Blood test can detect cancer of the prostate

A test that can detect ovarian cancer using a single drop of blood can also catch prostate cancer, potentially saving many men the embarrassment and discomfort of a biopsy.

It found prostate cancer in 95 per cent of men whose cancer was confirmed by more conventional means, and also screened out men suspected of having cancer, researchers said.

"This new technology has the potential to revolutionise how men are diagnosed with prostate cancer," said Dr David Ornstein, a urologist at the University of North Carolina, Chapel Hill, who worked on the study..

"It is likely that it will be possible to use a simple blood test to accurately identify men who are affected with a harmful prostate cancer but spare healthy men from undergoing unnecessary biopsies."

Prostate cancer is the second-biggest cancer killer of men in the United States. The American Cancer Society predicts that 189,000 men will be diagnosed with prostate cancer this year and 30,000 will die of it.

It is often found using a PSA test, which checks for levels of a protein called prostate-specific antigen that is over-produced by cancerous prostate cells.

Men with intermediate scores of between 4 and 10 on the PSA test are usually advised to get a biopsy - which means having a piece of tissue taken out of this delicate area for testing.

Up to 80 per cent of men who undergo such a biopsy do not turn out to have prostate cancer.

Writing in the Journal of the National Cancer Institute, a team including researchers at the Food and Drug Administration and the NCI described using the blood test, made by Bethesda, Maryland-based Correlogic Systems.

They compared blood samples from 31 men known to have prostate cancer with those of 25 cancer-free men. They marked out a baseline pattern of proteins found only in the blood of men with cancer.

They used this pattern to look for cancer in 266 new patients, many of whom had volunteered for a prostate screening programme in Chile. "The proteomic pattern correctly predicted 36 of 38 patients with prostate cancer, while 177 of 228 patients were correctly classified as having benign conditions," the researchers wrote.

The test results were not always entirely clear. The blood test suggested cancer in 51 men whose biopsies cleared them of cancer. "These may not all be false positives," the researchers wrote.

Some of the men could have cancer that was not detected by biopsy, they said, noting an earlier study that showed 20 per cent of men who have cancer-free biopsies the first time are diagnosed with cancer on a second biopsy.

So the researchers kept an eye on 70 of the men cleared of having cancer, and found that seven developed prostate cancer within five years. All had been correctly diagnosed by the Correlogic blood test.

Jamie Bearse, a spokesman for the Prostate Cancer Coalition, said his group was optimistic about the test.

"If the test continues to prove its accuracy, its use, along with the new complex PSA test, can significantly raise the accuracy of positively diagnosing prostate cancer - saving lives and eliminating the need for biopsies in many cases," he said.

Correlogic president Peter Levine said the finding helped validate his company's approach, which was found earlier this year to also work in predicting ovarian cancer, which is usually not diagnosed until an advanced stage.

"The presence of cancer can be revealed through hidden protein patterns," Levine said.

"This is truly the beginning of a revolution in early disease detection."

- REUTERS

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