A test developed by Yale promises to detect ovarian cancer in the early stages when it is most treatable. Currently, only about 20 percent of cases are detected when the cancer is limited to the ovaries, when the disease has a 90 percent survival rate. In the later stages, only 30 percent will survive five years.

However, the Food and Drug Administration and others caution that the test has not been proved effective at detecting the cancer in the early stages and may pose risks.