Meningiomas, Hormone Therapy, and the Questions Women Need to Ask

If you are a woman in midlife thinking about hormone replacement therapy, your doctor probably talked you through the usual risks. What they likely did not bring up is meningiomas.

What Is a Meningioma?

A meningioma is a tumor that grows from the protective tissue layers that surround the brain and spinal cord, also known as the meninges.

It does not start inside the brain itself, but because it grows right next to it, it can still cause serious neurological problems depending on where it sits and how large it gets.

Here is the number that stopped me when I first came across it: meningiomas account for more than one-third of all primary central nervous system tumors.

They are the most common intracranial tumors we know of. And yet most women have never heard the word.

These tumors are diagnosed and clinically confirmed in less than 1% of women, but meningiomas found on imaging or autopsies show a percentage as high as 2.8% in women.

Seems like a low number unless you're in that group.

It's important to note that most are slow-growing and cause no symptoms for years.

Many are found by accident during an MRI ordered for headaches, dizziness, a sinus issue, or something else entirely.

But here is what I want you to hold onto: a tumor can be pathologically benign and still be clinically dangerous. In a fixed space like the skull, location and mass effect often matter far more than the word "benign."

Who Gets Meningiomas?

Significantly more women than men, especially in midlife.

Meningiomas are diagnosed roughly twice as often in women than men.

They are most commonly found in middle-aged and older adults, which is exactly the window when HRT conversations are also happening.

That overlap is not a coincidence, and it is part of why researchers have long suspected a hormonal connection.

Risk is also higher with age, prior head or neck radiation, obesity, and certain inherited conditions such as neurofibromatosis type 2, a genetic syndrome that increases risk for multiple nervous system tumors.

But for most women, there is no single identifiable cause. These tumors appear to arise from accumulated genetic and molecular changes, and in many cases the trigger is simply not known.

The Grades of Meningiomas

The World Health Organization classifies meningiomas into three grades.

• Grade 1 is the most common, slow-growing, and least likely to come back after treatment.

• Grade 2 tumors are considered atypical and more likely to recur.

• Grade 3 tumors are the most aggressive, with the highest risk of recurrence and serious complications.

Treatment decisions depend on all of it: the grade, the size, the location, the symptoms, the patient's age, overall health, and increasingly, on molecular markers found in the tumor tissue itself.

Some specific genetic changes can push a tumor into a higher grade even if it looks lower-grade under the microscope.

This matters because "we'll just watch it" means something very different for a grade 1 tumor in a straightforward location than for a grade 2 in a critical area.

Meningioma Symptoms That Are Easy to Dismiss

Many meningiomas are completely silent for years. You would have no idea. But when they grow enough to press on nearby structures, the symptoms can include:

·      Persistent headaches

·      Seizures

·      Vision loss or double vision

·      Hearing changes

·      Facial numbness

·      Weakness on one side of the body

·      Balance problems or unexplained falls

·      Memory changes

·      Slowed thinking

·      Difficulty with speech

·      Personality changes

Some of these, particularly the cognitive ones, are easy to attribute to menopause, stress, aging, or simply being exhausted.

In many cases they likely are menopause related, but it's an opportunity to be proactive and ask the right questions to your physician.

What the Connection of Meningiomas to Hormones Actually Looks Like

Here is what we know, what we do not, and what I think deserves more attention than it is currently getting.

Multiple observational studies and a meta-analysis have found that hormone replacement therapy is associated with a higher meningioma risk.

The signal is strongest in current users and in long-term users. One large population study found that the risk rose with longer duration of use, and was highest after more than 10 years.

The strongest concern appears to be with progestogens, the progestin component of combined HRT, rather than estrogen alone.

Expert reviews have noted that progesterone agonists may be causally linked to meningioma progression, and in some documented cases, stopping the progestin led to tumor stabilization or even regression.

The picture is not perfectly uniform though.

One preliminary analysis suggested that estrogen-based HRT, without progestin, was not associated with faster tumor growth and may have been linked to smaller tumors overall.

So, this is not a blanket condemnation of all hormone therapy. But it is a reason to think carefully about which regimen you are on, for how long, and what your individual risk factors look like.

The fairest summary is this: hormone exposure appears to matter, especially for progestin-containing regimens.

The exact risk for any one woman depends on the type of hormone, the duration, whether a tumor is already present, and the biology of that particular tumor.

The Question Nobody Asks: What If You Already Have a Meningioma and Do Not Know?

This is the concern that keeps nagging at me.

A woman could be completely asymptomatic, start HRT for perfectly valid reasons, and have no idea that she already has a small, slow-growing meningioma. If hormones can influence tumor growth, that scenario deserves more attention than it is currently getting.

Right now, routine MRI screening before starting HRT is not recommended.

The reasoning is that most meningiomas are common enough and usually don’t grow to the point of causing problems.

So, scanning every woman to find many tumors that would never cause any trouble, would just generate downstream anxiety, cost, and a surveillance burden.

I understand that reasoning. I also think that every woman should understand it, weigh it against her own risk factors and risk tolerance, and have a real conversation with her physician rather than simply being handed a prescription.

That is the difference between being a passive recipient of healthcare and being an active participant in it.

What to Actually Say to Your Doctor

This is where I want to give you something practical.

Physicians respond better to specific, evidence-grounded questions than to general concerns. Here are some ways to open the conversation:

"I read that meningiomas are more common in women and that long-term hormone exposure, especially combined estrogen-progestogen therapy, has been associated with increased risk. I'd like to discuss whether brain imaging makes sense before I start HRT."

"I read that meningiomas are more common in women and that long-term hormone exposure, especially combined estrogen-progestogen therapy, has been associated with increased risk. My mother had a meningioma. Given my family history, I'd like to request an MRI to ensure I don't have one too before we move forward with hormones."

"I've been having persistent headaches and dizziness. I read that these can be symptoms of a meningioma. Could we rule that out with an MRI?"

"I'm planning to stay on HRT long term if it's the right option for me. I read that long term HRT can cause meningioma growth if one exists.  I'd like to be proactive and confirm I don't have an undiagnosed meningioma before committing to a longer course of HRT treatment."

You are not being alarmist by asking these questions. You are being informed. There is a difference.

If a Meningioma Is Found

Most small, asymptomatic meningiomas are managed with watchful waiting using serial MRI scans to monitor whether the tumor is growing.

Many never require any other intervention.

Surgery becomes the conversation when a tumor is symptomatic, is causing neurological deficits, is producing significant pressure or swelling in surrounding tissue, or shows clear growth on surveillance imaging.

Radiation, including stereotactic radiosurgery, is often used for residual disease, recurrence, or tumors in locations where surgery carries high risk.

The takeaway is that finding one is not automatically an emergency. But it is also not something to treat as irrelevant just because the pathology report says "benign."

What You Can Do Starting Now

Whether or not you are on HRT, here are practical steps that reduce the risk of a meningioma becoming a major problem:

• Take persistent neurological symptoms seriously. Headaches that do not respond to their usual remedies, vision changes, balance issues, cognitive shifts that feel different from ordinary tiredness warrant evaluation, not dismissal.

• If you are on HRT, ask about your progestin exposure specifically. If you want to stay on HRT for 10 years or more and haven’t had an MRI for a meningioma, start that conversation with your doctor.

• If a small non-symptomatic meningioma is found, follow the recommended imaging surveillance schedule. A benign tumor that is being watched is a very different situation from one that has been growing undetected for years.

• And if you have a known meningioma and are considering HRT, make sure the prescribing physician and your neurologist are talking to each other. That coordination does not always happen automatically.

The Bottom Line

Most women who start HRT will never have a clinically meaningful meningioma.

Meningiomas occur more often in women, they may respond to hormones, and new neurological symptoms during hormone therapy are not something to attribute to stress and move on from.

Being proactive about your health means asking the right questions to your doctor.

In this case, that question is: given everything I know about meningiomas and hormone exposure, what is the right approach for me?

That conversation is worth having.

Ready to Take a More Proactive Approach to Your Health?

If this is the kind of information you wish someone had told you sooner, that is exactly what health coaching is for.

I work with midlife women to review their medications and supplements, interpret their labs, translate physician recommendations into real daily plans, and ask the questions that tend to fall through the cracks of a busy clinical visit.

If you would like to start with a conversation, I offer a 55-minute Optimal Health Strategy Session where we review your full health picture together and leave with a concrete plan.

Book your session today!

Strategy Session

Your health is worth the extra question. Let's make sure someone is asking it.

References

• Goldbrunner R, Minniti G, Preusser M, et al. EANO guideline on the diagnosis and management of meningiomas.Neuro-Oncology. 2021;23(11):1821-1834.

• Wiemels J, Wrensch M, Claus EB. Epidemiology and etiology of meningioma. J Neurooncol. 2010;99(3):307-314.

• Huntoon K, et al. Meningioma: A Review of Epidemiology, Pathology, Diagnosis, Treatment, and Future Directions.Front Oncol. 2021.

• Louis DN, et al. The 2021 WHO Classification of Tumours of the Central Nervous System. Brain Pathology / WHO CNS update. 2021.

• Goldbrunner R, Minniti G, Preusser M, et al. EANO guideline on the diagnosis and management of meningiomas.Neuro-Oncology. 2021.

• Islim AI, et al. The management of incidental meningioma: an unresolved clinical conundrum. Neuro-Oncology.2023.

• Cea-Soriano L, et al. Incidental meningiomas and natural history / imaging follow-up literature. Neurosurg Focus.2011.

• Mayo Clinic. Meningioma — Symptoms and causes.

• Claus EB, et al. Family and personal medical history and risk of meningioma. J Neurosurg. 2011.

• Holly EA, et al. Meningioma and schwannoma risk in adults in relation to family history of cancer. Neuro-Oncology.2004.

• Kalasauskas D, et al. Familial clustering of meningiomas / hereditary susceptibility. J Neurooncol. 2017.

• Andersen L, et al. Hormone replacement therapy increases the risk of cranial meningioma. Eur J Cancer. 2013.

• Benson VS, et al. Hormone replacement therapy and risk of meningioma in women: a meta-analysis. Cancer Causes Control. 2013.

• Bourc’his / related review literature on hormone therapies in meningioma.

• Estrogen and Progesterone Therapy and Meningiomas. Endocrinology. 2022.

• Hormone therapies in meningioma—where are we? Review article. 2022.

• CUH NHS patient information: Hormone therapy and meningioma.

• Roland N, et al. Use of progestogens and the risk of intracranial meningioma. BMJ. 2024.

• Weill A, et al. Risk of intracranial meningioma with three potent progestogens: a population-based case-control study. Eur J Neurol. 2022.

• Recent review articles on progestogen-associated meningioma risk and management.

• Goldbrunner R, et al. EANO guideline on the diagnosis and management of meningiomas. Neuro-Oncology. 2021.

• Literature on stereotactic radiosurgery/CyberKnife for meningiomas, including reviews and outcome series.

• Evaluating the Efficacy and Safety of CyberKnife for Meningiomas. 2024 review.