When a man is told that he needs treatment for prostate cancer, his bones are unlikely to be the first thing on his mind. Understandably, the immediate focus is controlling the cancer. But some prostate cancer therapies can affect bone strength, muscle mass and the risk of falling — which is a reason to consider bone health from the beginning, not after a fracture has occurred.
Some prostate cancer therapies — particularly androgen-deprivation therapy (ADT), often called hormone therapy — can affect bone strength, muscle mass and the risk of falling. This does not mean that an effective cancer treatment should be avoided. It means that bone health should be considered from the beginning, rather than after a fracture has occurred.
ADT works by greatly reducing testosterone or blocking its effects. This can slow the growth of prostate cancer, but testosterone also plays an important role in maintaining bone and muscle.
The relationship is more complicated than testosterone alone. Some testosterone is naturally converted into oestradiol, a form of oestrogen that helps control bone breakdown in men. When testosterone levels fall sharply, oestradiol usually falls as well. Bone may then be broken down faster than it can be rebuilt.
ADT can also reduce muscle mass and physical strength. This matters because fractures are not caused by bone weakness alone: balance, mobility and the likelihood of falling are also important.
No. This distinction is extremely important.
Osteoporosis is a generalised reduction in bone strength that makes fractures more likely, sometimes following a relatively minor fall or movement.
Bone metastases occur when prostate cancer cells spread into the skeleton. Metastatic disease can also weaken bone, but it is not the same condition as osteoporosis.
A man may have osteoporosis without bone metastases, bone metastases without osteoporosis, or both at the same time. New back, hip or pelvic pain should therefore be assessed properly rather than automatically attributed to either cancer or osteoporosis.
Bone loss may begin surprisingly early.
A prospective study found that men newly starting ADT lost bone density at several skeletal sites during the following 12 months. Average reductions included approximately 2.5% at the total hip and 4% at the lumbar spine, with the greatest rate of change appearing to occur during the first year of therapy. Greenspan and colleagues estimated that these men were losing bone five to ten times faster than men with prostate cancer who were not receiving ADT, and than healthy comparison participants.
Bone density is not the same as fracture risk, but larger population studies have also reported more fractures among men receiving ADT. In a study involving more than 50,000 older prostate-cancer survivors, 19.4% of men who had received ADT experienced a fracture, compared with 12.6% of those who had not. Fractures also became more common with greater exposure to ADT. As this was an observational study, it cannot prove that hormone therapy caused every fracture, but the size and dose-related pattern of the association are difficult to ignore. Read the study.
Current UK guidance supports assessing fracture risk when ADT begins.
The National Osteoporosis Guideline Group recommends that all men starting ADT should have their fracture probability calculated using FRAX, recording ADT as a secondary cause of osteoporosis. Bone mineral density should be measured where available, and particularly when the result could alter a decision about bone-protecting medication. NOGG guidance.
An assessment should look beyond a scan result. It may include:
A normal bone-density result does not guarantee that a fracture will never occur. Equally, a low result does not mean that a fracture is inevitable. The scan, clinical history and overall fracture probability need to be considered together.
No. Bone protection should be matched to the individual man’s level of risk.
NICE does not recommend automatically giving bisphosphonates to everyone receiving ADT. It recommends fracture-risk assessment and treatment for men who have osteoporosis, with denosumab considered when bisphosphonates are unsuitable or not tolerated. NICE prostate-cancer guidance.
There is good evidence that several medicines can preserve bone density during ADT. Denosumab has also demonstrated a reduction in new vertebral fractures: in a large randomised trial, these occurred in 1.5% of men receiving denosumab and 3.9% receiving placebo over 36 months. Read the denosumab trial.
These medicines are not interchangeable and require appropriate assessment. Kidney function, calcium and vitamin D status, dental health, side effects and the eventual plan for stopping or changing therapy all need consideration.
The most useful approach combines skeletal assessment with support for muscle, balance and general health. Practical measures include:
Exercise deserves particular attention. Research shows that supervised resistance and aerobic exercise can improve muscle function and help counter some of the physical effects of androgen suppression. However, exercise must be appropriate for the individual. Men with bone metastases, vertebral fractures, severe pain or marked frailty may need a carefully adapted programme rather than unsupervised impact or heavy loading.
Calcium and vitamin D are important, but supplements alone cannot be expected to cancel out the hormonal effects of ADT. More is not automatically better, and supplementation should be guided by diet, blood levels and individual health considerations.
Androgen-deprivation therapy can be highly effective, and sometimes essential, in managing prostate cancer. Its effects on bone do not argue against appropriate cancer therapy. They do, however, argue against allowing bone loss to become an overlooked consequence. For the man receiving treatment, the objective is not simply to improve a scan result. It is to preserve a skeleton strong enough, and a body capable enough, to carry him through cancer treatment and into the life that follows.
This Practical Guide, produced by the Education Directorate of IIMHE, is only for educational and communication purposes. It reflects published research current to July 2026 and is intended to support, not replace, advice from your own doctor or specialist, who knows your individual health history. · IIMHE, July 2026
2nd February 2026 @ 20:00 GMT
Nutrition and musculoskeletal health
Given by: Dr Kimberley Zambito, Orthopaedic Consultant
Hosted by: Dr Nick Birch
Throughout 2026 and beyond, IIMHE (the International Institute of Musculoskeletal Health Education), in partnership with OsteoscanUK, will host a series of engaging educational webinars, open to anyone interested in bone and musculoskeletal health.
