Dramatic Shrinkage with Reduced Vascularization of Large Meningiomas After Cessation of Progestin Treatment

Respective roles of Pik3ca mutations and cyproterone acetate impregnation in mouse meningioma tumorigenesis

Despite their rarity, PIK3CA mutations in meningiomas have raised interest as potentially targetable, ubiquitous mutations owing to their presence in sporadic benign and malignant tumors but also in hormone-related cases. Using new genetically engineered mouse models, we here demonstrate that Pik3ca mutations in postnatal meningeal cells are sufficient to promote meningioma formation but also tumor progression in mice. Conversely, hormone impregnation, whether alone or in association with Pik3ca and Nf2 mutations, fails to induce meningioma tumorigenesis while promoting breast tumor formation. We then confirm in vitro the effect of Pik3ca mutations but not hormone impregnation on the proliferation of primary cultures of mouse meningeal cells. Finally, we show by exome analysis of breast tumors and meninges that hormone impregnation promotes breast tumor formation without additional somatic oncogenic mutation but is associated with an increased mutational burden on Pik3ca-mutant background. Taken together, these results tend to suggest a prominent role of Pik3ca mutations over hormone impregnation in meningioma tumorigenesis, the exact effect of the latter is still to be discovered.

Meningioma in patients exposed to progestin drugs: results from a real-life screening program

PURPOSE

To report the results of systematic meningioma screening program implemented by French authorities in patients exposed to progestin therapies (cyproterone (CPA), nomegestrol (NA), and chlormadinone (CMA) acetate).

METHODS

We conducted a prospective monocentric study on patients who, between September 2018 and April 2021, underwent standardized MRI (injection of gadolinium, then a T2 axial FLAIR and a 3D-T1 gradient-echo sequence) for meningioma screening.

RESULTS

Of the 210 included patients, 15 (7.1%) had at least one meningioma; seven (7/15, 47%) had multiple meningiomas. Meningiomas were more frequent in older patients and after exposure to CPA (13/103, 13%) compared to NA (1/22, 4%) or CMA (1/85, 1%; P = 0.005). After CPA exposure, meningiomas were associated with longer treatment duration (median = 20 vs 7 years, P = 0.001) and higher cumulative dose (median = 91 g vs. 62 g, P = 0.014). Similarly, their multiplicity was associated with higher dose of CPA (median = 244 g vs 61 g, P = 0.027). Most meningiomas were ≤ 1 cm³ (44/58, 76%) and were convexity meningiomas (36/58, 62%). At diagnosis, patients were non-symptomatic, and all were managed conservatively. Among 14 patients with meningioma who stopped progestin exposure, meningioma burden decreased in 11 (79%) cases with no case of progression during MR follow-up.

CONCLUSION

Systematic MR screening in progestin-exposed patients uncovers small and multiple meningiomas, which can be managed conservatively, decreasing in size after progestin discontinuation. The high rate of meningiomas after CPA exposure reinforces the need for systematic screening. For NA and CMA, further studies are needed to identify patients most likely to benefit from screening.

Spontaneous regression of a posterior fossa meningioma: A case report

Background:

Since most incidentally discovered meningiomas grow or remain unchanged, spontaneous regression is extremely rare. Here, we report a case of posterior fossa meningioma showing spontaneous regression.

Case Description:

A 55-year-old female was referred to our hospital because she was diagnosed with a left posterior fossa meningioma (diameter: 1.6 cm) during a brain check-up. The patient was followed up on periodic magnetic resonance imaging studies. Tumor size remained almost unchanged for 2 years but then began to regress. Twelve years after the initial examination, the tumor diameter idiopathically decreased from 1.6 cm to 1.1 cm while the tumor volume decreased from 2.3 cm³ to 0.5 cm³ (about 1/4^th the original size). Postmenopausal hormonal imbalances may have been associated with the observed spontaneous regression.

Conclusion:

Understanding the natural history of meningiomas is essential for a better selection of treatment approaches or appropriate follow-up. This case may provide new insights into the progression of meningiomas.

Abscopal effect leading to complete disappearance of extensive meningiomatosis after gamma knife radiosurgery: Case report

Background and Importance

The abscopal effect is partial or complete tumor response in a separate site that was not the target of prior local treatment. There have been only 50 well-documented cases from 1960 to 2014. Our case is the first one of presumed low-grade meningioma demonstrating a possible response via the abscopal effect after single-fraction stereotactic radiosurgery.

Clinical Presentation

A case of a 70-years-old female with extensive intracranial meningiomatosis who had complete disappearance of all tumors after gamma knife radiosurgery targeting the right petroclival part of the tumor. She had complete resolution of her symptoms, which included hearing loss, headache, ataxia and dysphagia.

Conclusion

The abscopal effect is an extremely rare phenomenon after local radiation therapy of a remote tumor. Our case demonstrates that this can occur in remote meningiomas after single fraction GKRS of a different tumor.

Natural history of meningiomas: a serial volumetric analysis of 240 tumors

OBJECTIVE

The management of asymptomatic intracranial meningiomas is controversial. Through the assessment of growth predictors, the authors aimed to create the basis for practicable clinical pathways for the management of these tumors.

METHODS

The authors volumetrically analyzed meningiomas radiologically diagnosed at their institution between 2003 and 2015. The primary endpoint was growth of tumor volume. The authors used significant variables from the multivariable regression model to construct a decision tree based on the exhaustive Chi-Square Automatic Interaction Detection (CHAID) algorithm.

RESULTS

Of 240 meningiomas, 159 (66.3%) demonstrated growth during a mean observation period of 46.9 months. On multivariable logistic regression analysis, older age (OR 0.979 [95% CI 0.958-1.000], p = 0.048) and presence of calcification (OR 0.442 [95% CI 0.224-0.872], p = 0.019) had a negative predictive value for tumor growth, while T2-signal iso-/hyperintensity (OR 4.415 [95% CI 2.056-9.479], p < 0.001) had a positive predictive value. A decision tree model yielded three growth risk groups based on T2 signal intensity and presence of calcifications. The median tumor volume doubling time (Td) was 185.7 months in the low-risk, 100.1 months in the intermediate-risk, and 51.7 months in the high-risk group (p < 0.001). Whereas 0% of meningiomas in the low- and intermediate-risk groups had a Td of ≤ 12 months, the percentage was 8.9% in the high-risk group (p = 0.021).

CONCLUSIONS

Most meningiomas demonstrated growth during follow-up. The absence of calcifications and iso-/hyperintensity on T2-weighted imaging offer a practical way of stratifying meningiomas as low, intermediate, or high risk. Small tumors in the low- or intermediate-risk categories can be monitored with longer follow-up intervals.

Estrogen and Progesterone Therapy and Meningiomas

Meningiomas are common intracranial tumors with a female predominance. Their etiology is still poorly documented. The role of sexual hormones has long been evoked, and data have been conflicting across studies. However, a dose-dependent relationship between the incidence and growth of meningiomas and hormonal treatment with the progestin cyproterone acetate (CPA) has recently been established. CPA-associated meningiomas seem to be mainly located in the anterior and middle skull base, are more likely to be multiple, may harbor P1K3CA mutations in up to one-third of cases, and are more common with a longer duration of treatment. A similar but lower risk of meningiomas has been recently reported with the use of chlormadinone acetate and nomegestrol acetate as progestin treatments. Concerning hormonal replacement therapy (HRT) in menopausal patients, evidence from epidemiological studies seem to favor an increased risk of meningiomas in treated patients although a recent study failed to show an increased growth of meningiomas in HRT treated vs nontreated patients. Until larger studies are available, it seems wise to recommend avoiding HRT in patients with meningiomas. Evidence from published data does not seem to support an increased risk of meningiomas with oral contraceptive oral contraceptive (OR) use. Data are too scarce to conclude on fertility treatments. Based on studies demonstrating the expression of hormonal receptors in meningiomas, therapies targeting these receptors have been tried but have failed to show an overall favorable clinical outcome in meningioma treatment.

Atypical evolution of meningiomatosis after discontinuation of cyproterone acetate: clinical cases and histomolecular characterization

PURPOSE

The long-term use of cyproterone acetate (CPA) is associated with an increased risk of developing intracranial meningiomas. CPA discontinuation most often induces a stabilization or regression of the tumor. The underlying biological mechanisms as well as the reasons why some meningiomas still grow after CPA discontinuation remain unknown. We reported a series of patients presenting CPA-induced meningiomatosis with opposed tumor evolutions following CPA discontinuation, highlighting the underlying histological and genetic features.

METHODS

Patients presenting several meningiomas with opposite tumor evolution (coexistence of growing and shrinking tumors) following CPA discontinuation were identified. Clinical and radiological data were reviewed. A retrospective volumetric analysis of the meningiomas was performed. All the growing meningiomas were operated. Each operated tumor was characterized by histological and genetic analyses.

RESULTS

Four women with multiple meningiomas and opposite tumor volume evolutions after CPA discontinuation were identified. Histopathological analysis characterized the convexity and tentorial tumors which continued to grow after CPA discontinuation as fibroblastic meningiomas. The decreasing skull base tumor was characterized as a fibroblastic meningioma with increased fibrosis and a widespread collagen formation. The two growing skull base meningiomas were identified as meningothelial and transitional meningiomas. The molecular characterization found two NF2 mutations among the growing meningiomas and a PIK3CA mutation in the skull base tumor which decreased.

CONCLUSION

To our knowledge, this is the first report describing an atypical tumor evolution of CPA-associated meningiomas after CPA discontinuation. The underlying biological mechanisms explaining this observation and especially the close relationship between mutational landscapes and embryologic origins of the meninges in CPA-related meningiomas as well as their clonal origin require further research.

[Meningiomas: A review of current knowledge]

Meningiomas are the most frequent among intracranial tumors, and represent more than 30% of primitive central nervous system neoplasms. Arising from the meninges, they are generally benign lesions and can be treated by either radio-clinical follow-up or surgical resection with excellent outcome. However, more than 20% of meningiomas harbor atypical or malignant features and represent challenges for both prognostic evaluation and therapeutic strategy. The discovery of the genetic and epigenetic landscapes of meningiomas enabled the identification of new prognostic markers and potential therapeutic targets for refractory meningiomas. This review summarizes current epidemiology, histological and molecular characteristics, diagnosis and treatments for meningiomas, and highlights the close relationship between the development of meningiomas and hormonal intake, as illustrated by recent recommendations of the "Agence Nationale de Securité du Medicament", the French national drug safety agency.

Sustained growth of intraosseous hormone-associated meningiomas after cessation of progestin therapy

Hormone-associated meningiomas tend to stop growing or decrease in size after cessation of certain progestins, mainly cyproterone acetate. We report three observations on the natural history of hormone-associated intraosseous meningiomas, showing in a first patient that those tumors may grow rapidly under nomegestrol. We then demonstrate the sustained growth of intraosseous hormone-associated meningiomas after cessation of promesgestone and nomegestrol, independently of the intracranial portion, which concurrently decreased in size in the second case or was resected at the time of nomegestrol withdrawal in the third case, thus giving new insights into the tumorigenesis mechanisms of hormone-associated intraosseous meningiomas.

Meningiomas in Gynecology and Reproduction: an Updated Overview for Clinical Practice

There is various evidence to suggest a relationship between female hormones and meningiomas; as clinicians, we often come to face challenging situations involving female patients diagnosed with meningiomas during the post-pubertal phases of their life. We aimed to review the specific circumstances (pregnancy, postpartum, hormonal contraception and hormone replacement therapy, gender-affirming hormonal treatment) clinicians might come to face during their daily clinical practice, given the absence of available guidelines. We therefore conducted a narrative review on articles found in PubMed and Embase databases using appropriate keywords. Ninety-six relevant articles were included. The available evidence on managing meningiomas in post-pubertal women often implies personal strategies, highlighting the lack of a unified approach. The knowledge of the biological links between female hormones and meningiomas is fundamental to correctly counsel patients in various life phases. Prospective randomized studies are required to improve available guidelines on how to best manage meningiomas in female post-pubertal patients.

Molecular alterations in meningioma: prognostic and therapeutic perspectives

PURPOSE OF REVIEW

To discuss recent advances in the meningioma biology and their clinical implications.

RECENT FINDINGS

Meningioma is the most common primary intracranial tumor. Mostly benign, 20% of cases display an aggressive behavior despite best standard of care. The genetic landscape of meningiomas is divided according to NF2 mutational status. Although about 60% of meningiomas display NF2 mutations, the other share is more heterogenous. Mutations in TRAF7, SMO, v-akt murine thymoma viral oncogene homolog 1 (AKT1), PI3KCA and KLF4 are seen mostly in WHO grade 1 meningiomas. In higher grade meningiomas, mutations of the TERT promoter and deletions of CDKN2A/B emerge and have prognostic value. Moreover, mutations in DMD, BAP1 and PBRM1 have recently been discovered and are being further explored. DNA methylation subgroups offer valuable insight into meningioma prognosis and its implementation in clinical setting is under evaluation. Moreover, the study of distinct meningioma populations such as radiation-induced meningioma and progestin-associated meningioma may provide further insight into meningioma oncogenesis and potential therapeutic targets.

SUMMARY

The mutational landscape of meningioma has expanded following the use of the new genetic sequencing approaches. Novel mutations have been characterized and reveal their prognostic and therapeutic applications. This improved understanding of meningioma biology has promising implications for novel treatment strategies.

Meningiomas and cyproterone acetate: a retrospective, monocentric cohort of 388 patients treated by surgery or radiotherapy for intracranial meningioma

PURPOSE

Meningiomas are the most common intracranial tumors, accounting for 20-30% of central nervous system tumors. Recently, the European Medicines Agency issued an alert on cyproterone acetate (CPA) based on the results of a study that found an increased risk of meningioma 7 to 20 times higher when a patient is on CPA. The primary objective of this study was to determine the prevalence of CPA exposure in patients who had one or more intracranial meningiomas treated surgically or with radiation therapy. The secondary objectives were to establish a description of the patients who had intracranial meningioma in Nantes and to establish whether there was a difference in the intrinsic and tumoral characteristics of patients exposed to CPA compared with patients who had no hormonal exposure and patients who had been exposed to other hormones.

METHODS

Monocentric, retrospective study including all patients treated by surgery or radiotherapy for intracranial meningioma from 2014 to 2017 excluding those with a history of exposure to ionizing radiation or neurofibromatosis type 2.

RESULTS

388 patients were included, 277 were treated by surgery and 111 by radiotherapy. 3.9% of the patients had a history or current use of CPA, 16.2% were taking other hormonal treatment. Compared with the group without hormonal exposure, the CPA-exposed group had significantly an earlier onset of meningiomas at 48.9 vs. 61.9 years (p = 0.0005) and had more multiple meningiomas, 26.7% vs. 6.1% (p = 0.0115).

CONCLUSIONS

In our study, patients with a history or current use of CPA had significantly more meningiomas and were significantly younger at the onset.

Spontaneus involution of meningioma. Case report and literature review

Meningiomas are tumors of the cerebral meninges, with slow growth and usually benign, whose treatment is essentially surgery. They have progesterone receptors, and to a lesser extent estrogen, which sometimes causes them to have growth or involution linked to hormonal treatment. Its spontaneous involution is extremely rare. We present the case of a male with a meningioma of the sphenoid planum. He had a history of diabetes mellitus, myasthenia gravis and prostate cancer. He was in treatment with analogs of GnRH (leuprorelin), antiandrogen (bicalutamide), β3 agonists and α1 blockers. 15 months after the hormonal blockade, a reduction of the tumor of approximately 90% of its volume was detected. Previous reports show that treatment with gonadotropin analogues produces growth in some meningiomas. Other reports of spontaneous involution affect diabetic patients and patients in treatment with α1 blockers. Literature focus on meningiomas with spontaneous involution is reviewed.

Possible Abscopal Effect Observed in Frontal Meningioma After Localized IMRT on Posterior Meningioma Resection Cavity Without Adjuvant Immunotherapy

Background: Localized radiation therapy (RT) is known to infrequently cause off-target or “abscopal” effects at distant metastatic lesions. The mechanism through which abscopal effects occur remains unknown, but is thought to be caused by a humoral immune response to tumor-specific antigens generated by RT. Combination treatment regimens involving RT and immunotherapy to boost the humoral immune response have demonstrated synergistic effects in promoting and accelerating abscopal effects in metastatic cancer. Nevertheless, abscopal effects, particularly after RT alone, remain exceedingly rare.

Case Presentation: We report the case of an 84-year-old man with an atypical meningioma, who demonstrated a radiographically significant response to an untreated second intracranial lesion, likely also a meningioma, after intensity-modulated radiation therapy (IMRT) to a separate, detatched resection cavity. Serial annual MRI imaging starting at 2- to 3.5-year (most recent) post-IMRT follow-up demonstrated a persistent decrease in both tumor size and surrounding edema in the untreated second lesion, suggestive of a possible abscopal effect.

Conclusions: We describe here the first report of a potential abscopal effect in meningioma, summarize the limited literature on the topic of abscopal effects in cancer, and detail the existing hypothesis on how this phenomenon may occur and possibly relate to the development of future treatments for patients with metastatic disease.

Spontaneous regression of meningiomas after interruption of nomegestrol acetate: a series of three patients

BACKGROUND

The relationship between increased meningioma incidence and growth and long-term hormonal therapy with cyproterone acetate (CPA) in women has been recently established in literature. Following the raise in awareness from hormonal treatment, we describe a potential relationship between the progesterone agonist nomegestrol acetate (NOMAC) and meningioma growth.

METHODS

After implementation of a screening protocol to detect potential interactions between hormonal exposure and occurrence of meningioma, we identified patients taking NOMAC and newly diagnosed with a meningioma. NOMAC was stopped and those patients were followed tightly both clinically and radiologically. Retrospective volumetric analysis of the tumors was performed on the imaging.

RESULTS

Three patients were identified for the study. After cessation of the NOMAC, tumor shrinkage was documented for all meningiomas within the first month. Up to 70% of tumor volume reduction was observed during the first year of follow-up in one of them. None of the patients developed new symptoms.

CONCLUSION

We report the first cases of meningiomas responsiveness to discontinuation of hormonal therapy with NOMAC. Similarly to cases associated with long-term CPA intake, tumor reduction, and improvement of clinical symptoms can be observed after cessation of NOMAC.