As of 2019, there are about 16 million cancer survivors in the US and about 32 million globally. Women with early-stage breast cancers and men with non-metastatic prostate cancers represent the two largest groups of survivors (40% of all cancer survivors). With an increasing number of cancer survivors, so also increases the health-related complications these people will experience as a result of their treatment. The focus of this article will be on one particular complication – bone loss. According to the 2019 ASCO Clinical Practice Guidelines, the “coalescence of survivors of cancer and osteoporosis [is] a health problem of near-epidemic proportion.”1 Bone health is a topic that should be discussed with your doctors, as fractures increase the risk of mortality by 10-20%.
There are numerous reasons why bone loss is a common issue after a cancer diagnosis. In men, androgen deprivation therapy (ADT) is the mainstay for systemic disease or biochemical recurrence and a rise in PSA after initial treatment. However, ADT is not without complications, bone loss being one of them. ADT causes a drop in testosterone and estrogen, both of which cause decreased bone formation. Men with prostate cancer who have taken ADT have a 5-10 fold greater annual bone loss compared to men the same age who do not have prostate cancer, and as a result have a 7-fold increased risk of fractures.
In women, the use of aromatase inhibitors (AIs) and premature ovarian failure secondary to chemotherapy are the two most common reasons for bone loss. AIs are used for breast cancer to prevent recurrence and are also used in metastatic settings. Bone loss due to AI use is well characterized, and numerous large trials have shown that bone loss is worse in women who use AIs compared to tamoxifen. Premature ovarian failure can result from the use of chemotherapy, particularly cyclophosphamide, etoposide, doxorubicin and vincristine. Premature ovarian failure results in the loss of estrogen production and subsequent harmful effects on the bone, and is more likely to occur in older women compared to younger women.
Below is a table describing the risk of osteopenia/osteoporosis, as well as the risk of fractures, in a variety of cancer-related situations.
| Situation | Bone Loss (osteopenia/osteoporosis) Risk | Fracture Risk |
| US Adults ≥50 years old | Osteopenia: 51.5% in women, 33.5% in men
Osteoporosis: 19.6% in women, 4.4% for men |
A woman’s lifetime risk for fracture: ~40% |
| Women with breast cancer receiving AI therapy | Incidence: 20% with 5 yrs
Risk increases 2-3% per year |
|
| Prostate cancer | Osteoporosis:
35% in hormone-naive patients 43% after 2 years of ADT 81% after 10 years of ADT |
With ADT, incidence: 17.5% (median time to fracture 31 month (IQR 15-56 mos) |
| Post-gastrectomy for stomach cancer | 53.5% get OP after 10 years | |
| Colorectal cancer survivors | 5 yr risk: 45% in women, 12% in men
10 yr risk: 68% in women, 22% in men 22 yr risk: 83% in women, 32% in men |
|
| Multiple myeloma | Up to 80% have osteolytic bone lesions at diagnosis | Incidence: ~60% |
| Allogenic Hematopoietic stem cell transplantation (HSCT) | ~20% have OP two years after HSCT
~50% have osteopenia after 4-6 years |
|
| Pelvic Radiotherapy | Prevalence of bone loss: 70% after 2 yrs | 15.7% after 3 years |
Patients with a history of stomach cancer have an increased risk of osteoporosis as they are more likely to have disrupted calcium and vitamin D absorption and weight loss. Patients with a history of pelvic radiotherapy have an increased risk of bone loss because of the effects that radiation has on both the bones of the pelvic girdle as well as the lumbar spine. Not in the above table but also worth mentioning is that both men and women with a history of esophageal cancer are at increased risk of osteoporosis. This is particularly true in those who continue to smoke, who identify as heavy drinkers, and who have lost a significant amount of weight.
In addition to asking your family doctor to refer you for a bone mineral density test, some other tests you can do yourself, and other signs to watch out for, include the following:
- Wall-occiput test – Your occiput is the base of your skull. When standing against a wall with your heels against the wall, you should be able to touch the base of your skull to the wall.
- Weight loss – if your weight is under 112 pounds, this is a risk factor for osteoporosis.
- Height – watch out for a loss of height over 2 cm in 1-3 years.
- Tooth loss – losing teeth is something to watch out for.
- Hump back – if you notice your back starting to hunch.
It is also suggested to test for vitamin D levels. Vitamin D in the range of 75-110 is optimal for fracture prevention. Higher vitamin D levels are also associated with less falls as we age. If your family doctor will not test vitamin D for you, please contact me for a requisition.
Exercise is also recommended to prevent osteoporosis. Physical activity is safe in those with low bone mass, and does tend to increase bone density in the long term. If you already have a fracture, physical activity must be taken with great care, and you should always ensure to speak with a qualified health care professional before undergoing an exercise regimen. I have recently completed a certification in Exercise Oncology, and therefore can serve as a good resource for you to help with providing exercise advice.
As a cancer survivor, you should be well informed about what other health conditions might affect your quality of life in the long term. Bone health is often overlooked, so please consider your risk factors for early bone loss, and make sure you speak with me or another qualified doctor about how to manage this risk.
1Shapiro CL, Poznak CV, Lacchetti C, et al. Management of Osteoporosis in Survivors of Adult Cancers With Nonmetastatic Disease: ASCO Clinical Practice Guideline. Journal of Clinical Oncology. 2019;37(31):2916-2946.
2 Panula J, Pihlajamäki H, Matila VM, et al. Mortality and cause of death in hip fracture patients aged 65 or older: a population-based study. BMC Musculoskelet Disord. 2011;12:105.
3 Greenspan SL, Coates P, Sereika SM, et al. Bone loss after initiation of androgen deprivation therapy in patients with prostate cancer. J Clin Endocrinol Metab. 2005;90:6410-6417
4 Higano CS. Androgen-deprivation-therapy-induced fractures in men with nonmetastatic prostate cancer: what do we really know? Nat Clin Pract Urol. 2008;5:24-34.
5 Behringer K, Wildt L, Mueller H, et al; German Hodgkin Study Group. No protection of the ovarian follicle pool with the use of GnRH- analogues or oral contraceptives in young women treated with escalated BEACOPP for advanced-stage Hodgkin lymphoma. Final results of a phase II trial from the German Hodgkin Study Group. Ann Oncol. 2010;21:2052-2060.
