Thursday, 10 November 2011

Is the NHS a world leader in cancer care?

The Guardian is pleased to report that "The prime minister and health secretary have criticised the NHS on cancer, but new figures suggest the service is a world leader".  This is based on a study published in the British Journal of Cancer, which says that "the NHS in England and Wales has helped achieve the biggest drop in cancer deaths and displayed the most efficient use of resources among 10 leading countries worldwide."

The Guardian doesn't link to the paper, and its report is a masterpiece of unclarity.  "While six countries saw falls of at least 20%, England and Wales – which in 1979-81 had the third highest rate with 4,156 deaths per million men – improved the most, achieving the fifth lowest rate among the 10 countries by 2004-06 with 2,869 deaths per million."  Which is to say that England and Wales improved from eighth to fifth out out of ten countries.

The actual paper, by Colin Pritchard and Tamas Hickish, is here.  It finds that England and Wales has had the largest reduction in male cancer deaths out of the ten countries over the 25-year period, and that England and Wales has the highest ratio of improvement in cancer mortality to percentage of GDP spent on cancer care.

The relative improvement for women is much less impressive.  I've tried averaging to get a rate for the sexes combined (the calculation ought to be more elaborate than a crude average, but this is useful estimate) and the result is that England and Wales has had the largest reduction by this measure too.

The data don't cover exactly the same dates in all ten countries, so I've calculated an annualized rate of improvement.  England and Wales is easily the best, at 1.2% per year (Germany is second at 0.99%).

Are these good measures of performance?  Tim Worstall pungently comments that "What [the figures] show is that the NHS used to be shite at cancer and now it’s only middle ranking".  He's right that England and Wales ranked in the middle of the ten countries for cancer mortality at the end of the period studied.  It had almost exactly the same cancer mortality rate as the USA (the USA data are from one year earlier).  The lowest mortality was in Japan and the highest in The Netherlands.  I don't believe this tells us anything about the relative merits of various healthcare systems, as Worstall might like it to.  Regarding the figures relative to GDP he adds "...a system which spends less to cure less cancer is going to be more efficient in its use of money to cure cases of cancer. Because it’s only curing the easy cases."  That's a fair point in theory.  But if the USA with all its extra spending is curing lots of hard cases, the effects aren't showing in the mortality data.

The government has a strategy document which proclaims that "we aim to save an additional 5,000 lives every year by 2014/15".  Cancer Research UK tells us that in 2009 there were 156,090 deaths from cancer, so that would be an improvement of about 3.2%, or about 1.06% per year over three years.  It seems the government's aim is to slow down the rate of improvement.  (The Pritchard and Hickish analysis is for ages 15-74 in England and Wales, so the comparison is not exact.)

It's genuinely hard to compare one health service with another.  If you compare mortality data, you are looking at different populations with different lifestyles and different methods of compiling statistics - differences in healthcare may be a minor factor.  By looking at improvements in mortality, Pritchard and Hickish eliminate some of these effects but have the problem that the quality of healthcare at the start date may differ markedly between the various countries.  The government analysis prefers to refer to survival times from diagnosis: the problem with this is that it's as much a measure of how early you diagnose as of how effectively you treat.


  1. You write: "the problem with this is that it's as much a measure of how early you diagnose as of how effectively you treat. "

    Why would that be a problem? Isn't it a sign of a good health care system that you diagnose early?

    The other considerations are entirely valid, though - the demographics, lifestyles, culture and many other things impact the helth of people, so direct comparisons between countries and systems are not that easy.

    Theoretically, you could devise a health care system where most people are tied to their beds, a few selected doctors keep everyone else sedated, and the "patients" fed through IV needles. They all live to 110 years because no one is exposed to accident risks, no one smokes, no one does anything risky. They might be healthy in the sense of selected health care metrics, but still the outcome would be rather dystopian, wouldn't it?

    So, let's be careful with what kind of health fascism we wish to have.

  2. Earlier diagnosis will improve survival time from diagnosis even if it doesn't prolong life at all. So survival time from diagnosis may not be a good measure of the extent to which a health service is prolonging the lives of people with cancer.