Table 1.
Cohort selection.
| Reason for exclusion | No. of patients (%) | Remaining sample |
|---|---|---|
| Initial sample of prostate cancer cases from SEER-Medicare data | 564,491 (100) | 564,491 |
| No record of surgical or biologic castration | 383,713 (67.98) | 180,778 |
| No record of second-line systemic therapy† after castration date | 168,388 (29.83) | 12,390 |
| Castration was on or before prostate cancer diagnosis date | 376 (0.07) | 12,014 |
| Diagnosis of any cancer other than prostate cancer or nonmelanoma skin cancer on or before potential cohort entry date | 5,543 (0.98) | 6,471 |
| Diagnostic code for exclusionary metastases (197X or 198X with exception of 198.2-skin or 198.5-bone) on or before potential cohort entry date | 1,767 (0.31) | 4,704 |
| Not aged at least 65 years on potential cohort entry date | 246 (0.04) | 4,458 |
| Not continuously enrolled in both Parts A and B Medicare coverage between the earlier of (1) 12 months before cohort entry or (2) the month of prostate cancer diagnosis and cohort entry date | 1,293 (0.23) | 3,165 |
| Enrolled in HMO either (1) in year before potential cohort entry date, or (2) at some time between diagnosis date of initial prostate cancer identified in SEER and potential cohort entry date | 931 (0.16) | 2,234 |
SEER, Surveillance, Epidemiology, and End Results program of the US National Cancer Institute; HMO, health maintenance organization.
† Abiraterone, cabazitaxel, docetaxel, enzalutamide, mitoxantrone, or sipuleucel-T.