A Mixture of Musings

: Statistics, Health

Forget the Beard, Shave your Arse for Movember

Or why mortality and gender-equality are terrible ways to determine healthcare policy

Quick disclaimer: I’m not a doctor. I’m a programmer who studied statistics for his PhD on topic-modelling, and who has previously worked for a cancer registry. Real doctors give much better advice than me.

Every November thousands of men strut around our streets with faces disfigured by patchy, scabrous accumulations of facial pubes which frankly would be better kept indoors. These attempts at mustaches, evidently the most manly of all facial accessories, are to celebrate and promote health for men (and men alone). Known as Movember it’s typically to promote prostate-cancer awareness in general.

Who could hate such a thing?

Me. I could. Movember illustrates exactly how the public, led by a willfully ignorant press, fails to think clearly about cancer. The result is worse health outcomes for everyone, men included.

The Twenty-First Century Discussion on Prostate Cancer

In the early noughties the prostate-specific antigen (PSA) test for prostate cancer hit the news, and not for happy resaons. Every major healthcare system in the world was refusing to employ it. As they patiently explained, the PSA test had a very high false-positive rate (a poor specificity in the medical jargon), and given how harsh prostate-cancer treatments are, it would be better not to deploy it, and instead spend the money on other diagnostic and treatment procedures.

This led to a peculiar campaign by journalists. Extensive screening was being deployed for breast cancer and cervical cancer; yet here was a screening for cancer in men that was not being taken up. To some, this was a clear case of “reverse-sexism”1. Prostate cancer, after all, kills more men than almost any other cancer bar lung-cancer2

This campaign gradually took a more positive turn, with the rise of the Movember campaign to promote prostate-cancer awareness and raise funds for research. This has grown massively in popularity: though more due to men’s fascination with beards, I suspect, rather than cancer.

 We all die of something eventually

So how bad is prostate cancer? I’m going to use figures from the UK here, courtesy of Cancer Research UK but the same patterns appear in most other developed nations.

As campaigners have pointed out, it is one of the most fatal cancers that affect men, being the second highest cause of death, exceeded only by lung cancer. For 2014, in the UK, the figures are:

Cancer Annual Male Deaths
Lung 19,563
Prostate 11,287
Bowel 8,566
Oesophagus 5,213
Pancreas 4,426.

However when one looks at the age breakdown, things get a bit more interesting. Let’s consider prostate cancer first, and compare it against figures for bowel cancer. Specifically, which percentage of deaths are in people below certain ages:

Age Prostate Bowel
<65 6% 20%
<75 26% 46%
<80 43% 63%
<85 65% 80%
>84 35% 20%

Prostate cancer is clearly an old man’s disease. Very much so in fact: men’s life-expectancy in the UK is 79 years of age, so 57% of deaths due to prostate cancer are in men who have already exceeded the average life-expectancy.

In a world where everyone dies of something eventually, dying of prostate cancer means you’ve lived a long enough to see your kids grow up and get married; more than half the time it means you’ve lived longer than more than half the men in Britain.

Bowel cancer, by contrast, is clearly cutting lives short to a much more drastic degree.

More than half the deaths due to prostate cancer occur in men who have exceeded Britain’s average male life expectancy of 79, while almost two thirds of deaths due to bowel cancer are in men who never lived that long.

It’s when you die that counts

When most people think of cancer they don’t think of dying peacefully in your bed in your eighties, surrounded by children and grandchildren. They think of lives cut short before people have had the chance to have children, or see them grow up.

The idea of how much a life has been cut short has been codified into a standard metric known as “years of life lost” (YLL), which is generally calculated either against a standard age (usually 75), or against the local life-expectancy.

Using YLL before the UK life-expectancy of 80 we get the following numbers3

Metric Prostate Bowel
Deaths < 80 4,692 5,481
YLL @ 80 38,712 67,157

There are 17% more deaths bowel cancer deaths than prostate cancer in men under 80: yet the the years of life lost is almost twice as large. This is because bowel cancer starts killing men from their early twenties, whereas prostate cancer deaths become numerous much later in life.

It’s interesting to compare these numbers against numbers for women dying from Breast and Cervical cancer.

Cancer YLL @ 804
Breast 126,557
Cervical 17,077

It’s clear how devastating breast cancer is. In fact a Norwegian study, whose results I suspect are equally applicable to the UK, found that while judged on mortality, men were worse affected by cancer than women; if one judged based on YLL before life-expectancy it was women that were the most affected.

The YLL@80 of cervical cancer is the lowest here, though that is mainly due to its lower overall incidence. It is unfortunately distinguished form the other cancers here in that it strikes people at a much younger age: 67 women under thirty-five die each year due to cervical cancer. Bowel cancer kills 41 men and 45 women under thirty-five, and prostate cancer typically causes just one death in this age-group. Fortunately the HPV vaccine should prevents 70% of all cervical cancer incidence in the future.

The Peculiar Difficulty of Promoting Bowel Cancer

The upshot of all this is that if you want to extend men’s lives to the greatest degree, it would make more sense to promote bowel cancer awareness, yet we haven’t done this.

One might think that the problem promoting bowel cancer might be the generally ickiness of anything involving bums, but prostate cancer features some fairly intimate time between men, the bottoms and their GP, and people have embraced it.

Perhaps it’s a misreading of science, which is also possible. Unlike the sports pages, where newspapers generally employ experts, science reporting is typically done by people that frequently lack knowledge of science or maths.

But I think the real problem is narrative.

The dominant theme of the prostate cancer debate has been a feeling that men’s cancers aren’t being treated as seriously as women’s cancers. This gender-equality statement, paired with mortality statistics, has been used to create a sense of

From the LA Times > Among men in their 50s who died of other causes, autopsies revealed that more than 1 in 5 had prostate cancer. Among men who died in their 70s, more than a third had prostate cancer. Doctors often say that men are more likely to die with prostate cancer than of it.

  1. In a way it’s quite interesting, looking back on this, how this entire phenomenon anticipated the peculiar sense of male victimisation which has since led to “Gamer”-gate, Red Pill, Trumpism and the like.

  2. Since over 85% of lung cancer incidence is caused by smoking, and so is mostly self-inflicted, it tends not to get mentioned in these sort of discussions. While quitting smoking will reduce your risk of heart-disease, your risk of lung cancer will remain elevated for your entire life. In short: never smoke.

  3. The full datasets with mortality broken down into five-year age-groups are available as Excel spreadsheets from Cancer Research UK. I’ve simply multiplied the average number of deaths for each age-group by the difference between 80 and the age-group median: e.g. There were 59 deaths from Bowel cancer in men from age 50 to 54 inclusive. For that group the YLL is 59 × (80 - 52.5). Summing these up for all age-groups up to 75-79 and then truncating the fractional part gives the final number.

  4. Life expectancy for women is actually 83 in the UK, but in order to make things more comparable I’ve used 80. Note that the higher life-expectancy means the true numbers are higher than those I’ve given here.