Now what about the more overt and truly unpleasant side-effects of anti-cancer treatment? Feelings of nausea, the need to vomit and even retch, unpleasant though they are, are part of a more primitive defence mechanism against unintentional and accidental ingestion of toxic substances belonging substantially to a bygone age. Some drugs, possessing toxic properties, can and do stimulate and thus ‘trigger off’ what amounts to a neural link or circuit, existing between the gut and a area in the brain known as the medulla (which is part of the brain stem). This is where the “vomiting centres” are known to be ‘housed’. Indeed, oncologists refer to this area as the “chemo receptor trigger zone”.
However – and although it is understood that some drugs used in chemotherapy do have a central action of this kind – our ‘old friend’, individual differences appears, almost as ever, to play an important role in such ensuing behaviour. Indeed, there exists sound evidence of real differences of this kind at work, even where two individuals have been drawn for comparison from the same family. Is this because their primitive defence mechanism of which we spoke, – possibly through loss of use to the point of redundancy over the ages – are less prominent in one than in another? Or is it, as at present appears more likely, to do with a more complex interaction of psychological excitory and inhibitory factors, which again vary widely from individual to individual?
Clearly anxiety (which also possesses known and powerful links gastro-intestinally) is implicated, since some anti-emetic (or anti-sickness) drugs have been purposely developed to work almost entirely on the principal of central sedation. Also – and as, hopefully we shall come to appreciate from future blogs in this series; relaxation and the power of suggestion (where consonant with the patients’ wishes and when delivered to patients already in states of deep relaxation) can play a significant role in anti-emesis. Other anti-emetic drugs work, (so it is claimed by proponents) by blocking the nausea and vomiting response centrally, in the chemoreceptor trigger zone. Other more recently introduced anti-emetic drugs, work peripherally, affecting vagus· nerve endings in the stomach.
In some instances (and in very small doses) steroids may be given to control sickness. Not infrequently one comes across somewhat lurid and horrific tales about the effects of drugs of this nature and one prolific ‘spawning ground’ for them can be the hospital waiting area. Incidentally, if you are being or have been troubled by such gossip, then why not take a portable tape recorder or CD player along with you and catch up on your Brahms, or indeed Wagner (assuming that such is your musical ‘tipple’). Just don’t be afraid to make it obvious that you do not wish to be disturbed. In this regard, I well remember my former SAS friend mentioned in an earlier blog in this series, who had had one or two problems of the kind with fellow patients, raising a laugh when he once produced (all in good humour) a little placard with a string to hang around his neck reading, “This construction is undergoing repair. Do not approach unless on business”. I don’t think he ever used it in the waiting area, possibly because as I gently pointed out to him, it could just attract more interest than it might deter. But to get back to the steroids, Cancer BACUP has published a really splendid fact sheet about these compounds that I have recommended to several patients. All it will take is a stamped addressed envelope and these marvellous people will gladly do the rest.