New Strategy Aims to Diagnose Ovarian Cancer EarlierAug 26, 2013
Researchers from the University of Texas MD Anderson Cancer Center and colleagues have found promising results from a study intended to find a way to accurately detect ovarian cancer in its early stages. Early detection has the potential to save many women’s lives, because survival rates are much higher when the disease is caught early. But currently, there is no proven strategy for early detection, and symptoms of the disease are the same as those of other, less serious conditions. Therefore, most ovarian cancer is diagnosed when it’s already advanced and survival rates are lower.
Part of the challenge of developing a screening strategy is the need for a test that is very accurate. Diagnosing ovarian cancer requires surgery to remove the ovaries. A screening test with as few false positives as possible would reduce the number of unnecessary operations.
According to Debbie Saslow, PhD, American Cancer Society director of breast and gynecologic cancer, “This is extremely important for ovarian cancer screening because we don’t have an easy way to biopsy the ovary unlike, say, breast or cervical cancer. There’s a significant risk of serious complications for following up a positive ovarian screening.”
“If we could find even half of ovarian cancers without finding more than a few false positives,” said Saslow, “that would be effective because we have no other detection method and a high mortality rate for this cancer.”
The study was published early online August 26, 2013 in Cancer, a peer-reviewed journal of the American Cancer Society.
The researchers used a computer program called the Risk of Ovarian Cancer Algorithm (ROCA) to calculate the risks and benefits for women to be screened for ovarian cancer. They developed a strategy to divide women into 3 risk groups – low, intermediate, and high – based on a blood test. The test looks for changes in the blood protein CA125, which is a known tumor marker.
They gave the blood test to more than 4,000 postmenopausal women and followed them for 11 years. Each year, most fell into the low risk category, and repeated the blood test the next year. An average 5.8% were categorized as intermediate risk, and repeated the blood test in 3 months. An average 0.9% were categorized as high risk. Those women underwent an ultrasound exam and 10 of them eventually had surgery based on the results. Four were diagnosed with invasive ovarian cancer in the early stages, 1 had endometrial cancer in Stage I, and the other 5 had other ovarian tumors.
The study’s authors say the next step in their screening strategy is more research. A larger study, involving 200,000 women, is being conducted in the United Kingdom. Results are expected in 2015.
Saslow said the Cancer study is very exciting. “It confirms what we saw in the preliminary results from the UK trial and is even better, but we need bigger numbers and mortality/survival data as well as harms/complications from the false positives, even though they are pretty uncommon in this study.”
False positives can lead to unneeded surgery, which can lead to complications including infection, bleeding, prolonged hospital stay, and potentially even death.
Signs and symptoms of ovarian cancer
One reason an accurate screening test is so badly needed is that symptoms alone are not reliable indicators of ovarian cancer. Often, symptoms don’t appear until the cancer has spread and it’s harder to treat. And when they do appear, they are usually identical to symptoms that are usually due to other, less serious conditions, including constipation, irritable bowel syndrome, pelvic prolapse, urinary tract infection, and interstitial cystitis (painful bladder syndrome). The most common symptoms are abdominal swelling or bloating, pelvic pressure or abdominal pain, trouble eating or feeling full quickly, and urinary symptoms, such as having to go right away or having to go often.
By the time ovarian cancer is considered as a possible cause, it usually has already spread beyond the ovaries. Still, prompt attention to symptoms may improve the odds of early diagnosis and successful treatment. If you have symptoms similar to those of ovarian cancer almost daily for more than a few weeks, and they can't be explained by other more common conditions, report them to your health care professional right away.
A two stage ovarian cancer screening strategy using the risk of ovarian cancer algorithm (ROCA) identifies early stage incident cancers and demonstrates high positive predictive value. Published early online August 26, 2013 in Cancer. First author: Karen Lu, MD, The University of Texas MD Anderson Cancer Center, Houston.