In what can only be described as an unexpected finding, a group of German researchers have documented a greater life expectancy for men diagnosed with early stage prostate cancer than for the male population in general, based on data from the Regensburg cancer registry!
Klotz et al. used epidemiological data from the Regensburg cancer registry to study the survival of patients diagnosed with organ-confined prostate cancer (T1-2N0M0) compared to the standardized age-adjusted survival of the normal male population.
Their analysis is based on data from 4,124 patients with prostate cancer diagnosed between 1998 and 2007, of whom 2,087 men had been diagnosed with localized disease. Here is what they claim to have been able to find:
- At 8 years after diagnosis, patients with T1-2N0Mo prostate cancer had a roughly 10 percent relative increase in survival compared with the normal male population.
- This relative increase in survival could be documented just 3 years after diagnosis.
What could possibly account for such a finding?
It can’t be explained by prostate cancer treatment, because any survival benefit from treatment takes at least 8 to 10 years and maybe longer (based on data from the ERSPC trial). The immediate implication is that (at least in Regensburg) men who have PSA tests (and therefore greater likelihood for a diagnosis of prostate cancer) may have better overall health status than men who do not.
This is not an entirely unreasonable suggestion. There is a well-understood phenomenon that associates positive health-related (“health-seeking”) behaviors with all sorts of other factors. Elsewhere on this site, we discuss the fact that although men who have vasectomies seem to be at greater risk for prostate cancer than men who do not have vasectomies, this is not because they have the vasectomies. Rather, it is because they exhibit such “health-seeking” behavior.
We suspect that in Regensburg (and potentially in many other places) having a PSA test is closely correlated with having regular health checks. Men who have regular health checks arguably may have a superior life expectancy to those who see doctor only when they absolutely have to (although such a benefit has never actually been documented, as far as we know). The other issue that then comes into play is whether men of higher income and/or better education are more likely to have regular health checks than those less fortunate. The authors refer to this in their paper as the relationship between PSA testing and a “socal gradient.”
Filed under: Diagnosis, Living with Prostate Cancer, Risk, Uncategorized Tagged: | increase, life expectancy, PSA, survival
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This paper is interesting, and the explanations make sense.
In addition to the “health seeking behavior” explanation, the “wake up call” factor may also be at work. Dr. Charles “Snuffy” Myers has stated that a diagnosis of prostate cancer is like the canary that dies in the mine, the diagnosis serving as an early warning, signalling that overall health is likely in jeopardy, not just from prostate cancer.
For instance, many newly diagnosed prostate cancer patients are deficient in vitamin D, and a diagnosis will trigger testing, revelation of a deficiency, vitamin D3 supplementation, and subsequent monitoring for some of us (me). Many others of us have been casual about good dietary and fitness practices, and a diagnosis of prostate cancer can be powerful motivation to change our ways. Cardiovascular health — so much more salient as a threat than prostate cancer — is one area where many of us improve. I now have outstanding lipid numbers, but for years before diagnosis I was happy with a high cholesterol that appeared to be offset by a good ratio. I would not have those great numbers if it were not for prostate cancer.
I had high triglicerides for years before my diagnosis. It also caused elevated liver enzymes that my doctor ignored as well. I fixed both with diet and exercise after looking more closely at my health after my diagnosis of prostate cancer. My diagnosis probably saved me from an early heart attack.
I changed my diet dramatically after my prostate cancer diagnosis 3 years ago. As a result, my cholesterol numbers have significantly improved. I gave up dairy and red meat, and I eat more fruit and vegetables. That could explain the Regensburg findings.
While I recognize that highly motivated individuals make major changes to their health-related behaviors after a diagnosis of prostate cancer (and indeed other significant diagnoses), most of mankind tend to be somewhat less able to reorient itself.
My general suspicion is still that the men most likely to go and get a PSA test in the beginning — as part of their annual health-seeking behavior — has an inbuilt likelihood to have better health outcomes over time than all of the rest of us.
An aspect of prostate cancer that struck me long ago, apart from the fact that the mortality rate is comparatively low, being less than 3% of male deaths in most countries, is that the median age for prostate cancer-related death is so so close to the normal male life expectancy.
The latest SEER statistics show the median age for diagnosis as 67 years of age, with the median age for disease-related death as 80 — a period of 13 years between these two ages.
The Social Security actuarial tables suggested for use in connection with the NCCN Guidelines show a median life expectancy of of 15.6 years for a man of 67 with a range of 50% either way.
Not a lot of difference then, given the rubbery nature of statistics, especially population-based statistics.
Dr. Scholz in Invasion of the Prostate Snatchers makes the same observation. He attributes it to the patient now being in the medical system and getting regular checkups that may detect other early stage diseases that can be then taken care of.