Detection of metastatic bone lesions in patients with prostate carcinoma: Tc-99(m) monoclonal antibody imaging

Bone scintigraphy has been shown to be sensitive in determining bone involvement in patients with malignancy, but it does not allow the assessment of bone marrow lesions in early disease. The aim of this study was to detect bone marrow invasion using Tc-99(m)-labelled monoclonal antigranulocyte antibody (AgMoAb) in patients with prostate carcinoma. We studied 56 patients whose mean(+/- S.D.) age was 67 +/- 7 years. The mean prostate-specific antigen level was 6.1 ng ml(-1) (normal range 0-5 ng ml(-1)). Twelve patients were in stage A, 16 in stage B, 17 in stage C and 11 in stage D. Six patients had been receiving chemotherapy and four patients radiotherapy before scanning. Bone scans were obtained 2 h after the intravenous injection of 555 MBq Tc-99(m)-methylene diphosphonate (Tc-99(m)-MDP). Within a week, bone marrow imaging was performed 4 and 24 h after the injection of 555 MBq Tc-99(m)-AgMoAb. Metastatic bone lesions were detected on the Tc-99(m)-MDP scans of 14/56 (25%) patients, of whom one was in stage A, two in stage B, four in stage C and seven in stage D. Hypoactive lesions in bone marrow were detected in 25/56 (45%) patients, of whom two were in stage A, five in stage B, seven in stage C and 11 in stage D. Bone marrow metastases were confirmed in six patients by computed tomography (CT) and magnetic resonance imaging (MRI) and in two patients by marrow aspiration biopsy. A false-positive immune scintigram was found in three patients previously receiving radiotherapy or chemotherapy. We suggest that Tc-99(m)-AgMoAb scintigraphy is a sensitive procedure for the detection of bone marrow lesions. However, the reason for false-positive and false-negative results should be considered and CT, MRI and marrow biopsy should be performed when clinically necessary