A better test for prostate cancer

Massimo Mischi, Ph.D. helped develop the new test

Prostate cancer is the most common type of cancer among men, but its diagnosis has up to now been inaccurate and unpleasant. Now researchers have developed an imaging technology that can accurately identify tumors.

The technology is based on ultrasound, and also has the potential to assess how aggressive tumors are. This can lead to better and more appropriate treatment, and to cost savings in health care.

Here's why this is important.

After determining the PSA (prostate-specific antigen) level in the blood, biopsies are performed to see if there are tumors in the prostate. However the PSA level is not a very good indicator: two-thirds of all biopsies turn out to have been unnecessary.

The biopsies also have disadvantages; for example they are not targeted, but instead tissue is sampled randomly using 6 to 12 needles. The chance that the needles will miss a tumor is high, causing a false negative result. In around one-third of cases with negative biopsies, tumors are later found to be present. Furthermore doctors often operate after a positive biopsy, but find a tumor so small that it would have been better not to operate.

Current state of the art is in the Dark Ages. Here's how the new test works.

The new technology uses the injection of microbubbles of a contrast agent with no side-effects. The response of the tiny bubbles to ultrasound is different from that of human tissue or blood. This makes the bubbles traceable from the outside, right into the smallest blood vessels. The pattern of blood vessels in tumors is different from that in healthy tissue. The researchers can recognize this pattern from advanced analysis of the bubble concentrations. And because tumors need blood -- and hence new blood vessels -- to grow, the researchers expect to be able to see how aggressive the cancer is from the pattern of the blood vessels.

Tell your doctor.