Many cancer patients use some form of complementary and alternative medicine (CAM), mostly as an adjunct to conventional cancer therapies to improve the symptoms of the disease or to alleviate the side-effects of the often harsh cancer-therapy. The hope is that this approach leads to less suffering and perhaps even longer survival – but is this really so?
In a recently published study, Korean researchers evaluated whether CAM-use influenced the survival and health-related quality of life (HRQOL) of terminal cancer patients. From July 2005 to October 2006, they prospectively studied a cohort study of 481 cancer patients. During a follow-up of 163.8 person-years, they identified 466 deceased patients. Their multivariate analyses of these data showed that, compared with non-users, CAM-users did not have better survival. Using mind-body interventions or prayer was even associated with significantly worse survival. CAM users reported significantly worse cognitive functioning and more fatigue than nonusers. In sub-group analyses, users of alternative medical treatments, prayer, vitamin supplements, mushrooms, or rice and cereal reported significantly worse HRQOL. The authors conclude that “CAM did not provide any definite survival benefit, CAM users reported clinically significant worse HRQOLs.”
Most proponents of CAM would find this result counter-intuitive and might think it is a one-off coincidental result or a fluke. But, in fact, it is not; similar data have been reported before. For instance, a Norwegian study from 2003 examined the association between CAM-use and cancer survival. Survival data were obtained with a follow-up of 8 years for 515 cancer patients. A total of 112 patients used CAM. During the follow-up period, 350 patients died. Death rates were higher in CAM-users (79%) than in those who did not use CAM (65%). The hazard ratio of death for CAM-use compared with no use was 1.30. The authors of this paper concluded that “use of CAM seems to predict a shorter survival from cancer.”
I imagine that, had the results been the opposite (i.e. showing that CAM-users live longer and have a better quality of life), most CAM-enthusiasts would not have hesitated in claiming a cause effect relationship (i.e. that the result was due to the use of alternative medicine). Critical thinkers, however, are more careful, after all, correlation is not causation! So, how can these findings be explained?
There are, of course, several possibilities, for example:
1) Some patients might use ineffective alternative therapies instead of effective cancer treatments thus shortening their life and reducing their quality of life.
2) Other patients might employ alternative treatments which cause direct harm; for this, there are numerous options; for instance, if they self-medicate St John’s Wort, they would decrease the effectiveness of many mainstream medications, including some cancer drugs.
3) Patients who elect to use alternative medicine as an adjunct to their conventional cancer treatment might, on average, be more sick than those who stay clear of alternative medicine.
The available data do not allow us to say which explanation applies. But things are rarely black or white, and I would not be surprised, if a complex combination of all three possibilities came closest to the truth.