Prostate cancer-specific mortality within the US VA medical system

A newly published article in the journal Frontiers in Oncology suggests that men diagnosed with prostate cancer at ≥ 70 years of age may be more likely to die of their prostate cancer than younger men, regardless of their PSA level at diagnosis. The entire text of this article by MacKintosh et al. is available on line, as is commentary on the article on the Renal & Urology News web site.

According to MacKintosh et al., in a study of US veterans between 50 and 89 years of age, all diagnosed and treated within the Veterans Administration (VA) medical system between 1999 and 2009,

  • 24,142/230,081 prostate cancer patients (10.5 percent) died of their prostate cancer during the 10-year study period.
  • 77.4 percent of the prostate cancer-specific deaths occurred among those diagnosed at age 70 to 89 years of age.
  • Higher PSA values prior to diagnosis predict a higher risk of death in all age groups (p < 0.0001).
  • Within the same PSA range, older age groups are at increased risk for death from prostate cancer (p < 0.0001).
  • For men with a PSA level between 7 and 10 ng/ml at time of diagnosis, cancer-specific death, 10 years after diagnosis, increased from 7 percent for men aged 50 to 59 years to 51 percent for men aged age 80 to 89 years.

Among their conclusions, the authors state that:

Our finding that older men have increased cancer-specific mortality risk across all PSA ranges suggests that older men may be presenting with later-stage cancers, have cancers that behave more aggressively, and/or receive less aggressive treatment than younger men.

Now the first question that this raises is this one: Do these data from the VA Medical System reflect experience across the entire US prostate cancer community, or do these data reflect something specific about men being treated within the VA Medical System?

The second question (that goes unanswered in this paper) is: What was the racial make-up of this cohort of patients? We know that the US military — and therefore the VA Medical System — has a higher percentage of African-Americans than the population as a whole. We also know that African-Americans are 2.4 times more likely that Caucasian-Americans to die of prostate cancer. Is this a relevant factor in the interpretation of the data presented by MacKintosh et al.? It may be.

The third question relates to screening policies for prostate cancer within the VA system. MacKinnon et al. point out that, among the men in this study who died of prostate cancer,

  • 54.6 percent were initially diagnosed with PSA levels >10 ng/ml.
  • 39.0 percent were initially diagnosed with PSA levels >20 ng/ml.

Thus a maximum of just 6.4 percent of the men in this study who died of prostate cancer were actually diagnosed with low-risk prostate cancer and a PSA level of < 10 ng/ml.

As the authors state,

This suggests that some men were unscreened prior to diagnosis, which is consistent with national screening rates at VA hospitals and clinics …. It also shows that much of the death risk is associated with PSA levels at diagnosis substantially above the screening guidelines used in the past.

The data presented by MacKinnon et al. are clearly worrisome. They show that men of 50 to 89 years of age, diagnosed with prostate cancer between 1999 and 2009 within the VA medical system, were at high risk from prostate cancer-specific mortality regardless of their PSA level at diagnosis. However, we should be cautious about any suggestion that this finding is necessarily applicable to the entire male population of America of the same age — unless other data can substantiate similar findings in that larger population.

There is more than one reason to consider that many of the men being managed within the VA medical system might have been at higher than average risk for prostate cancer (because of their race, their possible exposure to Agent Orange, etc.). What would appear to be the case is that the VA’s internal guidelines on testing for risk of prostate cancer, management of men diagnosed with prostate cancer, and various related factors are at odds with what many would see as a national obligation to provide high quality medical care to US veterans.

Managing older men with low-risk and perhaps favorable, intermediate-risk prostate cancer on some form of expectant management is one thing. Applying that standard of care to men with higher-risk forms of prostate cancer is a completely different concept that is far harder to justify based on the data available. The reasonable life expectancies of older men in America in 2013, based on the Social Security Actuarial Life Tables were:

  • 14.24 years for a man of 70
  • 11.83 years for a man of  75
  • 8.2 years for a man of 80

These factors need to be taken into account in determining when active treatment is or should be appropriate (together with the patient’s risk level). However, what is inappropriate is to be not diagnosing prostate cancer until the patient’s PSA levels are > 10 ng/ml. This may be placing patients in a unnecessarily high risk categories by the time decisions need to be made about how best they can be managed.

3 Responses

  1. I’m in the VA system. After reading the entire article I was surprised they didn’t attempt to identify those Vets who served in Vietnam and had AO exposure. It seems likely a large proportion of the study population in that age group served in Southeast Asia as most receiving care in the VA system do so based on a service connected disability or their service in Nam.

  2. I have not reviewed the article — for those who have, does the article identify what percentage of men were symptomatic at diagnosis … thus may have gotten a (first?) PSA test as part of the diagnostics?

  3. Rick:

    No. I don’t think there would have been any way to tell this from the database that was being used. The only way to tell this would have been to review every single one of the 230,000 actual patient records, and that simply wouldn’t be a feasible option.

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