Long-term health care costs for prostate cancer patients on androgen deprivation therapy.
BACKGROUND
Comparing relative costs for androgen deprivation therapy (adt) protocols in prostate cancer (pca) requires an examination of all health care resources, not only those specific to pca. The objective of the present study was to use administrative data to estimate total health care costs in a population-based cohort of pca patients.


METHODS
Patients in Ontario with pca who started 90 days or more of adt at age 66 years or older during 1995-2005 were selected from cancer registry and health care administrative databases. We classified patients (n= 21,818) by regimen (medical castration, orchiectomy, anti-androgen monotherapy, medical castration with anti-androgen, orchiectomy with anti-androgen) and indication (neoadjuvant, adjuvant, metastatic disease, biochemical recurrence, primary nonmetastatic). Using nonparametric regression methods, with inverse probability weighting to adjust for censoring, and bootstrapping, we computed mean 1-year, 5-year, and 10-year longitudinal total direct medical costs (2009 Canadian dollars).


RESULTS
Mean first-year costs were highest for metastatic disease, ranging from $24,400 for orchiectomy to $32,120 for anti-androgen monotherapy. Mean first-year costs for all other indications were less than $20,000. Mean 5-year and 10-year costs were lowest for neoadjuvant treatment: approximately $43,000 and $81,000 respectively, with differences of less than $4,000 between regimens. Annual costs were highest in the first year of adt. Orchiectomy was the least costly regimen for most time periods, but was limited to primary and metastatic indications. Outpatient drugs, including pharmacologic adt, accounted for 17%-65% of total first-year costs.


CONCLUSIONS
Compared with combined therapies, the adt monotherapies, particularly orchiectomy when clinically feasible, are more economical. Our methods exemplified the use of algorithms to elucidate clinical information from administrative data. Our approach can be adapted for other cancers to expand the range of studies using Canadian administrative data.
Toronto General Research Institute, Toronto General Hospital; Faculty of Pharmacy, University of Toronto, Toronto, ON.; Department of Medicine, University of Toronto, Toronto, ON.; Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, ON.; Toronto Health Economics and Technology Assessment Collaborative, University of Toronto, Toronto, ON.; Institute for Clinical Evaluative Sciences, University of Toronto, Toronto, ON.
M D
MD
Krahn
Toronto General Research Institute, Toronto General Hospital.
K E
KE
Bremner
Institute for Clinical Evaluative Sciences, University of Toronto, Toronto, ON.
J
J
Luo
Toronto General Research Institute, Toronto General Hospital; Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, ON.; Toronto Health Economics and Technology Assessment Collaborative, University of Toronto, Toronto, ON.; Dalla Lana School of Public Health, University of Toronto, Toronto, ON.
G
G
Tomlinson
Toronto General Research Institute, Toronto General Hospital; Department of Medicine, University of Toronto, Toronto, ON.; Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, ON.; Toronto Health Economics and Technology Assessment Collaborative, University of Toronto, Toronto, ON.
S M H
SM
Alibhai
Prostate neoplasms; androgen deprivation therapy; cost analyses; costs; orchiectomy