The pap smear -- a routine test women undergo to screen for cervical cancer -- could help screen for other types of cancer as well, a study said this week.
A new test takes the same fluid swab from the cervix and tests it for the presence of certain cancer-specific mutations.
The scientists were hoping to catch cases of ovarian and endometrial cancer -- two common and deadly cancers which, until now, were not able to be screened for routinely.
In the pilot study, the test was able to accurately detect each of 24 endometrial cancers, a 100 percent success rate, according to results published Wednesday in the US journal "Science Translational Medicine."
The test also detected nine of 22 ovarian cancers, for a 41 percent success rate during the pilot study. And in no cases were healthy women in the control group mis-identified as having cancer during the study.
The scientists cautioned that the process must be tested on a much larger scale before being made available to the public.
But if their findings hold up, the test could be a powerful tool in fighting these two cancers of the ovaries and the uterus lining.
Ovarian cancer causes more deaths than any other cancer of the female reproductive system, the CDC notes, adding that treatment is most effective when it is caught in its early stages.
Likewise, endometrial cancer is the most commonly diagnosed gynecologic cancer, the CDC said, and is best treated when caught early.
"Genomic-based tests could help detect ovarian and endometrial cancers early enough to cure more of them," Johns Hopkins graduate student Yuxuan Wang said in a statement.
She noted that the cost of the test could be similar to current cervical fluid HPV testing, which is less than $100.
"Our genomic sequencing approach may offer the potential to detect these cancer cells in a scalable and cost effective way," added lab director Luis Diaz.
He explained that the test works because the cervical fluid collected during the pap test occasionally contains cells shed from ovaries or the uterine lining.
So it followed that any cancer cells present in those organs could also be present in the cervical fluid.
But the 44 women included in the pilot study had already been diagnosed with either endometrial or ovarian cancer.
The test must now be conducted on women who appear healthy, to determine if it could detect cancers in their early stages.
They also aim to search for ways to increase the test's accuracy in detecting ovarian cancer.
"Performing the test at different times during the menstrual cycle, inserting the cervical brush deeper into the cervical canal, and assessing more regions of the genome may boost the sensitivity," said Chetan Bettegowda, an assistant professor of neurosurgery at Johns Hopkins.
Nearly 70,000 women in the US each year are diagnosed with either ovarian or endometrial cancer, and about a third of them die, the study authors said.