With no routine screening test currently available for uterine or ovarian cancer - the latter of which is extremely lethal - scientists have found promise in a new method that can detect both types using cervical fluid obtained during routine Pap tests.
A pilot study led by researchers at Johns Hopkins University's Kimmel Cancer Center, in Baltimore, reports that DNA analysis of cervical fluid detected 100% of uterine cancers and 41% of ovarian cancers in a small group of women, with no false-positive results.
"This initial proof-of-concept pilot study really laid the groundwork to move forward," said study author Dr. Luis Diaz, an associate professor of oncology. "So many [disease indicator] tests out there lead to ambiguous results, which lead to a lot of anxiety in patients and unnecessary diagnostic tests and costs. I think this test offers the possibility of not only being an effective cancer screening test, but also one we can do without increasing the cost of health care."
The study is published Jan. 9 in the journal Science Translational Medicine.
Pap smears and cancer
Since Pap tests were introduced in the 1940s, the incidence and death rate from cervical cancer - the leading cause of cancer deaths among women a century ago - have plummeted 75 percent, according to study background information. But deaths from ovarian and uterine cancers did not drop substantially in the same time period. More than 69,000 American women were diagnosed with these two gynaecological cancers in 2012, with 15,000 expected to die of ovarian cancer and 8,000 of uterine (also called endometrial) cancer each year.
The new research relied on the so-called PapGene test, which sequences the genes of cancer-specific mutations involved in ovarian and endometrial cancers. "Simple anatomy" explains why cervical fluid may contain more cells shed from the uterus instead of the ovaries, Diaz said, because ovaries are located farther up the reproductive tract and cells must first pass through the fallopian tubes.
Diaz and his colleagues applied the PapGene test to samples from ovarian and endometrial cancers of about 20 women with each type at Johns Hopkins and three other institutions, detecting both early and late-stage disease in both cancers tested.
The test - which is years away from being available clinically would cost less in several years after more research has been completed, Diaz said, adding that he'd like follow-up studies to include hundreds of women.
Another expert said the findings are "exciting" and indicate that the test has potential.
Help with early screening
"Ovarian cancer is really the cancer we have no way of screening for, and no early symptoms, so anything we can do to allow us to pick it up early is very exciting," said Dr. Diana Contreras, director of gynaecologic oncology at Long Island Jewish Medical Center in New Hyde Park, N.Y. "And certainly a test that can be done easily and cheaply is very exciting."
Abnormal bleeding in postmenopausal women is one way uterine cancer can be detected before reaching advanced stages. But ovarian cancer typically presents with vague symptoms easily mistaken for other conditions, making early detection extremely difficult.
Therefore, even a screening test detecting ovarian cancer 40 percent of the time it's present - especially with no false-positive results - is superior to what's available, Diaz and Contreras said.
"I think this study says the test has potential," Contreras said. "We must move forward with finding an answer, because ovarian cancer is so deadly."
The U.S. Department of Health and Human Services offers a Pap test fact sheet .
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