Prostate Biopsy Fun Facts! Also, Why Cancer Can be Missed in African American Men, and a Word about the Bacteria in your Rear End

I lied in the headline.

strawberriesA prostate biopsy is not actually fun. But if you need one – if your PSA has gone up more than 0.4 ng/ml a year, or if your doctor has felt something suspicious, like a hard spot on the prostate during the rectal exam – then you need one, so here are a few things you should know.

The way doctors look for cancer in the prostate is much like looking with a needle in a haystack. The needle in this case is a spring-loaded biopsy gun, a tiny device that’s attached to an ultrasound machine. It’s not like a sewing needle; this one has a hollow center, so that it can capture at least 10 to 12 tiny cores of tissue, each one about a millimeter thick. Those cores go to a pathologist, who studies them under the microscope.

The Seeds in the Strawberry

What are they looking for? Johns Hopkins urologist Patrick Walsh, my co-author of Dr. Patrick Walsh‘s Guide to Surviving Prostate Cancer, uses this image with his patients: Imagine the prostate as a large strawberry.

Prostate cancer is multifocal. It causes what scientists call a field change. Multiple tumors pop up like dandelions, all at about the same time.

These seeds are tumors, and three to seven is the average number of separate cancers found in a radical prostatectomy (the operation to remove the entire prostate) specimen. How can a man develop several different spots of cancer? Prostate cancer is multifocal. It causes what scientists call a “field change” – basically, the entire prostate undergoes a transformation. Multiple tumors pop up like dandelions, all at about the same time. Each spot can be millimeters in size.

So this is what the urologist is looking for with the biopsy needle. But it’s not easy to hit a tiny seed inside a strawberry, especially one you can’t always see.

Why Cancer Can be Missed in African American Men

In another post, I mentioned the important work that another Johns Hopkins urologist, Ted Schaeffer, is doing in understanding how prostate cancer is different in African American men. One reason it may be more aggressive when it’s diagnosed is that black men with prostate cancer make less PSA per gram of cancerous tissue, “So their PSA score could be misleading,” says Schaeffer. “There are fewer early warning signs.”

But even when an African American man does get a biopsy, his cancer can be missed. This is because his cancer, for some ornery reason, picks the hardest-to-get-to, easiest-to-miss-on-a-biopsy region of the prostate. “The way I explain it to patients,” says Schaeffer, “is, think about your prostate like a house.

“You have a basement. Just under that basement, the sub-basement, is the rectum, where we do the biopsies. You have a first floor, and an attic. Tumors in most Caucasians occur in the basement. If you’re taking tissue samples of the prostate from the sub-basement, you can get a good sampling of that area and are more likely to pick up a cancer. But if you’re African American, you have a high chance of having what we call an anterior tumor, in the attic of the house. It’s just harder, frankly, to be able to sample that area on a standard biopsy.”

This is why Schaeffer and colleagues get MRI images of their patients at highest risk, including African American men. “If we see something suspicious, we do an MRI-guided biopsy. We’re not the only place in the world doing this, but we’re doing it for reasons that were discovered at Hopkins.”

So, this is what I hope will be the take-home message:

If you are a black man, you need to be checked for prostate cancer starting at age 40. Get a baseline PSA test and have a rectal exam. If your PSA goes up more than 0.4 ng/ml a year – even if the number itself is low – you need a biopsy. Ideally, you need an MRI-guided biopsy. If no cancer is found, and that PSA keeps going up, you need another biopsy. If your doctor does not feel this way, find another one – a doctor who understands that prostate cancer is different in African American men in several important ways.

And Now, a Word About the Bacteria in Your Rear End

No offense, but you have bacteria in your bottom. We all do, so it’s nothing personal here. But it becomes an issue, so to speak, when you need a prostate biopsy. You’ve probably heard of nasty bugs known as multi-drug-resistant bacteria. When the biopsy needle goes into the prostate, it goes “transrectally” – through the rectum. To minimize the risk of infection, the standard protocol is for men to have an enema and to take antibiotics.

But this is not always enough. It turns out that one out of every five men has this multi-drug-resistant bacteria. If you have it, and you get an infection, “you can get very sick,” says Ted Schaeffer. The men most at risk? “Diabetics and health care providers. He made this observation in a study of a huge Medicare database of patients. His father, noted urologist Anthony J. Schaeffer, Urologist-in-Chief at Northwestern, is an expert on infection. Together, they came up with a protocol to lower the risk of a bad infection. “Before any biopsy, we sample the rectal flora” – the butt bacteria, if you will – with a simple swab test. “If we detect resistant bacteria, we then appropriately modify the antibiotic we give before the biopsy. That’s very important, because we’re preventing infectious complications that could be life-threatening.”

Before your biopsy, talk to your doctor about the risk of infection, and whether it would be possible to get a simple swab test ahead of time.

©Janet Farrar Worthington

Regular disclaimer:  This is a blog.  It is not an encyclopedia article or a research paper published in a peer-reviewed journal. If a relevant publication is involved in the story, I mention it. Otherwise, don’t look for a lot of citations, especially if I’m quoting from a medical professional.