What is it?
Receiving a diagnosis of ovarian cancer is difficult and life changing. Fortunately, medical advances have made treatments more effective. Women diagnosed in the earliest stages have a five-year survival rate of nearly 93 percent.
Until recently, ovarian cancer was known as a "silent killer" because it usually wasn't found until it had spread to other areas of your body. But new evidence shows that most women may have symptoms even in the early stages, and awareness of symptoms may hopefully lead to earlier detection.
Early detection is important; still, only about 20 percent of ovarian cancers are found before tumor growth has spread beyond the ovaries. Your chance of surviving ovarian cancer is better if the cancer is found early.
Symptoms of ovarian cancer are nonspecific and mimic those of many other more common conditions, including digestive and bladder disorders. A woman with ovarian cancer may be diagnosed with another condition before finally learning she has cancer. Common misdiagnoses include irritable bowel syndrome, stress and depression.
The key seems to be persistent or worsening signs and symptoms. With most digestive disorders, symptoms tend to come and go, or they occur in certain situations or after eating certain foods. With ovarian cancer, there's typically little fluctuation — symptoms are constant and gradually worsen.
Recent studies have shown that women with ovarian cancer are more likely than are other women to consistently experience the following symptoms:
- Abdominal pressure, fullness, swelling or bloating
- Urinary urgency
- Pelvic discomfort or pain
Additional signs and symptoms that women with ovarian cancer may experience include:
- Persistent indigestion, gas or nausea
- Unexplained changes in bowel habits, such as constipation
- Changes in bladder habits, including a frequent need to urinate
- Loss of appetite or quickly feeling full
- Increased abdominal girth or clothes fitting tighter around your waist
- Pain during intercourse (dyspareunia)
- A persistent lack of energy
- Low back pain
- Changes in menstruation
Women have two ovaries, one on either side of the uterus. The ovaries — each about the size of an almond — produce eggs (ova) as well as the female sex hormones estrogen and progesterone. An ovarian tumor is a growth of abnormal cells that may be either noncancerous (benign) or cancerous (malignant). Although benign tumors are made up of abnormal cells, these cells don't spread to other body tissues (metastasize). Ovarian cancer cells metastasize in one of two ways. Generally, they spread directly to adjacent tissue or organs in the pelvis and abdomen. They can also spread through your bloodstream or lymph channels to other parts of your body.
Three basic types of ovarian tumors exist, designated by where they form in the ovary. They include:
- Epithelial tumours. About 85 to 90 percent of ovarian cancers develop in the epithelium, the thin layer of tissue that covers the ovaries.
- Germ cell tumours. These tumours occur in the egg-producing cells of the ovary and generally occur in younger women.
- Stromal tumours. These tumours develop in the oestrogen- and progesterone-producing tissue that holds the ovary together.
The exact cause of ovarian cancer remains unknown. Some researchers believe it has to do with the tissue-repair process that follows the monthly release of an egg through a tiny tear in an ovarian follicle (ovulation) during a woman's reproductive years. The formation and division of new cells at the rupture site may set up a situation in which genetic errors occur. Others propose that the increased hormone levels before and during ovulation may stimulate the growth of abnormal cells.
Certain factors may increase your risk of ovarian cancer. Having one or more of these risk factors doesn't mean that you're sure to develop ovarian cancer, but your risk may be higher than that of the average woman. These risk factors include:
- Inherited gene mutations. While the vast majority of women who develop ovarian cancer don't have an inherited gene mutation, the most significant risk factor for ovarian cancer is having an inherited mutation in one of two genes called breast cancer gene 1 (BRCA1) and breast cancer gene 2 (BRCA2). These genes were originally identified in families with multiple cases of breast cancer, which is how they got their names, but people with these mutations also have a significantly increased risk of ovarian cancer. Women with the BRCA1 mutation have a 35 to 70 percent higher risk of ovarian cancer than do women without this mutation, and for women with a BRCA2 mutation, the risk is between 10 and 30 percent higher. For most women, the overall lifetime risk is about 1.5 percent, according to the ACS. You're at particularly high risk of carrying these types of mutations if you're of Ashkenazi Jewish descent. Another known genetic link involves an inherited syndrome called hereditary nonpolyposis colorectal cancer (HNPCC). Women in HNPCC families are at increased risk of cancers of the uterine lining (endometrium), colon, ovary and stomach. Risk of ovarian cancer associated with HNPCC is lower than is that of ovarian cancer associated with BRCA mutations.
- Family history. Sometimes, ovarian cancer occurs in more than one family member but isn't the result of any known inherited gene alteration. Having a family history of ovarian cancer increases your risk of the disease by 10 to 15 percent, according to the ACS.
- A history of breast cancer. If you've been diagnosed with breast cancer, your risk of ovarian cancer also is elevated.
- Age. Ovarian cancer most often develops after menopause. Your risk of ovarian cancer increases with age through your late 70s. Although most cases of ovarian cancer are diagnosed in postmenopausal women, the disease also occurs in premenopausal women.
- Childbearing status. Women who have had at least one pregnancy appear to have a lower risk of developing ovarian cancer. Similarly, the use of oral contraceptives appears to offer some protection against ovarian cancer.
- Infertility. If you've had trouble conceiving, you may be at increased risk. Although the link is poorly understood, studies indicate that infertility increases the risk of ovarian cancer, even without use of fertility drugs. Some research has also suggested that taking fertility drugs, such as clomiphene (Clomid), for more than one year may increase your risk of ovarian cancer, but it's not clear whether the increased risk actually comes from the drug or from the infertility.
- Hormone replacement therapy (HRT). Findings about the possible link between postmenopausal use of the hormones estrogen and progestin and risk of ovarian cancer have been inconsistent. However, a recent analysis of numerous studies, published in the journal Gynecologic Oncology, confirmed an association between HRT and ovarian cancer, particularly for those who took estrogen only. The risk appears to be highest among women who took HRT for more than five years.
- Obesity. Women who are obese have a greater risk of ovarian cancer. Obesity may also be linked to more-aggressive ovarian cancers, which can result in a shorter time to disease relapse and a decrease in the overall survival rate.
- Male hormones. The medication danazol, a male hormone (androgen), is used to treat endometriosis and has been linked to an increased risk of ovarian cancer. More study is needed to further define this association.
Because no standardised screening test exists to reliably detect ovarian cancer, doctors don't recommend screening for this type of cancer for most women. If you have a high risk of ovarian cancer, you need to have a careful discussion with your doctor about the risks and benefits of undergoing screening tests. While you may wonder what harm could come from a screening test, such tests can lead to unnecessary operations or other procedures that have significant side effects. Along with the potential complications of surgery, unnecessary procedures can cause anxiety, loss of work and substantial financial costs.
Several screening tests for ovarian cancer are commercially available, but none has been proved to lead to an early diagnosis that improves outcome. Additionally, these tests may lead to false-positives, which may subject women to unnecessary procedures and worry.
If your doctor suspects your symptoms suggest the presence of ovarian cancer, he or she may recommend one or more of the following tests to diagnose ovarian cancer:
- Pelvic examination. Your doctor examines your vagina, uterus, rectum and pelvis, including your ovaries, for masses or growths. If you've had your uterus removed (hysterectomy) but still have your ovaries, continue getting regular pelvic exams.
- Ultrasound. Ultrasound uses high-frequency sound waves to produce images of the inside of the body. Pelvic ultrasound provides a safe, noninvasive way to evaluate the size, shape and configuration of the ovaries. If a mass is found, however, ultrasound can't reliably differentiate a cancerous growth from one that's not cancerous. Ultrasound can also detect fluid in your abdominal cavity (ascites), a possible sign of ovarian cancer. Because ascites develops in many conditions other than ovarian cancer, however, its presence necessitates more testing.
- CA 125 blood test. CA 125 is a protein made by your body in response to many different conditions. Many women with ovarian cancer have abnormally high levels of CA 125 in their blood. However, a number of noncancerous conditions also cause elevated CA 125 levels, and many women with early-stage ovarian cancer have normal CA 125 levels. Because of this lack of specificity, the CA 125 test isn't used for routine screening in average-risk women and is of uncertain benefit in high-risk women.
Other diagnostic tests may include computerized tomography (CT) and magnetic resonance imaging (MRI), which both provide detailed, cross-sectional images of the inside of your body. Your doctor may also order a chest X-ray to determine if cancer has spread to the lungs or to the pleural space surrounding the lungs, where fluid can accumulate. If fluid is present, a needle may be inserted into the space to remove it. The fluid is then checked in the laboratory for cancer cells.
Confirming the diagnosis
If these tests suggest ovarian cancer, you'll need an operation to confirm the diagnosis. In a surgical procedure called laparotomy, a gynecologic oncologist makes an incision in your abdomen and explores your abdominal cavity to determine whether cancer is present. The surgeon may collect samples of abdominal fluid and remove an ovary for examination by a pathologist.
In certain cases, a less invasive surgical procedure called laparoscopy may be used. Laparoscopy requires only a couple of small incisions, through which a lighted instrument is inserted, along with small tools used to perform the surgery. Laparoscopy may be used if a surgeon wants to remove a tissue mass to determine whether it's cancerous before proceeding with a more invasive operation.
If ovarian cancer is confirmed, the surgeon and pathologist identify the type of tumor and determine whether the cancer has spread. This will help determine the stage of the disease. The surgeon usually will then need to extend the incision so that he or she can perform a more extensive operation to remove as much cancer as possible. It's important that this type of surgery be performed by a doctor specifically trained to treat gynecologic cancers.
Before you have a diagnostic operation, talk with your doctor about what your treatment options will be if you turn out to have a noncancerous abnormality on your ovary. If you're near or past menopause, your doctor may recommend removing both of your ovaries to decrease your risk of ovarian cancer.
Staging your cancer
Ovarian cancer is classified in stages I through IV, with stage I being the earliest and stage IV, the most advanced. Staging is determined at the time of surgical evaluation of the disease:
- Stage I. Ovarian cancer is confined to one or both ovaries.
- Stage II. Ovarian cancer has spread to other locations in the pelvis, such as the uterus or fallopian tubes.
- Stage III. Ovarian cancer has spread to the lining of the abdomen (peritoneum) or to the lymph nodes within the abdomen. This is the most common stage of disease identified at the time of diagnosis.
- Stage IV. Ovarian cancer has spread to organs beyond the abdomen.