The Pap test has already reduced the incidence of cervical cancer by more than 60 percent. Now it may become a key step in the early detection of two other gynecological malignancies — ovarian and endometrial cancers — that have been notorious killers because they’re typically caught so late.
A new study has found that by genetically analyzing the harvest of cells from a Pap smear, doctors could identify 81 percent of endometrial cancers and 33 percent of ovarian cancers.
Some of those cancers were in their earliest stages, when they’re more likely to respond to treatment.
When the Johns Hopkins University researchers tested an alternative means of collecting cells — a longer brush that sweeps cells from the lining of the uterus — they positively identified endometrial cancer in 93 percent of cases and ovarian cancer in 45 percent of cases.
And when they added a blood test to the ovarian cancer screening regimen, they were able to detect that deadly cancer in 63 percent of patients who had it.
“Having the possibility to detect these cancers earlier is very exciting,” said Dr. Nickolas Papadopoulos, a coauthor of the study, which was published on Wednesday in the journal Science Translational Medicine.
It’s the latest example of how scientists hope to detect cancer earlier and with greater precision by looking in blood and other easily accessible fluids for cells that bear the telltale genetic mutations of cancer.
While such “liquid biopsies” have not yet made their way into widespread use, they hold the promise of revolutionizing cancer screening.
In January, the same research team presented promising findings in the journal Science on a blood test called CancerSEEK that’s capable of detecting malignancies of the liver, stomach, pancreas, esophagus, colon, lung and breast. Earlier this week, they published findings in the journal eLife on a urine test to detect cancers of the urothelial tract or urinary bladder.
As a screening test for cervical cancer, the Pap smear has been a staple of gynecological checkups for more than six decades.
The Pap test has dramatically driven down deaths from cervical cancer, which used to be one of the most common cancers in women. However, the test does a poor job of detecting endometrial or ovarian cancer, which together kill about 25,000 women in the United States each year.
Researchers measured the accuracy of their PapSeek test on 1,658 women. They already knew that 1,002 of the women were free of either cancer and 656 of them had either ovarian or endometrial cancer.