​Life-saving drugs used in the treatment of breast cancer could potentially leave a small percentage of women vulnerable to fractures. Therefore Dr Karin Baatjes, a specialist surgeon at Stellenbosch University's Faculty of Medicine and Health Sciences (FMHS), has set out to identify women who are at risk and to customise their treatment to prevent negative side effects of their breast cancer treatment.

Baatjes, who regularly treats breast cancer patients at Tygerberg Hospital, is studying a group of postmenopausal women with breast cancer receiving a certain type of treatment called aromatase inhibitors, in order to identify those with a high risk of developing osteoporosis. The study forms part of her PhD.

Aromatase inhibitors are used to treat oestrogen-sensitive breast cancer and prevent the body from producing oestrogen, thereby preventing the cancer from growing. An unfortunate side effect of aromatase inhibitors is that they could decrease bone density in a small number or women. Low bone density, known as osteoporosis, increases the risk for bone fractures. Currently there is a lack of data about the bone density of and prevalence of fractures in postmenopausal breast cancer patients in South Africa.

“The long-term survival of breast cancer patients is often very good, but we don't want them to suffer crippling side effects that decrease their quality of life," says Baatjes. “We want to optimise both the length and quality of these women's lives."

Women over the age of 50 are at an increased risk of developing osteoporosis, while other factors, such as calcium and vitamin D deficiency, a low body weight, smoking and a family history of osteoporosis, further increase the risk of developing the disease.

In addition to identifying breast cancer patients' clinical osteoporosis risk, genetic testing is done as part of the study to evaluate the genetic influence on the processing of medication, which may influence bone health.

“Breast cancer patients taking aromatase inhibitors who have some of the additional risk factors, run a very real risk of developing osteoporosis and experiencing fractures further down the line. The ideal would be to try and identify the high-risk patients at the start of therapy, and either change the drug or implement interventions to prevent a decrease in bone density," says Baatjes. With information obtained from her research, she will develop guidelines to tailor treatment for each breast cancer patient according to their unique medical profile.

“People have asked why, as a surgeon, I'm studying cancer drugs. In a resource-limited setting such as ours, we have fewer oncologists, and as surgeons we are often the ones who prescribe medication and follow up on patients. We don't only have to understand the disease, but also the effects of treatment on our patients," she concluded.

Her research has been published in the World Journal of Surgery and Anti-Cancer Agents in Medicinal Chemistry.