CORRELATION BETWEEN BONE-SCAN FINDINGS AND COLLAGENASE ACTIVITIES IN PATIENTS WITH BREAST-CANCER

RATIONALE AND OBJECTIVES. This study correlates nuclear bone scan find ings and measurements of type IV collagenases for the evaluation of bo ny metastasis in patients with proven breast cancer. METHODS. The auth ors retrospectively evaluated the final diagnosis of a bone scan and t he results of an immunohistochemical staining for 92 kDa and 72 kDa ty pe IV collagenases in, respectively, 30 and 30 patients with metastati c breast cancer, and, respectively, 27 and 26 patients with primary br east cancer. The immunohistochemical staining was performed with tissu e specimens obtained from a primary or metastatic breast tumor lesion. The amounts of the enzyme were graded from 0 to 4 and scored by multi plication with the percentage of tumor cells. The confidence of bone s can interpretation also was scored from 1 to 5 with increasing probabi lity. RESULTS. There was a significant difference in enzyme scores bet ween patients with and without metastases. Patients with <170 92 kDa ( 26 of 27), 72 kDa (26 of 26) type IV collagenase, showed no active bon y, lung, or liver metastases. However, there were variable bone scan f indings in patients with a >200 enzyme score. CONCLUSIONS. Bone scan p rovides no additional benefit in breast cancer patients with a type IV collagenase score of <170. A bone scan is necessary to confirm, local ize, or follow-up bony metastases in patients with an enzyme score of >200.