The burden of symptomatic skeletal events in castrate-resistant prostate cancer patients with bone metastases at three Canadian uro-oncology centres.

Introduction: Metastatic bone disease in castrate-resistant prostate cancer risks significant morbidity, including symptomatic skeletal events. We estimated the healthcare resource costs of managing skeletal events.

Methods: A retrospective chart review was conducted for patients who died from or were treated palliatively for metastatic castrate-resistant prostate cancer from 2006-2013 at Centre Hospitalier de l'Université de Montréal (Montreal), Princess Margaret Cancer Centre (Toronto), or Vancouver General Hospital (Vancouver).

Results: Of 393 patients, 275 (70%) experienced 833 events (85 per 100 patient-years), with a median (95% confidence interval) time (months) to first event of 17.6 (15.3, 21.7). The mean metastatic bone disease-related healthcare resource use cost (2014 Canadian dollars) estimate for patients without symptomatic skeletal events was $9550 and between $22 101 (observed) and $34 615 (adjusted) for patients with at least one event. Fewer patients in Montreal (55%) experienced events compared to Toronto (79%) or Vancouver (76%). Median time (months) to first event was longer in Montreal (25.0 [18.5, 32.6]) than in Toronto (14.6 [9.7, 16.8] or Vancouver (17.3 [14.8, 24.0]). More patients received bone-targeted therapy in Montreal (64%) and Toronto (60%) than in Vancouver (24%). Bone-targeted therapy was mostly administered every 3-4 weeks in Montréal and every 3-4 months in Toronto.

Conclusions: Metastatic bone disease-related healthcare resource use costs for Canadian castrate-resistant prostate cancer patients are high. Symptomatic skeletal events occurred frequently, with the incremental cost of one or more events estimated between $12 641 and $25 120. Symptomatic skeletal event incidence and bone-targeted therapy use varied considerably between three Canadian uro-oncology centres. An important limitation is that only patients who died from prostate cancer were included, potentially overestimating costs.