Okay guys and gals, let's talk about one of the most confusing and most common types of cancer: prostate cancer. Prostate cancer causes endless confusion and worry, because in many cases doing nothing -- also called "watchful waiting" -- is the best approach. But in other cases, the cancer can be aggressive, move to other parts of the body, and then it's another story altogether.
There's big news this week that can help us figure out what we need to do.
Researchers at Johns Hopkins University announced that an updated version of the standard prostate cancer test, which they've dubbed the Prostate Health Index, can improve predictions about which men need immediate treatment, and which don't. It's basically an amped-up version of PSA screening, which measures the blood levels of a protein produced by prostate cells called prostate-specific androgen. The new test measures blood levels of three different types of PSA, called pro-PSA, free PSA, and serum total PSA. When combined with annual biopsies, or tissue samples, it turned out to be approximately 70 percent accurate in separating the aggressive tumors from those that didn't require treatment.
The researchers, who are reporting this study on Sunday at the annual meeting of the American Association for Cancer Research in Washington, D.C., followed 71 men who'd been diagnosed with small, low-grade, and low-stage prostate tumors -- the kind that are least likely to prove aggressive.
What the researchers wanted to know: Which men's tumors were going to progress, and which weren't?
The men took the new Prostate Health Index blood tests twice a year, along with a digital rectal exam to measure tumor size. They also continued to have their annual biopsy, and the tissue sample was subjected to a DNA test that looked at the number of chromosomes in each cell. (Normal cells contain two chromosomes, while cancer cells can have more or less.)
According to the test results, the men whose DNA test suggested cancerous changes also scored higher on the Prostate Health Index, suggesting that the blood test for all three types of PSA was accurately predicting whose cancer was aggressive.
Interestingly, the group split almost 50/50; 39 men had indications their tumors were becoming aggressive, while 32 men didn't show any signs of progression. What this means is that instead of all 71 men being treated the same way, the 32 men with the favorable prognosis can avoid treatments such as radiation and surgery, which carry with them a high risk of side effects, including incontinence and sexual issues.
The Prostate Health Index (PHI) still has to make its way through the FDA approval process here in the States, but it's already available in Europe, where it's being actively marketed by Beckman Coulter, a clinical diagnostics company. If you or someone in your family has been diagnosed with an early-stage prostate tumor, ask your doctor to keep you up to date on new tests as they become available.
The James Buchanan Brady Urological Institute at Johns Hopkins has been a major center of prostate cancer research over the past few years. Researchers there have also been studying two other biomarkers for prostate cancer, one called EPCA-2 and one called PCA-3. I've also written before about another test for the amino acid sarcosine that could also proves useful in separating aggressive tumors from non-aggressive ones. So far none of these have lived up to the early hype, but studies are continuing. The goal? To offer men something more definitive than the PSA test and gambling on treatment decisions based on the PSA.
If you or a man in your life is worrying about a prostate cancer diagnosis, we'd love to hear your story.