Fears about the cancer causing effects of the second most prescribed group of drugs in the Western world have been put to rest, following the largest ever study into their use.
'Proton pump inhibitors' (PPI) are the most commonly used treatment for chronic acid reflux, or 'heartburn', a painful burning sensation in the chest, neck and throat which is experienced by almost a third of people in developed countries.
Regular and prolonged heartburn is known to cause 'benign oesophagitis', a reversible inflammation of the gullet. However if left untreated a condition called Barrett's Oesophagus (BE) occurs in around 10 per cent of sufferers, which can in turn develop into a potentially fatal cancer called oesophageal adenocarcinoma.
BE is twice as common in the UK as it is in the USA, and oesophageal cancer rates in the UK are the highest in the world; up to four times more common than in other European countries.
Despite their excellent safety record, it was unclear if long-term use of PPIs to reduce the discomfort of heartburn could increase the risk of developing either BE or the spread of the associated cancer.
New research carried out at Queen Mary, University of London and Leicester Royal Infirmary, has given the most conclusive evidence yet that this is not the case. The work is published in the peer reviewed journal Gut.
Professor Janusz Jankowski, who co-authored the study, said: "This is one of the most detailed studies investigating both the laboratory and clinical side of proton pump inhibitor drugs. As a consequence we are now better able to inform patients of the good benefit/risk ratio of this commonly prescribed therapy."
Tests carried out during the two-year study looked at tissue sampled from the oesophagus lining of ninety volunteers, each of whom were given PPI drugs at either a high or low dosage. Researchers found there was no difference in the rate at which BE developed, neither was there a change in the number of precancerous cells in either group.
While there had also been fears about how the treatments might affect people already suffering from BE, the study also showed that there was no evidence that this led to any worsening of the condition or any extra incidences of cancer.
BE is marked by changes in the cells of the oesophagus lining (squamous epithelium) that makes them more like the cells of the intestines (columnar epithelium). As well as increasing the risk of oesophageal cancer, the condition narrows the oesophagus and patients can experience pain whilst swallowing. The chance of cancer developing is proportional to the length of BE.
PPIs work by blocking the action of gastrin, a hormone that controls acid levels in the stomach, and is known to increase the normal movement of cells in the gastro-intestinal tract. Since PPI therapy increases the levels of gastrin in the body, it had been thought this could cause expansion of BE affected tissue, but this was not found to be the case: the scientists observed neither expansion or contraction of the abnormal tissue. This is concordant with current UK practice, where PPI therapy is currently only licensed to treat heartburn and 'oesophagitis' but not BE.
To hear an interview with Professor Jankowski, visit http://podcasts.bmj.com/themes/gut/mp3/BMJ_GUT_podcast_September_2009.mp3
The article Long term proton pump induced hypergastrinaemia does induce lineage-specific restitution but not clonal expansion in benign Barrett's Oesophagus in vivo [doi:10.1136/gut.2009.186775] can be downloaded from http://gut.bmj.com
For more information, please contact:
Simon Levey
Communications Officer (Science and Engineering)
Queen Mary, University of London
Mob: +44 (0) 20 7882 5404
Email: s.levey@qmul.ac.uk
Notes to Editors
Professor Janusz Jankowski holds the Sir James Black chair in Gastroinestinal Biology and Trials at the Centre for Gastroenterology, Barts and The London School of Medicine and Dentistry at Queen Mary, University of London.
Gut is the official journal of the British Society of Gastroenterology
Gut is a leading international journal in gastroenterology and has an established reputation for publishing first class clinical research of the alimentary tract, the liver, biliary tree and pancreas. Gut delivers up-to-date, authoritative, clinically oriented coverage of all areas in gastroenterology. Regular features include articles by leading authorities, reports on the latest treatments for diseases, reviews and commentaries. The journal has an authoritative global Editorial Board and a growing international readership.
Queen Mary, University of London
Queen Mary, University of London is one of the UK's leading research-focused higher education institutions with some 15,000 undergraduate and postgraduate students. Amongst the largest of the colleges of the University of London, Queen Mary's 3,000 staff deliver world class degree programmes and research across 21 academic departments and institutes, within three sectors: Science and Engineering; Humanities, Social Sciences and Laws; and the School of Medicine and Dentistry.
Queen Mary is ranked 11th in the UK according to the Guardian analysis of the 2008 Research Assessment Exercise, and has been described as 'the biggest star among the research-intensive institutions' by the Times Higher Education.
The College has a strong international reputation, with around 20 per cent of students coming from over 100 countries.
Queen Mary has an annual turnover of £220 million, research income worth £61 million, and generates employment and output worth £600 million to the UK economy each year.
Queen Mary, as a member of the 1994 Group of research-focused universities, has made a strategic commitment to the highest quality of research, but also to the best possible educational, cultural and social experience for its students. The College is unique amongst London's universities in being able to offer a completely integrated residential campus, with a 2,000-bed award-winning Student Village on its Mile End campus.
Journal
Gut