PP148 Liquid Biopsy For The Detection Of Ovarian Or Endometrial Cancer In Samples Taken From The Pap Smear: PapSEEK

Abstract

Introduction

The PapSEEK test is an emerging minimally invasive technique in which samples are collected from the endocervical or intrauterine cavity with the Papanicolaou (Pap) brush or the Tao brush to detect somatic mutations or aneuploidies indicating the presence of endometrial or ovarian cancer.

Methods

We systematically searched for articles published up to October 2020 in the following electronic databases: Medline, Embase, the Cochrane Library, and the Centre for Reviews and Dissemination. We included experimental studies, observational primary studies, and cost-effectiveness studies evaluating the safety, effectiveness, and cost effectiveness of the PapSEEK test for the early detection of ovarian or endometrial cancer. Relevant outcomes included sensitivity, specificity, the coefficient of variation, re-test rates, the incremental cost-effectiveness ratio, the incremental cost-utility ratio, and the cost of each alternative.

Results

A single relevant retrospective study was identified. In this study, samples from women with endometrial cancer (n = 656) and ovarian cancer (n = 254) were collected with the Pap brush and Tao brush and compared with samples from healthy women (n = 1,002). The diagnostic validity for somatic mutation or aneuploidies obtained with a Pap brush had a sensitivity of 81% for endometrial cancer and 33% for ovarian cancer, and a specificity of 99% for both conditions. When samples were collected from the intrauterine cavity with a Tao brush, the sensitivity increased to 93% for endometrial cancer and to 45% for ovarian cancer. The sensitivity of the PapSEEK test increased only for ovarian cancer when plasma samples to detect circulating tumor DNA were collected in addition to Pap smear samples. This strategy provided a diagnostic validity of 43%, which was higher in late-stage ovarian cancer (56% versus 35%), and a specificity of 100%.

Conclusions

Prospectively designed studies are required to assess the safety and effectiveness of the PapSEEK test in screening settings, as well as studies comparing the technology with conventional screening methods. No cost-effectiveness studies have been conducted for the PapSEEK test.