Is It Possible to Substitute a Scan for Prostate Biopsy?

man receiving medical scan for prostate cancer diagnosis
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There are two different ways to do a prostate biopsy -  targeted and random. The random 12-core prostate biopsy is standard and has been in use for over 25 years. Now, since MRI imaging has greatly improved, the number of needle biopsies can be reduced substantially. A couple of cores can be directed at a single target within the gland. There are pros and cons with a targeted biopsy. The first concern is that perhaps 10% of small, high-grade cancers can be missed by modern scanning. Second, targeting a prostate lesion takes skill and experience; the technology is new and some doctors are still on a learning curve.

Accuracy of Biopsies

Apart from these concerns, most men would much prefer a single targeted biopsy rather than being randomly punctured 12 times. In addition, random biopsy has another huge disadvantage— it grossly over-diagnoses harmless, grade-6 cancer. Grade 6 is the most common type of prostate cancer. It does not need treatment but unfortunately often gets treated anyway. Studies show that too many men are getting treatment for low-grade harmless cancers. Logically then, isn’t it clear that too many men are being diagnosedDiagnosing a “cancer” that doesn’t require treatment is harmful, not helpful.

Neither random biopsy nor targeted biopsy is 100% accurate. Random biopsy can miss high-grade cancer 15% of the time. The real question is, “How good do we really need to be?” Everyone is in agreement that as things stand, using the existing system of random biopsy, we are grossly over-diagnosing prostate cancer at a furious rate. We should, therefore, be looking at any reasonable alternative for reducing the number of men undergoing biopsy.

The 3-Tesla Multi-parametric Prostate MRI

Of course, let’s be absolutely clear. The right technology and the right people using the technology are required to obtain reliable images. Good technicians are needed to perform the scans properly. The physicians who read the scans also need to be specifically trained in reading 3-Tesla multi-parametric prostate scans. Unfortunately, some of the doctors in the community are performing these scans, but don't have the experience yet to interpret them accurately. Patients need to use experienced centers. Otherwise, the scan report will be of questionable accuracy. It's vitally important to use approved facilities - centers of excellence that know how to do 3-Tesla multi-parametric prostate MRI properly.

Bottom line is we can tolerate the fact that well-performed scans still have a 10% chance of missing high-grade prostate cancer. The cancers that will be missed are bound to be small. If a small, but clinically-significant tumor is missed on the initial scan, the scan can be repeated in 6-12 months. By definition, for a tumor to be clinically significant, it has to grow. The good news is that prostate cancers typically don't spread until they get to a certain size. Sequential scanning should be sufficient to detect an enlarging high-grade tumor while it is still early-stage and curable. On the other hand, if nothing appears after a couple of years of annual scanning, the chance that there is an underlying clinically-significant prostate cancer, is greatly diminished if not eliminated.

Closing Thoughts

Using a policy of scanning men with high PSA levels, rather than doing a random biopsy, is a major improvement. Over a million men undergo random biopsy every year. Now that scanning technology is so improved, it is time to start talking about leaving the random biopsy out of the picture altogether. Rather than undergoing a random biopsy, men should have a 3-Tesla multi-parametric MRI followed by a targeted biopsy. This approach would help stop the mad rush to overtreatment that is so common in the United States. If men can avoid being labeled with “cancer,” there is no temptation for them to undergo radical surgery or radiation.