Treatments for Metastatic Prostate Cancer (mPC): A Review of Costing Evidence.

BACKGROUND: Prostate cancer (PC) is the most common cancer in Western countries. More than one third of PC patients develop metastatic disease, and the 5-year expected survival in distant disease is about 35%. During the last few years, new treatments have been launched for metastatic castrate-resistant prostate cancer (mCRPC).
OBJECTIVES: We aimed to review the current literature on health economic analysis on the treatment of metastatic prostate cancer (mPC), compare the studies, summarize the findings and make the results available to administrators and decision makers.
METHODS: A systematic literature search was done for economic evaluations (cost-minimization, cost-effectiveness, cost-utility, cost-of-illness, cost-of-drug, and cost-benefit analyses). We employed the PubMed® search engine and searched for publications published between 2012 and 2016. The terms used were "prostate cancer", "metastatic" and "cost". An initial screening of all headlines was performed, selected abstracts were analysed, and finally the full papers investigated. Study characteristics, treatment and comparator, country, type of evaluation, perspective, year of value, time horizon, efficacy data, discount rate, total costs and sensitivity analysis were analysed. The quality was assessed using the Quality of Health Economic Studies (QHES) instrument.
RESULTS: A total of 227 publications were detected and screened, 58 selected for full-text assessment and 31 included in the final analyses. Despite the significant international literature on the treatment of mCRPC, there were only 15 studies focusing on cost-effectiveness analysis (CEA). Medical treatment constituted two thirds of the selected studies. Significant costs in the treatment of mCRPC were disclosed. In the pre-docetaxel setting, both abiraterone acetate (AA) and enzalutamide were concluded beyond accepted cost/quality-adjusted life year limits. In the docetaxel refractory setting, most studies concluded that enzalutamide was cost-effective and superior to AA. In most studies, cabazitaxel was not recommended, because of high cost. Looking at bone-targeting drugs, generic zoledronic acid (ZA) was recommended. External beam radiotherapy (EBRT) was analysed in three studies, and single fraction radiotherapy was concluded to be cost saving. Radium-223 was documented as beneficial, but costly. The quality of the studies was generally good, but sensitivity analyses, discounting and the measurement of health outcomes were present in less than two thirds of the selected studies.
CONCLUSIONS: The treatment of mCRPC was associated with significant cost. In the post-docetaxel setting, single fraction radiotherapy and enzalutamide were considered cost-effective in most studies. Generic ZA was the recommended bone-targeting therapy.