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Accurate diagnosis of prostate cancer with ultrasound
By Dross at 2010-12-09 02:24
Accurate diagnosis of prostate cancer with ultrasound

Prostate cancer is the most common type of cancer among men, but its diagnosis has up to now been inaccurate and unpleasant. Researchers at Eindhoven University of Technology (TU/e), in cooperation with AMC Amsterdam, 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.

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 tumors in the prostate. However the PSA level is not a very good indicator: two-thirds of all biopsies turn out to afterwards 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.

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.

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 tumors 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.

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 tumors untouched and monitor these tumors, in cases where a tumor 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 tumor itself. A further positive effect of this new approach is that the total costs will be reduced.

As well as TU/e and the AMC Amsterdam, the Catharina Hospital in Eindhoven and a number of ultrasound companies are also involved in the research. Dr.ir. Massimo Mischi received a Vidi grant worth eur 800,000 from the NWO (Netherlands Organisation for Scientific Research) last year for this research. The research also receives financial support from the Cure for Cancer Foundation.



2 comments | 1859 reads

by gdpawel on Tue, 2012-04-17 23:30
An ultrasound therapy that destroys cancer cells shows promise for treating prostate cancer without causing the incontinence and impotence common after surgery or radiation.

But the experimental treatment, called high-intensity focused ultrasound (HIFU), was tried on just 41 men and has not been directly compared with other therapies or assessed for long-term effectiveness.

A 41-patient study in the journal Lancet Oncology suggests targeted ultrasound treatment could reduce the risk of impotence and incontinence.

Researchers say it could transform future treatment if the findings are repeated in larger studies.

The Medical Research Council (MRC), which funded the study, welcomed the results, which it said were promising.

Each year 37,000 men in the UK are diagnosed with prostate cancer.

Many face a difficult dilemma: the disease kills about 10,000 men every year, but for some it may not get worse if left untreated.

Standard treatment with surgery or radiotherapy involves treating the whole prostate gland, and can harm surrounding tissue, with a serious risk of side-effects, including urinary incontinence and impotence.

Doctors at University College Hospital in London have carried out the first trial using high-intensity focused ultrasound (HIFU) aimed at small patches of cancer cells on the prostate.

This was a "proof of concept" study involving 41 patients.

They used a probe, placed close to the prostate, which emits sound waves that heat the targeted cells to 80C, while causing minimal damage to surrounding nerves and muscles.

Hashim Ahmed, a urological surgeon at the trust who led the study, says the results, 12 months after treatment, are very encouraging.

"We've shown in this study that focal therapy - by targeting the individual areas of cancer - can avoid the collateral damage. We've shown that nine in 10 men had no impotence and none of the men in the study had incontinence of urine."

Mr Ahmed says the early evidence on cancer control is also very good. But he says this needs to be evaluated in much larger studies.

"This could offer a transformation of the way we treat prostate cancer. It could offer a cost-effective treatment for the NHS, and offer men with early prostate cancer an opportunity to treat their disease, but with very few side-effects."

The study was funded by the Medical Research Council, the Pelican Cancer Foundation and St Peter's Trust.

Professor Gillies McKenna, director of the Gray Institute for Radiation Oncology and Biology, a joint collaboration between the MRC and Cancer Research UK, welcomed the findings.

"If these promising results can be confirmed in a randomised controlled trial, focal therapy could soon become a reasonable treatment choice for prostate cancer alongside other proven effective therapies."

The chief executive of the Prostate Cancer Charity, Owen Sharp, also emphasised the importance of further research.

"We welcome the development of any prostate-cancer treatment which limits the possibility of damaging side-effects, such as incontinence and impotence. These early results certainly indicate that focal HIFU has the potential to achieve this in the future.

"However, we need to remember that this treatment was given to fewer than 50 men, without follow-up over a sustained period of time.

"We look forward to the results of further trials, which we hope will provide a clearer idea of whether this treatment can control cancer in the long term whilst ridding men of the fear that treating their cancer might mean losing their quality of life."

BBC Health News

by gdpawel on Wed, 2012-04-18 06:14
The results of this small study look promising. Men with early (localised) prostate cancer that has not spread can often live for years without developing life-threatening symptoms, and are often faced with a difficult decision about whether or not to have conventional treatment, which can have side effects. A treatment that can target areas of cancer without damaging healthy tissue might enable more men to have treatment for prostate cancer at an early stage.

However, it’s important to point out that this is an early “proof of concept” study and that a far larger trial is required to assess both its effectiveness and safety.

The study was carried out by researchers from University College London, and was funded by the UK Medical Research Council, the Pelican Cancer Foundation and St Peter’s Trust. The study was published in the peer-reviewed medical journal The Lancet Oncology.

The study was intended primarily to assess the frequency of side effects of treatment, rather than its success in treating prostate cancer. This was a trial of a treatment for early (localised) prostate cancer, which has not spread to other organs or tissue. Its findings do not apply to more advanced disease.

This was an early (prospective development) study looking at a new treatment for localised prostate cancer called high-intensity focused ultrasound (HIFU).
Prostate cancer is the most common cancer in men, yet, as the authors point out, treating localised prostate cancer is difficult since the disease often progresses slowly and may not cause any symptoms for many years.

There are several standard treatments for localised prostate cancer. Some involve treating the whole prostate with radiotherapy or removing it with surgery, and these can damage surrounding healthy tissue. The more destructive treatments of the whole prostate gland lead to undesirable side effects, in particular, erection problems (affecting 30-70% of men treated) and urinary incontinence (affecting 5-20%). One alternative for men at present is to have no active treatment but to undergo regular checks. This is known as active surveillance (waitful watching).

The new treatment, say the authors, is less aggressive and able to target the cancer site rather than the whole organ. In this respect, it is similar to treatment for other malignancies, such as localised breast cancer (where a lumpectomy is now an alternative to mastectomy). They say that in a previous study they had used HIFU to destroy one half of the prostate where the cancer was situated. But they point out that only one in five men have disease in one half of the prostate only. Their new study looked at whether HIFU could be used for treating cancer at specific sites within the prostate.

Between 2007 and 2010, the researchers recruited 42 men to their study. To be eligible they had to be aged 45 to 80 years and have been diagnosed with localised prostate cancer ranging from low to high risk. They also had to have had no previous treatment for prostate cancer or other conditions of the prostate and they had to be fit for a general anaesthetic and for MRI scanning. At the start of the study, they were also asked about whether they suffered from erectile dysfunction or urinary incontinence.

In order for researchers to pinpoint the exact location of their cancers, all the men underwent two diagnostic techniques – a special type of MRI (magnetic resonance imaging) scan and a “mapping” or “template guided” biopsy. The patients, under general anaesthetic, then underwent the treatment with an HIFU device, a probe inserted close to the prostate through the rectum. The device emits high-frequency sound waves that heat the targeted cells to 80°C. Researchers ensured that general guidelines for all treatments were followed, in order to protect nerve cells and healthy tissue.

The men were followed up at one, three, six, nine and twelve months. On each occasion they were given a PSA blood test (which measures levels of prostate specific antigen, a chemical marker that can indicate the presence or recurrence of prostate cancer), and were given validated questionnaires asking about side effects. At six months they had a further MRI and a biopsy. Men who had a positive diagnosis were given further HIFU treatment. A further MRI scan was carried out after a year.

The researchers were primarily interested in whether the treatment was acceptable and in rates of side effects, in particular erectile dysfunction and urinary incontinence. Quality of life was assessed, and the reasearchers also looked at the progress of the cancer.

The researchers included 41 men in their final analyses as one man died of unrelated causes three months after focal therapy. Of these, 30 (73%) had intermediate and high-risk disease.

The main findings following treatment with HIFU were:

At six months, 30 of 39 men who had a biopsy, (77%, 95% confidence interval 61 to 89) showed no evidence of cancer and 36 men (92%, 95% confidence interval 79 to 98) were free of clinically significant cancer.

At 12 months, after treatment was repeated in four men, 39 of 41 (95%, 95% confidence interval 83 to 99) had no evidence of disease on an MRI scan.

At 12 months, of 35 men who had no erection problems at the start of the study, 31 (89%, 95% confidence interval 73 to 97) had erections sufficient for penetration.

Of 38 men who had no urinary incontinence at the start of the study, all were leak-free and pad-free at nine months. Of 40 men who did not use pads at the start, all were pad-free by three months and maintained pad-free continence at 12 months.

Some men suffered mild side effects after the treatment, such as urinary tract infection. Two men were admitted to hospital for acute urinary problems.

In these 41 men with an average PSA blood test of 6.6ng/ml, there was a significant decrease in PSA levels at 12 months.

“Focal therapy of individual prostate cancer lesions leads to a low rate of genitourinary side effects and an encouraging rate of early absence of clinically significant prostate cancer,” the researchers say.

Conclusion

The results of this small early trial are promising, but a large-scale randomised controlled trial comparing the effectiveness and safety of the new treatment with both standard treatments and “active surveillance” is now needed. As the authors note, the study had several limitations:

It was a small observational study of 41 men.

It was an uncontrolled trial. This means that there was no group who did not receive treatment (control group) against which this treatment could be compared. This is because it was designed primarily to assess the rate of side effects associated with the new treatment and not its effectiveness in combating prostate cancer.

The authors refer to other ablative therapies as well as brachytherapy and image-guided radiosurgery, which can be used to treat smaller volumes of prostate tissue while seeking to preserve function. These have not yet been assessed against this ultrasound focal therapy.

As an early “proof of concept” study the results will probably be used to support and design larger trials to assess both effectiveness and safety of HIFU compared to current best practice.

NHS Choices

Note: According to Dr. Matt Cooperberg, assistant professor at UCSF, active surveillance for prostate cancer means that based on the information available, the likelihood of cancer progressing in the short-term, while not zero, appears to be very low. Active surveillance does not mean the cancer will never need to be treated, but rather that it does not need treatment now. The "window of opportunity" for curing low risk prostate cancer is measurable in years in most cases, if not decades. In the meantime, men can avoid the risks and costs of surgery, radiation therapy and other interventions.

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