A closer look at ovarian cancer screening

Editor's note: May 8 is World Ovarian Cancer Day.

By Mayo Clinic staff

There are well-established screening programs for certain cancers, such as breast, colon and cervical cancer. Screenings include colonoscopies, mammograms, Pap tests and other diagnostic tests, which can help prevent cancers from developing or detect them at an early stage when treatments are more effective.

Because most people are familiar with these screening tests, it's common for women to wonder if they also should be screened for ovarian cancer. The short answer is no. There isn't a universal screening program in place for ovarian cancer.

Many factors determine the effectiveness of a cancer screening program. Some of these factors include how common the cancer is, how well healthcare professionals understand the development of the cancer, how the cancer behaves, what testing options are available and how accessible the affected organ is.

A screening program for ovarian cancer is unlikely to be effective for several reasons. The current testing options often lead to high rates of false-positive and false-negative results. Ovarian cancer also is a relatively rare disease, doesn't predictably develop precancerous cells, and it's difficult to get tissue samples from the ovaries.

How common is ovarian cancer?

Ovarian cancer is a rare disease with about 10 cases occurring for every 100,000 women annually in the U.S. The National Cancer Institute estimates that about 1% of women will develop ovarian cancer during their lifetime.

What tests can help detect ovarian cancer?

The most relevant tools for finding ovarian cancer are imaging tests, such an ultrasound, and tumor markers that can be found in the blood, such as cancer antigen 125, or CA 125.

Ultrasounds are good at identifying cysts or other masses growing on the ovaries. The challenging part is that these masses are quite common, and most are not cancers. While the appearance of an ovarian mass can give some clues about its chance of cancer, it's often difficult to tell the difference between masses that are cancers and those that are not cancers with an ultrasound.

What is CA 125?

CA 125 is a protein in the blood that can be elevated when ovarian cancers are present. However, it also can be elevated with other conditions, such as menstruation, uterine fibroids and endometriosis, leading to false-positive results. Early detection is the goal of a good screening program, but CA 125 can miss a significant number of early-stage ovarian cancers.

Ultrasounds and CA 125 tests have been evaluated as potential screening tools. Unfortunately, they could not consistently detect ovarian cancer early enough to improve patient outcomes and have a high false-positive result rate, increasing the risk of unnecessary stress, anxiety and surgery.

However, there are some situations in which these tests are used to screen for ovarian cancer, such as in patients with genetic mutations that put them at high risk for cancer and in certain patients previously treated for ovarian cancer.

What are the symptoms of ovarian cancer?

Symptoms of ovarian cancer are often vague and also can occur with several other common conditions.

Common symptoms of ovarian cancer include:

• Abdominal bloating
• Change in bowel function
• Fatigue
• Feeling full more quickly when eating
• Pelvic pain
• Unintentional weight loss

While experiencing one or more of these symptoms is common and does not mean you have ovarian cancer, discussing them with your healthcare team is a good idea. — Brad Nitzsche, M.D., is an OB-GYN with Mayo Clinic Health System in La Crosse, Wisconsin.

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Learn more about ovarian cancer and find a clinical trial at Mayo Clinic.

Join the Gynecologic Cancers Support Group on Mayo Clinic Connect, an online community moderated by Mayo Clinic for patients and caregivers.

Also, read these articles:

• Ovarian cancer: New treatments and research
• Harnessing the immune system to fight ovarian cancer
• Life after ovarian cancer: Coping with side effects, fear of recurrence, and finding support
• New surgical method for ovarian cancer lights up lesions

A version of this article was originally published on the Mayo Clinic Health System blog.