"Early diagnosis can help prolong or save lives, but clinicians currently have no sensitive screening method because the disease shows few symptoms," says Mor in a news release. Mor is an associate professor of obstetrics, gynecology, and reproductive sciences at Yale University's medical school.
About Ovarian Cancer
Ovarian cancer often has few early symptomsfew early symptoms and is often diagnosed late, when chances of survival are poor, says Mor's study, which appears in the early edition of Proceedings of the National Academy of the Sciences of the United States of America.
This year, about 22,000 U.S. women will be diagnosed with ovarian cancer and 16,210 will die from it, says the American Cancer Society (ACS). The main reason for the poor outcome is the advanced stage of the cancer at the time of diagnosis in most cases. Symptoms appear only in the late stages of the disease.
The overall five-year survival is only 20%-30%, according to the American College of Obstetricians and Gynecologists (ACOG). However, women diagnosed at earlier stages have a better probability of a cure.
Ovarian cancer rates have gone down since 1991, says the ACS, noting that a woman's risk of getting ovarian cancer in her lifetime is about one in 58. Her risk of dying from ovarian cancer is one in 98, says the ACS.
About 80% of ovarian cancer patients are diagnosed with advanced stages of the disease, say Mor and colleagues. "In patients with advanced disease, 80% to 90% will initially respond to chemotherapy, but [less than] 10-15% will remain in permanent remission," they write.
For women diagnosed at early stages (stages I or II), five-year survival is 60% to 90%, says the study.
"Currently, it appears that the best way to detect early ovarian cancer is for both the patient and her clinician to have a high index of suspicion of the diagnosis in a symptomatic woman," says ACOG. Unfortunately there is no screening test for ovarian cancer that has proved effective in screening low-risk asymptomatic women, they add.
Women at high risk of ovarian cancer (such as those with a strong family history of the disease) may be screened with ultrasound and blood tests, says the ACS. Those methods aren't used for routine screening of women not at high risk.
Women at risk for ovarian cancer are those who have never been pregnant, have decreased fertility, and those who delayed childbearing but did not use oral contraception. Some studies have also linked the use of fertility drugs to an increased risk of ovarian cancer.
"This test should improve our ability to accurately detect premalignant change or early stage ovarian cancer in asymptomatic women at increased risk for the development of ovarian cancer," write Mor and colleagues.
However, more work is needed before the test can be used by the general public, say the researchers. "There is significant need for further improvement of the [test] reported here if [it] is to be used for general population screening," they write.
About the Test
The test was tried on 106 healthy women and 100 with ovarian cancer. Each of the four proteins had been mentioned as possible markers, but this is the first test to screen for all four at once, say the researchers.
The test's results relied on all four proteins. "No single protein could completely distinguish the cancer group from the healthy [group]," says the study.
Could those four proteins also indicate other kinds of cancer? That "must be investigated rigorously," say the researchers, noting that some cancers already have well-established detection methods (such as mammography for breast cancer).
Progress Against Female Reproductive Cancers
News of the ovarian cancer blood test comes almost six months after another cancer of the female reproductive system was in the headlines.