Do smoking and alcohol behaviours influence GI cancer survival?

Little is known about the role of alcohol and smoking in GI cancer survival compared to GI cancer development. We systematically reviewed the evidence for a role of smoking and alcohol in prognosis among GI cancer patients and inform whether smoking or alcohol cessation interventions or guidelines for GI cancer patients are likely to improve prognosis. A total of 84 relevant studies were identified. Continued smokers, particularly heavy smokers, had worse prognosis than never smokers in most GI cancers. However, more evidence is needed to establish the likely impact of smoking cessation interventions amongst GI cancer patients. Heavy alcohol drinkers had worse prognosis in oesophageal squamous cell carcinoma and hepatocellular carcinoma patients. Light alcohol consumption was not associated with worse prognosis from any GI cancer, though further studies are needed. UK guidelines for the general population recommending under 14 units (∼7 drinks) per week may be sufficient for GI cancer patients, until further evidence is available.