A population-based study of the use of radium 223 in metastatic castration-resistant prostate cancer: Factors associated with treatment completion

  • Sunil Parimi Medical Oncology, British Columbia Cancer Agency
  • Erica Tsang Internal Medicine, University of British Columbia
  • Abraham Alexander Radiation Oncology, British Columbia Cancer Agency
  • Michael McKenzie Radiation Oncology, British Columbia Cancer Agency
  • Francois Bachand Radiation Oncology, British Columbia Cancer Agency
  • Katherine Sunderland Genitourinary Cancer Outcomes Unit, British Columbia Cancer Agency
  • Kim N. Chi Medical Oncology, British Columbia Cancer Agency
  • Maria Aparicio Genitourinary Cancer Outcomes Unit, British Columbia Cancer Agency
  • Daniel Worsley
  • Scott Tyldesley Radiation Oncology, British Columbia Cancer Agency

Abstract

Introduction: Radium 223 (Ra223) given for six cycles has proven efficacy in clinical trials, but its population-level generalizability has not been well-described. The objectives of this study were to describe population-based Ra223 use in the abiraterone and enzalutamide era and identify factors associated with completion.

Methods: All Ra223 patients at the British Columbia Cancer Agency between September 2013 and February 2016 were identified. Patients who completed <5 vs. ≥5 cycles were compared on patient characteristics, lines of prior therapy, prostate-specific antigen (PSA) and alkaline phosphatase (ALP) decline >30% from baseline (R30%), and survival, to identify factors associated with therapy completion.

Results: Ninety-one patients were identified; 48 (52.7%) completed ≥5 cycles. Median overall survival (mOS) was 10.7 months, PSA and ALP R30% were 21% and 52%, respectively. Completion of <5 cycles was associated with higher baseline ALP (p=0.05) and lower baseline hemoglobin (Hb) levels (p=0.03). Patients in the ≥5 cycles group had longer mOS than those in the <5 cycles group (16.2 vs. 5.9 months; p<0.0001), as well as higher PSA R30% (33.3% vs. 7.0%; p=0.002) and ALP R30% (66.7% vs. 34.9%; p=0.03). Patients with ALP ≥220 and Hb ≤118 had 3.85 times the odds of not completing ≥5 cycles vs. ALP <220 and Hb >118.

Conclusions: Compared to clinical trials, patients in a populationbased setting had more lines of therapy and shorter survival. Lower ALP and higher hemoglobin were associated with completion of ≥5 cycles, longer mOS, and greater incidence of PSA and ALP response.

Author Biographies

Sunil Parimi, Medical Oncology, British Columbia Cancer Agency
Medical Oncologist, Department of Medical Oncology, British Columbia Cancer Agency
Erica Tsang, Internal Medicine, University of British Columbia
Medical Student, Department of Medical Oncology, British Columbia Cancer agency
Abraham Alexander, Radiation Oncology, British Columbia Cancer Agency
Radiation Oncologist, Department Radiation Oncology, British Columbia Cancer Agency
Michael McKenzie, Radiation Oncology, British Columbia Cancer Agency

Radiation Oncologist, Department Radiation Oncology, British Columbia Cancer Agency

Francois Bachand, Radiation Oncology, British Columbia Cancer Agency

Radiation Oncologist, Radiation Oncology, BC Cancer Agency

Katherine Sunderland, Genitourinary Cancer Outcomes Unit, British Columbia Cancer Agency
Methodologist, Genitourinary Cancer Outcomes Unit, British Columbia Cancer Agency
Kim N. Chi, Medical Oncology, British Columbia Cancer Agency

Physician, Department Medical Oncology, British Columbia Cancer Agency

Maria Aparicio, Genitourinary Cancer Outcomes Unit, British Columbia Cancer Agency
Summer intern, Genitourinary Cancer Outcomes Unit
Scott Tyldesley, Radiation Oncology, British Columbia Cancer Agency

Provincial Lead, Radiation Therapy, British Columbia Cancer Agency

Radiation Oncologist, Radiation Oncology Department, British Columbia Cancer Agency

Clinical professor, Department of Surgery, University of British Columbia

Published
2017-10-12
How to Cite
Parimi, S., Tsang, E., Alexander, A., McKenzie, M., Bachand, F., Sunderland, K., Chi, K. N., Aparicio, M., Worsley, D., & Tyldesley, S. (2017). A population-based study of the use of radium 223 in metastatic castration-resistant prostate cancer: Factors associated with treatment completion. Canadian Urological Association Journal, 11(10), 350-5. https://doi.org/10.5489/cuaj.4415
Section
Original Research