according to an initial analysis.
The test, under development by Delfi Diagnostics, “looks very sensitive for detecting ovarian cancer early,” said company founder and board member Victor E. Velculescu, MD, PhD, codirector of Cancer Genetics and Epigenetics at Johns Hopkins University, Baltimore.
The assay uses machine learning to integrate cell-free DNA fragment patterns with concentrations of two ovarian cancer biomarkers — CA125 and HE4 — to detect tumors.
While fragmentation patterns are organized in healthy people, they are chaotic in cancer and reveal both its presence and location, said Velculescu who presented the findings at the American Association for Cancer Research annual meeting.
The researchers tested the assay in 134 women with ovarian cancer, 204 women without cancer, and 203 women with benign adnexal masses. The approach identified 69% of stage 1 cancers, 76% of stage 2, 85% of stage 3, and 100% of stage 4 at a specificity of over 99% and an area under the curve (AUC) of 0.97.
The test identified 91% of high-grade serous ovarian cancers — the most common type of ovarian cancer.
The AUC for distinguishing benign masses from cancer was 0.87, with 60% of ovarian cancers detected at a specificity of 95%.
“In the preoperative setting where lower specificity is acceptable, this approach may improve management of adnexal masses,” the investigators said in their abstract.
Dr. Velculescu cautioned that the report “is an initial analysis” and that his team is working on validating the finding on a larger scale in both average and high-risk women.
If validated, the test “could enable population-wide ovarian cancer screening,” he added.
Delfi recently launched a lung cancer screening blood test — FirstLook Lung— that also uses a “fragmentomics” approach to detect tumors. The company is hopeful it will reach the market with a similar test for ovarian cancer, but it’s not a certainty.
With lung cancer, we know screening helps. For ovarian cancer, however, it’s unclear whether this will help or not, said Dr. Velculescu. But based on the study findings, but “we are now optimistic that this could make an impact. We have more work to do.”
This presentation was one of many at the meeting about liquid biopsies using DNA, RNA, and proteins to detect cancer, including a new assay for pancreatic cancer, another cancer that like ovarian cancer is difficult to detect in the early stages.
“This is the future,” said study moderator Roy S. Herbst, MD, PhD, chief of medical oncology at Yale University in New Haven, Connecticut.
He called liquid biopsy “a great advance” in many oncology settings, including cancer screening because finding tumors early offers the best chance at cure.
However, one of the main concerns about rolling out liquid biopsies for wide-scale cancer screening is the possibility that a test will come back positive, but no tumor will be seen on diagnostic imaging, said Herbst. It won’t be clear if the test was a false positive or if the patient has a brewing tumor that can’t be located and treated, a difficult situation for both patients and doctors.
What to do in that situation is “a policy question that the entire country is asking now as liquid biopsies are moving forward,” he said. We are going to have to come together to figure it out and learn how to use these tests.
The work was funded by Delfi Diagnostics, the National Institutes of Health, and others. Dr. Velculescu, in addition to founding Delfi, holds patents on the technology. Dr. Herbst is a consultant, researcher, and/or holds stock in many companies, including AstraZeneca, Pfizer, and Checkpoint Therapeutics.
A version of this article appeared on Medscape.com .