Basics of how, what and when of ovarian cancer

By John Roberts

I’ve had some questions recently about ovarian cancer so I’ll try and tackle this complex subject. This cancer is frightening because it often has very few signs or symptoms before it becomes very advanced. Recent statistics show about 20,000 women are diagnosed and about 15,000 die from ovarian cancer each year. It accounts for three percent of all female cancers. It is the eighth leading cause of female cancer and the fifth leading cause of cancer deaths in women. Less than half of women will survive five years after their diagnosis.

The chance of developing ovarian cancer increases with age and peaks in the late 70s. The average risk of developing it is about 1.6 percent. The good news is the incidence has gone down about one percent a year since 1987.

Women at increased risk include those who take estrogen, are obese, or have a family history of breast or ovarian cancer (especially those who test positive for the BRCA1 or BRCA2 genes). Women with one first-degree relative (mother or sister) with ovarian cancer have an increased risk of about 4 to 5 percent while those with two first-degree relatives have about a 7 percent risk.

Ovarian cancer seems to be linked to the number of times a woman ovulates. Women who have been pregnant have a 50 percent reduction in risk since they ovulate less often. Those who take birth control pills for an extended period also have lower risk. Women who have had a tubal ligation or a hysterectomy may also have lower risk.

Signs and symptoms of ovarian cancer may be quite subtle or absent entirely. The most common sign is enlargement of the abdomen due to excess fluid. Some women may experience any combination of bloating, pelvic or abdominal pain. Decreased appetite or a feeling of getting full quickly has been described. A strong urge to urinate or urinary frequency may be present as well as a change in bowel habits.

Like most cancers, early diagnosis of ovarian cancer leads to improved survival. It would be nice to have screening tests available to help identify women at earlier stages of the disease. Unfortunately, routine screening of low-risk, asymptomatic women is not recommended because there are no useful screening tests available.

The disease is occasionally detected on routine pelvic exam, often when it is in an advanced stage. Women who are at high risk for ovarian cancer (such as those with a strong family history) or who have persistent, unexplained pelvic or abdominal symptoms, may benefit from a combination of pelvic examination, pelvic ultrasound and a blood test called CA-125.

The CA-125 blood test is often mentioned in social media posts as a screening tool for ovarian cancer. Some readers may have even received an e-mail touting the benefits of having a yearly CA-125 blood test to screen for ovarian cancer. Various versions of this e-mail have been circulating since 1998. The message indicates that if you don’t get the test done you may be putting your life in danger. It also intimates that the medical community and insurance companies are withholding the test from women (apparently because doctors like to see their patients suffer and insurance companies prefer not to detect an illness early when it’s less expensive to treat).

While the CA-125 test is useful for following women with known ovarian cancer in order to gauge their response to treatment, the utility of the test as a screening tool is very poor. Ongoing studies continue to confirm this.

The test is not very sensitive since it’s only elevated in about half of women with ovarian cancer and it frequently doesn’t become elevated until the cancer has already spread. In other words, a negative test does not mean a woman doesn’t have ovarian cancer.

The test is also very non-specific. It can be elevated for a number of reasons including normal menses, endometriosis, pregnancy and uterine fibroids (benign tumors of the uterus). It can also be elevated with pancreatitis, appendicitis and other cancers such as breast, lung and colon.

Probably the biggest problem with the test is the high rate of false positives (the test is positive but the woman has no problem). This can lead to added expense and wild goose chases that may include additional testing and perhaps surgery that can put women at risk for complications from those procedures.  Finally, screening with CA-125 has never been shown to improve survival from ovarian cancer.

So, when should a woman be concerned? If she has any of the symptoms mentioned above for more than a few weeks, she should consult her physician and have a pelvic examination. Her physician may recommend additional testing based on her overall risk and physical findings at her visit.

As an aside, Consumer Reports published an absolutely stellar article on cancer screening in the March 2013 issue. I highly recommend that all our readers take the time to find a copy and read it.