Tampon Test Detects Endometrial Cancer

The Mayo Clinic and Xact Sciences are developing an easy, noninvasive test to detect endometrial cancer in women with abnormal vaginal bleeding. 

It analyzes vaginal fluid collected on tampons for methylated DNA biomarkers of endometrial cancer. An earlier version of the test required 33 biomarkers, but investigators have since whittled it down to just six.

The latest study results were announced at the Society of Gynecologic Oncology Annual Meeting in Seattle. Senior investigator Jamie Bakkum-Gamez, MD, a Mayo Clinic gynecologic oncologist in Rochester, Minnesota, reported that the six-marker assay had an area under the curve of 0.93 for discriminating between benign endometrium and endometrial cancer.

“The results are very good in terms of diagnostic accuracy.” The test has “very promising diagnostic value,” said study discussant Benoit You, MD, PhD, a medical oncologist and researcher at Lyon University, Lyon, France.

Bakkum-Gamez explained that the goal of the work is to develop an assay that saves women from needless suffering.

Endometrial sampling is the current gold standard for evaluating abnormal vaginal bleeding in women aged ≥ 45 years and in younger women if they have at least one endometrial cancer risk factor.

However, only about 5%-10% will turn out to have cancer or a cancer precursor. Other women undergo the discomfort and sometimes excruciating pain of in office endometrial sampling for little benefit.

To address the situation, “we want to identify women who can avoid the procedure safely and reduce the number of unnecessary endometrial samplings,” Bakkum-Gamez said.

If test development continues to be successful, and a commercial product reaches the market, it might well prove to be an “easy, practical” tool to avoid “noncontributive curettage and biopsy,” You said.

Bakkum-Gamez presented her team’s latest work at the meeting, a prospective validation case-control study with two cohorts, one including women scheduled for endometrial sampling for abnormal vaginal bleeding and the other with women scheduled for a hysterectomy due to biopsy-confirmed endometrial cancer or atypical hyperplasia.

Vaginal secretions were collected by tampon before the procedures and analyzed. The results were compared subsequent to pathology reports. 

The study included 374 women with benign endometrium findings, 256 with endometrial cancer, 37 with atypical hyperplasia, and 29 with benign hyperplasia. The majority of cancers were grade 1 endometrioid tumors. 

At a specificity of 85%, the overall sensitivity of the test to detect endometrial cancer was 89%. Sensitivity increased with increasing tumor grade; it was 82% for grade 1, 92% for grade 2, and 100% for grade 3 tumors. 

Sensitivity was 95% for type 2 endometrial cancers (serous carcinoma, clear cell carcinoma, and carcinosarcoma) but fell to 36% for atypical hyperplasia.

Additional studies are underway to further develop and validate the approach, Bakkum-Gamez said. 

The work is funded by Xact Sciences. Bakkum-Gamez reported research funding from the company. You is a consultant for and has other ties to many pharmaceutical companies, including Merck, Pfizer, Roche, Novartis, Pfizer, and Amgen, among others. 

M. Alexander Otto is a physician assistant with a master’s degree in medical science and a journalism degree from Newhouse. He is an award-winning medical journalist who worked for several major news outlets before joining Medscape Medical News. Alex is also an MIT Knight Science Journalism fellow. Email: [email protected].