Madison, Wis. — When Ruth O’Regan, MD, came to Wisconsin for a job at the UW Carbone Cancer Center, she noticed many of the breast cancer patients she was seeing had something in common: weakened bones.
Coming from a job down south, osteoporosis wasn’t something she saw as much. But here, it was something that came up time and time again.
“It’s a chronic issue,” said O’Regan, an oncologist and head of hematology, medical oncology, and palliative care in the Department of Medicine at the UW School of Medicine and Public Health.
There are a handful of factors that contribute to osteoporosis, a common bone disease which weakens bone mass and density. The act of simply aging heightens risk, especially for women. Menopause dramatically reduces the production of estrogen, a hormone which plays a large role in maintaining bone density.
But there’s one other big culprit that may help explain things: vitamin D deficiency. And as anyone who has ever spent the winter in Wisconsin can tell you, getting enough vitamin D can be a big challenge.
“Because of this beautiful weather we have in the winter, many of my patients are vitamin D deficient, on top of the fact that the pills we use to reduce their risk of breast cancer recurrence further decrease their estrogen levels, with resultant bone loss and osteoporosis,” O’Regan said. “So we end up treating their bones, as well as treating their breast cancer.”
It’s important to point out that the osteoporosis isn’t causing breast cancer and breast cancer isn’t causing osteoporosis. Rather, O’Regan says that one of the main drugs used to treat breast cancer has been shown to cause bone loss. Because of that, patients have a bone density test prior to starting cancer treatment, which is when bone loss is often discovered. It can be treated with a bisphosphonate, a type of medication that can help with low bone density.
“That actually has been shown to, at least, maintain their bone density, but also reduce the risk of breast cancer recurrence in post-menopausal women,” O’Regan said.
Additionally, the bisphosphonate can be taken in conjunction with the breast cancer treatment, with little impact to the patient. “Every time we add in medication, there’s more potential side effects, but thankfully, they’re quite well tolerated,” O’Regan said. In some cases, oncologists will work with endocrinologists to find other therapies that may be useful to patients.
Ensuring good bone density is important, because a fall can be serious. The snow and ice, which came early this year, make the threat of a fractured or broken bone even worse. Even with the osteoporosis treatment, O’Regan says there are still other things that patients should consider to mitigate the effects of the cancer drug on bones.
First off: get a healthy dose of vitamin D. With sunshine in short supply this time of year, supplements are often needed. Exercise can also help, especially weight-bearing exercises. While the phrase “weight-bearing” might conjure up images of pumping weights at the gym, it really just means walking, jogging or even climbing stairs: anything that forces your body to work against gravity.
Finally, O’Regan says it’s important to get a bone density test done every two years. This not only helps the patient, but also the physicians who are caring for them and assessing their risk.
“If they have osteoporosis and they slip in the snow and break their hips, that’s very serious,” O’Regan said. “So it’s important that we keep on top of it.”