CANCER PATTERNS AROUND THE WORLD
Unsurprisingly, the death toll that results from the avalanche of new cases also has lung cancer at the top of the list with 1.2 million (17.5% of all cancer deaths). However, the next biggest worldwide cancer killers are stomach (0.7 million), liver (598,000) and colon (529,000), accounting for 10.4%, 8.9% and 7.9% of all cancer deaths, respectively. In 2009, the UK weighed in with a contribution of 156,090 to the 7 million. In 2010, the USA provided 299,200 male and 270,290 female cancer deaths. We’ve already noted that on the UK and USA incidence lists prostate displaces stomach and so it’s unsurprising that it does the same on the killer lists, with stomach cancer being sixth in the UK and thirteenth in the USA (Fig.1).
All the same, ’was not ever thus: go back 80 years in the USA and stomach cancer was the biggest cancer killer, albeit that in 1930 the total death toll was only ~120,000. Nowadays nearly two-thirds of stomach cancers occur in the developing world, to which we will return in a moment, but there to the incidence is declining, as it has done in the USA, for reasons that are not entirely evident but may include the increasing availability of fresh fruit and vegetables and of meat preserved by refrigeration rather than by salting. Nevertheless, 10,540 will die of stomach cancer in the USA in 2012.
Despite having the second highest incidence, breast cancer is only fifth on the mortality list with 458,503 deaths in 2008 (11,633 in the UK in 2010; 39,840 in the USA in 2010). This figure of about half a million represents 1.6% of all female deaths but again there is an imbalance – this time in the other direction. In rich countries, 2% of all female deaths are due to breast cancer but in poor countries, the figure is only 0.5%. Here the difference roughly reflects incidence – about five times lower in developing countries where the average age of populations is younger. The distribution pattern of cancer mortality between men and women in the USA is closely mirrored in the UK (Figs. 2 and 3).
The two notable exceptions are liver cancer, comparatively common in the USA, and stomach cancer, which is more significant in the UK. The latter may reflect dietary differences in at least some regions of Britain and high protein and cholesterol diets may be a factor in the USA liver rates.
The pattern across European nations (Fig. 4) shows the overall cancer death rates to be generally higher in eastern Europe (Hungary is the highest with 234 per 100,000) with the lowest being in Finland (138 per 100,000).
Even so, for women over the period 2000–2004, Denmark, Scotland and Hungary were the top three (141, 123 and 132/100,000, respectively). One might expect that the variations between countries in total cancer mortality would be strongly dependent on differences in the toll of the major cancers. Indeed the pattern of breast cancer, for example, broadly follows that of total cancer deaths, although there is one notable exception: Poland has the third highest rate of total cancer deaths but one of the lowest breast cancer rates. Despite these generalities, it should be borne in mind that breast cancer and other major cancers, such as melanoma and prostate cancer, vary markedly in national impact.