A way of screening for ovarian cancer appears to detect the disease in early stages, and if confirmed in clinical trials, the test could become a routine screening for women. In the study, researchers tested the screening on more than 4,000 women over an 11-year period. The women underwent yearly blood tests, and the researchers recorded the levels of a protein called CA-125, which is produced by the majority of ovarian tumors. Women who had sudden increases in CA-125 levels were referred to a gynecologist and were given an ultrasound. On the basis of their ultrasound results, 10 women underwent surgery during the study period. It turned out that four women had ovarian cancers still in an early stage, and five others had ovarian tumors that were either benign, or of low malignant potential (tumors that may become cancerous, but usually do not). The study was published Monday in the journal Cancer. Despite advances in treatment, ovarian cancer remains a highly lethal disease, mainly because most women with ovarian cancer are diagnosed when the disease is at a late stage. When caught at an early stage, 75 to 90 percent of patients survive at least five years, the researchers said.