Ovarian cancer best predicted by blood levels of certain protein

In an effort to develop an improved blood test for early detection of ovarian cancer, a rigorous landmark validation study of 49 potential markers shows that blood levels of CA-125 protein remain the best bet.

Researchers from Brigham and Women's Hospital, Boston, Massachusetts, included phase II specimens taken at diagnosis from 180 symptomatic women with ovarian cancer from the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial and from 660 benign disease or general population controls. The researchers found that none of the markers investigated outperformed CA-125. Even panels of markers added little value to CA-125 alone.

After CA-125, top-performing markers on the phase II specimens were HE4, transthyretin, CA15.3, and CA72.4 with sensitivity at 95% and specificity ranging from 0.73 to 0.40. Except for transthyretin, all the markers had similar or better sensitivity when used on phase III specimens that were drawn within 6 months of diagnosis. Performance of all markers declined in phase III specimens obtained more than 6 months from diagnosis. Researchers say the optimal marker would detect a tumor signal more than 6 months prior to diagnosis, but even CA-125 has its strongest signal within the 6-month window.

Some researchers believe that a rise in blood levels of markers over time may be used for early detection, hypothesizing that each woman has an individual baseline level for each marker, and that 1 or more of these markers rises above that baseline when she develops ovarian cancer. Detected rises then can be followed with transvaginal ultrasound for verification of disease.

Cramer DW, Bast RC Jr, Berg CD, et al. Ovarian cancer biomarker performance in prostate, lung, colorectal, and ovarian cancer screening trial specimens. Cancer Prev Res (Phila). 2011;4(3):365-374.