The basics
- Guidelines for treating this cancer have been developed by the Gynecology Tumour Group.
- For health professional information on treating this cancer, please see our Cancer Management Guidelines (Epithelial Ovary and Non-epithelial Ovary cancers).
- Patients can view online videos of presentations from the annual Gynecologic Cancer Education Forum.
- The ovaries are two glands in the reproductive system. They are located in the pelvis, one on each side of the uterus.
- They are almond-shaped, measuring about 4 cm (1.5") in length.
- Ovaries produce and release the eggs that are needed for reproduction.
- They are the main source of the hormones, estrogen and progesterone.
- There are three main types of tumours which can occur in the ovaries. They are named for the types of cells that they are made of:
- Epithelial is the most common and comes from the surface cells of the ovaries. This type of cancer mostly affects middle-aged and older individuals. Epithelial ovarian cancer is the cancer referred to by patients and doctors as "ovarian cancer."
- Germ cell tumours are another type of cancer, which may rarely occur in the ovary. These cancers start in the egg-producing cells of the ovary and affect mostly younger people. Surgery can maintain the potential of fertility. They are also very responsive to chemotherapy. These tumours behave and are treated in a similar way to testicular germ cell tumours.
- Sex-cord stromal tumours are also rare. They are not associated with any particular age group.
What causes it and who gets it?
Some of the known risk factors for this cancer are listed below. Not all of the risk factors below may cause this cancer, but they may be contributing factors.
- The exact cause of ovarian cancer is unknown.
- Most cases are not caused by inherited genes.
- Most cases of ovarian cancer occur after age 50.
- Having a family history of cancer (ovarian, breast, uterus, colon and rectum) increases the risk of the disease.
- BRCA1 or BRCA2 gene
- People with a BRCA1 or BRCA2 gene mutation are more at risk for ovarian cancer.
- People of European (Ashkenazi) Jewish ancestry have a higher than average chance of having a BRCA gene mutation.
- There is more information on hereditary cancer and genetic testing from our Hereditary Cancer Program.
- People who have had breast cancer are more likely to get ovarian cancer.
- It is more common in people who did not give birth or had their first child after age 30.
- People who have early menstruation (before age 12) and late menopause (after age 50) have a higher risk.
- Hormonal medicines may raise a person's risk:
- Menopausal hormone replacement therapy (HRT)
- Hormones taken by transgendered / transsexual persons
- Fertility drugs
- A diet with high levels of saturated fat may increase risk.
- Exposure to asbestos seems to increase the risk of ovarian cancer.
- Statistics
NOTE: Available statistics do not have information about the inclusion of transgender and gender diverse participants. Unless specified, it is unknown how these statistics apply to transgender and gender diverse people. Patients are advised to speak with their primary care provider or specialists about their individual considerations and recommendations.
Can I help to prevent it?
Since the causes of ovarian cancer are not understood well, prevention is difficult to discuss with any certainty.
- Birth control medications can reduce risk by up to 50% if used for 5 or more years. However, these medications do have possible side effects and are usually only recommended for the prevention of ovarian cancer in people known to have a hereditary ovarian cancer gene.
- Pregnancy and breast-feeding can also reduce risk.
- If you are at high risk because of a hereditary ovarian cancer gene, a prophylactic oophorectomy may protect against future cancers. This is the surgical removal of both ovaries before any cancer appears. The oopherectomy should also include the removal of the fallopian tubes.
- If you are having a hysterectomy for non-cancer reasons, including the removal of the fallopian tubes during this procedure should reduce your risk.
- Eating a diet high in vegetables can help prevent ovarian cancer.
Screening for this cancer
No effective screening program exists for this cancer yet.
Pap smears are not effective for ovarian cancer screening. They test the cervix, not the ovaries.
There have been trials which tested screening methods based on physical examination, ultrasound imaging, and a biomarker called CA 125. These methods of screening proved unreliable. They produced a high rate of false positives, which means many healthy people would be wrongly diagnosed with ovarian cancer and have unnecessary surgery.
Signs and Symptoms
- Ovarian cancer is difficult to find in its early stages.
- It usually has vague, non-specific symptoms, such as:
- Abdominal discomfort or pain
- Lower abdominal swelling or bloating
- Indigestion, gas, nausea, constipation, diarrhea
- Unusual bleeding (heavy periods or bleeding after menopause)
- Frequent and urgent need to urinate
- Loss of appetite
- Feeling full even after a light meal
- Pain in lower back or legs
- Pain during sex
