Joe O’Sullivan, MD, of Queen’s University Belfast, Belfast, UK, first discusses the importance of conducting large randomized trials to identify the toxic effects of anti-cancer therapies, before raising concerns on adherence to guidelines when treating patients. Prof. O’Sullivan also questions the current rationale behind weighing up the benefits and risks in the implementation of cancer therapies, and proposes suggestions on possible criteria for guidelines set by organizations. This video was recorded at the European Society for Medical Oncology (ESMO) 2018 Congress, in Munich, Germany.