Combined liquid-based Pap and cell-free tumor DNA (CT-DNA) may be a new method for tumor-derived driver mutation screening in primary ovarian carcinoma (OC), according to a study presented at the 2017 Society of Gynecologic Oncology Annual Meeting.1
Previous studies demonstrated that liquid-based Pap smears detect tumor-derived DNA in up to 40% of patients with OC, and other studies have investigated the use of CT-DNA. The purpose of this study was to evaluate the ability of liquid Pap and CT-DNA plasma testing together as a detection method for tumor-derived DNA driver mutations.
In this prospective case-control study, 80 patients with OC and 97 controls without OC underwent Pap and plasma testing. In patients with OC, testing was conducted at the time of primary surgery. Purified DNA was evaluated for driver mutations in 18 genes known to be associated with OC and 16 additional genes. A positive test was defined as at least 1 driver mutation detected by either test.
Among the OC cohort, 33% had stage I to II disease and 80% had high-grade serous histology.
Driver mutations were detected in 76.1% of patients with OC and 1.5% of the control cohort. Among patients with stage I to II disease, driver mutations were present in 63.6% and in 97.1% with stage III to IV disease. The specificity of the combined testing was 98.5%.
The results of this study indicate that combined liquid-based Pap and CT-DNA plasma testing can detect tumor-derived DNA mutations with high specificity in OC. A prospective, validation study is ongoing to further define the role of this screening test.
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