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In Canada, 1 in 70 women will develop ovarian cancer in their lifetime. More Canadian women die from ovarian cancer than all other gynecologic cancers combined, including cervical and endometrial (uterine) cancers.

Ovarian cancer remains difficult to detect. Although the 5-year survival rate is approximately 70% to 100% when ovarian cancer is detected in its earliest stages, 70% of cases are diagnosed at an advanced stage where 5-year survival is 10% to 20% at best.

Currently, no reliable screening test exists for ovarian cancer.

The causes of ovarian cancer are not known. Some factors that may increase the risk of ovarian cancer include the following:

• aged 50 years and above
• family history of ovarian cancer or breast cancer
• having had cancer before (e.g., breast, uterine, colon)
• inherited gene mutation (e.g., in people of Ashkenazi Jewish descent)
• having never been pregnant
• obesity
• use of hormone replacement therapy for more than 5 years, especially if using estrogen only

Some people with ovarian cancer do not have these risk factors, and others people who have these risk factors do not go on to have ovarian cancer.

Other risk factors such as early onset of menstruation or late menopause are not well proven.

Fertility treatments that include stimulation of ovulation may also increase the risk of ovarian cancer, but this is also not well proven and difficult to assess for any individual woman.

Ovarian cancer often goes undiagnosed until it reaches an advanced stage, primarily because symptoms are not common in the early stages and when they do occur, the symptoms may be general and non-specific.

Symptoms of ovarian cancer can include:

• pelvic pain
• bloating or increase in abdominal size
• gas
• abdominal discomfort
• fatigue
• abnormal vaginal bleeding
• backache
• loss of appetite
• weight loss or gain
• frequent urination
• changes in bowel movements (e.g., constipation)
• pain during sexual intercourse
• feeling full earlier than normal
• upset stomach
• indigestion

These symptoms appear commonly and may be normal or can be associated with a variety of other conditions, but if they persist, talk to your doctor.

Unfortunately, no reliable screening test exists for ovarian cancer, and approximately 70% of ovarian cancers are diagnosed in advanced stages.

If ovarian cancer is suspected, the following tests may be performed:

• physical examination, including a pelvic and abdomen exam
• ultrasound - transvaginal/pelvic and abdominal - a test used to create a "picture" of the pelvic and abdominal contents
• CT scans (computed tomography), or MRI (magnetic resonance imaging), or bone scans to see if the cancer has spread
• blood tests to check your blood cells, organ function (e.g., kidney, liver), and to test for a tumour marker called Cancer Antigen 125 (CA125)

A CA125 test uses an antibody to detect a chemical produced at higher levels by ovarian cancer cells. However, it is only elevated in approximately 50% of cases of early-stage ovarian cancer and can also be present in noncancerous conditions, especially in pre-menopausal women. In instances where ovarian cancer is suspected, the CA125 will assist in the diagnosis in combination with other tests.

If the results of these tests suggest ovarian cancer, additional tests will be required to confirm the diagnosis. However, it is important to keep in mind that not all ovarian tumours are cancerous - many turn out to be benign (noncancerous).

To confirm a diagnosis of ovarian cancer, cancer tissue or cancer cells must be obtained by one of the following procedures:

• taking a sample of abdominal fluid if it is present: This is usually a simple procedure done with local anaesthetic. Pathologists then examine the fluid for cancer cells.
• obtaining a biopsy of the tumour: This is a fairly simple procedure and is done under local anaesthetic, usually with CT or ultrasound guidance.
• undergoing a laparotomy: This is a surgical exploration of the abdomen to help confirm a diagnosis and, if need be, to also remove all evidence of the cancer as the first step in treatment.

If ovarian cancer is confirmed, the above tests also help determine the stage of ovarian cancer. Ovarian cancer has the following stages:

• stage 1: confined to one or both ovaries
• stage 2: spread to other areas in the pelvis (e.g., fallopian tubes, uterus)
• stage 3: spread to the organs or lymph nodes within the abdomen
• stage 4: spread to organs beyond the abdomen

From a biopsy, the grade of the tumour can be determined. The grade describes how quickly the cancer is growing. Ovarian cancer has three grades:

• grade 1: growing slowly and less likely to spread
• grade 2: growing at a moderate rate
• grade 3: fast growing and more likely to spread

It may not be possible to prevent ovarian cancer. Ovarian cancer may be related to ovulation and the menstrual cycle. Using the birth control pill, which suppresses ovulation, has been shown to decrease the risk of ovarian cancer, although the reason for this is unclear.

Women who have a hereditary ovarian cancer risk may choose to surgically remove (prophylactic surgery) the ovaries, fallopian tubes, and uterus before cancer occurs. Tubal ligation has also been shown to decrease the risk of ovarian cancer for women with this genetic profile. While prophylactic surgery offers what is thought to be the greatest reduction in risk, it may not completely eliminate it.

Treatment of ovarian cancer usually involves a combination of surgery, chemotherapy, and sometimes, radiation. During a laparotomy, the surgeon may remove the ovaries, fallopian tubes, some of the fatty tissue covering the abdomen, uterus, cervix, and lymph nodes, and any other areas to which the cancer has spread.

With early-stage ovarian cancer, women who wish to still be able to have children may choose to have only one fallopian tube and ovary removed. However, these women will be advised that there may still be a chance that cancer appears in the other ovary, the fallopian tube, or the uterus.

Chemotherapy with anticancer medications usually involves taking a combination of medications. A complete response to the treatment (remission) occurs when no detectable cancer is found either through examination by an oncologist or through tests such as an ultrasound or CT. Recurrence rates of ovarian cancer can be as high as 70%.

Certain individuals may also be candidates for radiation therapy. Biotherapy and immunotherapy treatments are currently under study. Women with ovarian cancer should also talk to their doctor about available clinical trials.