Prof. Michael IRWIN
Professor and Head, Department of Anaesthesiology, University of Hong Kong, Hong Kong
Michael G. Irwin, MB ChB, MD, FRCA, FCAI, FANZCA, FHKAM, is the Daniel CK Yu Professor, Department of Anaesthesiology, University of Hong Kong, Chief of Service in Anaesthesia and Critical Care at Gleneagles Hospital. Past President of the Society of Anaesthetists of Hong Kong and of the Hong Kong College of Anaesthesiology, where he is also a member of the education and examination committees. Prof. Irwin has published around 300 articles in peer reviewed scientific journals (h index 43) and is a regular invited journal reviewer. He is an editor of Anaesthesia, Perioperative Medicine, Expert Opinion on Pharmacotherapy and senior editor of the HK Medical Journal. He is on the Faculty of Evidence Based Perioperative Medicine (EBPOM) and was Chairman of the organising committee for the World Congress of Anaesthesia 2016. Research interests include intravenous anaesthesia, pharmacology, perioperative medicine/enhanced recovery and organ preconditioning.
The incidence of cancer is rising rapidly with an aging population and better prevention and treatment of other diseases. Approximately 80% of patients with cancer will need surgery and these procedures can be very extensive. Anaesthesia has an important role as part of a multidisciplinary perioperative team to optimise patients for surgery, take them smoothly through the procedure and facilitate smooth and rapid recovery. Return to intended oncological therapy (RIOT) and enhanced recovery (ERAS) are two oft used acronyms which reflect the importance of a number of factors that can have an important bearing on survival. The choice of anaesthesia technique is crucial to ensure physiological stability, analgesia and good recovery as these patients are susceptible to many factors which inhibit RIOT e.g. sarcopenia, nutritional deficit, DVT etc. Nitrous oxide is associated with adverse effects caused by depression of vitamin B12 function as well as nausea and vomiting and should be avoided. The adverse effects of newer halogenated hydrocarbons are less well recognized. Chronic exposure may cause reduction in antioxidant activity in plasma and erythrocytes, inhibition of neutrophil apoptosis, depression of central neuro-respiratory activity, increased DNA breaks, effects on cerebral blood circulation and altered renal function. Total intravenous anaesthesia (TIVA) with propofol has important advantages over inhalational drugs. A number of retrospective studies have suggested a fairly dramatic increase in survival compared with inhalational anaesthetics and prospective trials are underway. This exciting development could be due to its effects on HIF, antioxidant and anti-inflammatory properties or simply be a benefit of the avoidance of inhalational drugs. Opioids encourage angiogenesis which is a theoretical disadvantage but also inhibit proliferation of certain tumour cell lines. Currently there is no evidence that avoiding opioids is an advantage and they are often an important component of multimodal analgesia which, in itself, is very important. Modest doses of steroids reduce nausea and pain after surgery. While they may reduce immunity, the attenuation of the inflammatory response may be more significant in cancer. Other drugs such as NSAIDs/coxibs and beta blockers may have a protective role in theory, but are not well studied.
Anesthesia and Long-Term Oncological Outcomes. Chang CY; Wu MY; Chien YJ; Su IM; Wang, Shih-Ching; Kao MC. Anesth Analg 2020 October - Publish Ahead of Print - Issue -doi: 10.1213.
Impact of Regional Anesthesia on Gastroesophageal Cancer Surgery Outcomes: A Systematic Review of the Literature. Pérez-González O et al. Anesth Analg 2018 Sep;127(3):753-758.
Long-term Survival for Patients Undergoing Volatile versus IV Anesthesia for Cancer Surgery: A Retrospective Analysis. Wigmore TJ, Mohammed K, Jhanji S. Anesthesiology 2016 Jan;124(1):69-79.
Effects of propofol on cancer development and chemotherapy: Potential mechanisms. Jiang S, Liu Y, Huang L, Zhang F, Kang R. Eur J Pharmacol. 2018 Jul 15;831:46-51.