Bone-targeted agent use for bone metastases from breast cancer and prostate cancer: A patient survey.

Background: In order to design studies assessing the optimal use of bone-targeted agents (BTAs) patient input is clearly desirable.

Methods: Patients who were receiving a BTA for metastatic prostate or breast cancer were surveyed at two Canadian cancer centres. Statistical analysis of respondent data was performed to establish relevant proportions of patient responses.

Results: Responses were received from 141 patients, 76 (53.9%) with prostate cancer and 65 (46.1%) with breast cancer. Duration of BTA use was <3 months (15.9%) to >24 months (35.2%). Patients were uncertain how long they would remain on a BTA. While most felt their BTA was given to reduce the chance of bone fractures (77%), 52% thought it would slow tumour growth. Prostate patients were more likely to receive denosumab and breast cancer patients, pamidronate. There was more variability in the dosing interval for breast cancer patients. Given a choice, most patients (49-57%) would prefer injection therapy to oral therapy (21-23%). Most patients (58-64%) were interested in enrolling in clinical trials of de-escalated therapy.

Conclusion: While there were clear differences in the types of BTAs patients received, our survey showed similarity for both prostate and breast cancer patients with respect to their perceptions of the goals of therapy. Patients were interested in participating in trials of de-escalated therapy. However, given that patients receive a range of agents for varying periods of time and in different locations (e.g. hospital vs. home), the design of future trials will need to be pragmatic to reflect this.