Re: Mortality Spike was .....Swedish Study [1 Attachment]

[Guest guest]

Thanks Terry. I guess I'm wondering if I was wrong to have surgery (or any treatment) with my scores: PSA 4.95, Gleason 7 (3+4), 7 of 12 cores cancerous. If treatment doesn't add to life expectancy, why bother.

Mike

Subject: Mortality Spike was .....Swedish Study [1 Attachment]To: ProstateCancerSupport Date: Sunday, April 3, 2011, 7:59 PM

[Attachment(s) from Terry Herbert included below]

Mike,

In writing this piece I want to acknowledge that I am no statistician. All I know about statistics comes from many years of working in the insurance industry where I gained a clear insight into how inaccurate statistics can be because of basic errors or assumptions and how easily statistics can be manipulated by the adjustment of assumptions. There is an old joke about the insurance manager looking for an actuary. All applicants were presented with base data and asked to make a series of projections. All were rejected until at last an applicant asked the manager what result he wanted to see.

The figures that demonstrate the significant rise in prostate cancer deaths after the introduction come from the SEER (Surveillance, Epidemiology, and End Results Program) statistics - http://seer.cancer.gov/ - which are accessible to all of us. They are said to be the most accurate figures available but of course there are, as is the case for all statistics, some issues in the collection and compilation of the data which can affect the reported outcome and estimates. Here are some of the basic points from my limited point of view:

1. It is said that the SEER data represents about 10% of the US population. National statistics are extrapolated from this data. Clearly an error in the base data will be significantly compounded when extrapolated to this extent.

2. The base data is collected from a limited number of institutions and not from all institutions in the US . A NCI pre4ss release in 2002 said in part <snip> Ten population-based registries report this

information to the NCI's Surveillance, Epidemiology, and End Results (SEER) Program. <snip> Clearly they must be very large institutions if threes ten represent 10% of the population. My personal experiences tend to make me think that large institutions often have built in error rates that may be higher than smaller institutions.

3. Calculations for incidence rates and the like are made using the data from the Census. Just which Census is used can make a significant difference in projected, extrapolated data. For many years data from an old Census was used (I think it was 1976?) This was then changed to a more modern Census with a warning that it might make some figures not directly comparable.

It is important, when looking at points 2 and 3 to realize that because of racially and or economically differing incidence and mortality rates, there may be significant discrepancies that develop if for example, there have been large population movements or even if the reporting institutions change or move their location. There is a good example of the kind of distortion that can be introduced which was mentioned in a study in Britain . The incidence of prostate cancer was very much higher in an institution in inner London where the inhabitants might be described as economically disadvantaged compared with the more affluent area served by an institution away from the city in what might be termed the ‘broker belt. The study suggested that diet, living conditions, ability to seek good advice, levels of service etc

accounted for the difference. The point of this is that if the inner city data were extrapolated into a national statistic, there would be a very different set of rates than if the second institution’s data was used.

4. There is a time lag in reporting data which, incredibly, seems to have worsened despite the advent of sophisticated computer based systems. The 2002 press release referred to above (15-Oct-2002 Journal of the National Cancer Institute) was issued because there was some puzzlement about the apparent decline in prostate cancer incidence rates which curiously enough occurred in the same time frame as the reduction in prostate cancer mortality rates. This report stated in part <snip> The standard time between a cancer diagnosis and its initial inclusion in cancer incidence statistics is about 2 years………. They found that it would take 4 to 17 years for 99% or more of the cancer cases to be reported. <snip> This raised the question of accuracy in my mind – bering in mind my views on the way

in which large institutions may operate.

I have tried on many occasions to get an informed discussion going on the lock step rises and falls of mortality and incidence rates following the introduction of PSA testing in 1986. We know why the incidence rate rose – because more men were biopsied and the more men you biopsy the more prostate cancer you will find. As the 2004 study demonstrated so clearly if you biopsy men with a PSA under 4.0 ng/ml you will find more cells currently defined as prostate cancer than if you only biopsy men with a PSA higher than 4.0 ng/ml. But why did the mortality rate rise. And why did the incidence rate AND the mortality rate start to fall after 1991, five years later?

No one has ever come up with a definitive answer. One of the leading activists has always dismissed my desire for such a discussion as saying that the two items have nothing to do with each other and doggedly repeats his mantra that the mortality rate has fallen, as indeed it has, depending on where you measure it from. He no longer responds to my postings.

My point has always been that we need an explanation as to why both measures changed. We have to understand that if we are to attribute the observed fall in mortality rates from it’s all time high in 1991. From my limited viewpoint, significant changes like these in a population statistical base can come from a change in definition. Just what is a prostate cancer death? How is it defined? Did all reporting institutions use the same definitions? Did any definitions change? Those are the questions that no one can answer for me. There have been some glimmers of light shone on the subject:

a. No less a person than Dr Walsh (who was apparently at some conference discussing the importance of screening in reducing mortality) was quoted last year as being questioned as to why the mortality rates in Britain had fallen when there was not the same emphasis or amount of screening in that country. His response was that they had changed the definition of prostate cancer related eeath to exclude pneumonia and this one factor had led to a reduction in prostate cancer related deaths. On raising this point in a forum I was told that this could not happen in the US . End of discussion.

b. Soon after I read of Dr Walsh’s remarks, I came on a piece describing how the large European study (ERSPC) had agreed to ‘standardize’ their definition of prostate cancer to only include needle biopsy results that result in a Gleason Score of 6 or higher – in other words anyone who had a diagnosis of GS 5 would not be included in their data. This single change may well have produced the discrepancy in the ERSPC reported results of ‘lives saved’ when compared with the US study that showed ‘no lives saved’. Again I tried to discuss this change in definition and wondered if this was a contributing fator in the decline in reported deaths – after all if you are not diagnosed with PCa, you cannot die of the disease. My thoughts on the subject were ignored ar denied. Spurred on by this item I then

found that in practical terms, leading pathologists in the US had been applying this criterion since about 2005 and in January this year the proposal was formally adopted – see http://www.yananow.org/StrangePlace/forest.html#gleason for a summary of the changes. This has led to a significant change in the profile of diagnosed prostate cancer and the so-called ‘Migration†of Gleason Grades and Scores – see http://tinyurl.com/2jnpbu

In summary after what many will have considered a long and boring post, in answer to your question <snip> Your thoughts on the 30% increase and what it means? <snip> I think that a number of changes in diagnosis, definition, formulae and focus may have all resulted in the changes observed in the population data.

All the best

Prostate men need enlightening, not frightening

Terry Herbert - diagnosed in 1996 and still going strong

Read A Strange Place for unbiased information at http://www.yananow.org/StrangePlace/index.html

Attachment(s) from Terry Herbert

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