In laboratory tests on mice, researchers found that a medication often used to reduce toxic side effects of chemotherapy induced bone loss and helped tumors grow in bone. So the researchers at Washington University School of Medicine in St. Louis are recommending increased awareness of bone health during cancer treatments.
The medication studied is a growth factor commonly used to help cancer patients recover healthy blood counts after chemotherapy, which can destroy white blood cells. Low levels of white blood cells leave patients susceptible to infection.
“This growth factor encourages bone breakdown, and any therapy that decreases bone density could potentially enhance tumor growth in bone,” says senior author Katherine Weilbaecher, M.D., assistant professor of medicine and of cell biology and physiology. “But there are things that can be done to counteract this. Physicians should carefully monitor their cancer patient’s bone health with regular bone density scans (DEXA) and prescribe medications to prevent bone loss when needed. And patients should consume enough calcium and vitamin D and get sufficient exercise to maintain strong bones.”
Weilbaecher and her colleagues found that when they gave mice an eight-day course of the growth factor, called granulocyte colony-stimulating factor (G-CSF), the mice lost bone mass and experienced increased bone tumor growth when injected with cancer cells. Their study will appear in an upcoming issue of the journal Blood and is now available online.
G-CSF is known by the trade names Neupogen, Neulasta and Granocyte. Clinical use of G-CSF has recently increased because by speeding blood cell regrowth it allows patients to undergo more intensive chemotherapy regimens in which anticancer agents are given at more frequent intervals. Studies have suggested these dose-dense therapies could prolong survival in women with breast cancer.