Global 'epidemic' of gullet cancer seems to have started in UK in 1950s

http://www.eurekalert.org/pub_releases/2012-08/bmj-go082112.php

Public release date: 22-Aug-2012
Contact: Stephanie Burns
BMJ-British Medical Journal
Common, but as yet unidentified factor, behind sudden surge in cases around the world

A global assessment of the oesophageal adenocarcinoma epidemic Online First doi 10.1136/gutjnl-2012-302412

The global "epidemic" of one type of gullet cancer (adenocarcinoma) seems to have started in the UK during the 1950s, sparked by some as yet unknown, but common, factor, suggests research published online in Gut.

There are two distinct types of gullet (oesophageal) cancer—squamous and adenocarcinoma, the latter typically affecting the lower third of the oesophagus.

It was first realised that diagnoses of adenocarcinoma were increasing rapidly in several regions of the world in the mid-1980s. But the reasons behind this dramatic increase still remain something of an enigma.

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The authors suggest that as the analysis was restricted to countries and regions with reliable and longstanding data, it seems unlikely that more than a fraction of these patterns could be attributable to mistakes in correctly identifying the cases.

And as there has been little change in the proportion of patients with localised disease or death rates, changes in diagnostic accuracy are unlikely to explain the trends either.

Obesity, which is linked to acid reflux—a well known cause of the disease—has been rising rapidly too, but the pattern does not fully match that of oesophageal adenocarcinoma, say the authors, nor does it explain the gender difference seen in this type of cancer.

Smoking, an increase in acid reflux, and a fall in Helicobacter pylori infections have all probably played a part in rising incidence, say the authors. But they add: "They are unlikely to explain either the abrupt change or the astounding rate of increase."

And they conclude: "Therefore, it seems reasonable to hypothesise that the effects of a strong, highly prevalent and yet unidentified causal factor—first introduced in the UK in the middle of the 20th century—have been superimposed on the effects of known risk factors."