Retooled Pap smear, expanded DNA testing could detect more cancers
WASHINGTON — For years, doctors have lamented that there's no Pap test for deadly ovarian cancer. On Wednesday, scientists reported encouraging signs that one day, there might be.
Researchers are trying to retool the Pap, a test for cervical cancer that millions of women get, so that it could spot early signs of other gynecologic cancers, too.
How? It turns out that cells can flake off of tumors in the ovaries or the lining of the uterus, and float down to rest in the cervix, where Pap tests are performed. These cells are too rare to recognize under the microscope. But researchers from Johns Hopkins University used some sophisticated DNA testing on the Pap samples to uncover the evidence — gene mutations that show cancer is present.
In a pilot study, they analyzed Pap smears from 46 women who were diagnosed with either ovarian or endometrial cancer. The new technique found all the endometrial cancers and 41 percent of the ovarian tumors, the team reported in the journal Science Translational Medicine.
This is very early-stage research, and women shouldn't expect any change in their routine Paps. It will take years of testing to prove if the so-called PapGene technique really could work as a screening tool, used to spot cancer in women who thought they were healthy.
“Now the hard work begins,” said Hopkins oncologist Luis Diaz, whose team is collecting hundreds of additional Pap samples for more study and is exploring ways to enhance the detection of ovarian cancer.
But if it ultimately pans out, “the neat part about this is, the patient won't feel anything different,” and the Pap wouldn't be performed differently, Dr. Diaz added. The extra work would come in a lab.
The gene-based technique marks a new approach toward cancer screening, and specialists are watching closely.
“This is very encouraging, and it shows great potential,” American Cancer Society genetics expert Michael Melner said.
“We are a long way from being able to see any impact on our patients,” cautioned Dr. Shannon Westin of the University of Texas MD Anderson Cancer Center in Houston. She reviewed the research in an accompanying editorial, and said the ovarian cancer detection would need improvement if the test is to work.
But she noted that ovarian cancer has poor survival rates because it's rarely caught early.