Researchers at University College London have admitted defeat in their two-decade long trial to save lives. The trials involved 200,000 people over two decades to detect Ovarian cancer through annual blood
tests.
Ovarian cancer is difficult to diagnose because symptoms are frequently mistaken for less serious and often vague problems, such as feeling bloated, feeling full when eating, frequently needing to urinate. Too often
original ovarian cancer symptoms are initially mistaken for something else and diagnosis is often too late.
Although some ovarian cancers were detected earlier in the trials, the cases proved still highly aggressive and difficult to treat successfully. Ovarian cancer needs to be diagnosed even earlier to affect survival rates. Researchers will now start new long-term and large-scale screening trials across hospitals across the globe.
The trials will check other chemicals in the blood; fragments of DNA released by tumour, and microscopic fatty spheres that break off from cancerous cells.
Ovarian cancer is the eighth most commonly occurring in women worldwide and some 4,000 people die from this cancer every year in UK. Ovarian cancer has a poor survival rate due to late diagnosis. Improved methods are needed for.
early detection and diagnosis of symptoms if this mortality rate is to be brought down.
Professor Ian Hampson comments:
Population wide screening for ovarian cancer is not easy.
The current incidence of ovarian cancer in the UK is
approximately 22 per 100,000 women. This means you
need to screen 4500 women per year to identify just one
with the disease. A test with 99% accuracy and a 1 % rate of
false positives, would identify 45 false positives for every one
ovarian cancer detected. Screening a million women would
thus produce 10,000 false positives to identify 220 with the
disease.More seriously, every test also has a rate of false negatives
where the disease can be missed. As a consequence, it is not
hard to appreciate that any test used for population wide
ovarian cancer screening, has to be very accurate.
Further Reading
US National Library of Medicine
Ovarian Cancer in the World; epidemiology and risk factors.
The Lancet
Ovarian Cancer Population Screening.
Keywords: Ovarian Cancer, screening diagnosis, blood tests,
false positives.
