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- Cancer risk
- IBD therapy
- cancer risk
- colorectal cancer
- 13C-urea breath test
- intestinal bacteria
- IBD clinical
- 2,4,6-trinitrobenzene sulphonic acid
- inflammatory diseases
Although there has been a recent trend towards a decreased absolute age-standardised mortality from cancer in Europe,1 in 2004, for the first time, cancer became the main cause of death in the general population in France.2 This apparent paradox is explained by a faster improvement of the prognosis of non-cancer diseases. Cancer risk has therefore become a lifelong major fear for gastroenterologists and patients when considering the long-term impact of the natural history and treatment of inflammatory bowel diseases (IBDs).
Overall mortality from cancer in IBD
Life expectancy is normal for patients with ulcerative colitis (UC), with no excess mortality from cancer in population-based studies.3 For patients with Crohn's disease (CD), life expectancy is slightly reduced.4 A significant increase in deaths from cancer was reported in the most recent meta-analysis of population-based studies,4 but this was probably due to an over-representation of smoking-related causes of death in a disease where smokers are over-represented. In a Californian medico-administrative database, no overall excess mortality from cancer was demonstrated in either type of IBD, irrespective of the treatments used.5 This reassuring general background must be highlighted before discussion of the specific details of inflammation and immunosuppression-related cancers in IBD.
Theoretical links between IBD and cancer
There is no evidence for a common genetic background between IBD and a susceptibility to cancer. For environmental factors, increased and decreased proportions of smokers in CD and UC compared with the general population are associated with corresponding variations in the incidence of lung and urinary bladder cancers.6 Finally, immunosuppression and inflammation are the two main drivers of IBD-related carcinogenesis. The difficulty is that these two mechanisms may be interlinked, particularly in the intestinal tissues; thus, we will now distinguish the true (negative and positive) effects of IBD treatments.
Cancers related to immunosuppressive therapy
We have learnt …