The cost impact of disease progression to metastatic castration-sensitive prostate cancer

BACKGROUND: Metastatic prostate cancer (PC) is associated with declining survival rates and increased health care expenditure. However, there are few studies quantifying these increased costs. OBJECTIVE: To estimate overall health care resource utilization and costs associated with progression to metastatic disease in Medicare or commercially insured patients with nonmetastatic castration-sensitive PC (nmCSPC) or previously undiagnosed PC. METHODS: In this retrospective, observational cohort study, we used data from the IBM MarketScan Commercial and MarketScan Medicare Supplemental Databases. Included patients were aged 18 years or older, had 2 or more health care claims associated with a diagnosis of PC, and had a diagnosis of metastatic disease (index date) between January 1, 2014, and December 31, 2016. Patients with PC were identified at index as either progressing from a localized disease state (nmCSPC) without evidence of castration resistance (progressors) or de novo metastatic without a prior PC diagnosis. Unadjusted all-cause direct health care costs for the 2-year pre-index period and up to 2 years post-index were summarized. Metastasis-related incremental all-cause direct health care costs were estimated using regression modeling to adjust for patient baseline characteristics, follow-up duration, and possible selection bias. RESULTS: We identified 3,854 patients who met the criteria for CSPC at metastasis: 2,766 Medicare patients (mean age 78.8 ± 7.6 years) and 1,088 commercial patients (mean age 57.6 ± 4.3 years), with de novo patients accounting for 28.9% and 34.5% of the 2 analysis populations, respectively. Mean unadjusted total all-cause health care costs over the 24-month pre-index period among progressors were $52,661 (Medicare) and $43,111 (commercial); those among de novo patients were $39,756 (Medicare) and $22,090 (commercial). Mean unadjusted post-index costs for progressors were $100,331 (Medicare) and $127,374 (commercial) over a mean follow-up duration of 14.63 and 18.41 months, respectively, and $124,538 (Medicare) and $173,408 (commercial) over a mean follow-up duration of 14.14 and 17.29 months for patients with de novo disease. After multivariate adjustment, incremental cost increases due to metastasis in patients with CSPC pre-index were estimated at $104,051 (Medicare) and $93,334 (commercial), assuming data are available for 24 months post-index. Allowing for variation in the postindex observation period, estimates were $71,308 (Medicare) and $82,336 (commercial). Among de novo patients, cost increases due to metastasis were estimated at $180,932 (Medicare) and $215,397 (commercial), assuming all patients have data for 24 months postindex. Allowing for variable follow-up, estimates were $113,253 (Medicare) and $161,714 (commercial). CONCLUSIONS: Development of metastatic CSPC is associated with considerable costs over a 24-month follow-up period. Cost increases are greater for de novo patients than for those who progressed from localized disease.