Dear readers, according to the World Health Organization, certain digestive cancers (stomach, oesophagus, liver and colorectal) accounted for 23.8% of new cancers diagnosed worldwide in 2018. Colorectal cancer alone caused nearly 900,000 deaths globally last year. Although it has long been known that diet has an undeniable influence on the occurrence of digestive tumours, the related link between these diseases and the gut microbiota has been advanced more recently. This has led to a paradigm shift in which cancer is now considered to be a disease with a strong environmental component. Runaway fervour or fundamentally true? If one believes the scientific literature – which mirrors the evident international craze – the second option could well bring its share of discoveries.
Recent preclinical and clinical research provides evidence for the links that the scientific community has suspected: how some Fusobacterium species could stimulate the development of a pro-inflammatory environment in the gut mucosa and promote the emergence and progression of colorectal tumours; how Helicobacter pylori – like other bacterial species and together with multiple factors – could promote gastric tumours; or how the intestinal microbiota could modulate the antitumor immune response. In other words, intestinal dysbiosis would be implicated in the entire tumour process, from pathogenesis to the response to chemotherapy and immune checkpoint inhibitor treatments.
Professor Iradj Sobhani (Université Paris-Est Créteil and Henri-Mondor University Hospital, Créteil, France) sheds some light on this latter point in particular. He describes current evidence showing that the intestinal microbial community, as a whole, metabolizes anticancer drugs like gemcitabine and lowers its efficacy, and also influences the effects of ionizing radiation treatments and postoperative healing. He also mentions the deleterious effects of antibiotic therapy underlying the variability of response to anti-PD-1 and anti-PD-L1 immunotherapies in patients with metastatic cancer. A review that highlights the importance of the intestinal microbiota as a factor of personalized medicine in the booming field of immuno-oncology.
Microbiology and oncology go hand in hand in this issue. An occasion for Professor Harry Sokol (Hôpital Saint-Antoine, Paris, France) to revisit an article published in Science Translational Medicine showing that autologous faecal microbiota transplantation could find a promising application in haematology. As far as patient benefits go, Professor Emmanuel Mas (Hôpital des Enfants, Toulouse, France) unveils an effective dietary treatment that is well tolerated in patients with Crohn’s disease.
Enjoy your reading.