Quantitative bone scintigraphy: usefulness in the survey of patients treated for bone metastasis of prostatic cancer

The purpose of this study was to develop a quantitative bone scintigraphy (QBS) method in order to evaluate the evolution of bone metastases in patients treated for disseminated prostatic cancer. Data obtained by whole body scintigraphy after injection of 99mTc-methylene diphosphonate enabled us to define three indexes, GR, R1 and R2. They respectively represent the amount of activity retained in the bones, in the metastatic sites and in pathological sites related to the global activity of the skeleton. Repeated QBSs have been performed on 59 patients with prostatic carcinoma treated for bone metastasis with hormonal therapy. Results of QBS are well correlated to clinical findings, particularly pain evolution. In addition, the calculated indexes of QBS made it possible to distinguish three groups of patients according to regression, stabilization or evolution of their lesions under hormonal therapy. QBS seems to be a sensitive and useful test for the evaluation of the therapeutic efficiency on bone metastases from prostatic carcinoma.