Prostate Biopsy- Is it a Perfect Procedure?

Joseph C. Presti Jr. says in "Prostate Cancer: Principles and Practice" (page 23):

"...needle biopsy of the prostate represents a sampling of the gland, and accurate prediction of tumor grade within the prostate may be hindered by sampling error. In general, in several series correlating tumor grade on the biopsy with the grade of tumor in the radical prostatectomy specimen, needle biopsies exactly correlate with the prostatectomy in 31% to 59% of cases. The magnitude of this grading error is greater than or equal to 2 points in the Gleason sum in 26% to 38% of cases, with the needle biopsy more likely underestimating the tumor grade in comparison to the radical prostatectomy specimen."

In the book "Prostate Cancer", by Sylvan Meyer and Dr. Seymour C. Nash (page 55), Dr. Nash says:

"Why are so many prostate cancers understaged, some 50% of the cases we operate on? Because we got them tardily. Because PCa is a multifocal disease. It may not just be in one spot. It hides. In a rectal exam, there are multiple areas you can't feel. I'd say half the cases are multifocal and not in one area. That's why if you biopsy one area and the cells are well differentiated, another area could be totally undifferentiated. So, what you get in tests may not be what's there. "

In Ferris Clinical Advisor 2004-6th Ed (page 491), we read the following:

"The use of serum-free PSA for prostate screening has been proposed by some urologists as a means to decrease unwarranted biopsies without missing a significant number of prostate cancers. This approach is based on the higher free PSA in men with benign prostatic hyperplasia and the higher protein-bound PSA levels in men with prostate cancer. For example, in men with total PSA levels of 4 to 10 ng/ml, the cancer probability is 0.25, but if the percent free PSA is =17%, the probability of cancer increases to 0.45."

So unfortunately no, it's not perfect. The tumor is a compact mass of cells and that is what is normally felt during a DRE. Some cancers are already in an advanced stage, and only few biopsy samples are needed. But we should not forget that "cancer" means "crab". This gives us a clue of its possible complexity: it can have many small legs, spreading throughout the prostate and even worse, metastasizing throughout the body. Which is why sometimes, "more" is "better" as far as prostatic samples are concerned.

Someone compared a biopsy to chasing a worm inside an apple, with a needle: there's a possibility you won't get it the first time.

But it is extremely useful in many cases...

<<Prostate Biopsy | Prostate Biopsy- - Reason & Preparation>>