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New Screening Technique Could Detect Twice as Many Women With Ovarian Cancer

Researchers track changes in CA125 protein level

A new screening method can identify twice as many women with ovarian cancer as conventional strategies, according to a study conducted in the United Kingdom.

The method uses a statistical calculation to interpret changing levels in women’s blood of a protein called CA125, which is linked to ovarian cancer. This calculation gives a more accurate prediction of a woman’s individual risk of developing cancer compared with the conventional screening method, which uses a fixed cut-off point for CA125. The new method detected cancer in 86% of women with invasive epithelial ovarian cancer (iEOC), whereas the conventional test used in previous trials or in clinical practice would have identified fewer than half of these women (41% or 48%, respectively).

The results come from an analysis of one arm of the UK Collaborative Trial of Ovarian Cancer Screening (UKCTOCS), the world’s largest ovarian cancer screening trial, led by University College London. The study involved 202,638 postmenopausal women aged 50 years or older who were randomly assigned to two different annual screening strategies (multimodal screening or transvaginal ultrasound) or to no test at all.

The study, published in the Journal of Clinical Oncology, evaluated 46,237 women who continued to attend annual multimodal screening after the initial screen. Their blood was tested once a year for CA125 levels, and then a computer algorithm was used to interpret their risk of ovarian cancer based on various factors, including the woman’s age, the original levels of CA125, and how that level changed over time. The serial pattern was compared with known cases of cancer and controls to estimate the risk of having ovarian cancer.

Professor Ian Jacobs, the chief investigator of UKCTOCS and co-inventor of the new statistical approach, said: “CA125 as a biological marker for ovarian cancer has been called into question. Our findings indicate that this can be an accurate and sensitive screening tool when used in the context of a woman’s pattern of CA125 over time. What’s normal for one woman may not be so for another. It is the change in levels of this protein that’s important.”

Previous ovarian cancer screening trials have used a fixed cut-off for CA125 (more than 35 U/mL) to identify a possible abnormality. But some women can have much higher levels and not have cancer, while others with levels below this threshold could be harboring the disease, the authors said.

A total of 640 women had surgery for suspected ovarian cancer, of whom 133 had iEOC. A further 22 women were diagnosed with iEOC within 1 year of the last annual screening.

Cancer expert Dr. James Brenton said: “A blood test to find women at risk of ovarian cancer is an exciting prospect, but this work still needs to be tested in women to see if it can save lives. By tracking how the levels of the CA125 protein change over time, we might have an early signal to detect tumors. Ovarian cancer is particularly hard to spot at an early stage, so it’s vital that we find ways to diagnose the cancer sooner.”

Source: Medical Xpress; May 4, 2015.

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