Prognostic value of mitotic counts and Ki-67 immunoreactivity in adult-type granulosa cell tumour of the ovary

Abstract

Aims: The identification of reliable prognostic factors in patients with stage 1 adult-type granulosa cell tumour (GCT) has proved problematic. Some reports have suggested that proliferation indices may be of value but the data are conflicting and the methods of assessment often poorly defined. In this study we have assessed mitotic activity and Ki-67 immunohistochemistry in a series of GCT using carefully specified methodology and have correlated the findings with clinico-pathological findings.

Methods: Tumour proliferation was assessed in 38 primary GCT by counting mitotic figures (MF) in 50 high power fields (x500 magnification) with results expressed as a mean count/ 2mm2 standardised area. The number of MF and Ki-67 immunoreactive cells/10,000 tumour cells was also assessed using an ocular cell counting graticule. The results were correlated with tumour stage at presentation and with the development of tumour recurrence.

Results: Twenty-nine patients were stage 1 at presentation while 9 patients had high stage disease (extra-ovarian spread). Nine patients with initial stage 1 disease developed metastases while 20 patients had no evidence of recurrence over a mean follow up period of 11.1 years. There was no significant correlation between any of the proliferation indices and with clinical outcomes.

Conclusions: These results suggest that proliferation assessment is of limited value in the pathological assessment of GCT. Future studies should carefully specify the methods of assessing cell proliferation to ensure a reliable comparison of results.