Moving toward catching the 'silent killer' earlier
If detected in the more advanced stages of the disease (stage III or higher), the survival rate for ovarian cancer is just 30 percent. But if caught early, the survival rate jumps to 90 percent.
This is why researchers at Rush and around the country are zeroing in on finding effective screening and diagnostic tools. Catch ovarian cancer early when it hasn't spread and is easier to treat, and thousands of lives can be saved.
But only 19 percent of cases are detected at the early stages. Dubbed "the silent killer," ovarian cancer’s symptoms — which include bloating, feeling full quickly and a feeling of heaviness in the pelvic area — can be overlooked or mistaken for other conditions, such as irritable bowel syndrome.
And, unlike breast cancer and colon cancer, there's currently no single screening or diagnostic test. In fact, the only way to find out for certain if a woman has ovarian cancer is via surgery. "Mostly early-stage cancer is picked up incidentally — we'll be operating on something else, for example," says Jacob Rotmensch, MD, medical director of the gynecologic cancer program at Rush.
While screening by ultrasound or a blood test for the CA-125 tumor marker (a protein that is found in more ovarian cancer cells than in other cells) may help detect ovarian cancer, it's no guarantee. "Many times the CA-125 findings can be normal, the ultrasound can be normal and the patient can have advanced-stage ovarian cancer," Rotmensch says. "But it's still the best we have."
To find a better tool for screening and diagnosis, researchers at Rush and across the country have been tackling the problem from a variety of angles that offer promise.
New tool helps refer high-risk patients to cancer specialists
In an effort to help primary care doctors and ob/gyns identify patients in need of specialized cancer care, like that offered by Rotmensch and his colleagues, the Food and Drug Administration approved a test called OVA1 in 2011.
Here's how the test works: When a woman is found to have a pelvic mass, a blood sample is tested for five proteins, which are altered due to ovarian cancer. The findings of each result are combined to come up with a score, ranging from 0 to 10: a higher score indicates a higher risk for ovarian cancer. If malignancy is suspected, then the recommendation is to refer the patient to a gynecologic oncologist.
And seeing a specialist is important. Recommendations from the American College of Obstetricians and Gynecologists and the Society of Gynecologic Oncologists suggest that patients with ovarian cancer have improved survival when the surgery is performed by gynecologic oncologists as opposed to general gynecologists or surgeons.
Antibody in infertile women provides a new clue
While the reason is still unclear, women with infertility have been found to be at a higher risk for ovarian cancer. Knowing this, Rush researcher Judith Luborsky, PhD, and her team compared tissue from women with a risk of ovarian cancer (infertile women) and those with ovarian cancer to see what they had in common.
What they found was this: When the body is exposed to a protein called mesothelin, which is found in abundance on the surface of ovarian cancer cells but present only in limited amounts in normal human tissue – it jumpstarts the immune system and produces special antibodies. These molecules, or antibodies, are designed to detect and destroy invaders like viruses and bacteria.
"With the discovery of the mesothelin antibody, we now have what appears to be a biomarker – a molecule in the blood or tissues that signifies a condition or disease — that can potentially be used in screening tests to help us conquer ovarian cancer," Luborsky says.
Sizing up CA-125 molecules could provide insights
Elsewhere at Rush, investigators Rotmensch and Liaohai Chen, PhD, have teamed up with Argonne Laboratories, a leading-edge scientific research facility, to take a closer look at CA-125 proteins. Currently cancer specialists evaluate the amount of CA-125 in the blood; the higher the level, the more likely the presence of ovarian cancer. But sometimes patients with advanced ovarian cancer have low CA-125 levels and women who don’t have ovarian cancer have high levels, making the tool less than reliable if one looks at just amounts of CA-125.
Size of the CA-125 particles, however, could be more indicative of the presence of cancer than the counts, according to researchers. The challenge is how to measure the particles.
Rotmensch and Chen have hypothesized that using a tool called fluorescence correlation spectroscopy could accurately measure these particles. And once they succeed in doing that, a more accurate screening test, and perhaps even a diagnostic test, could be developed.
While a single screening or diagnostic tool is not yet available, there has been progress in the efforts to catch ovarian cancer early.
Until an effective tool is found, women should arm themselves with an awareness of risk factors and symptoms and a proactive approach in discussing any concerns with their physicians.