OBJECTIVETo evaluate the therapeutic effects of strontium-89 on osseous metastases of prostate cancer by bone scanning and bone alkaline phosphatase (B-AKP) measurement.

METHODSOne week before and within 6 months after strontium-89 therapy, bone scanning and B-AKP measurement were performed in 73 patients with bone metastases of prostate cancer. 1. According to the number of osseous lesions on bone imaging, the patients were divided into Grade 0, 1, 2 and 3, and the numbers of bone lesions before and after therapy were compared by t-test. 2. Tumor to non-tumor ratios(T/NT) before and after treatment were calculated and compared. 3. Changes in B-AKP before and after therapy were compared.

RESULTS1. Among the 73 patients, bone scanning revealed 618 bone lesions, averaging 8.6 +/- 7.4 before treatment. The number decreased to 349, averaging 3.8 +/- 6.7 after treatment, which showed a significant reduction (t = 4.079, P < 0.01). 2. After therapy, T/NT of bone lesions decreased significantly (t = 7.907, P < 0.01) from 5.36 +/- 4.67 to 3.17 +/- 2.95. 3. B-AKP decreased significantly (t = 3.349, P < 0.002) from (28.4 +/- 14.8) microgram/L to (20.9 +/- 11.7) microgram/L. 4. By bone scanning combined with B-AKP measurement, 5 false positive cases and 6 false negative cases were corrected.

CONCLUSIONThere is certain complementarity between bone scanning and B-AKP measurement, and they should be used in a combined way to achieve accurate evaluation of the therapeutic effects of strontium-89.