A new, highly-sensitive blood test may help provide the first tool to detect ovarian cancer before the disease produces any symptoms, said researchers in the Feb. 16 issue of the journal The Lancet (Vol. 359: 572-579). The test looks for certain protein patterns in the blood.

The article was published Feb. 7 on theThe Lancet's Web site.

The new finding is a needed one. Currently, more than 80% of women with ovarian cancer are diagnosed only after the disease produces recognizable symptoms. By then, it is in an advanced stage when survival rates are low, said the researchers.

There is another protein in blood sometimes used to detect ovarian cancer — CA125 — but it can be high because of non-cancer conditions, and isn't useful in early-stage disease, the researchers noted.

"We applied this technology to ovarian cancer because of the tremendous clinical need," said Emanuel F. Petricoin III, PhD, a senior investigator and co-director of the Food and Drug Administration (FDA) — National Cancer Institute (NCI) Clinical Proteomics Program, which developed the test along with a private company.

The test correctly identified 100% of the 50 women who had ovarian cancer, including all 18 of those with Stage I disease in which surgery alone can cure ovarian cancer.

The test had only a 5% false positive rate, incorrectly tagging three women in 66 without the disease as having it.

The researchers noted that in regular use of the test, any woman whose blood showed the patterns suggesting the presence of the disease would be given a repeat test and other tests as well.

They also noted that what looks now like false positives could be from ovarian tumors too small to detect by other tests now available.

All the women were from clinics for those at high risk of developing ovarian cancer.

"This is a very exciting new development — the first quantum leap in testing for this disease in 20 years," said Carolyn Runowicz, MD, professor at Albert Einstein College of Medicine in New York and vice-chair of Obstetrics and Gynecology at St. Luke's Roosevelt Hospital.

Runowicz, a member of the American Cancer Society gynecologic cancer advisory board, said more work still needs to be done to help lower, or clarify, the rate of false-positives, because a true false-positive causes unnecessary anxiety for the patient, and in some cases may lead to more invasive procedures.

Although the 5% false-positive rate sounds low, said Runowicz, that percentage among the millions who might be screened could affect large numbers of women.

And because the study was a small one done among women at high risk of developing ovarian cancer, studies involving more women at average risk – most women – are needed to learn if it is as useful for them, she said.

Runowicz said that will take some time, and the protein-pattern test is not something likely to be available to the general public very soon except through upcoming clinical trials.

"But this is a test with real potential to make a major difference in the fight against ovarian cancer," she concluded.

The test uses a sophisticated biochip and computer analysis to reveal the presence, and absence, of thousands of proteins in telltale patterns.

"It's the pattern, not the proteins, that reveals the disease," noted Lance A. Liotta, MD, co-director of the program.

To develop the program, the researchers fed data from blood protein samples into a computer. The samples were from 50 women with ovarian cancer and 50 without the disease.

The computer produced a horizontal line showing peaks representing high amounts of certain kinds of proteins, and valleys indicating low levels of other proteins — a kind of "signature line" for each sample.

An artificial intelligence program then "trained" the researchers' software to recognize all signature line patterns present only in those with ovarian cancer.

Developed through collaboration between the NCI, the FDA, and a private company, the test is the first of many the group hopes to develop. Other tests will target cancers of the breast, lung, prostate, and colon, the researchers said.