Effect of long term imatinib on bone in adults with chronic myelogenous leukemia and gastrointestinal stromal tumors

Patients with chronic myelogenous leukemia (CML) or gastrointestinal stromal tumors (GIST) who take imatinib have abnormalities of bone metabolism. However, it is unclear what impact these changes have on bone mineral density (BMD). We prospectively analayzed levels of osteocalcin, a marker of bone formation secreted by osteoblasts, and serum N-telopeptide of type I collagen (NTX), a marker of bone resorption, as well as other minerals involved in bone metabolism in 19 patients with either CML or GIST We correlated these results with changes in bone mineral density as measured by serial dual energy X-ray absorptiometry (DEXA) scans over a two year period. Osteocalcin levels were low in 95% of patients and 37% had no measurable amount. Levels of NTX were less consistent. Nine patients (47%) had a decrease in BMD, four patients (2%) had an increase in BMD, and six patients (32%) had no change. There was no correlation between metabolic markers and change in BMD. We suggest that ongoing management of patients who take imatinib should include monitoring of bone health on a long term basis.