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Ovacome is a national charity providing support options to people with ovarian cancer.  We give information about symptoms, diagnosis, treatments and research.  Ovacome also runs a telephone and email support line that you can access from home, and works to raise awareness and give a voice to all those affected by ovarian cancer.

This page gives information about low grade cancer of the ovary, a rarer form of the disease.  It describes what low grade is, how it is diagnosed and treated and gives information on potential new treatments and research.


Low grade serous is a form of ovarian cancer that is invasive and grows slowly on surface tissue.

Unlike other more common forms of ovarian cancer its cells are more like normal body cells, but this means it is less likely to respond to chemotherapy.

It is a rarer form of ovarian cancer, most commonly found in patients aged between 45 and 57 but many cases are in women in their 20s and 30s.  There are about 560 cases diagnosed in the UK each year.

Between five and 10 per cent (one in 20 and one in 10) of women thought to have the most common form of ovarian cancer, which is epithelial serous ovarian cancer, are found to have low grade serous ovarian cancer (LGSOC).  Up to 10 per cent (one in 10) of women diagnosed with advanced, serous borderline tumours go on to develop low grade serous ovarian cancer.

Low grade serous ovarian cancer does not develop into high grade serous ovarian cancer apart from in exceptional cases. 


Did you know that Ovacome runs and online group for people with a rarer ovarian cancer? Find out more here.


Signs, symptoms and diagnosis

Low grade serous ovarian cancer has similar signs and symptoms to other forms of the disease; pain, bloating, difficulty eating and bowel and urinary changes as pelvic and abdominal organs are gradually affected.

It is thought to start in the fallopian tubes and is usually at stages 2 to 4 when it is diagnosed meaning that it has spread away from the fallopian tubes and ovaries into the pelvis and then the abdomen.  You can find more information on our pages about stage 2, stage 3 and stage 4 ovarian cancer.

Low grade serous ovarian cancer is diagnosed using clinical examination including a pelvic examination.  You should be offered a CA125 blood test which can detect a protein in the blood that is a cancer marker.  If you are found to have symptoms and the CA125 test comes back at a level of 35 or above you should be referred for a scan within two weeks. This may involve an abdominal or transvaginal ultrasound. It is important to know that CA125 levels in those with low grade serous ovarian cancer may be less than the 35 threshold.


Read Katie


How is low grade serous ovarian cancer treated?

Treatment is usually surgery to remove all visible signs of the cancer.  If it is diagnosed when it is still at stage 1, contained in the ovaries, you may only need surgery. 

If you have not had your menopause and are diagnosed very early at stage 1a you should be offered fertility–preserving surgery.  This means just one ovary is removed. If you have questions about stage 1 ovarian cancer, visit our information page.

Most people with low grade serous ovarian cancer are diagnosed when the cancer has spread so surgery will usually mean removing the ovaries, fallopian tubes, womb, cervix and omentum (a layer of tissue in the abdomen).  The surgeon may also want to see if the cancer has spread to lymph nodes.   If the cancer has spread further, more distant organs may need to be removed. 

If surgery is not possible straight away, perhaps because you are too ill, you will probably be offered chemotherapy then surgery followed by further chemotherapy.  If surgery is not recommended you will be treated using other therapies.  You may be offered hormone therapies.


Chemotherapy and maintenance therapies

Low grade cancer that has advanced further than stage 1 is usually treated with chemotherapy, although low grade does not respond to this as fully as other forms of ovarian cancer. 

If your cancer was diagnosed early you will probably be offered carboplatin, a platinum based drug.  If you were diagnosed later paclitaxel (Taxol) will also be offered.  Because low grade serous ovarian cancer is less responsive to chemotherapy, you may be offered Avastin (bevacizumab).  This is a targeted therapy that affects the blood supply to cancer cells. It can be used alongside chemotherapy. Read about the possible side effects of chemotherapy and targeted therapies on our information pages.

After your chemotherapy you may be offered medication that reduces the amount of the female hormone oestrogen in your body, or that blocks the effect of oestrogen.   This is because oestrogen can encourage the growth of low grade serous ovarian cancer. 

You may be offered hormonal therapies such as letrozole or tamoxifen or other drugs that reduce oestrogen and that can be taken long term as maintenance therapies.

These drugs are not yet licensed for use with ovarian cancer but research has shown that using hormone therapy after first line chemotherapy can keep the disease controlled for longer.


What if low grade serous ovarian cancer comes back?

Most people diagnosed with low grade serous ovarian cancer experience a recurrence at some point.

It may be possible to treat this with further, secondary, surgery.  If you have had a long period of being cancer-free, if the cancer has come back in just a few places and if you do not have ascites (a build-up of fluid caused by the cancer which can lead to abdominal bloating) then surgery may be an option.  After surgery you may be offered hormone therapy.

If you have a recurrence your condition may be managed using chemotherapy including Caelyx and topotecan, hormonal therapies and targeted therapies which are drugs that target cancer cells which have specific changes.


The emotional impact

Low grade serous ovarian cancer is a slow growing chronic disease that is rare and can been hard to treat effectively.  Those with the disease may experience significant emotional difficulties living with LGSOC, continuing treatments and an uncertain future.  Anxiety and distress is an understandable response to this situation.  

If this is affecting you, ask your GP or clinical team for support.  You can get more information from Ovacome’s Living with ovarian cancer information on Coping with anxiety at www.ovacome.org.uk.  You can also call the Ovacome free supportline on 0800 008 7054.


Read Diane


Research and future treatments

A recent trial has shown that a new drug called trametinib halved the rate of cancer progression among women diagnosed with low grade ovarian cancer compared to standard therapies. 

The trial, called LOGS in the UK, was of 260 women whose cancer had recurred or was progressive.  It included women with low grade serous peritoneal cancer. The results showed that that the percentage of patients whose cancer reduced was four times higher in the women using trametinib than in those using standard chemotherapy and hormone therapy.

Trametinib is a new MEK inhibitor that disrupts processes within cancer cells and so restricts the cancer’s ability to spread.  It is currently being used successfully to treat the skin cancer melanoma

Trametinib is now viewed by the researchers as being the most effective treatment for relapsed low grade serous ovarian cancer.  However, it is not yet licensed for this use. 

A future trial is being planned to see if using other therapies can get a better response than using chemotherapy.


Watch Latest developments in low grade serous ovarian cancer, an Ovacome webinar with Dr Susana Banerjee

Recorded November 2021



Watch Research update in rare ovarian cancers, an Ovacome webinar with Dr Marcia Hall

Recorded July 2021



Support for you

Ovarian cancer support services    Join our rarer ovarian cancers group


If you would like more information on the sources and references for this page, please call us on 0800 008 7054.

If you would like to discuss anything about ovarian cancer, please phone our support line on 0800 008 7054 Monday to Friday between 10am and 5pm.

Booklet text reviewed by Professor Charlie Gourley, Honorary Consultant in Medical Oncology, University of Edinburgh.

Last updated January 2020

Due for review January 2022


Ovacome aim to provide the best quality information and support. We make every effort to ensure the accuracy and reliability of the information at the time of printing. The information we give is not a substitute for professional medical care. If you suspect you have cancer you should consult your doctor as quickly as possible. Ovacome cannot accept liability for any inaccuracy in linked sources. Rights reserved.

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