Prostate testing: The lowdown on PSA testing

Imagine youre flying in a commercial jet and the pilot tells you hell be putting the aircraft on autopilot. That probably wouldnt be a concern. But imagine youre at your doctors office and he tells you that hes just put his judgment on autopilot.

Two questions: Wheres the parachute, and wheres the exit?

Unfortunately, doctors often simply go with basic procedures theyve always used. But things change, and when doctors dont stay on top of changes, patients sometimes suffer.

One perfect example of an autopilot medical mindset concerns the prostate-specific antigen (PSA) test used to determine prostate cancer risk. Ive shared this warning several times before, but the mainstream still hasnt picked up on it so it cant be repeated enough: Men, if your doctor suggests a biopsy based on a high PSA level, he may be flying on autopilot.

A new supplement study inadvertently demonstrates that a PSA reading should be considered a useful tool, as long as its viewed with healthy scepticism. 

Putting on the brakes
PSA is a protein thats naturally produced by the prostate gland. Prostate tumours typically cause an over-production of PSA, so when a blood test reveals an elevated level of the protein, its a red flag that warns of possible cancer.

Urology researchers in Rotterdam, the Netherlands, created a trial to examine the effect of certain nutrients on PSA levels.

As reported in the International Journal of Cancer, the Rotterdam team recruited 37 men who had prostate cancer and increasing PSA levels. For a period of six weeks, about half of the subjects supplemented their diets with a formula that contained antioxidants, green tea extract, soy extract, vitamin E, selenium and plant sterols.

The other subjects took a placebo. In the second phase of the study, those taking the supplement switched to placebo for six additional weeks, while the first placebo group began taking the supplement.

Blood tests taken throughout the study showed that PSA continued to increase during the placebo phase, but the increase was significantly slowed during the supplement phase. Nevertheless, there was no indication that the nutrients had any effect on the cancer.

In an interview with Reuters Health, the lead author of the study, Dr Ries Kranse admitted that a change in PSA progression does not necessarily mean that tumour size is reduced. What this study does help confirm is that something as simple as a dietary change may cause fluctuations in PSA levels.

Time for caution
Alternative healthcare pioneer, US physician, Dr William Campbell Douglass is no fan of PSA tests or their follow-up biopsies. Dr. Douglass refers to this one-two punch as, the mainstreams slash-and-burn approach to prostate cancer. A 2003 editorial in the British Medical Journal put it another way: At present the one certainty about PSA testing is that it causes harm.

Its not the test itself that causes harm, of course, its the reaction to the test. When PSA is elevated, many doctors recommend a biopsy of the prostate; a painful procedure that can result in bleeding and infection. But recent evidence shows that a great number of these biopsies are completely unnecessary.

In a study from the Memorial Sloan-Kettering Cancer Centre in New York City, US researchers examined fluctuations in PSA levels to test the reliability of a single PSA result.

Over a 4-year period, the Sloan-Kettering team collected five blood samples each from nearly 1,000 men whose median age was 62 years. More than 20 percent of the subjects were found to have PSA levels high enough that many doctors would have recommended a biopsy. Half of those men, however, had follow-up tests with normal PSA levels.

The Sloan-Kettering team concluded that an isolated PSA screening with an elevated level should be followed with an additional screening several weeks later before proceeding with further testing or a biopsy.

This research backs up another study I told you about in a previous e-alert in which doctors at the Fred Hutchinson Cancer Research Centre (FHCRC) in the US estimated that PSA screening may result in an over-diagnosis rate of more than 40 percent.

Fibre option 
Although the Rotterdam research didnt show that supplements slow the progression of prostate cancer, other tests have indicated that certain foods may offer protection against the disease.

In an e-alert I sent you last month (The full lowdown on drinking water 22/02/05), I looked at an Italian study that surveyed the dietary habits of more than 1,700 middle-aged and elderly men.

Researchers found that a high intake of any type of fibre reduced prostate cancer risk slightly. Soluble fibre intake appeared to offer some protection, but when fruit, vegetable and grain fibre intakes were compared, vegetable fibre was associated with the lowest risk.

But was fibre responsible for the prevention, or was it the lifestyle? As one researcher noted, those who choose to include generous amounts of vegetables in their diets may be more likely to incorporate other healthy habits in their daily routines.

That sounds like a pretty good plan for prostate cancer prevention.