Washington, November 20 : Loyola University researchers have allayed some fear about the risk that certain medicines used for treating cancer may lead to bone loss, by finding out that breast cancer survivors may suffer this problem due to some other curable causes too.
Dr. Pauline Camacho, an associate professor at the Loyola University Chicago Stritch School of Medicine, says that cancer drugs are not the only culprits.
The researcher has revealed that among 64 breast cancer patients referred to a bone health clinic, 78 percent had at least one other cause of bone loss that included vitamin D deficiency, excessive calcium excretion in urine, or an overactive parathyroid gland.
"Doctors evaluating breast cancer patients for possible bone loss should look further than cancer drugs," said Camacho, lead author of the study in the Journal of Clinical Oncology.
Study co-author Dr. Kathy Albain, a professor in the Department of Medicine, said: "(Breast cancer survivors) are just like the normal population as they age in that bone loss can be due to many treatable causes."
Studies conducted in the past have suggested that medications used for chemotherapy can cause bone loss, and that a class of breast cancer drugs called aromatase inhibitors can decrease bone mineral density and increase the risk of fractures in postmenopausal women.
Aromatase inhibitors decrease the body's production of oestrogen, which are known to protect against osteoporosis.
In the current study, the researchers reviewed charts of 238 consecutive postmenopausal patients who had osteoporosis or osteopenia-a condition in which an individual has lower than normal bone mineral density, but not low enough to be classified as osteoporosis.
The study subjects included 64 women with breast cancer referred from Loyola's Cardinal Bernardin Cancer Center, and 174 patients without breast cancer referred from primary care physicians.
The researchers observed that 38 percent of the breast cancer patients had vitamin D deficiency, compared with 51 percent of the non-breast cancer patients.
They said that another cause of osteoporosis, excessive calcium excretion in urine, was found in 16 percent of cancer patients and 8 percent of non-cancer patients.
According to them, in five percent of the patients, the parathyroid gland was overactive, producing a hormone that causes bone to lose calcium.
The team point out in their study report that vitamin D deficiency can be treated with prescription doses of vitamin D supplements, and excessive calcium excretion can be treated with a "water pill" that's also used to treat high blood pressure.
Camacho also says that there are various treatments for parathyroid gland disorder, depending on its cause.
The researcher adds that in certain breast cancer patients, bone loss from cancer drugs can be treated with osteoporosis drugs.
Albain suggests that breast cancer patients be referred for a comprehensive bone health evaluation when osteopenia or osteoporosis is discovered.
"Just prescribing a medication for osteoporosis may not be enough for many of our patients. They deserve a thorough workup," Albain said.