Inaccurate screening tests and scalpel-happy surgeons could be inflating the real number of cases in this so-called epidemic and leaving many people worse off than before.
How do you treat prostate cancer? The specialists can't agree whether it's best to treat tumours with surgery or radiotherapy, or simply leave them alone.
At the moment, we've got the worst of both worlds. In the UK, sufferers seek help for prostate cancer when it's too late for therapy. And in America, every man over 50 is supposed to have a yearly check-up; if a tumour is found, it's removed automatically, but so far there isn't any evidence to show this approach makes you live longer (JAMA, September 14, 1994).
Prostate cancer currently accounts for 14,000 new cases each year in Britain and is the third most common cancer among British men (The Lancet, May 22, 1993). It's also the most frequently occurring cancer among American men-165,000 new prostate cancer cases were diagnosed in 1993 (JAMA, May 26, 1993). A year later, this had supposedly grown to around 200,000 cases; prostate cancer was supposedly detected in 30 per cent of men over 50. Black rather than white males are more likely to contract it. The highest number of Black sufferers live in America.
Although it predominantly affects older men, it has been estimated that men dying of prostate cancer in America on average lose nine years of their life (National Cancer Institute 1989; No 89-2789).
The problem is that most doctors these days are scalpel happy. Surgery is the first-line and most dangerous treatment. Although the incidence of cancer hasn't really gone up, aggressive treatment like surgery has increased by 36 per cent, leading everyone to worry that prostate cancer is becoming epidemic.
The most famous study of this , entitled the SEER programme (Surveillance, Epidemiology and End Results), conducted by the Center for Evaluative Clinical Sciences in Hanover, New Hampshire, found that while prostate cancer had only increased modestly in America during the Eighties, the rates of prostatectomy were increasing by 35 per cent per year, and even more in different areas of the country. Nevertheless, according to the SEER study, this wasn't having any impact on survival rates.
A tendency to prostate cancer may be hereditary, although many environmental factors such as diet appear important in bringing on the disease (see box, p 3). If, say, a brother or father has prostate cancer, a patient is more than twice as likely to develop it than someone without any family links. And the risk increases according to the number of sufferers in the family. For example, two relatives would quadruple the risk.
Tests carried out over a number of years at Britain's Atomic Energy Authority also show nuclear workers exposed to some radioactive substances have an increased risk of contracting prostate cancer, although the effect of each substance is not known (BMJ, November 27, 1993).
Sexual activity or sexually transmitted diseases may also be associated with prostate cancer (The Lancet, October 9, 1993), as may vasectomy. Two US studies showed that vasectomized men had a 60 per cent increased risk of prostate cancer (JAMA, 1993; 269 (7): 878-82 and The Lancet, May 22, 1993). However, a medical panel reporting in the Journal of the American Medical Association rushed in to claim that the studies were found to be flawed from "detection bias" those men who had vasectomies were under the care of a urologist and may have been more likely to be examined and diagnosed with prostate cancer.
Nevertheless, the current recommendation is that although vasectomies should still be performed, patients should be given informed consent about a possible link with prostate cancer.
At the moment, screening for prostate cancer is just a simple matter of a blood test and a rectal check to see whether it's likely that a cancer is developing. But the Prostatic Specific Antigen (PSA) blood test has attracted much criticism (JAMA 1992; 267: 2236-8). It's feared such tests can't accurately establish whether patients thought to be free from prostate cancer actually have it (JAMA, December 9, 1992) because so much has still to be learned about the way that prostate cancer behaves.
There is also a fear that nationwide screening to include PSA tests could lead to over-treatment of large numbers of men with drugs, surgery, or radiotherapy unnecessarily, when monitoring the patient and improving the diet would be a far more effective course of action to take. It would also cost a fortune, running at many times the cost of today's treatment (Urol Clin North Am, 1990; 17: 719-735).
Screening programmes carried out in America show that an annual examination alone may be insufficiently frequent and/or sensitive to prevent deaths from prostate cancer and therefore contradicts the conventional wisdom that early detection and treatment of cancer saves lives (JAMA 1993; 269: 61-64). It doesn't.
One can draw parallels here with the thinking on breast cancer, where 20 years ago it was assumed that visits to breast screening clinics where breast cancer could be spotted earlier would therefore lead to its effective treatment. It hasn't (JAMA, September 15, 1993). However, the rationale behind prostate cancer screening is not based on a series of controlled trials which show it actually works, but on a subjective sense that it ought to help. No treatment at any stage of the disease has been shown to improve survival in an adequate clinical trial (BMJ, March 27, 1993).
Research conducted earlier in the year by the Harvard Medical School and the Harvard School of Public Health concludes that we shouldn't write off PSA screening entirely since further tests into its costs and clinical effectiveness could well improve the way we spot prostate cancer in its early stages of development (JAMA, January 25, 1995, February 15, 1995 and September 14, 1994).
The National Cancer Institute has also launched a major examination of such tests the prostate, lung, colon rectum, and ovary cancer screening trial. This will evaluate the screening tests for these four diseases and plans to report before the end of the century (Ann of Int Med 1993; 119: 914-923).
However, there are reasons to be concerned about whether a clear answer will be forthcoming, even if the study is completed. Mostly for practical reasons, the study includes men aged between 60 and 74. So, regardless of the examination's outcome, the impact of screening on men younger than 60 will not be known (JAMA , June 1, 1994).
This is really bad news when other trials suggest that screening for prostate cancer should be confined to high-risk, young men who ought to have the greatest chance to benefit from early detection (The Lancet, 1994; 344: 1594-98 and BMJ, 1995; 310: 1139-40).
Transrectal ultrasound (TRUS) and magnetic resonance imaging are also being used to spot and monitor potential cancers. However, the technology has been shown to be inaccurate where prostate cancer is concerned, not indicating clearly whether or not the cancer is malignant (JAMA, August 17, 1994).
Even if you're lucky enough to be correctly diagnosed, getting prostate cancer treated is rather like having a game of Russian Roulette. It's very much a hit-and-miss affair because the medical profession doesn't really know why cancer of the prostate occurs, and can't agree upon a common method of treatment.
A major study of radical prostatectomies (where the cancerous prostate is removed altogether) shows patients who undergo the operation can die from a number of major heart-related complications which usually occur within 30 days of the operation being performed (JAMA, May 26, 1993). Those who do survive often have weeks of recuperation.
Furthermore, it is grossly overused, even though it is supposed to be used with those with very early cancer only affecting the prostate gland itself and no tissue or the capsule surrounding it. It is particularly risky for for men over 70, when it has been shown to kill one in 50 (JAMA, 1993; 270: 948-54),
However, prostate cancer is unique in that the majority of cases perhaps as many as 90 per cent never become "clinically significant". "There is variance in the way a cancer develops in each individual," says Philip Dunn, founder of the Prostate Help Association, a charity to provide sufferers with more information about prostate-related disease. "Many men are never diagnosed with prostate cancer and it is only after death, from some other reason, that the condition is discovered. With others, you can't tell whether the cancer is one which will spread quickly, or grow very slowly," concludes Dunn.
In the main, however, prostate cancer is very slow growing and doesn't spread; two studies have shown that 86 per cent of patients with prostate cancer survive 10 years after diagnosis and in two-thirds of cases, the cancer hadn't spread (New Eng J Med, January 27, 1994 and JAMA, April 22/29, 1992). Particularly if you are over 70, you are far more likely to die with prostate cancer than of it. Autopsy studies in Europe have shown that a third of European men have prostate cancer, but only 1 per cent died from it (The Lancet, February 13, 1993).
The biggest problem with surgery is that it makes most men impotent and a fair number incontinent. In surgery, the latest rage is the "nerve sparing" technique, which is supposed to preserve sexual potency. Several studies report excellent survival rates (National Cancer Institute 1988; 7: 117-126) because just the inner gland and the capsule of the prostate are removed; most of the nerves are spared and patients are supposedly able to maintain a normal sex life.
Reginald Lloyd-Davies, Senior Consultant Urologist at St Thomas' Hospital in London, says 80 per cent of patients can now expect to live for a further five to 10 years with the new technique, but half of all patients still lose potency and around five per cent become incontinent. This is also major abdominal surgery, performed above the pubic bone, and so must be done by an experienced surgeon.
Drug therapy is now the less invasive alternative. Prostate cancer appears to depend on the male hormone testosterone. Anti-testosterone drugs are used to shrink cancerous tissue, but how long the patient remains trouble-free depends on how fast the tumour has been growing. Hormone treatment can become ineffective as the famous example of musician Frank Zappa showed a couple of years ago. He died at 52 after his fast-growing tumour slipped out of hormonal control.
As you might expect, treating the cancer with drugs is controversial. In the US, trials have been carried out with 7,000 high-risk patients to see if being routinely treated with Proscar (finasteride), a drug which shrinks the prostate, could do for men's prostates what tamoxifen, an anti-estrogen drug, reputedly does to save women from breast cancer. Urologists have not been convinced about the drug's effectiveness. It takes between three and six months for symptoms to improve, and the drug only appears to work in a minority of patients (see Drug of the Month, p 7). The biggest problem with anti-testosterone (or luteinizing hormone-releasing hormone) drugs like goserelin, besides affecting your sex drive and causing some feminizing, is that there is a risk of any cancer that has spread getting worse and increased pain from cancer in the bones.
Cyprostat (cyproterone acetate), a steroid, which blocks the production and effects of androgens, is often used to counter the effects of LH drugs. But this category of drugs has its own set of potential side effects, including osteoporosis. Nevertheless, these side effects may be worth putting up with, as against surgery which hasn't been proven to do any good.
Non steroids which can be used include: Flutamide (hormone), Nilutamide and Casodex. Currently, drug companies are trying to develop a new breed of alpha blocker which has few side effects and works directly on the prostate.
Clive Couldwell writes for the London Times, The Daily Telegraph and The Financial Times newspapers.