Characteristics of stage III and IV M0 prostate cancer (PCa) patients in SEER-Medicare who develop bone metastasis (BM) following diagnosis.

Abstract

e15146 Background: BM is diagnosed in 70-80% of men with metastatic PCa. Less is known about the timing of BM diagnosis following incident non-metastatic PCa and associated patient characteristics. In this study, we determined the incidence and timing of post-diagnosis BM (BMpd) among PCa patients (pts) by incident stage, age, race and year of diagnosis using a large observational dataset. Methods: We analyzed pts aged 66 or older from the linked Surveillance, Epidemiology, and End Results and Medicare (SEER-Medicare) database. Pts with PCa were identified between 2000 and 2007 and were followed until death, Medicare disenrollment, HMO enrollment, or end of the study (December 31, 2009). The cohort included incident stage III and IV(M0) PCa in SEER, and identified BM occurring either within (i.e., +/-) 1 month of the SEER diagnosis month (BM90) or beyond the initial 90-day window (BMgt90) based on the presence of at least one inpatient or one outpatient claim with a diagnosis code of 198.5. We calculated summary and chi-square statistics to examine BMpd, BM90, and BMgt90 by incident stage, age, race and year of PCa diagnosis. Results: Among 9,188 Stage III (72%) and IV(M0) (28%) PCa pts who met inclusion/exclusion criteria, 14.6% (n=1,345) had BMpd: 2.3% (n= 217) had BM90 and 12.3% (n=1,128) had BMgt90. Average age was 72 years and 9% were African American (AA). Incidence of BMpd varied by stage (stage III: 11%; stage IV/M0: 25%; p<0.001) and by age group (66-74 years: 13%; 75-84 years: 19%; >85 years: 22%; p<0.001) but not by race (White: 15%; AA: 16%; Other: 13%; p=0.49). The diagnosis BM90 and BMgt90 varied with stage (stage III: 2% and 9%; stage IV(M0): 4% and 21%; p<0.0001) and age (66-74 years: 2% and 11%; 75-84 years: 3% and 16%; >85 years: 5% and 17%; p<0.001). The incidence of BM decreased over time whether considering BMpd (19% in 2000 to 9% in 2007; p<0.001), BM90 (4% in 2000 to 2% in 2007; p=0.03) or BMgt90 (16% in 2000 to 6% in 2007; p<0.001). Conclusions: BM occurred in only 2% of incident stage III/IV(M0) PCa pts within 1 month of diagnosis, but nearly 15% were diagnosed with BM during a median follow-up of 57 months. Prevalence of BM was highest in stage IV(M0) and older pts.