Global "epidemic" of gullet cancer

A novel study from Karolinska Institutet and Harvard University shows that since the 1950s there has been a global, almost epidemic, increase of gullet cancer - which seems to have started in the UK. According to the scientist, it is a common but as yet unidentified factor behind this sudden surge in cases around the world. The findings are published online in the scientific journal GUT.

There are two distinct types of gullet (oesophageal) cancer, squamous and adenocarcinoma, the latter typically affecting the lower third. In the mid 1980s it was first realized that diagnoses of adenocarcinoma were increasing rapidly in several regions of the world. But the reasons behind this dramatic increase remain something of an enigma.

In a bid to identify any discernible patterns, the scientists looked at data from 16 population based cancer registries in seven countries, going back between 29 and 54 years. The countries comprised Australia, Denmark, Finland, Norway, Sweden, the UK, and the US.

The results showed that the incidence of oesophageal adenocarcinoma continued to increase rapidly in all 16 registers, and there is little evidence that this trend is beginning to plateau. Men continue to be between three and nine times as likely to develop the disease as womena pattern that has remained consistent over time.

Although experienced at different periods, with a gap of around 30 years, in around half the registers, a low and seemingly stable rate of new diagnoses shifted abruptly to a rapidly and consistently linear increase. In the remainder of the registers, the phase of low and stable rate could not be observed because the rate was already above this level and rising when the registration started.

The timeline analysis indicated that the first discernible surge probably occurred around 1960 in Scotland and England, with a similar surge in the US starting in the mid-1970s, and another beginning in 1991 in Sweden, the last country among those studied, to experience this.

Obesity, which is linked to acid reflux - a well known cause of gullet cancer - has been rising rapidly too during the investigated time period. However, the pattern does not fully match that of oesophageal adenocarcinoma, the authors point out, nor does it explain the gender difference seen in this type of cancer.

Science news reference: 

A global assessment of the oesophageal adenocarcinoma epidemic. Gustaf Edgren, Hans-Olov Adami, Elisabete Weiderpass, Olof Nyrén. GUT, Online First 23 August 2012, doi 10.1136/gutjnl-2012-302412

Science news source: 

Karolinska Institute