As other illnesses have become less frequent and we have become better at treating them, cancer has become the most common reason for needing general anaesthesia. Advances in radiotherapy and chemotherapy, many originating from my own hospital St Bartholomew’s in London, together with surgery remain the mainstay of treatment although immunotherapy and genetics offer exciting hope for the future. Little thought has been given to whether the operation itself, either surgery or anaesthesia, affects the progression of cancer.

We are a long way from being able to say definitively what is the best anaesthetic or surgical management to optimise the immune system and to reduce the risk of cancer recurrence or progression. Many studies only exist in vitro (in the test tube) and others are contradictory but it is clear that the perioperative period has a major effect on the immune system.

There is increasing evidence that the use of an epidural or spinal anaesthetic preserves the immune system and its ability to destroy cancer cells. In part this is due to avoiding general anaesthetic agents that may affect gene progression or the effectiveness of cells such as natural killer cells and lymphocytes. However the regional anaesthetic also blocks the so-called stress response where the pituitary fires up the endocrine system releasing multiple chemicals. In addition the local anaesthetics used in an epidural or spinal anaesthetic appear to have a positive effect on the immune system although perhaps not in the doses commonly used.

Opiates (morphine etc) also have an effect mostly to suppress the immune system. However pain itself has a poor outcome in terms of cancer so a difficult balancing act exists. It would appear that using pain relieving drugs other than opiates are beneficial but non-steroidals such as ibuprofen suppress the inflammatory response which is vital for the immune system and appear to be contraindicated. Ketamine clearly suppresses white cells and clonidine, another pain killer, appears contraindicated.

For those patients who need a general anaesthetic the main question is whether they should have a total intravenous anaesthetic with drugs such as propofol or whether they should breathe anaesthetic drugs such as sevoflurane. Some of my colleagues demand a total intravenous anaesthetic for all cancer patients but I believe this is difficult to justify. Sevoflurane appears to reduce the risk of recurrence in colon cancer whereas propofol appears to be beneficial in breast cancer. A total intravenous anaesthetic may have disadvantages for certain operations so one size certainly does not fit all.

There is interesting data suggesting that patients with stress and mental anxiety have a higher recurrence rate and one study implies that giving patients propranolol to reduce anxiety may be beneficial although it may need to be given before diagnosis!

Over the next few years I am sure many of these issues will be clarified. We will realise that anaesthesia plays a big part in the immune system and the outcome for patients with cancer. As with so much in medicine the best advice is to ensure that your anaesthetist is experienced in this particular field and to talk to him at preassessment about his recommended anaesthetic technique

About the author

Dr Aubrey Bristow is a consultant anaesthetist in central London. These articles are his personal views and reflect individual issues of interest to patients. They are not a comprehensive review of the subject nor a substitute for a consultation with your anaesthetist.