Prostate Cancer Screening: Misleading Results & Overtreatment (Part 3 of 3)

The dilemma continues as more problems and consequences are posed by prostate cancer screening:

False negative PSA. Anyone who has been in practice for more than a couple of years has had patients with aggressive prostate cancer with PSA levels less than 2 and even more below the common threshold of 4. Some of these men have a normal prostate that is detectable with digital rectal examination. As a result, some men and their doctors will have a false sense of reassurance.

False positive testing. This means that the patient has an abnormal serum Prostate-Specific Antigen (PSA) but the prostate biopsy demonstrates no cancer. But this does not afford the patient the reassurance he expected. Unfortunately, prostate biopsy has a 30-40% false negative rate, requiring many men to undergo the procedure again. The patient suffers fear and stress in the meantime. I used to meet patients who had four sets of biopsies who were extremely anxious. One of whom told me: "The guy before I mt you told me he knew I had cancer, he just had to find it." Yikes! I typically stopped at two sets of biopsies on most patients while maintaining a close watch over them and constant open communication.

False positive diagnosis. I wish to propose another version of false positives: a false positive biopsy that identifies a small volume of Gleason 6 cancer cells, which suggests a slow-growing tumor. False positives, according to my definition, may occur in 35-60% of cases and represent tumors which would be unlikely to cause any symptoms, much less death. Yes, these would be ideal candidates for Active Surveillance (AS). However, we cannot overestimate the burden still imposed upon our patients. Most AS requires biannual follow up, which include repeat PSA testing and biopsy. They cannot simply forget about a cancer diagnosis. As mentioned in part two of this series, some will opt for definitive treatment simply due to fear.

Adverse effects from biopsies and overtreatment. After an abnormal blood test has been obtained from the appropriate patient, what's next? Though it is routine for us, a prostate biopsy is not a casual undertaking. We must obtain our specimens through a septic cavity (the rectum) and place patients at risk for urinary tract infection, sepsis, and bleeding — all of which patients will see in their blood, from their rectum, and in their semen. There has been an increase in infections due to the resistance to the usual preventive antibiotics. Incidentally, diabetes is associated with a higher rate of infection. This gives pause, yet again, as to the screening criteria of some men with Diabetes Mellitus.

A study from Johns Hopkins Medical School in 2012 showed that hospitalization was more than double for men over 65 in the 30 days following prostate biopsy when compared to age-matched peers (6.9% vs. 2.9%). Hospitalizations were not surprisingly due to infection and bleeding. However, it is disturbing to note that some hospitalizations were due to exacerbation of underlying conditions, such as congestive heart failure and respiratory disease. The study also did not capture the number of men who required urgent clinic appointments to resolve complications or who visited emergency rooms.

Many men have received treatment for tumors which statistically would be unlikely to cause harm or death. If all goes smoothly, the ethics of this approach are misleadingly unquestioned. However, urinary incontinence, weakened bladder, muscles, and erectile dysfunction are not uncommon complications of prostatectomy. These add to the cost of the treatment by requiring additional testing, medications, and sometimes more surgery. The additional costs are immeasurable in terms of their emotional and social impact.

shared decision-making and informed consent are key

Obviously, there are no perfect screening tools, diagnostic procedures, or treatments. It has seemed to me that sometimes we are too obsessed with our reliance upon tests as an excuse for relinquishing the role of our relationships with our patients. Newer screening tools are being developed — such as the isoPSA — to enhance the sensitivity and specificity of screening to better identify the patient who will most benefit from screening and treatment. We have shown that the PSA, comparable to a coin toss (Potts, Cancer, 2010). Other supplemental screenings include blood tests, such as the 4K or MRI, which would ideally provide confidence to men as they could avoid further testing.

Doubts and fears will remain, albeit less so. This is why I am a physician, a healer, an educator, and a caregiver — not a robot. This is the essence of shared decision-making: a shared risk taken together.