Pathomechanism of osteoporosis in childhood cancer

Improvement of diagnostic and therapeutic procedures brought about an increase of survival rate in childhood malignancies. Now approximately two-thirds of all patients are treated successfully and grow up without relapse. Therefore, long-term side effects of treatment and malignant diseases themselves become a very serious problem. One of them is osteoporosis. The frequency of diminished bone density ranges from 1 to 8% of patients at the moment of diagnosis of the malignant disease and from 8 to 23% of survivors after cessation of treatment. Pathomechanism of osteoporosis in children undergoing therapy for malignances is little known. It is known that accumulation of peak bone mass occurs in childhood and especially during adolescence. Impairment of this process may lead to low peak bone mass and thereby it may predispose to the development of osteoporosis. Risk factors include the disease process itself, malnutrition, reduced physical activity and side effects of chemo- and radiotherapy. Glucocorticoids and methotrexate used in chemotherapy have an adverse effect on osteogenesis. Endocrinological complications such as hypogonadism, hypothyreosis and growth hormone deficiency may lead to the reduction of bone mass. Because of the significance of the problem it seems that only precise recognition of pathomechanism of osteoporosis in childhood malignances may allow for effective and complex standards of prophylaxis and treatment of this complication to be developed.