Background: Surgery is challenging in patients with multiple or recurrent meningiomas. With the discovery of progesterone receptors (PR) on meningioma cells, there is an increased interest in the hormonal treatment using mifepristone, a PR blocker.
Materials and methods: A systematic review of clinical studies evaluating the efficacy and side effects of mifepristone in recurrent, unresectable, or multiple meningiomas was done. The primary outcome of this review was to study the efficacy in terms of tumor regression and clinical symptoms. Secondarily, we also reviewed the frequency and severity of different side effects reported by various studies.
Results: A total of 7 studies, including one Phase III randomized controlled trial, were found relevant to the topic. Though a few studies showed some response in terms of clinical improvement and tumor size reduction, the response was either minimal or temporary. The only subset showing a good response was the "diffuse meningiomatosis" group. None of the studies evaluated the relation of the PR isoform with mifepristone responsiveness. However, long-term mifepristone administration was well tolerated in most of the patients.
Conclusions: Use of mifepristone as a hormonal agent for meningiomas has produced mixed results. We propose that the possible mechanisms of action of mifepristone on meningioma cells must be studied in further detail by in-vitro studies. This may help in the identification of a mifepristone responsive subset of meningioma. This must be followed up with appropriately designed clinical studies with detailed baseline evaluation and standardized clinical and radiological follow-up.
Keywords: Hormonal treatment; meningioma; mifepristone; multiple; recurrent; unresectable.