Some very encouraging news broke today in the fight to detect ovarian cancers earlier. Often called “the silent killer” or the “disease that whispers” ovarian cancer often first presents itself when it is already at an advanced stage and when the prognosis is not very favourable. The irony is that women whose ovarian cancers are caught early in Stage I have excellent 5-year survival rates, in excess of 80-90%.
In this case, the earlier the detection the better. But this has proven elusive in that we have not had very good screening test for ovarian cancer.
Today some encouraging results were unveiled by a group at the University of Texas MD Anderson Cancer Center (and elsewhere) that may steer us down a path to easier detection. In a paper entitled A 2-stage ovarian cancer screening strategy using the Risk of Ovarian Cancer Algorithm (ROCA) identifies early-stage incident cancers and demonstrates high positive predictive value Dr. Karen Lu and colleagues demonstrated a new twist in some old tests.
The new test regimen uses a familiar antigen known as CA-125 which has long been know to be elevated in a high percentage of ovarian cancers. But like Prostate Specific Antigen (PSA) in men, using CA-125 on its own as a marker for ovarian cancer is poor, in that it is not very sensitive (i.e. women have ovarian cancer but the test doesn’t catch them) or it can lead to a number of false positives (i.e. women have elevated levels of CA-125 but do NOT have ovarian cancer).
The new tests still use CA-125, but instead of relying on a single measurement that is fraught with uncertainly, they are using a slightly different approach, and this also takes its cue from some of the prostate cancer research by measuring the amount of CA-125 at different intervals and looking at the RISE in CA-125 as a more reliable measure.
The researchers took an initial blood test to measure baseline CA-125 levels Then they used that information to sort women into risk categories and then retested at different intervals depending on which category.
- Those deemed low risk were retested after 1 year
- Those deemed at medium risk were retested after 3 months
- Those deemed high risk were sent for a trans-vaginal ultrasound to image the ovaries directly
So really, there is no new technology, but the refined use of already available tools seems indeed to be cause for great optimism. The overall sensitivity of the test still leaves lots of room for improvement, and the numbers of ovarian cancers in the cohort are not very large, meaning that this really needs to be confirmed and extended in a larger group of patients. But a cause for great optimism, however, is that the specificity of this new regimen appears to be very high – in other words the number of false positives was very low.
All in all, this seems to be a good advance down a path to much more predictable and sensitive screening for ovarian cancer, screening that could accurately detect cancers at stages early enough to really translate into many women’s lives saved.
And that is always good news.