Screening for early ovarian cancer has improved
Researchers are trying to devise a simple blood test to screen women for ovarian cancer. Some day, a reliable blood test will be available. But for now, women must rely on a less-sensitive blood test called the CA125 test or ultrasound examinations to look for disease. A study published this week in the journal Lancet Oncology, however, shows that both of these older screening methods have been fine-tuned enough in recent years to be used as screening tools.
Ovarian cancer is one of the most lethal types of cancer. About 21,000 U.S. women are diagnosed each year and more than 15,000 die. The high death rate is due to the fact that the disease is often detected at a late stage of development, when chances for a cure are much lower. Having a reliable test to detect the disease earlier could save many lives.
The CA125 blood test looks for a compound produced by tumors, but conditions other than ovarian cancer can cause the test to be abnormal. Ultrasound examinations look for abnormalities on the ovaries. The tests are typically ordered only when a doctor has a reason to suspect a woman may have the disease or is at high risk.
In recent years, however, both screening tools have undergone some improvements to enhance their reliability. The new study shows that both tests now look good enough to be used for screening large numbers of women to detect early-stage ovarian cancer. The study of more than 200,000 women is the largest, randomized controlled trial of ovarian cancer screening. Postmenopausal women were assigned to either no screening, ultrasound alone annually or both tests annually. Among women who got both tests, 90% of cancers were detected compared with 75% among women undergoing ultrasound. Nearly half of the cases of cancers detected were early-stage cancer, which are highly curable.
The results show that both methods are satisfactory good screening tools, each offering slight advantages and disadvantages, said the authors of the study, from University College London. The women in the study will continue to be followed to gather more data, such as whether the annual screening lowers death rates. Another big question that remains is whether it would be cost-effective to screen every adult woman for ovarian cancer using one or both of these methods.
-- Shari Roan
Photo credit: EPA / Piyal Adhikary