Table 2.

Dietary and general recommendations for patients and physicians prior to commencement of ICI [133].

Dietary
• Patients to diversify their diets as much as possible, by aiming to consume a greater variety of food types and colours
• Patients should aim to meet their recommended daily fibre intake of 30 g/day
• Patients should aim to consume at least 30 plant species per week (includes nuts, seeds, herbs, grains, fruit and vegetables)
• Consumption of artificial flavours, sweeteners and additives should be minimised, as well as ultra-processed foods with multiple additives
• Where possible, patients should aim to eliminate processed meats and replace protein sources with nuts, mushrooms and legumes
• Where animal meats are consumed, patients should reduce excess meat-eating and purchase the highest quality meats they can afford
• Patients should be advised that data on extreme diets is lacking and sudden and significant changes in eating patterns could potentially be dangerous
• Patients should be advised against consumption of store-bought commercial probiotic supplements and where possible, regularly consume fermented foods containing live microbes, where appropriate
General
• Patients with cancer should have access to nutritional support through a qualified dietician or nutritionist, and side effects of dietary changes should be monitored
• Patients and their general practitioners should be advised that broad-spectrum antibiotic usage in the 3 months prior to, but particularly during the month before ICI initiation, should be avoided unless absolutely necessary clinically
• If antibiotics are deemed necessary, microbiology consultation and efforts to narrow the spectrum of antimicrobial cover should be considered
• Pending more complete data, future consideration may be given to temporary delay of initiation of non-urgent ICI (e.g. very low volume metastatic disease) if a patient has had broad-spectrum antibiotics within 1 month of planned treatment initiation to allow for reconstitution of the GM
• PPI treatment should be stopped in patients with cancer where there is no obvious indication for it. Where patients do have a requirement for gastric protection, consideration should be given to a switch to a histamine H2-receptor antagonist, as they have not been shown to induce the same dysbiosis as with PPIs