Cancer survivors are at an increased risk of osteoporotic fractures due to the accelerated loss of bone mineral density as a result of their treatment. Bone loss from cancer therapy is faster and more severe than bone less from aging; rates of bone loss are up to sevenfold higher when they occur from cancer therapy. To address this issue, ASCO has published a new guideline to provide direction on how to manage osteoporosis in adult survivors of nonmetastatic cancer.1
“For those with substantial risk of osteoporotic fracture, the clinician should obtain a [bone mineral density] test,” the guideline states. “The bone health of all patients may benefit from optimizing nutrition, exercise, and lifestyle. When a pharmacologic agent is indicated, bisphosphonates or denosumab, at osteoporosis-indicated dosages, are the preferred interventions.”
Redefining the Survivors at Risk
The fracture risks for postmenopausal women are well known, but this guideline “recognizes that osteoporosis is a problem for all cancer survivors, as bone loss is more rapid and severe in this population. A lot of our treatments cause bone loss,” said expert panel Co-Chair Charles Shapiro, MD, FASCO, of The Mount Sinai Hospital.
Charles Shapiro, MD, FASCO
Joan Neuner, MD, MPH
Overall survival and progression-free survival numbers are increasing in most cancers; older patients “have other chronic illnesses and frailty that also predisposes them to osteoporotic fractures. We now have to deal with more chronic long-term problems in cancer survivors, and that’s good news,” said expert panel Co-Chair Joan Neuner, MD, MPH, of Medical College of Wisconsin.
Over the years, Dr. Neuner said there has generally been a “decreased enthusiasm” for osteoporosis screening in U.S. patient populations, and well-publicized, long-term measurable risks of osteoporosis treatment may be contributory factors.
ASCO wanted to raise awareness of osteoporosis in breast and prostate cancer survivors “because they’re the traditional long-term survivors, but also with patients who received organ transplants or patients with early-stage colon or lung cancers,” Dr. Shapiro said.
ASCO sought to address four primary questions in its guideline:
There is a long list of criteria where patients should be considered at an increased risk of developing osteoporotic fractures, including:
Clinicians should also consider the cancer treatment as another potential baseline risk factor.
If patients meet any of the listed criteria, they should be offered bone mineral density testing with central/axial dual-energy x-ray absorptiometry, according to the guideline. In settings where such testing is not available or technically feasible, other bone mineral density testing (for example, quantitative ultrasound or calcaneal dual-energy x-ray absorptiometry) should be offered. This testing should be offered every 2 years (more frequently if deemed medically necessary).
Clinicians should encourage patients to consume a diet with adequate calcium and vitamin D. Further, if the intake of calcium (1,000 to 1,200 mg/d) and vitamin D (at least 800 to 1,000 IU/d) is not being consumed at those target levels, then supplements to reach those levels are recommended.
The guideline states that for patients with nonmetastatic cancer with osteoporosis (T-scores of 2.5 or less in the femoral neck, total hip, or lumbar spine) or who are at increased risk of osteoporotic fractures based on clinical assessment or risk assessment tools (10-year probability of ≥ 20% for major osteoporotic fractures or ≥ 3% for hip fractures based on the U.S.–adapted Fracture Risk Assessment tool), bone-modifying agents, such as oral bisphosphonates, intravenous bisphosphonates, or subcutaneous denosumab, at the osteoporosis-indicated dosage may be offered to reduce the fracture risk.
“This guideline covers the screening and when to pull the trigger on bone-modifying agents for the treatment of osteoporosis,” Dr. Shapiro said.
Evidence is lacking to determine “how much of a risk factor cytotoxic chemotherapy is for fractures, and studies have not found striking patterns,” Dr. Neuner said. “There have been some hints with methotrexate, but that’s been it so far.”
Educating Patients on Their Risk
Some patients may be fully aware of their risks—especially if treatment includes aromatase inhibitors or they already have bone loss issues—whereas others may not hear about bone loss until it has occurred.
Osteoporosis and fractures are “major side effects of cancer treatment,” Dr. Shapiro said. “Treatment can also induce hypogonadism, which is another risk factor. Long-term exposure to glucocorticoids and aromatase inhibitors is also a risk factor. Aromatase inhibitor use is huge in people with breast and prostate cancers,” Dr. Shapiro said.
Patients can lose bone mass “quite quickly just from having treatments, even if the treatments themselves aren’t toxic to the bone,” Dr. Neuner added.
Patients need to know that these late effects may not manifest themselves for 20 years post-treatment, Dr. Shapiro said, which is why referral to primary care and/or endocrinologists is also advised.
DISCLOSURE: Drs. Shapiro and Neuner reported no conflicts of interest.
1. Shapiro CL, Van Poznak C, Lacchetti C, et al: Management of osteoporosis in survivors of adult cancers with non-metastatic disease: ASCO Clinical Practice Guideline. J Clin Oncol 37:2916-2946, 2019.
Originally published in ASCO Daily News. © American Society of Clinical Oncology. ASCO Daily News, September 19, 2019. All rights reserved.