Toronto General Research Institute, Department of Medicine, Toronto General Hospital, Toronto, Canada.University Health Network Faculty of Pharmacy Department of Medicine Toronto Health Economics and Technology Assessment Collaborative Dalla Lana School of Public Health, University of Toronto Institute for Clinical Evaluative Sciences School of Kinesiology and Health Science, York University Population Studies and Surveillance, Cancer Care Ontario Baycrest Centre for Geriatric Care Toronto Rehabilitation Institute, Canada.
Study Type - Therapy (cohort) Level of Evidence 2b.
To describe patterns of initiation of androgen deprivation therapy (ADT) in a population-based cohort of patients with prostate cancer.
All patients with prostate cancer in Ontario, Canada, who started ≥90 days of ADT at age ≥66 years in 1995-2005 were classified by ADT regimen: medical castration [oestrogen and/or luteinizing hormone-releasing hormone (LHRH) agonist); orchidectomy; antiandrogen monotherapy; combined androgen blockade (CAB) medical (medical castration plus antiandrogen); CAB surgical (orchidectomy plus antiandrogen). Indications for ADT were as follows: neoadjuvant (short-term before prostatectomy or radiation therapy); adjuvant (long-term with prostatectomy or radiation therapy); metastatic disease; biochemical recurrence; primary (localized disease); other. We examined trends in ADT regimen and indication over time.
The number of patients initiating ADT increased from 1995 to 2001 (2106-2916 per year) and declined thereafter to 2200-2300 annually (total n= 26 809). However, prostate cancer prevalence doubled over these years, and the rate of ADT initiation decreased from 16 to 7 per 100 person-years. Patterns varied by regimen and indication. Medical castration increased from 12% of all ADT in 1995 to 47% in 2005; orchidectomy decreased from 17 to 4%. Use for metastatic disease remained stable, but adjuvant therapy increased from <3% of all ADT in 1995 to 13% in 2005. Primary therapy was the most common indication, but decreased over time.
ADT initiation has fallen and marked changes occurred in treatment patterns for prostate cancer. Changes might be driven by increasing awareness of potential harms and costs, and by new evidence supporting ADT for specific indications.
Krahn M, Bremner KE, Tomlinson G, Luo J, Ritvo P, Naglie G, Alibhai SM. Are you the author?
Reference: BJU Int. 2011 Mar 31. Epub ahead of print.