DEAR MAYO CLINIC: I've heard that ovarian cancer is hard to detect. Can you tell me more about the symptoms and if there are any screenings?
ANSWER: Ovarian cancer is relatively rare. However, it's often fatal in later stages of the disease. The cancer begins in the ovaries and spreads to the abdomen and pelvis if it isn't diagnosed and treated early. It primarily affects older women; about half of those diagnosed are age 63 or older.
Here are some statistics for ovarian cancer:
- In the U.S., it's the second-most common female reproductive organ cancer after uterine cancer.
- The risk of getting ovarian cancer in a woman's lifetime is about 1 in 91. Nearly 21,000 women are diagnosed with ovarian cancer every year.
- Roughly 250 women die of this disease each week.
- Even though uterine cancer is 3 times more common, the number of women dying from ovarian cancer each year is almost the same (around 13,000 deaths). This death rate points to the difficulty of detecting this aggressive form of cancer.
Recognizing the symptoms
As with any cancer, early diagnosis of ovarian cancer can improve the chances of successful treatment. If you are experiencing these symptoms, see your healthcare clinician:
- Quickly feeling full when eating
- Abdominal bloating or swelling
- Weight loss
- Frequent need to urinate
- Changes in bowel habits
- Discomfort in the pelvic area
Understanding the risk factors
A family history of ovarian cancer and personal factors can increase your risk of ovarian cancer, including:
- Obesity
- Hormone replacement therapy
- Personal history of cancer or endometriosis
- Increasing age or reproductive history and infertility
Some factors that can decrease your risk include:
- Oral contraceptive use
- Pregnancy and breastfeeding
- Removal of the ovaries and fallopian tubes
- Hysterectomy or tubal ligation
Detecting ovarian cancer
There are well-established screening programs for certain cancers, such as breast, colon and cervical cancer, which can help prevent these cancers from developing. Screening also can detect cancer at an early stage when treatments are more effective.
Unfortunately, there isn't a universal screening program for ovarian cancer. That's because testing options often lead to high rates of false-positive and false-negative results. Also, ovarian cancer doesn't predictably develop precancerous cells, and it's difficult to get tissue samples from the ovaries.
The most relevant tools for finding ovarian cancer are imaging tests, such as 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 being cancerous, with an ultrasound, it's often difficult to tell the difference between masses that are cancers and those that aren't.
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 can't consistently detect ovarian cancer early enough to improve patient outcomes. They also have a high false-positive result rate, increasing the risk of unnecessary stress, anxiety and surgery.
However, in some situations, 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 patients previously treated for ovarian cancer.
By Sandeep Basu, M.D., Breast Cancer Care, Hematology and Oncology, Mayo Clinic Health System, Eau Claire, Wisconsin