Measuring the unmeasurable

In September 1990 the Lancet published a study of women with breast cancer who, in addition to their conventional treatment, had been to the Bristol Cancer Help Centre. The relapse rate and the survival of these women were significantly worse than in control groups who had received only conventional treatment. The investigators discussed several possible explanations in their paper, but, in the publicity that followed, only one of these possibilities attracted much attention—the likelihood that some aspect of the Bristol Centre's regimen of stringent vegan diet, counselling, meditation, and healing was responsible. The validity of the findings was soon challenged. The authors of the paper reanalysed their data and modified their conclusions. A month later they acknowledged in a letter to the Lancet that the most likely explanation for their findings was that women who went to the Bristol Centre had more severe disease.

The Bristol Cancer Help Centre is now in debt and about to close; it blames the research and the publicity that went with it. This BBC documentary claimed to tell the full story. It sketched out a version of events that almost suggested medical conspiracy: the generalissimos of cancer, feeling threatened by the success of alternative medicine, challenged its advocates to ordeal by clinical trial and then rigged the results.

The programme presented women with breast cancer as a group that modern orthodox medicine has failed. It dwelt on the alienating and frightening treatment. We heard warning klaxons sound as a woman began radiotherapy; a professor describing his clinic as a patient factory; patients complaining about the callous way in which they were told the diagnosis and describing their feelings of losing control of their life. Cut to views of meals being prepared in the kitchens of the Bristol Centre, a circle of women lying on sun loungers in a large airy room, a dangling crystal, a flickering candle, a scene of faith healing. Clips of the press conference held when the paper was published were shown through a distorting lens—was this a visual metaphor for the astigmatic view that doctors take of alternative treatment?

Doctors won't like this programme very much. But if we can get beyond its one sidedness, it illustrates an important point. Some philosophers of science, Kuhn and Feyerabend for instance, have argued that competing theories are often incommensurable. What they mean is that no external standard exists by which they can be independently assessed. Each theory contains its own assumptions and its own rules for inferring conclusions from data. Using the rules of one theory to test the other is almost bound to make it look nonsense. It would, to take a hackneyed example, be pointless to investigate the existence of God by a controlled trial of the efficacy of prayer.

The treatment offered at Bristol wasn't really aimed at altering the slope of the survival curve of patients with breast cancer. It was intended to help women to come to terms with a catastrophic life experience. One of the women who took part in the study realised that it was misconceived: “I lost faith in the value of the questionnaire. It didn't tap into what I felt were the important things: the positive way that I was going to look at my life and the way that I could control some part of it.” Doctors could react positively to this programme by asking themselves why women with breast cancer found the approach taken at the Bristol Centre so helpful.—CHRISTOPHER MARTYN, MRC Environmental Epidemiology Unit, Southampton General Hospital