Adenomyosis and Cancer Symptoms: Can It Turn Into Cancer?

No. Adenomyosis is not cancer, and adenomyosis itself does not cause cancer or lead to cancer. Cancer that starts inside an area of adenomyosis is very rare, and it is reported in about 1 in 100 cases, mostly in older women.

Some symptoms of adenomyosis and of womb cancer are the same, such as heavy or unusual bleeding. This is why it helps to know which changes need a check, whatever the cause. This guide explains what the research shows, which symptoms to take to a doctor, how doctors tell the two apart and what to track before your visit. It is general information and not medical advice.

What adenomyosis is

Adenomyosis happens when tissue like the lining of the womb grows into the muscle wall of the womb. It can make the womb thicker and larger, sometimes up to two or three times its usual size. The most common symptoms are heavy, painful periods and pelvic pain. Read the full list in our guide to adenomyosis symptoms, and see how it differs from endometriosis in adenomyosis vs endometriosis.

Adenomyosis is a benign (non-cancer) condition. Oestrogen makes the tissue grow, so symptoms usually go away after menopause, but the womb can stay larger than usual.

Can adenomyosis turn into cancer?

It is possible but very rare. When doctors find cancer that started inside adenomyosis, it is reported in only about 1% of cases. Most of these cancers are a type called endometrioid carcinoma, and they usually affect older women. The most common risk factor is a long time of exposure to oestrogen. Most of what we know comes from case reports and small groups of patients, so the exact number is not certain.

There are also case reports of sarcomas (cancers of the muscle or support tissue) that started in adenomyosis. These are rarer still.

Does adenomyosis raise the risk of womb cancer?

Some studies show a small link with cancer of the womb lining (endometrial cancer). In a large study from Taiwan that followed over 12,000 women with adenomyosis, endometrial cancer was about twice as common as in women without adenomyosis. But the number of cases stayed small in both groups:

These numbers are from the same Taiwan study, in women born between 1951 and 1984. Twice a very small number is still a small number. The link is still not clear, and the researchers say that more studies are needed. A study like this cannot show that adenomyosis causes cancer.

If you have adenomyosis, this is not a reason for fear. It is a reason to know the warning signs below and to get new symptoms checked.

Why adenomyosis and cancer can be confused

Adenomyosis, womb cancer and uterine sarcoma can all cause some of the same things:

• Heavy or unusual bleeding. Adenomyosis often causes heavy, long periods with clots. Heavy periods that are unusual for you are also a main symptom of womb cancer. Read more in how much period bleeding is too much.
• A larger womb or a swollen belly. Adenomyosis can enlarge the womb and give a full, bloated belly. See adenomyosis belly. A lump or swelling in your tummy or pelvis is also a possible sign of womb cancer.
• Pelvic pain and pain during sex. These are common in adenomyosis, and they are also on the list of other symptoms of womb cancer.

The symptoms of uterine sarcoma are similar to those of womb cancer and of benign growths such as fibroids. This overlap does not mean that your symptoms are cancer. These symptoms are common and have many different causes. It means that a doctor should look at what is new or different.

Symptoms that need a prompt check

See a doctor soon if you have any of these, even if you already have a diagnosis of adenomyosis. They are reasons to get checked. They are not a diagnosis.

• Any bleeding after menopause. Bleeding or spotting after menopause always needs a check by a doctor, even if it is small or happens only once. It is usually not serious, but it can be a sign of cancer. In the UK, you should not wait more than 2 weeks to see a specialist.
• New bleeding between periods. Bleeding between your periods is a main symptom to get checked.
• Periods that become heavier than is usual for you. A change from your normal pattern matters more than one heavy month.
• A change to your vaginal discharge. This is also on the list of main symptoms.
• A new lump, swelling or pain in your tummy or pelvis, or a change in how often you pee or poo.

Do not wait for your next routine visit. Finding cancer early can make it easier to treat, and most of the time the check gives you peace of mind.

Write down what has changed and when, so you can show your doctor.

How doctors tell adenomyosis from cancer

Your doctor starts with your symptoms and a pelvic exam. Then the usual tests are:

• Ultrasound. A scan with a small probe in the vagina can show thickening of the womb wall in adenomyosis. It is also the first test for bleeding after menopause.
• MRI. An MRI scan can show an enlarged womb and thick areas in the womb wall. Doctors also use pelvic MRI to look for uterine sarcoma.
• Biopsy. Your doctor may take a biopsy to rule out more serious conditions. A pathologist looks at the tissue under a microscope. For bleeding after menopause, a hysteroscopy can take a tissue sample for testing.

No single scan gives the full answer. Only the tissue gives a sure answer: a pathologist's check of the tissue is the standard for cancer in adenomyosis. Tests of the lining often look normal in adenomyosis, because adenomyosis is in the muscle wall and not in the lining. So if your symptoms change after a normal result, tell your doctor.

What treatment choices mean for cancer risk

Treatment for adenomyosis is mainly about easing pain and bleeding. Choices include anti-inflammatory painkillers, tranexamic acid, hormonal medicines such as the pill, the Depo-Provera injection or a hormonal IUD, surgery to remove adenomyosis, and hysterectomy.

A few points link treatment and cancer risk:

• Hysterectomy. If you do not plan to have children, a hysterectomy (surgery to remove the womb) can cure adenomyosis. With the womb removed, cancer of the womb cannot start there.
• Checks before surgery. Rare cancers can look like benign conditions, and the cutting up of a benign growth during surgery (morcellation) is listed as a risk factor. Ask your surgeon how they check the womb before and during the operation.
• Other medicines. Long-term use of tamoxifen, a breast cancer medicine, is a listed risk factor, and it also slightly increases the risk of uterine sarcoma. If you take it, tell your gynaecologist.

Do not stop a medicine because of this page. Talk to your doctor about what is right for you.

What to track and bring to your visit

A clear record helps your doctor to see what is new. Write down:

• Bleeding pattern. The first and last day of each period, and any bleeding between periods or after sex.
• Flow and clots. How often you change pads or tampons, flooding, and the size of any clots. See blood clots during your period.
• Pain. How bad it is from 0 to 10, where it is and which days it happens. Our guide on how to describe period pain can help.
• Belly changes. Swelling, fullness or a lump, and when you first saw it.
• Pee and poo changes. If you go more often or less often than usual.
• Medicines. What you take, including hormones and tamoxifen, and if they help.
• Past results. Dates of scans and biopsies and what they showed.

Endolog is a pain and symptom diary for endometriosis and adenomyosis. You log pain severity, where it hurts, bleeding, and bowel and urinary symptoms on the days they happen, so you have a clear record to show your doctor. For a paper version, print the free pain diary.

Frequently asked questions

Is adenomyosis a type of cancer?

No. Adenomyosis is a benign condition of the womb muscle. It does not cause cancer or lead to cancer.

How common is cancer in adenomyosis?

Very rare. Cancer that starts in adenomyosis is reported in about 1% of cases, mostly in older women.

What are the warning signs to watch for?

Any bleeding after menopause, new bleeding between periods, periods that are heavier than usual for you, a change in discharge, or a new lump or swelling in your tummy. These are the main symptoms to get checked.

Can an ultrasound tell adenomyosis from cancer?

An ultrasound can show signs of adenomyosis and changes in the womb lining, but a sure answer about cancer needs a tissue sample checked by a pathologist.

Does adenomyosis go away after menopause?

The symptoms usually go away after menopause, but the womb can stay enlarged. Any bleeding after menopause needs a check by a doctor.

This article is for general information. It is not medical advice and does not replace advice from your own doctor. If you have heavy bleeding with dizziness or fainting, or very bad pain, get urgent medical help.