New hope for ovarian cancer screening
September is Ovarian Cancer Month
Ovarian cancer is the second most common cancer of the reproductive system, but the most deadly, killing more women than all other gynecological cancers combined. Although it accounts for only 3 percent of all new cases of cancers in women, it is the fifth leading cause of cancer-related deaths among women.
According to the American Cancer Society, more than 22,000 new cases of ovarian cancer and 14,000 deaths are estimated for 2013. The incidence and death rate are highest in white women, but black women die at a higher rate than all minorities except for Native Americans.
When cases are caught very early — which occurs less than 20 percent of the time — the five-year survival rate exceeds 92 percent. It drops to 27 percent if the cancer spreads to other parts of the body, according to statistics from the National Cancer Institute.
The problem is detecting the symptoms and making the right diagnosis. All too often, women are incorrectly diagnosed as having urinary or digestive problems and treated for those sorts of ailments.
But a study published in the Journal of the American Medical Association in 2004 reported that four symptoms in particular — bloating with increased abdominal size, urinary problems (frequency or urgency), pelvic or abdominal pain and trouble eating or feeling full quickly — were found more often in those with ovarian cancer. The study further revealed that the symptoms signaled a stark contrast from the norm and were frequent, persistent and severe.
In June 2007, the American Cancer Society, in concert with the Gynecologic Cancer Foundation and the Society of Gynecologic Oncologists, formed a consensus statement agreeing that the four symptoms signaled ovarian cancer — and that the disease is not a silent killer, as previously thought.
Unlike cervical cancer, which touts Pap tests for screening and Gardasil for prevention, ovarian cancer offers no comparable solution. There is now a glimmer of hope of an effective screening tool, according to researchers at The University of Texas M. D. Anderson Cancer Center in Houston (MDA).
CA-125 is a protein that has long been used for predicting ovarian cancer recurrence. That is the protein, which is released in the blood by most ovarian cancers, is a marker for those already diagnosed with the disease. As a screening test for average-risk women, however, it has fallen short, since CA-125 can become elevated for other reasons, such as uterine fibroids or even menstruation, thus causing false positives. Yet, the protein may be an effective screening tool by evaluating changes in concentrations over a period of time.
Over 4,000 healthy post-menopausal women with no strong family history of breast or ovarian cancer were enrolled in an 11-year study led by MDA. Each woman received a baseline CA-125 blood test and were divided into three risk categories – low, intermediate and high, based on the findings. Those of low and intermediate risk were scheduled for retesting at later dates, while women at highest risk received additional testing (transvaginal ultrasound) and a referral to a gynecologic oncologist.
Of the eighty-five women in the high risk category, 10 required surgery. The screening found six cases of ovarian cancer, both invasive and non-invasive, and three cases of non-cancerous ovarian tumors as well as one case of uterine cancer. A significant finding is that the four women with invasive cancer were monitored at low risk for three years prior to a rise in the level of CA-125.
CA-125 is not a perfect test; it failed to detect two non-invasive ovarian cancers. The findings are not definitive or practice-changing. “The results are encouraging,” said Dr. Robert Bast, co-investigator of the study. ”It’s a good first step, but we need to know if the screening saves lives.”
That answer the researchers hope will come from research under way in the United Kingdom which involves 200,000 women. Results should be known by 2015.