March 3, 2011

Unneccessary Biopsies For Prostate Cancer?

(Ivanhoe Newswire) -- Prostate cancer is one of the most controversial cancers in both diagnosis and treatment; and with recommendations from several cancer organizations to men with a rapid rise in PSA to immediately have a biopsy for prostate . . . it only adds to the already heated debate.   However, change in PSA "“ commonly referred to as PSA velocity "“ isn't the most accurate predictor for this second most common cancer.  The recent guidelines released from these institutes may lead to more than a few unnecessary biopsies.

It's common knowledge that PSA velocity is statistically correlated with prostate cancer risk; well, common knowledge for researchers at least.  Nevertheless, not too much is known regarding how much PSA velocity and how it adds to the value of other indicators.  It's also still unclear how useful it is to men and their physicians when making decisions about biopsies.  The study adds that moreover, there has never been a study of PSA velocity with men who received biopsies previously in the absence of an elevated PSA or a positive digital rectal exam.

Meet Ander Vickers, Ph.D. and his team of colleagues from memorial Sloan-Kettering Cancer Center.  This group of go-getters set out to access how well PSA velocity actually predicted cancer.  With 5,519 men taking part in the Prostate Cancer Prevention Trial, Vickers began his decent into the truth.  All of the men in this analysis received a placebo as to not influence their prostate cancer risk via the drug finasteride (Proscar).  Regardless of PSA levels, PSA velocity and other indicators, all of the participating men received a biopsy at the end of the study.

"There was little evidence that PSA velocity adds an important level of predictive accuracy to either standard predictors or to PSA alone," which the authors of the study were quoted as saying.

Vickers and his group then delved into the guidelines stating men with an increase in PSA should have a biopsy regardless of abnormal findings on a clinical exam.  80 percent of the men that fell into this category did not have cancer, which utterly suggests that the use of PSA velocity will lead to needless biopsies.  Vickers adds that PSA alone was a better predictor of biopsy outcome than merely PSA velocity.

"In other words," they write, "if a clinician feels that the current PSA thresholds are insufficiently sensitive, he or she would be better off identifying patients to biopsy by using low PSA thresholds than by adding PSA velocity as a criterion for biopsy."

The researchers concluded that PSA velocity should not be included in prostate cancer screening guidelines.

"PSA velocity measurements take time to acquire, and recognizing that such data add relatively little information may help prevent inappropriate postponement of follow-up in affected patients," they write. "Avoiding the wait to acquire subsequent PSA values may also help reduce some of the anxiety associated with testing." They go on to say that the results of this study serve to "remind us that the use of PSA as a screening tool still leaves much to be desired."

SOURCE: Journal of the National Cancer Institute, 24 February 2011