Ovarian Cancer

What is ovarian cancer?

Ovarian cancer is the uncontrolled growth of cells within a woman's ovary. The ovaries are reproductive glands that are located on either side of the uterus in the lower abdomen. They have two main functions: to produce estrogen and progesterone, hormones that are responsible for the development of secondary sexual characteristics and regulation of the reproductive cycle; and to develop and release an egg into the fallopian tube once a month during childbearing years.

Ovarian cancer is the fifth most common cause of cancer death in women. According to the American Cancer Society, the life-time risk of developing ovarian cancer is about 1/75. They estimate that about 22,280 new cases are diagnosed each year in the United States and about 14,240 women die of it. Invasive ovarian cancer is a more common cause of death than the more prevalent and easily detected cancers of the uterus and cervix. Currently, about 20% of ovarian cancers are found in the early stages before they have spread outside the ovary.

Ovarian tumors can be benign or malignant. It is not usually possible to tell whether a tumor is cancerous until the ovary has been biopsied or removed or the cancer has spread to other parts of the body. Three types of tumors are seen:

Epithelial tumors (majority of ovarian tumors) – begin in the epithelial cells covering the outside of the ovaries
Germ cell tumors (less than 2% of all ovarian tumors) – occur in the egg-producing cells and are more often seen in younger women
Stromal tumors (about 1% of all ovarian tumors) – derive from connective tissues of the ovary that produce estrogen and progesterone

While benign tumors do not metastasize, cancerous ovarian tumors will spread if left undiagnosed and untreated – first throughout the ovary, then to the uterus, bladder, rectum, and the lining of the abdomen. Eventually, cancerous cells will reach the lymph nodes and spread throughout the body.

About Ovarian Cancer

Risk Factors

The main risk factor for ovarian cancer is a positive family history. A history of ovarian cancer on either the mother's or father's side of the family can increase a woman's risk. According to the American Cancer Society, about 5% to 10% of ovarian cancers develop from an inherited tendency.

Mutations in the BRCA1 and BRCA2 genes are associated with a significantly increased lifetime risk of developing ovarian cancer. For those with BRCA1, the risk is estimated to be 35-70% and for BRCA2 it is 10-30%. Women without these mutations have a lifetime risk of about 2%.

The prevalence of ovarian cancer is low in young women (younger than 40) but increases with age, with half the ovarian cancers found in women 63 years of age or older. Most ovarian cancers develop after menopause. Ovarian cancers are more common in Caucasian women than in African American women.

The risk of developing ovarian cancer is increased in women with a personal history of breast cancer and somewhat increased in women who have not had children, are taking fertility drugs, are obese during early adulthood, and perhaps also in those who take hormone replacement therapy or are on fertility drugs. Slightly decreased risks may be associated with women having a tubal ligation (tubes tied), taking oral contraceptives, having children, breast feeding, and being on a low-fat diet.
Signs and Symptoms
The primary reasons ovarian cancers go undetected are that there is no reliable screening test and the symptoms are subtle and fairly non-specific. They may include:

Abdominal discomfort, pressure, bloating, or swelling

Urinary urgency and/or change in bowel habits

Pelvic pain/discomfort

Loss of appetite, indigestion, gas or nausea
Tests
Currently, there is no specific screening test for ovarian cancer. In 2012, the U.S. Preventive Services Task Force (USPSTF) reaffirmed a 2008 recommendation against screening women for ovarian cancer. This recommendation applies to asymptomatic women but not to women at a high risk of developing ovarian cancer, such as those with a genetic mutation (e.g., BRCA mutation).

The need for a reliable method for early detection of ovarian cancer among asymptomatic women continues to drive ongoing research. Molecular (gene) tests and multimarker approaches are being explored to improve early detection of ovarian cancers. For example, the OVA-1 blood test, which measures levels of five proteins, is used to categorize tumors in ovarian cancer patients as low or high risk. In the meantime, regular physicals, pelvic exams, and an awareness of family history and symptoms are important.

Laboratory Tests

CA-125 (Cancer antigen 125) – this is the main laboratory test used to detect and monitor this condition in symptomatic women, even though this tumor marker is not recommended for screening.

HE4 (Human epididymis protein 4) – a relatively new tumor marker that shows promise is; it is used to monitor epithelial ovarian cancer in treated patients.

BRCA-1 and BRCA-2 – genetic tests that can determine if a woman is at high risk of developing ovarian cancer, but these tests are not used for diagnosis or monitoring.

Other tests that may be ordered to help detect and monitor different types of ovarian tumors include:

Epithelial tumors
Carcinoembryonic antigen (CEA) – less specific and sensitive than CA-125; not recommended for routine use

Germ cell tumors
Alpha-fetoprotein (AFP)

Human chorionic gonadotropin (hCG)

Lactate dehydrogenase (LD)

Stromal tumors
Inhibin

Non-laboratory Tests

Non-laboratory tests that are used to evaluate abnormalities include:

Ultrasound (pelvic and/or transvaginal) – uses sound waves to create a picture of the uterus and ovaries; it can help determine whether an ovarian growth is likely to be a cancer or a fluid-filled cyst.

CT scan (computerized tomography)

X-ray of the gastrointestinal tract

MRI (magnetic resonance imaging)

It is important to have regular checkups and to consult with a healthcare practitioner if symptoms develop. Symptoms associated with ovarian cancer are subtle and non-specific, and there are many non-cancerous conditions that can cause similar symptoms.
Treatment
When abnormalities are found and ovarian cancer is suspected, a surgical biopsy is required to confirm the diagnosis. If cancer is found, surgery to remove the cancerous tissue is performed (oophorectomy). Depending on the stage of the disease, additional tissues may have to be removed. One of four stages of cancer is identified depending on the spread of the tumor. They are:

Stage 1 – cancer is confined to one or both ovaries (about 20% of ovarian cancers diagnosed with best prognostic outcomes)

Stage 2 – cancer has spread to the uterus and/or fallopian tubes

Stage 3 – cancer has spread to the abdomen lining or surrounding lymph nodes (most common stage seen at time of diagnosis)

Stage 4 – cancer has spread to other organs beyond the abdomen

Follow-up treatment usually involves chemotherapy, hormone therapy, targeted therapy, sometimes radiation treatments, and monitoring of CA-125, AFP, or hCG for response to treatment and recurrence.

Ovarian cancer treatment is constantly evolving. New drugs, immunotherapies, gene therapies, and bone marrow transplants are being studied for their effectiveness. A woman's healthcare provider and/or cancer team can help determine the treatment course that is right for her.