Serum inhibin and disease status in women with ovarian granulosa cell tumors

Objective. To determine if immunoreactive inhibin assayed in serum from women with granulosa cell tumors correlated with tumor burden, reflected response to treatment, or predicted recurrent disease. Study design. Serum samples were collected following bilateral oophorectomy (BSO) with or without other indicated surgery in 15 patients with granulosa cell tumors. Inhibin radioimmunoassay (RIA-Inh) was performed on all samples and results were correlated with tumor burden, disease status, and treatment response. Results. Fifteen patients had serum assayed for inhibin with levels ranging from 0 to 7470 U/liter. In 4 patients with measurable recurrent disease, inhibin levels correlated directly with tumor burden (r(2) = 0.96). Four patients had serum drawn during clinical remission and in all 4 patients elevated inhibin levels predated recurrence by a median interval of 11.5 months (range 7-20). The remaining 7 were treated for primary disease and were in clinical remission with a median follow-up of 33 months (range 9-53). Four of these 7 patients were surgically staged: 2 were FIGO Stage I and inhibin levels fell to O U/liter; 2 patients had metastatic disease (Stage Ilc and ma) and their inhibin levels were found to be elevated following complete resection. The remaining 3 were not surgically staged, and all had elevated inhibin levels while in clinical remission, suggesting occult disease. Of the 15 total patients, 1 who was treated with chemotherapy for recurrent disease was followed with serial inhibin levels. She showed a complete response to therapy with inhibin levels falling from 975 to O U/liter with 15 months follow-up. Conclusions. Serum inhibin levels reflect tumor burden and may be valuable in assessing response to chemotherapy or predicting recurrent disease in women with granulosa cell tumors who have had BSO. Serum inhibin level evaluation should be incorporated into large-group trials of therapy for granulosa cell tumors. (C) 1997 Academic Press