Prostate Cancer Screening

I really like my husband.  I would be very grateful if we could grow old together.  He is a physician and therefore as is often the case, he is a terrible patient.  He is very reticent to see a doctor and he understands the harms that can come from too much treatment or testing.  (Check out this article he recently sent me about the dangers of overtreatment and overdiagnosis. It’s a great background for the rest of this blog post.)  His father had a run in with prostate cancer in his late 50’s.  Having a first degree relative with prostate cancer doubles the risk of getting prostate cancer, which freaks me out.  Especially given that prostate cancer is the most common cancer in men worldwide, with an estimated 233,000 cases and 29,480 deaths in 2014 (according to the world cancer report).  So, what can I do to help keep my hubby healthy and happy until the golden years? There is controversy over screening for prostate cancer.  Check out my prior blog on the USPSTF to get a sense of this controversy.  I believe that the basis for this controversy lies in the fact that even though the risk of developing prostate cancer is high (16% in American men), the risk of dying from prostate cancer is fairly low (2.9% in American men).  The idea is that prostate cancer often grows very slowly and that most men will die of other causes before the prostate cancer could lead to any problems.

The largest problem with the widely available prostate cancer screening tests we have now is that it’s very difficult to differentiate who will have an aggressive prostate cancer and who ends up with a slow growing one.  Any diagnosis of cancer is frightening and it’s hard to imagine just waiting around knowing one has cancer.  So, many men who might have been fine, have their prostates removed or they pursue radiation of their prostate.  A number of these men will suffer consequences from these invasive approaches (like incontinence, impotence and sometimes more serious consequences like heart attacks, strokes, blood clots or death).

Allow me to get a bit deeper into explaining the most common prostate cancer test, called the PSA (prostate specific antigen).  PSA is a substance produced by normal prostate cells, it’s processed and released into the bloodstream where we can measure it and make some guesses about what is going on in the prostate.  In a normal man, the prostate will grow as he ages, so the PSA levels have different ranges of normal (slightly higher values are considered more acceptable as one ages).  When cancer cells invade the prostate, they break down the barriers of the cells thus releasing the PSA before it’s processed.  This quick release increases the overall PSA in the blood (even though the cancer cells actually produce less PSA).  Thus a quick rise in the overall PSA may be related to prostate cancer.  The problem is, that it can also  be elevated in connection with prostate infection, trauma (bicycle riding), medications, sexual activity, a rectal exam or colonoscopy, to name a few.  Thus many men could be exposed to a needless biopsy related to a falsely elevated PSA.

The type of PSA released by cancer cells is different than that released by normal prostate cells because it isn’t fully processed by the cell.  The thought is, if we look at levels of this unprocessed PSA (called the [-2]pro psa), we can more precisely decide who needs a biopsy.  This testing was FDA approved in 2012 and, in combination with a number of other factors to calculate something they call a Prostate Health Index (phi), has been shown to be more precise.  Some have posited that this test also predicts the more aggressive cancers.  However, this test is still new and hasn’t been fully vetted to validate that claim.  Some prominent scientists warn of the ongoing risks of overdiagnosis and overtreatment when pursuing this test.

The digital rectal examination (DRE), the often joked about “bend-over” part of a doctor’s visit, is mostly done to screen for prostate cancer.  Here is a picture of the anatomy so you can better understand how this works.  When we do a DRE we are only able to feel the back of the prostate.  Unfortunately many prostate cancers occur at the front of the prostate, or are not at all palpable.  When looking at the statistics, it appears that adding a DRE for screening doesn’t increase survival from prostate cancer, however it does increase detection of cancer very slightly when done with the PSA.

In deciding on screening, I believe it’s important to understand what has been associated with a higher risk of prostate cancer.  I mentioned a family history of prostate cancer does increase the risk.  Race is another prominent factor in stratifying those at a higher risk for prostate cancer.  African American men carry a significantly higher risk of cancer than their caucasian, hispanic, or asian counterparts.  Some studies have suggested an association between high levels of omega-3 fatty acids (such as those found in fish oil supplements) with high grade prostate cancer.  However, these studies were not definitive so should be taken in that context.  Some studies have shown that higher levels of coffee intake (decaf or regular) are associated with a lower risk of more aggressive prostate cancer.  Many studies have shown a link between intake of dairy products and calcium and a higher risk of prostate cancer.

So, prostate cancer is extremely common and we don’t have a great system to save lives from it.  For now, based on the fact that there is really no clear right answer, I have to let my dear husband decide for himself on whether or not to pursue PSA testing, knowing that choosing to do nothing is a perfectly acceptable decision.