[Bone metastases in breast cancer and its risk factor--follow up study by bone scintigraphy].

Breast cancer is considered to often involve bone metastasis. Early detection and treatment of bone metastasis are essential in improving the prognosis of this disease. In 47 patients with bone metastasis confirmed with bone scintigraphy, we examined the appearance time of bone metastasis; bone metastasis was frequently observed with the progress of stage, but no association with the appearance time was found. Age was not associated with the incidence of bone metastasis but was found to be closely related to its appearance time. That is to say, patients with breast cancer below 40 years of age showed relatively early bone metastasis. Bone scintigraphy is required every 6 months at least for 3 years after the operation. In patients over 40 years of age, on the other hand, bone scintigraphy is required only once a year but has to be continued for 5 years or more, because they often show relatively late bone metastasis.