Serum levels of macrophage colony-stimulating factor in trophoblastic disease

Objectives. The aims of this study were to measure levels of colony stimulating factor (CSF-1) in patients with trophoblastic disease, to determine whether such measurement may be useful to supplement measurement of the prognostically reliable human chorionic gonadotrophin (hCG), and to assess whether measurement of CSF-1 may be helpful in predicting requirement for chemotherapy in patients with hydatidiform mole. Methods. Serial weekly serum samples were selected for CSF-1 assay from representative diagnostic groups of patients with trophoblastic disease: hydatidiform-mole with spontaneous resolution, low-risk post-hydatidiform-mole trophoblastic tumor, partial hydatidiform mole, high-risk metastatic gestational trophoblastic tumor, primary ovarian choriocarcinoma, and placental site trophoblastic tumor, hCG was measured by an in-house radioimmunoassay that measures all parts of the hCG molecule. CSF-1 was measured by radioimmunoassay with ¹²⁵I-labeled recombinant CSF-1. The upper level of normal CSF-1 was taken as 8 ng/ml. Results. In this study of 45 patients with trophoblastic disease, some very high levels of CSF-1 were encountered. In a few patients there was dramatic correlation with hCG. Generally, however, CSF-1 and hCG did not correlate. CSF-1 was frequently not elevated when hCG was still significantly elevated and conversely CSF-1 was elevated when hCG was negative. Conclusion: The measurement of CSF-1 does not appear to be useful in managing trophoblastic disease as it does not correlate with the level of hCG. Occasionally, high levels of CSF-1 were found in patients with trophoblastic disease.