Ultrasound shows if prostate cancer biopsy or operation is necessary
21 Dec 2010
A new technique that uses microbubbles to highlight prostate
cancer in ultrasound images has been developed researchers at Eindhoven
University of Technology (TU/e) in the Netherlands, in cooperation with
AMC Amsterdam.
The technology has the potential to assess how aggressive prostate
tumours are. This can lead to better and more appropriate treatment,
and to cost savings in healthcare.
About 11% of men who die of cancer in the western world do so as
a result of prostate cancer. Each year 200,000 men are diagnosed
with the disease in the US alone. But diagnosis is still
rudimentary. After determining the PSA (prostate-specific antigen)
level in the blood-, biopsies are performed to see if there are
tumours in the prostate. However the PSA level is not a very good
indicator: two-thirds of all biopsies turn out afterwards to have
been unnecessary.
Biopsies are not targeted
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 tumour is high,
causing a false negative result. In around one-third of cases with
negative biopsies, tumours are later found to be present.
Furthermore doctors often operate after a positive biopsy, but find
a tumour so small that it would have been better not to operate.
Aggressive
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 tumours
is different from that in healthy tissue. The researchers can
recognize this pattern from advanced analysis of the bubble
concentrations. And because tumours 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.
The technology has been tested on four patients from whom the
affected prostate was removed, dr.ir. Massimo Mischi of the TU/e
department of Electrical Engineering explains. The location and size
of the tumours turned out to match accurately with the images
produced using the new technology. Mischi presented these first,
promising results at a recent conference in Chicago.
No biopsies
Next year the research team will carry out a pilot with biopsies
guided by images made using the new technology. This allows the
biopsies to be targeted, and therefore more effective. In a later
phase the ultrasound technology will be used to decide whether
biopsies are required, which will reduce the number of biopsies
carried out.
The researchers expect their technology to be available in
hospitals within five years. The ultimate goal is for doctors to be
able to determine if an operation is necessary, and if so what kind
of operation, based on the images produced, without the need for
biopsies.
All in all doctors will eventually be able to intervene much more
accurately, expects prof.dr.ir. Hessel Wijkstra, head of urology
research at AMC Amsterdam. Wijkstra was appointed part-time
professor of Hemodynamic Contrast Sonography at TU/e last month.
Furthermore he believes that there will be less unnecessary
operations.
In some cases doctors may decide to leave small, non-aggressive
tumours untouched and monitor these tumours, in cases where a tumour
is not causing any symptoms and is not impairing the health of the
patient. In these cases the health effects of surgery are worse than
those of the tumour itself. A further positive effect of this new
approach is that the total costs will be reduced.