Prostate Cancer – Updates On New Drugs And Investigating

By Dr Harold Gunatillake - Health Writer

More than 36,000 men are diagnosed with prostate cancer each year in the UK and of them more than 10,000 die. In Sri Lanka the numbers are increasing though figures are not available. The Sri Lankan cancer registry data show a low rate of CaP, but the actual incidence of CaP in Sri Lanka is probably higher than reported, as seen in the densely populated districts and the high rate of incidental diagnosis of CaP in TURP (Transurethral Resection) specimens.

PSA Test
Even with the commonly done Prostate Specific Antibody (PSA) annual test may not indicate the presence of the disease in the body.On the contrary to PSA testing, most prostate cancers are now found before they cause symptoms. PSA is a protein produced by the gland. Even with a PSA within the normal range, one could brew up the disease within unknowingly. Furthermore, you may not have any symptoms and signs for a long period whilst the disease is brewing up.
Likewise, high PSA may not reveal quite definitely that you suffer from the disease, because as one grows older the PSA also rises. This is notoriously inaccurate because although 10-15% of men will have high enough PSA levels to warrant carrying out a prostate biopsy, only 2-3% will require any treatment. The question keeps arising and never been satisfactorily answered. Now it has come up again, in the context of a provocative new study on the popular P.S.A. test for prostate cancer. The paper, published in The Journal of Clinical Oncology, finds that men in their 70s are being screened at nearly twice the rate of men in their 50s — and men ages 80 to 85 are being screened as often as those 30 years younger.

"That is mind-boggling," said the lead author, Dr Scott E. Eggener, a University of Chicago urologist. "What we were hoping was that young, healthy men who were most likely to benefit would be screened at higher rates and that screening would tail off in older men." The American Cancer Society and the American Urological Society discourage screening for men whose life expectancy is 10 years or less.
The cancer is so slow-growing that it can take that long for screening to show a benefit. The United States Preventive Services Task Force recently concluded that screening should stop at 75. Dr Mary Barton, scientific director for the group, said "it is more than just a lack of data" that led to that conclusion. "What data we do have for this group suggests it is a net-harm situation," she added.

But although 80-year-olds are much more likely than 50-year-olds to have chronic illnesses and a limited life expectancy, age should not be the deciding factor, Dr Eggener said. Health condition and life expectancy are far more important," he said. "There are 50-year-olds that shouldn't be screened and 70-year-olds that may benefit from it." (Screening Prostates by Gina Kolata published April 11, 2011)

Chemical EN2 found in urine

In the UK the researchers have discovered that a protein found in urine is affected by a genetic change linked to the cancer.

Study leader Dr Hayley Whitaker, from Cancer Research UK charity's Cambridge Research Institute, said: "We looked in tissue and urine from over 350 men with and without prostate cancer to detect the link. "We then looked to see who had the genetic change. It was really exciting to find out that the genetic change and the amount of protein were linked. "The protein is easy to detect because it is found in urine and would potentially be a very simple test to carry out on men to identify those most at risk of developing the disease." Dr Kate Holmes, research manager at The Prostate Cancer Charity, described the test as "potentially… a powerful way to predict how likely a man is to develop prostate cancer".
(BBC Health 14 Oct 2010)

Scientists at the University of Surrey have discovered that prostate cancers secrete a chemical called EN2 that can be found in a urine test.
Their findings from a study of 288 patients, published in the journal Clinical Cancer Research, suggest this is better than the PSA check at detecting cancers, with far fewer false positives.

Professor Hardev Pandha University of Surrey one of the researchers, said the new EN2 test was more reliable and accurate. "In this study we showed that the new test was twice as good at finding prostate cancer as the standard PSA test," he said. "Only rarely did we find EN2 in the urine of men who were cancer free, so if we find EN2, we can be reasonably sure that a man has prostate cancer." Larger-scale trials are now being planned in the UK and the United States. The researchers envisage the EN2 urine check would be used alongside the PSA blood test. A group of new drugs reveal promising results to prolong the lives and also relieve the symptoms of prostatic cancer. All the following new drugs are approved by the FDA.

Cabozantinib- (Exelixis) – seems to eradicate bone metastasis in some patients.
Docetaxel (chemotherapy drug)
Dendreon's Provenge (works by training the body's immune system to fight the cancer). Provenge costs $ 93,000 for the full course
Johnson & Johnson's Zytiga (new form of chemotherapy- inhibits an enzyme called CYP17, clamps downon testosterone production)).
Zytiga costs $5,000 a month
Sanofi's Jevtana (chemotherapy drug). Jevtana costs about $ 8,000 every three weeks.
Alpharadin (Norway Company)
Abiraterone (Janssen)
Abiraterone acetate interferes with the production of the hormone testosterone, which can fuel the growth of prostate cancer. The trials involved more than 1,000 men with very advanced, aggressive cancers, whose prognosis was poor, with only months left to live. The 797 patients given abiraterone plus a steroid lived for an average of 14.8 months, compared to 10.9 months for the remainder who simply got the steroid. Another advantage of the drug was the relative lack of side effects compared with chemotherapy or radiotherapy, making it a far more attractive prospect for patients.

The drug was first discovered at the Institute of Cancer Research in London, and its chief executive Professor Peter Rigby said he was "very proud" that men with advanced prostate cancer had this new treatment option. (BBC News 11 Oct.2010) These drugs are considered only for those whose growth has spread to beyond the prostate gland and with no response to check with hormone therapy. They are the last resorts.Life expectancy can be prolonged by two years, approximately. Presently, they are very expensive.

The standard treatment if the cancer is caught before spread beyond the gland can be cured by surgery and radiation therapy.

The Cell-Search machine

A major advance in the treatment of advanced prostate cancer in Australian men has been announced at an international conference on the disease on the Gold Coast. The Cell-Search machine, the first of its kind in Australasia, tests for circulating tumour cells which detach from solid tumours and enter the blood stream with the potential to spread cancers to other parts of the body. The conference was told the machine, as well as a new multidisciplinary team clinic at Brisbane's Princess Alexandra Hospital (PAH), represent a major leap forward in fighting the prostate cancer.Queensland University of Technology's (QUT) Chair of Prostate Cancer, Professor Coleen Nelson, said the equipment would be a national resource for monitoring treatment response and predicting survival in patients with metastatic prostate, breast and colorectal cancer.

"Scientifically, the Cell-Search facility will enable us to capture prostate cancer cells and investigate them at a molecular level," said Professor Nelson. "It will be used in clinical trials of prostate cancer treatments and to monitor the treatment of cancer in individual patients from around Australia."

PSA screening benefits

Dr Gerald L. Andriole, a urologic surgeon at Washington University, as a director of national Cancer institute study of 7,000 men had failed to find a screening benefit after 10 years. The men were aged 55 to 74 when the study began. P.S.A. screening is controversial at any age. Screening proponents say the cancer institute study was flawed and point to a European study of 162,000 men aged 55 to 69 that showed a 20 percent drop in the prostate cancer death rate with screening.

They note that prostate cancer is a common cancer, found in most men's prostates on autopsy, although often the men had no idea they had it. The cancer can be lethal, but it usually grows so slowly that men die with it, not because of it. For most men, screening only has harms because it leads to biopsies and treatments with unpleasant side effects. And, they say, it might not help cure many deadly prostate cancers because those cancers may have already spread outside the prostate, microscopically seeding other organs, long before a P.S.A. test indicates a possible problem

One reason treatment is the most common choice is that it is hard to know if a cancer is lethal. Pathologists can distinguish between cancers that look particularly aggressive and those that do not, but there is a real possibility that even if tissue obtained at a biopsy has only less aggressive tumour cells, more aggressive cells might still be lurking in the prostate.

"It is the hardest thing in the world not to look for a cancer and not to treat it," Dr Andriole says. And doctors, he added, have many inducements to screen. They often are afraid they could be sued if they do not screen and a man is found to have a lethal cancer. And there are financial incentives.

Dr Brooks of the cancer society says he travels the country and talks to primary care doctors about screening, and has learned that many have misconceptions about the test's benefits.

"They often don't appreciate the downside of screening," Dr Brooks said, "and they don't appreciate the delay in benefit." In addition, Dr Brooks said, primary care doctors often "overestimate the likelihood that early detection of prostate cancer will lead to survival benefits."

Added to that, Dr Brooks said, is the length of time it takes to discuss the pros and cons of screening with patients. Often it is easier to just order the test. Dr Bruce Roth, a professor of medicine at the University of Washington, said that ideally, a doctor should take a man's overall health into account and not just go by age in ordering P.S.A. tests. But if a man has been screened year after year, it can be hard to suggest he stop because he may not live much longer. (Screening Prostates at any age by Gina Kolata)

Whatever, the above discussion reveal, all men must have their PSA checked annually, during the productive years of one's life.

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