Movember: The Improvement in Prostate Cancer Mortality

A success story in men's health

Nov 19, 2021

Last Week, I posted about my Movember fundraising, and thanks to everybody who boosted up my numbers! Huzzah! (Update at end of post)

Also, today is International Men’s Day:

Yay for men!

Movember centers on men’s health, and, in particular, around three main causes: prostate cancer, testicular cancer, and suicide, as these three items disproportionately affect men. The first two for obvious reasons, and the third for a less obvious reason.

Today, I’m going to talk about prostate cancer, because there’s a happy story for the long-term trend.

Prostate cancer mortality: crude rate and age-adjusted rate

First, let’s look at two long-term mortality trend lines:

There are two things going on here, and the crude rate of death due to prostate cancer is the easier of the two trends to understand.

Simply put, this tells us how many men per year, per 100K men, die from prostate cancer.

We had a peak in that crude rate in the early 1990s, it came down after that, and in recent years it started climbing again.

However, the recent climb in prostate cancer deaths is a little misleading if you want a clear idea of how prostate cancer trends are going, as this is also reflecting the aging of the population as a whole, which is why we really want to look at age-adjusted death rates if we want to remove that effect.

As I’ve explained about age-adjusted death rates before, it’s simply a weighted average of death rates by age groups, where the rates are standardized so we can compare over time. In the U.S., we generally use a set of weights that are close to population weights from the year 2000 (it’s approximate, because pretty much everything has to be an approximation. The CDC can’t simply wait around for the Census Bureau to get its numbers together.)

So the age-adjusted trend is crisper: there was a peak in the early 1990s in prostate cancer deaths, and it came down fairly rapidly from the mid-1990s to 2010 or so, and improvement has slowed since then.

Even more detail behind prostate cancer mortality improvement

But we can get more detailed than that.

We can see what the death rates look like for the various age groups.

Here the age-differential is very clear. As is the drop-off in mortality.

Let me give you some clear breakpoints in the trend, and you can see the percentage change in mortality rates:

You can see that for the first 20 years of my graph the rates generally increased for the oldest men, but then rates really came down after that (thus the negative percentages).

PSA blood tests have saved lives

Somebody posited that the PSA blood tests had the effect, so I looked into it:

Mary Pat Campbell @meepbobeep

@nightbirdsf btw, it does seem that the PSA test is what made a huge difference: [not going to make you wait for the post] ncbi.nlm.nih.gov/pmc/articles/P… "45%–70% of this mortality decrease is attributed directly to PSA screening"

ncbi.nlm.nih.govHistory of the discovery and clinical translation of prostate-specific antigen

History of the discovery and clinical translation of prostate-specific antigen:

Before the development of the PSA blood test, prostatic acid phosphatase was the most important blood test for prostate cancer, but it was of no value for the early detection of prostate cancer, because serum acid phosphatase levels became elevated mainly in men who already had bone metastases.
….
In the early 1990s, it was first demonstrated that the PSA blood test could be used as a first-line screening test for prostate cancer…
4. PSA testing reduces prostate cancer-specific mortality
During the “PSA era” in the United States, the proportion of patients having advanced disease at diagnosis has decreased by 80%, and the age-adjusted prostate cancer mortality rate has decreased by more than 42% [28]. Statistical modeling studies have estimated that 45%–70% of this mortality decrease is attributed directly to PSA screening

For the record, Stu had bone metastases when he was diagnosed with prostate cancer, and he was just unlucky, just like many other men who have had aggressive forms of cancer.

However, with the PSA test, and improvement in treatment as well, the 5-year survival rates for prostate cancer are excellent and even for “distant” (that is, metastatic prostate cancer), the survival rates are now about 30%. When I looked at research papers when Stu was diagnosed… it wasn’t 30%. It was 2% (at which point, I stopped looking at those papers, when I realized they were based on research a decade old.)

So the news with prostate cancer has been good, and has been getting better.

While metastatic prostate cancer isn’t curable currently, neither are other conditions like Type 1 diabetes nor AIDS, but both are treated as chronic conditions. The point is that the survival curves for these keep getting pushed out farther.