Using cervical fluid collected from routine smear tests, US researchers were able to spot genetic changes caused by both ovarian and endometrial cancers, offering promise for a new kind of screening test for these deadly cancers.
We could detect 100 per cent of endometrial cancers and 40 per cent of ovarian cancers, even at the earliest stages of their disease, and we can do it without any false positives
Experts say that although the test has tremendous potential, it is still years from widespread use. But if proven effective with more testing, it would fill a significant void.
Currently, there are no tests that can reliably detect either ovarian or endometrial cancer, which affects the uterine lining.
Research teams have been trying for several years to find a screening test that could identify these cancers early, when there is a better chance of a cure.
“Pap smears have had a tremendous impact in reducing the rate of cervical cancer in the US,” said Andrea Myers of Dana-Farber Cancer Institute, a co-author of the commentary on the study published in Science Translational Medicine.
“The lack of an equally effective screening test for women at high risk for endometrial or ovarian cancer has created a great deal of interest in developing tests that could identify these cancers by their genetic ‘signature’ – the collection of specific mutations within them,” she said.
“This new study is an important step in that direction.”
The new approach, developed by a team at Johns Hopkins Kimmel Cancer Centre in Baltimore, piggybacks on routine Papanicolaou or Pap testing, which is already done routinely to detect cervical cancer.
The idea is to take fluid collected from the cervix for smear tests and use gene sequencing technology to look for genetic changes that would only be found in endometrial and ovarian tumours.
Smear tests occasionally contain cells shed from the ovaries or the lining of the uterus. Cancer cells from these organs could be present in the fluid as well. The team tested for mutations in 24 endometrial and 22 ovarian cancers.
“We could detect 100 per cent of endometrial cancers and 40 per cent of ovarian cancers, even at the earliest stages of their disease, and we can do it without any false positives,” said Luis Diaz, associate professor of oncology at Johns Hopkins, who worked on the study and called it “an exciting first step”.
“We’re seeing high sensitivity in endometrial cancer. We’re seeing moderate sensitivity in ovarian cancer, and we’re seeing no false positives,” he said.
That offered enough rationale to start tests on 100 ovarian cancers of different stages and 100 endometrial cancers, as well as a large number of samples from healthy women. The team hopes to complete that testing by the end of the year.