Ovarian cancer

Ovarian cancer is when cells grow in an abnormal or uncontrolled way in the ovary, fallopian tube or the peritoneum – the outer covering of the abdominal and pelvic organs.

The ovaries are two organs in the female reproductive system, located on either side of the uterus. The ovaries are mainly made of three types of cells: 

• Epithelial cells which form the outer layer of tissues around the ovary
• Sex cord-stromal cells which form the structural tissue cells in the ovaries 
• Germ cells which form the eggs.  

Ovaries produce eggs and female hormones such as oestrogen and progesterone. 

Cancer Australia estimated that more than 1,700 people were diagnosed with ovarian cancer in Australia in 2023. In advanced disease, ovarian cancer cells can spread to other parts of the body to form secondary cancers, in a process called metastasis. Up to 20% of ovarian cancers have a genetic link, that is they are related to a person having a BRCA1/2, PALB2, RAD51C or BRIP1 gene mutation. 

When you are diagnosed with ovarian cancer, it is important to understand the type of ovarian cancer (or tumour) you have. This helps your doctors know how best to treat the cancer. Knowing the type of cancer can also help determine which type of chemotherapy or immunotherapy will work best.

In terms of inherited risk of cancer, it is important for women to know what kind of ovarian cancer they have so they can learn about their genetic risk and any potential risk for other family members.

This section is designed to answer your questions about ovarian cancer and the inherited cancer risks associated with ovarian cancer. 

How common is ovarian cancer?

The three main types of ovarian cancer are related to which ovarian cells are affected:

• Epithelial cells which form the outer layer of tissues around the ovary
• Sex cord-stromal cells which form the structural tissue cells in the ovaries 
• Germ cells which form the eggs.

Epithelial tumours

Epithelial is the most common type of ovarian cancer and accounts for approximately 90% of all ovarian cancer. 

Epithelial cancer occurs in the surface layer of cells covering the uterus. It is most common in women over the age of 50. Within this category of ovarian cancer, there are subgroups, with serous tumours being the most common. Traditionally, epithelial ovarian cancer is treated with a combination of surgery and chemotherapy. Hormone therapy may also be prescribed if required. 

Another type of epithelial ovarian cancer is called endometrioid, which is the same kind of cancer that can be found in the lining of the uterus. This type of tumour can occasionally be associated with endometriosis, although most women with endometriosis do not have this malignancy.

The third type of epithelial ovarian is called mucinous which makes mucus-like fluid and is believed to develop from the glands around the ovary.

Sex cord-stromal tumours

Sex cord-stromal tumours come from the stroma, which is the supporting structure around the ovary and affect the hormone-producing cells in the ovary. These types of cancers account for approximately 3%-5% of all primary ovarian cancers, and most are diagnosed at an early stage. They can be treated with surgery alone when caught early enough.

The most common type of sex cord-stromal tumours is called a granulosa or theca cell tumour. Sex cord-stromal tumours usually develop in women in their 30s and 40s but can occasionally develop in older women and young girls. 

When a woman has both a mass (growth) and bleeding, doctors consider the possibility of this type of ovarian tumour. A blood test will reveal whether a woman is producing a high level of a substance called inhibin, which in turn indicates a sex cord-stromal tumour.

Germ cell tumours

Germ cell tumours account for about 4% of all primary ovarian cancer diagnoses. These tumours arise in the ovarian cells that develop eggs and tend to develop in younger girls and women in their early 20s. 

Most germ cell ovarian tumours are diagnosed early and treated with surgery. Chemotherapy is not generally necessary unless the cancer is at a later stage.

What are the stages of ovarian cancer?

Ovarian cancer is staged according to the International Federation of Gynaecology and Obstetrics (FIGO) system. There are 4 stages:

Stage I: cancer found in one or both ovaries or in the fallopian tubes.

Stage II: cancer in one or both ovaries or fallopian tubes as well as other organs in the pelvis, such as the uterus, bladder or bowel.

Stage III: cancer in one or both ovaries or fallopian tubes that has spread to the lining of the abdomen (peritoneum) or lymph nodes.

Stage IV: cancer has spread outside the abdomen to other organs such as lungs or liver.

How can I screen for ovarian cancer?

There is no screening test for ovarian cancer, so the best thing you can do is know your body. 

Several risk factors may increase your risk of ovarian cancer and symptoms that can alert you to the presence of ovarian cancer. It is important to familiarise yourself with the risk factors and symptoms to know when something is not normal.

What are the common symptoms of ovarian cancer?

The following symptoms are common of ovarian cancer and usually occur suddenly and persistently get worse over time:

• Abdominal or pelvic pain
• Difficulty eating or filling more quickly than usual
• Loss of appetite
• Sudden or persistent bloating, this might feel like pressure from the inside
• Urinary abnormalities like using the bathroom more frequently or needing to go more urgently than usual
• Abnormal vaginal bleeding or discharge
• Persistent fatigue
• Pain during intercourse.

These symptoms may seem hard to differentiate from other less serious problems, such as digestion issues or a urinary tract infection. If you know your body and what is normal, you can identify when these kinds of symptoms are occurring in an unusual combination or are abnormally persistent.

If any of these symptoms occur in a way that is unusual for you, contact your GP as soon as possible. To learn more about the signs and symptoms of ovarian cancer, visit Ovarian Cancer Australia’s website.

How is ovarian cancer diagnosed?

To assess any persistent symptoms associated with ovarian cancer, GPs have several options to determine if there is evidence of ovarian cancer depending on the age of the patient. 

Ultrasound
A transvaginal ultrasound is minimally invasive and does not include radiation. An ultrasound can be used as an initial screening test if a woman has persistent symptoms. If the ovary looks unusual, then additional assessments will be undertaken.

CA 125 test
For women who are menopausal, CA 125 test can be useful to measure the amount of cancer antigen 125 protein in the blood, which can indicate ovarian cancer. 

In younger women, the CA 125 test is not as reliable, as the blood test marker can be influenced by other factors such as having a period. 

Risk of malignancy index

If the ultrasound and CA 125 test indicate there is something unusual, the risk of malignancy index (RMI) will be used to help plan the patient’s next steps. The RMI is an algorithm which uses the results from the ultrasound, CA 125 test and menopausal status to predict ovarian cancer. 

If you have a family history of ovarian cancer and receive unusual ultrasound and CA 125 test results, you should be referred to a gynae-oncologist to discuss next steps to confirm if cancer is present. 

What are my treatment options?

If you have been diagnosed with ovarian cancer, your doctor will recommend treatment based on:

• the location, type and stage of your cancer 
• your age and general health
• the severity of your symptoms
• if your cancer is related to a particular gene mutation
• if you plan to have children in the future, and 
• your own wishes.

If you have ovarian cancer, you may wish to undertake tumour testing as this could impact your treatment pathway. Learn more about ‘Tumour Testing’ and if this should be considered after your diagnosis

For more information about your treatment plan, team and options click here.

Learn more about the different surgery options available.