Serum copper and zinc measurements in patients with osteogenic sarcoma

Serum copper level (SCL), serum zinc level (SZL), and SCL/SZL ratio were measured in 18 patients with biopsy‐proven osteogenic sarcoma. Measurements were made on sequentially collected serum samples beginning prior to the institution of therapy and continuing periodically until documented relapse. All patients were treated by curative resection and adjuvant therapy consisting of high dose methotrexate (with leucovorin rescue) with or without BCG immunotherapy. The SCL, SZL, and SCL/SZL determinations were made using proton‐induced x‐ray fluorescence spectrometry. SCL was significantly elevated (p < 0.0001) in the 18 patients with primary untreated osteogenic sarcoma (173 ± 30 μg/dl) compared with a sex and age‐matched normal group (115 ± 16 μg/dl). A significantly different SZL was not found, however, so that an elevated SCL/SZL ratio in the osteogenic sarcoma patients was primarily due to the altered SCL. SCL and SCL/SZL did not change significantly following curative surgery or become more abnormal in those patients who developed recurrent disease. The SCL and SCL/SZL were noted to be markedly elevated in those patients receiving BCG therapy, thus raising concern regarding the specificity of these tests as markers of tumor activity. SCL, SZL, and SCL/SZL did not appear useful as markers of tumor activity in patients with osteogenic sarcoma.