What is ovarian cancer?
Ovarian cancer is any cancerous growth that may occur in different parts of the ovary or Fallopian tubes. The majority of ovarian cancers arise from the skin of the outer lining of the ovary.
It is most common in women who have already been through the menopause (usually over the age of 60), although it can affect women of any age.
There are many types of ovarian cancer, with epithelial ovarian cancer being by far the most common form. Germ cell and stromal ovarian cancers are much less common. Ovarian cancer can also result from a cancer somewhere else in the body that has spread (metastatic cancer):
- Epithelial ovarian cancer (epithelial ovarian tumours) – derived from cells on the surface of the ovary
- Germ cell ovarian cancer (germ cell ovarian tumours) – derived from the egg-producing cells within the body of the ovary. This rare type of cancer more commonly affects teenagers.
- Stromal ovarian cancer (sex cord stromal tumours) – develops within the cells that hold the ovaries together.
- Cancers from other organs in the body can spread to the ovaries – metastatic cancers – a metastatic cancer is one that spreads from where it first arose as a primary tumour to other locations in the body.
How does it develop?
Cancer begins with a change (mutation) in the structure of the DNA in cells, which can affect how they grow. This means that cells grow and reproduce uncontrollably, producing a lump of tissue called a tumour.
In ovarian cancer, cells in the ovary start to change and grow abnormally. If the cancer isn’t identified at an early stage, it can spread to the abdomen and pelvis.
Key signs and symptoms
If diagnosed at an early stage, the outcome for ovarian cancer is typically relatively positive. However, because some of the symptoms of ovarian cancer are often the same as symptoms of other less serious conditions, such as irritable bowel syndrome (IBS) or pre-menstrual syndrome (PMS), it can be difficult to recognise the symptoms particularly in its early stages – which is why most women are not diagnosed until the disease has spread.
However, three main symptoms are more frequent in women diagnosed with ovarian cancer. They are:
- increased abdominal size and persistent bloating (not bloating that comes and goes)
- persistent pelvic and abdominal pain
- difficulty eating and feeling full quickly, or feeling nauseous
Other symptoms, such as back pain, needing to pass urine more frequently than usual, and pain during sex may be the result of other conditions in the pelvic area. However, it is most likely that these symptoms are not ovarian cancer but may be present in some women with the disease.
We don’t know exactly what causes epithelial ovarian cancer. But some factors may increase the risk.
Many factors seem to be related to how the ovaries work. When one of your ovaries produces an egg (ovulation), the surface layer of the ovary bursts to release the egg. The surface cells then divide to repair the damage. The more eggs your ovaries produce during your life time, the more cells need to divide and the higher the chance that damage will occur that could lead to cancer.
The risk of ovarian cancer may be increased by the following factors:
Your risk of ovarian cancer increases with age, with most cases occurring after the menopause. More than 8 out of 10 cases of ovarian cancer occur in women who are over 50 years of age.
If you have two or more close relatives (mother, sister or daughter) who developed ovarian cancer or breast cancer, your risk of also developing the condition may be increased.
If your relatives developed cancer before the age of 50, it’s more likely it was the result of an inherited faulty gene. BRCA1 and BRCA2 are faulty genes that are linked to ovarian cancer. They’re also known to increase the risk of breast cancer.
You may be at a high risk of having a faulty gene if you have:
- One relative diagnosed with ovarian cancer at any age and at least two close relatives with breast cancer whose average age is under 60; or alternatively at least one close relative with breast cancer under the age of 50. All of these relatives should be on the same side of your family (either your mother’s OR father’s side)
- Two relatives from the same side of the family diagnosed with ovarian cancer at any age
If you’re at a higher risk of having a faulty gene, your GP can refer you for tests to check for faulty BRCA1 and BRCA2 genes.
Ovulation and fertility
Every time an egg is released into the reproductive system, the surface of the ovary breaks to let it out. The surface of the ovary is damaged during this process and needs to be repaired. Each time this happens, there’s a greater chance of abnormal cell growth during the repair.
This may be why the risk of ovarian cancer decreases if you take the contraceptive pill, or have multiple pregnancies or periods of breastfeeding as eggs aren’t released during this period.
This condition may also increase your risk of peritoneal cancer (a rare type of ovarian cancer). In endometriosis, the cells that usually line the womb grow elsewhere in the body.
How is it diagnosed?
Your GP will gently feel your tummy (abdomen) and ask you about your symptoms, general health and whether there’s a history of ovarian or breast cancer in your family.
They may carry out an internal examination and may take a blood sample or refer you for an ultrasound scan. If needed, you may also be referred to a gynaecological oncologist.
In 2015, the National Institute for Health and Care Excellence (NICE) published guidelines to help GPs recognise the signs and symptoms of ovarian cancer and refer people for the right tests faster. To find out if you should be referred for further tests for suspected ovarian cancer, read the NICE 2015 guidelines on Suspected Cancer: Recognition and Referral.
Blood test (CA125)
You may have a blood test to look for a protein called CA125 in your blood. CA125 is produced by some ovarian cancer cells. A very high level of CA125 may indicate that you have ovarian cancer.
CA125 isn’t specific to ovarian cancer and it can be raised in conditions including endometriosis and pelvic inflammatory disease, so a raised CA125 level doesn’t definitely mean you have ovarian cancer. However, around half of all women with early stage ovarian cancer have a raised level of CA125 in their blood. If your CA125 level is raised, you’ll be referred for an ultrasound scan.
An ultrasound scan uses high-frequency sound waves to create an image of your ovaries. You may have an internal ultrasound where the ultrasound probe is inserted into your vagina, or you may have an external ultrasound, where the probe touches (or is rolled over / strokes the skin of your abdomen).
The image produced can show the size and texture of your ovaries, plus any cysts or other swellings that are present.
If you’ve been diagnosed with ovarian cancer, you may have further tests to see how large the cancer is and if it’s spread. This is called staging.
Other tests you may have include:
- a CT scan
- a biopsy – small tissue samples taken from your ovaries for testing
The CT scan helps your doctors to decide on the best kind of treatment for your condition. However, it’s important to remember that the stage of your ovarian cancer alone cannot predict how your condition will progress.
Most women with ovarian cancer will be considered for surgery.
Your doctor will discuss what will happen during surgery. It will probably involve removing:
- both ovaries and the fallopian tubes (a bilateral salpingo-oophorectomy)
- the womb (a total abdominal hysterectomy)
The surgeon may also remove samples of nearby tissue, to find out whether the cancer has spread. If it has spread, the surgeon will try to remove as much of it as possible. This is known as “debulking surgery”.