New Ovarian Cancer Screening Tool is More Accurate

Researchers at Peking University Third Hospital’s Department of Obstetrics and Gynecology in Beijing, China, have developed a new ovarian cancer screening technology. The study team describes the markers and procedures used to establish the test in an article titled “Profiling the metabolome of uterine fluid for early detection of ovarian cancer,” which was published in Cell Reports Medicine.

The researchers collected uterine fluid from 219 women with ovarian cancer or benign gynecological illnesses at various stages. There were no healthy patients tested. The study of 1,213 metabolites resulted in the identification of only seven having significant relationships with ovarian cancer.

The study found an overall 88% accuracy with their seven-marker method in testing diagnostic abilities, compared to 79% with the existing CA125 blood marker test.

The researchers suggest their study identifies specific metabolites as downstream indicators of genes and proteins involved in tumor initiation and “…not only reveals metabolic features in uterine fluid of gynecological patients but also establishes a noninvasive approach for the early diagnosis of ovarian cancer.”

While the test shows a decreased percentage of false negatives when compared to existing blood tests, the study lacks a rigorous control group of patients without cancer or benign gynecological illnesses.

The rate of false positives with the test is unknown in the absence of a healthy control. A control group of at least five healthy persons would normally be expected for each pathological case in the study, however this is not the case in the current investigation. Further studies may provide light on this matter.

Identifying an illness while avoiding false positives is the problem for any pre-diagnosis disorder screening tool. While a test done solely by persons who have diagnostic indications of a disease can be a substantial confirmation, screening to catch disease markers before a diagnosis means that the screening approach is used on largely healthy people.

Ovarian cancer affects only about 1.3% of women in a population (at some point in their lives), therefore in a population of 1,000 people screened, the objective is to detect the 13 (or less, because the 1.3% risk is cumulative) at risk for early indications of the disease.

Assume the test has a 12% false positive rate. In such situation, 120 more women who are not at risk would test positive within the same population of 1,000, making the test less than 10% accurate and potentially triggering alarm and unnecessary intrusive diagnostic treatments.

A negative test result would be 98% accurate if given to the general population, even with 12% false positive and false negative rates. When the test is limited to patients with diagnostic signs, the false negative rate lowers significantly, as only about 12% of patients have erroneous negative results.

A stand-alone ovarian cancer diagnostic screening method for the general population is unlikely to have been discovered, although subsequent study may prove differently.

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