Prostate cancer patients receiving hormone treatment (androgen deprivation therapy, or ADT) are at increased risk of developing bone loss and osteoporosis as side effects. To prevent this, guidelines recommend participation in healthy bone behaviours including weight-bearing exercise and adequate calcium/vitamin D intake. However, prior studies have shown that patients are not regularly screened or counselled regarding healthy bone behaviours while receiving ADT. Maintaining bone health in prostate cancer patients is important because men on ADT are at increased risk of fractures. In this study, the investigators will examine whether an intervention designed to improve healthy bone behaviours among prostate cancer patients on ADT can be implemented. The intervention consists of a written "healthy bones prescription", brief verbal counseling, and printed educational materials for participants. Investigators hope to obtain an initial estimate of whether the intervention works. They also hope to show that this simple intervention can be implemented in a real, working cancer clinic.

The investigators hypothesize that an intervention to improve bone health in prostate cancer patients receiving ADT (healthy bones prescription, verbal counseling, and printed educational materials) is effective, implementable, and accepted by clinicians and patients.

The study has a before-and-after design, to allow comparison of the intervention before its implementation and after its implementation. This design permits a reliable assessment of baseline characteristics prior to implementation of intervention and over time, particularly in situations where randomization is not feasible (e.g. due to contamination of treating physicians). The point at which the intervention will start to be delivered for new study participants is when 150 patients are accrued to the Before arm.

1. Before/control arm (Before arm) Usual care by Princess Margaret Cancer Centre (PM) oncologist.
2. After/intervention arm (After arm) Provision of a healthy bones prescription, verbal counselling, and written educational materials regarding healthy bone behaviours by PM oncologist or delegate (e.g. clinical fellow), in addition to usual care by oncologist. The intervention may be delivered again at a subsequent follow-up at the request of the patient and/or at the discretion of the oncologist.

Inclusion Criteria:

Prostate cancer patients receiving ADT at study entry (for a maximum of 12 months prior to study entry or planning to receive ADT within 3 weeks of study entry), for an expected duration of >6 months; Eastern Cooperative Oncology Group (ECOG) performance status <3

Exclusion Criteria: Unable to exercise (e.g. major physical disability, severe osteoarthritis, or other severe comorbidity); severe cardiac disease (congestive heart failure with New York Heart Association (NYHA) class >2, angioplasty/coronary artery bypass surgery within 3 months of study entry); patients with bone endocrinopathy (parathyroid disorders, osteomalacia); stage IV-V chronic kidney disease (estimated glomerular filtration rate [eGFR] <30 mL/min/1.75 m2; prior serum creatinine not required for entry into study); allergy to components of calcium & vitamin D tablets.