Cancer Pain Management
Dr J C D Wells, Liverpool, UK
The cornerstones of good management of cancer pain are accurate patient assessment, recognition of all correctable factors, psychological, social, physical and the use of adequate doses of appropriate drugs. This includes the use of opioids in an appropriate formulation and strength. Obviously this achieves good pain control in the majority of sufferers. However there are a small number of patients who go on to have significant pan, which can only be alleviated by more aggressive and invasive procedures. It must be stressed that in this day and age these should only be undertaken after this initial appropriate management; gone are the days when Pain Specialists could attack the central nervous system without proper assessment and without proper pre-block management.
Neuro-ablative procedures for cancer pain relief have been carried out for over 40 years. Their use was developed in the days when morphine was not freely available, and often not properly used. It is impossible to cover all of the different techniques, but it is worthwhile considering the place in the present day of the popular techniques of the past:-
1) Spinal blocks with Phenol or alcohol. The technique has been well documented, and initial response is good. However, the relief is often short-lived and produces significant side-effects and neurolytic dysfunction. The technique should only be used in carefully selected patients and carried out by adequately trained practitioners. This is not a procedure that many find useful in a significant number of patients.
2) Coeliac plexus blockade. This well-known and well-established procedure is widely practised, although by a variety of different techniques. There is no evidence at present that any one method is better than others. General efficacy is variable, as reported in many trials, but is generally thought to be useful. However, signfiicant side-effects can accrue. Permanent paralysis can occur in some patients.
3) Pituitary destruction. This was popularised in the 1960s by Moricca in Italy and has enjoyed resurgences of popularity since. Not all patients derive benefit from the technique, and the mechanism of action isnt clear. A significant side-effect profile means that this technique is used infrequently, and extreme care in selection of patients is mandatory.
4) Percutaneous cordotomy. This is a logical and elegant way of interrupting pain fibres. The technique is difficult and should only be attempted by an experienced operator. The results in educated hands are good, especially with carefully selected patients. Adverse reactions can occur, but can be minimised by careful technique.
Patients with difficult pain syndromes include those with incident pain, those with neurogenic pain and those in whom opiates, for whatever reason, have initially helped but now fail to give benefit. In some of this latter group, drug delivery systems can be inserted and acceptable pain control, with a minimum of side-effects from medication, can be achieved.
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