The co-authors of Invasion of the Prostate Snatchers, blog alternate posts weekly. We invite you to post your comments.

Tuesday, March 27, 2012

Biopsy, Biopsy Everywhere


A month ago I promised to expound more concerning our national passion for prostate biopsy. A million men are biopsied every year. Two hundred thousand will be diagnosed, the majority with Low-Risk disease, a condition that can be safely monitored without immediate treatment. Even so, most will undergo prompt radical treatment. Irrational fears drive most men into taking immediate action.

Since diagnosis overwhelmingly portends overtreatment, some experts have suggested that we put a stop to PSA testing. Practically speaking this will never happen. Patients and doctors alike are unwilling to forgo the information that PSA provides, imperfect as it may be.
Realistically speaking, PSA testing per se is not the real problem.  The problem is doctors and patients overreacting to the information PSA supplies. The solution is not less frequent PSA testing, but rather convincing physicians to slow down the rush to immediately biopsy men with slight PSA increases. Diagnosing every single case of prostate cancer is of highly questionable value. Many men would rather be spared the unnecessary knowledge that they have a non-threatening Low-Risk prostate cancer.

Rushing into an immediate biopsy only makes sense when aggressive cancer is present and that is much less common.

So where is the middle ground between immediate biopsy of every PSA elevation and forgoing PSA testing and biopsy altogether?

Before deciding to do a biopsy, the prostate gland should be measured with an ultrasound scan to determine whether it is abnormally enlarged.  If the amount of PSA elevation is proportionate to the degree of prostate enlargement, then the PSA elevation is due to benign cause. Rather than proceeding with an immediate biopsy, additional PSA monitoring and a urine test called PCA-3 may be helpful. 

PCA-3 is a relatively new test that measures ribonucleic acid (RNA) secreted by the cancer cells into the urine following manual massage of the prostate. Studies show that the amount of PCA-3 in the urine increases in proportion to both the size and aggressiveness of a man’s prostate cancer. Unlike PSA, PCA-3 is unaffected by the size of the prostate. Low amounts of PCA-3 in the urine, say less than 40, indicate that the presence of an underlying aggressive cancer is less likely.

If the PCA-3 and PSA density are favorable, further monitoring with some form of imaging offers additional insurance against missing the diagnosis of aggressive cancer.  Modern 3-Tesla endorectal MRI and high-resolution color Doppler ultrasound, while not perfect, are reasonably accurate methods for detecting aggressive cancers. 

So in summary, biopsy should be reserved for men with elevated PSA levels that can’t be explained by a prostate infection, laboratory error or recent sexual activity. Here are some signs that a biopsy may be needed:

1.                  A PSA elevation out of proportion to the size of their gland or
2.                  Abnormally elevated PCA-3 levels or
3.                  An abnormality felt on digital rectal examination or
4.                  Imaging studies suggestive of underlying aggressive cancer.

PSA is a remarkable tool that has transformed the management of prostate cancer over the last 20 years. Rather than triggering an immediate biopsy, an elevated PSA should lead to further investigation. Rushing to a biopsy simply because PSA is elevated frequently leads to unnecessary radical treatment with detrimental lifelong consequences.


Doug said...

What is the sensitivity and specificity of the PCA-3 test? I am asking this since saw Dr Fred Lee last fall, and asked him about this test. He did not recommend doing it.

Mark, I want to thank Ralph and you very much for writing Prostate Snatchers, bringing clarity to this land of confusion I found myself in recently. The initial recommendations made to me did not make sense. And if not for your book, and Dr Lee's opinion I would have made a disastrous decision.

Anonymous said...

Great presentation! I have been emphasizing this with our support group for some time. All urologists should have to pass a test on this.

Gene Van Vleet
Informed Prostate Cancer Support Group

Prostate Oncology Specialists said...

Sensitivity and specificity is a little better than PSA. That is to say, not that good.

Mark Scholz, MD

Lawrenzo said...

I am just now learning of the rush to biopsy think in the medical field. My PSA has bounced from 6 in Feb to 4 in April to 4.7 in June. Yet my PCA3 test came in at an extremely low 0.7! That tells me that the likelyhood of cancer is extremely low, yet my Urologist instantly ordered up a biopsy. Not so fast there Mr!