While the majority of ovarian cysts after menopause are benign (non-cancerous), ovarian cancer does need to be ruled out. Hence, such cysts are managed slightly differently, compared to cysts in pre-menopausal women. So, if it’s been over a year since your last regular period, and an ovarian cyst has been seen on ultrasound, it’s worth reading this blog. It will explain some background about post-menopausal cysts, what your GP and gynaecologist might recommend, and if / when to be concerned.

Why are ovarian cysts taken more seriously after menopause?

When any woman goes through menopause, her ovaries slowly wind down, eventually stop producing female hormones, and stop producing eggs (or ‘ovulating’). Hence, many non-cancerous types of cysts shouldn’t develop after menopause (eg. simple / functional / physiological cysts, haemorrhagic cysts, endometriomas etc). Based on this alone, it means that any cyst found is more likely to have a suspicious origin, compared to an ovarian cyst in a pre-menopausal woman.

If you are post-menopausal, and have a symptomatic ovarian cyst, there is a 3 in 1,000 (ie. 0.3%) chance that you have ovarian cancer; a pre-menopausal woman’s chances are only 1 in 1,000 (ie. 0.1%).

Because of the above factors, an ovarian cyst > 1cm is considered significant after menopause, and warrants further investigation. (As opposed to before menopause, when a cyst generally needs to be > 3cm before it needs to be investigated / managed.)

What further investigations will my doctor recommend?

Depending on what your initial ultrasound showed, your GP may recommend:

• A higher quality, specialist women’s ultrasound, performed by a specialist team such as Siles Health or Western Imaging for Women
• A repeat ultrasound a few months later (to see if the cyst is getting smaller or bigger)
• Some blood tests (such as CA125, which is discussed below)

Your GP may already have enough information to refer you directly to a gynaecologist, without needing any additional investigations.

What blood tests will my doctor recommend?

If you are post-menopausal, and have been found to have an ovarian cyst, your doctor should recommend that you have so-called ‘ovarian cancer tumour marker’ blood tests completed. This includes ‘CA125’, which is the best blood test to detect ovarian cancer in post-menopausal women. (It’s not a perfect screening tool, and is only abnormally high in approximately 80% of ovarian cancer. But unfortunately it’s the best tool we’ve currently got…)

Having your CA125 blood test performed enables your gynaecologist to calculate your ‘Risk of Malignancy Index’, as discussed below.

Risk of Malignancy Index (RMI)

Once you have had both a high quality, specialist women’s ultrasound, plus a CA125 blood test, your gynaecologist can calculate your so-called ‘Risk of Malignancy Index’ (or RMI). This helps to guide further management, as follows:

RMI < 25 = low risk

This means that you have a low (< 3%) risk of ovarian cancer. A benign gynaecologist, such as those at Maven Centre, can continue to manage your care.

RMI 25 – 200 = moderate risk

This means that you have a moderate risk (20%) of having an underlying ovarian cancer. Your Maven Centre gynaecologist can probably continue to lead your care, but may ask that you see a gynae-oncologist (a sub-specialist gynaecologist, who has completed an additional three years of training in the management of women’s cancer), to confirm that this is appropriate.

Your gynaecologist is likely to recommend keyhole surgery to remove both left and right ovaries, plus both Fallopian tubes: an operation called a ‘laparoscopic bilateral salpingo-oophorectomy’. This is because neither the ovaries nor Fallopian tubes serve any functional purpose after menopause, yet they may become cancerous in future. So the benefits of having them removed (thereby negating any chance of ovarian cancer in future) are thought to outweigh the potential risks of such an operation.

Sadly, ovarian cancer is notoriously hard to diagnose at an early stage, when prognosis is much better than at later stages. In addition, a significant minority of ‘ovarian’ cancer actually starts in the Fallopian tube. Hence, gynaecologists have a relatively low threshold to recommend surgical removal of both ovaries, plus both Fallopian tubes, in post-menopausal women. Such surgery is very safe, and the peace-of-mind afforded by excluding current (and preventing future) ovarian cancer is priceless.

RMI > 200 = high risk

Having an RMI over 200 means that you have high risk (75%) of having an underlying ovarian cancer. Your GP or Maven Centre gynaecologist is likely to:

• Organise a CT scan of your abdomen and pelvis, to look at your lymph nodes and the tissues near the ovaries
• Refer you to see a gynae-oncologist (a gynaecologist who specialises in the management of women’s cancers), to take over and lead your care thereafter

Further management will be guided by your gynae-oncologist, but may include an open operation to have your uterus, Fallopian tubes, and ovaries removed.

If I need surgery, what surgery will be suggested?

If you are post-menopausal, the ovaries aren’t really doing anything helpful: during menopause, they became quiescent, and stopped producing any female hormones. There is always a risk that ovaries may become cancerous in future. So, if surgery is needed to remove an innocent (non-cancerous) ovarian cyst after menopause, best practice is to also remove the ovary: it’s not serving any purpose, and may become cancerous in future.

If we are going to perform keyhole surgery to remove one ovarian cyst (and ovary), we often recommend removing the other ovary as well: this ovary isn’t serving any purpose, and may become cancerous in future also.

There is growing evidence that about 50% of all ‘ovarian’ cancers actually begin in the Fallopian tubes. The only purpose Fallopian tubes serve is to enable egg and sperm to meet, to fall pregnant naturally. Once you have gone through menopause, the Fallopian tubes don’t serve any purpose; they may become cancerous in future.

Hence, if surgery is needed to remove an ovarian cyst after menopause, best practice is for your gynaecologist to remove not only the ovarian cyst, but also both left and right ovaries, and both left and right Fallopian tubes. This operation is called ‘laparoscopic bilateral salpingo-oophorectomy’.

These discussions can be quite nuanced: please ask your gynaecologist any questions you have about your planned operation.

Topic area frequently asked questions (FAQs)

My ovarian cyst has been described as ‘simple’. How will this be managed?

If your ovarian cyst has been described as ‘simple’ on a specialist women’s ultrasound, and if it’s < 5cm in size, it will probably resolve spontaneously over the coming 3 months. Hence, your doctor may suggest a repeat ultrasound in 3 months’ time, to confirm that this has occurred.

If:

• You have any symptoms from this cyst (eg. pelvic pain on that side)
• You have abnormal tumour marker blood tests
• You want a guarantee that it is not cancerous
• And / or the cyst is getting bigger on subsequent ultrasound

keyhole surgery to remove the cyst (and ovary) will probably be suggested to you.

Is it really worth paying to get a specialist women’s ultrasound?

It is sometimes possible to have a basic transvaginal ultrasound without significant out-of-pocket expenses, especially if you find a provider that will bulk-bill your ultrasound. However, having a specialist women’s ultrasound can carry an out-of-pocket cost of approximately $280 – 300.

There are several reasons why this may still be money well spent, including:

• Sonographers in general radiology practices scan all genders, from head-to-toe. So while they can provide a screening ultrasound, they are no experts at gynaecological scanning. In contrast, clinicians who specialise in women’s ultrasounds spend all day, every day, scanning women’s ovaries and uteruses.
• Classifying ovarian cysts on ultrasound often comes down to ‘pattern recognition’: the sonographer (and reporting radiologist / gynaecologist) looking for, recognising, and reporting very subtle characteristics of your ovarian cyst. This ‘pattern recognition’ often affords a very educated guess as to the exact type of ovarian cyst you have.
• Use of sophisticated formulae to estimate ovarian cancer risk. Clinicians with expertise in ovarian cysts can employ various tools (eg. RMI, O-RADS, IOTA scoring systems) to estimate the chances that your ovarian cyst is benign, ‘borderline’, or outright cancerous.

So, while it’s easy for me to say that this is money well spent (as it’s not my money), a specialist women’s ultrasound scan can prove priceless, when guiding further management.