Patterns of use of docetaxel in stage IV prostate cancer (PCa) patients in SEER-Medicare.

Abstract

4658 Background: To date, docetaxel (D) is the only chemotherapy agent that has provided a survival benefit to metastatic castration resistant PCa patients (pts). The objective of this study was to determine usage patterns of D in a large observational dataset, with stratification by demographics, treatment regimen, and time. Methods: We analyzed pts aged 66 or older from the linked Surveillance, Epidemiology, and End Results and Medicare (SEER-Medicare) database who received any type of chemotherapy. Pts were diagnosed with PCa between 2000 and 2005 and were followed until death or the end of the study period (December 31, 2007). We restricted the cohort to those with incident Stage IV disease (according to the AJCC-TNM classification). Using weekly and monthly data we calculated summary statistics and chi-square tests on D usage patterns by race groups, by age groups, and over time. Results: Application of the inclusion/exclusion criteria resulted in 1,248 Stage IV PCa pts on chemotherapy with 788 on D, of which 97% (N=761) also report receipt of androgen deprivation therapy (ADT). Docetaxel use increased from 55% in 2000 to 71% in 2005 (p-value <0.001). Among D pts, similar increases over time were noted for the proportion with M1 disease (73% to 91%; p- value <0.001), while the proportion using ADT remained high (97%) and stable over time. The distribution of D pts according to race (White; African American; Other) and age (66-74; 75-84; 85+) were [85%; 11%; 4%] and [59%; 38%; 3%], respectively. Among D pts, the vast majority (97%) received only D. A histogram of the average time between D claims followed a right-skewed, bimodal distribution with peaks at 1 week (34%) and 3 weeks (27%). The peaks were more defined by conditioning on ADT receipt, in the 66-74 year old (v. 75+) and 2003-2005 (v. 2000-2002) patient subgroups. Conclusions: The SEER-Medicare data set allows a rich characterization of docetaxel usage patterns. We find that the use of docetaxel varies over time and patient subgroups. Author Disclosure Employment or Leadership Position Consultant or Advisory Role Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration sanofi-aventis Amgen, Bayer, Bristol-Myers Squibb, Genentech, GlaxoSmithKline, Lilly, Merck, Novartis, Pfizer, sanofi-aventis sanofi-aventis Pfizer, sanofi-aventis GlaxoSmithKline, Novartis, Pfizer, sanofi-aventis