaining analyses between the other races/ethnicities and Caucasians did not exhibit significant differences in CSM. OCM rates were comparable between examined races/ethnicities.

Apart from potentially other unmeasured prognostic factors within the SEER database, it is a matter of discussion whether differences in modifiable factors (e.g. lifestyle and dietary, access to health-care, socioeconomic status) and/or non-modifiable factors (e.g. genetic factors or differences in testosterone levels, radiosensitivity of the prostate, response to systemic treatment), might play a role in the lower CSM of Asian metastatic prostate cancer patients (mPCa) patients and warrants further investigation.

Written by: Christoph Würnschimmel, MD, Martini-Klinik Prostate Cancer Center Hamburg, University Hospital Hamburg-Eppendorf

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