Prostate Guideline Causes Many Needless Biopsies, Study Says
By NICHOLAS BAKALAR

Current guidelines for the early detection of prostate cancer recommend a biopsy for men whose P.S.A. rises rapidly, no matter what the initial level. But a new study says that the practice does not help patients find aggressive cancers and results in many unnecessary biopsies.

P.S.A., or prostate-specific antigen, rises with age, and what is considered normal varies. In general, a level under 4 nanograms per milliliter is considered safe. But even with a normal reading, an increase of 0.35 nanograms per year is widely believed to be high enough to require a biopsy.

Researchers examined the records of 5,519 men with a base-line P.S.A. under 3. They followed them for seven years with yearly tests and a biopsy if the level rose above 4.

They also analyzed P.S.A. velocity — the rate of change in readings from year to year. But after adjusting for age, base-line P.S.A. and other factors, they found little evidence that ordering a biopsy for men whose velocity was greater than 0.35 helped find prostate cancer. And it was particularly useless in uncovering the most aggressive types of cancer, the ones most important to treat.

The researchers, writing in the March 16 issue of The Journal of the National Cancer Institute, concluded that using P.S.A. velocity for prostate cancer detection is ineffective, that it leads to unnecessary biopsies and that references to it should be removed from professional guidelines and policy statements.

Andrew J. Vickers, the lead author, drew an analogy: A basketball player’s height, he said, is important to his ability to play, and it correlates very closely with his shoe size. But once you know his height, his shoe size is irrelevant to judging his value as a player.

Similarly, it is easy to demonstrate a statistical relationship between sharp rises in P.S.A. and cancer, but the correlation reveals no more information than is already available with a P.S.A. reading, a digital examination and a family history. It is irrelevant in deciding whether a biopsy is needed.

Not all experts agree. Dr. Anthony V. D’Amico, a professor of radiation oncology at Harvard, said that the methodology of Dr. Vickers’s study was sound, but that the data gathered was almost certainly flawed.

The problem, Dr. D’Amico said, is that many factors that have nothing to do with prostate cancer can cause a rapid increase in prostate-specific antigen. Sexual activity, riding on a bicycle or on horseback, a recent colonoscopy, a bladder or prostate infection, even variations in the ways laboratories perform the test can radically affect the readings.

“It may well be that the high velocity in your case is not important,” he said. “But before you reach that conclusion, I would get a repeat P.S.A.” If there is still a spike after eliminating those other possible causes, he continued, a biopsy should be the next step.

Dr. Vickers, a researcher at Memorial Sloan-Kettering Cancer Center in New York, agreed that prostate cancer was only one of many reasons for a high P.S.A. “A doctor sees a high P.S.A. and says, ‘Could this be cancer or some other reason?’ ” he said. “Well, the thought was that P.S.A. velocity could help you think this through” — that measuring the rate of change would be decisive.

But in practice, Dr. Vickers said, it does not work. If he had strictly applied the guidelines to the men in his study, he said, one in every seven would have required a biopsy. This would mean millions of American men would need biopsies, he said, with almost none revealing a cancer.

Dr. Vickers and his colleagues acknowledged that there might be better methods of calculating P.S.A. velocity that could lead to more accurate predictions, and that some effect might have been found if the patients had been followed for more than seven years.

But at this point, he is firmly against biopsies on the basis of velocity alone. “If your P.S.A. is in the normal range, you shouldn’t get a biopsy,” he said. “Changes or spikes in P.S.A. are not something to worry about if your P.S.A. is still normal.”