ASCO 2018: Long-Term Patterns in Race-specific, Distant Metastasis-free Survival Following Radiation Treatment for Prostate Cancer

Chicago, IL ( It is known that prostate cancer (PC) outcomes vary according to race. African Americans (AA) have a 1.5-fold greater incidence of PC and 2-fold greater mortality than Caucasian Americans (CA).
The authors of this study aimed to compare distant metastasis free survival (DMFS) of AA and CA military health care beneficiaries treated with radiotherapy for prostate cancer over a 20-year period.

This was a retrospective study in the center for prostate disease research multicenter national database. Patients diagnosed with prostate cancer between 1989 and 2013 were included in the analysis. All patients were treated with radiotherapy and had to have at least 2 years of follow-up. The primary outcome was DMFS. Patients were stratified according to the NCCN risk stratification.

A total of 4299 patients were eligible for the analysis. Table 1 demonstrates the characteristics of the patients.

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Figure 1 demonstrate Kaplan Meir graph, showing that race did not predict DMFS for patients treated with EBRT.

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However, a significant difference was noted in patients treated with brachytherapy.
Multivariable analysis controlling for age, year of treatment, and NCCN risk category, did not show that race predicted DMFS among EBRT patients, but did predict it among brachytherapy patients with a 4.7-fold increased probability of having distant metastasis, in AA compared to CA.

The authors concluded that DMFS did not vary significantly across AA and CA. According to the authors, the reasons for this observation are currently unknown. The main strengths of this study include it large cohort, equal access health care system (military), and median patient follow-up longer than 6 years. The main limitations of this study include lack of data on androgen deprivation therapy, selection bias, retrospective nature, and reduced external generalizability due to focus on a primary military cohort.

Presented by: Jennifer Cullen, Center for Prostate Disease Research, Rockville, MD

Written by: Hanan Goldberg, MD, Urologic Oncology Fellow (SUO), University of Toronto, Princess Margaret Cancer Centre, Twitter:@GoldbergHanan at the 2018 ASCO Annual Meeting - June 1-5, 2018 – Chicago, IL USA