Traditional Chinese medicine (TCM) is often promoted as an effective therapy for cancer, and are numerous controlled clinical studies published in Chinese literature, yet no systematic analysis has been done of this body of evidence. This systematic review summarizes the evidence from controlled clinical studies published in Chinese on this subject.
The researchers looked for controlled clinical studies of TCM therapies for all kinds of cancers published in Chinese in four main Chinese electronic databases and found 2964 reports including 2385 randomized clinical trials and 579 non-randomized controlled studies.
The top seven cancer types treated were lung cancer, liver cancer, stomach cancer, breast cancer, esophagus cancer, colorectal cancer and nasopharyngeal cancer. The majority of studies (72%) applied TCM therapy combined with conventional treatments, whilst fewer (28%) applied only TCM therapy in the experimental groups. Herbal medicine was the most frequently tested TCM therapy (2677 studies, 90.32%).
The most frequently reported outcome was clinical symptom improvement (1667 studies, 56.24%) followed by biomarker indices (1270 studies, 42.85%), quality of life (1129 studies, 38.09%), chemo/radiotherapy induced side effects (1094 studies, 36.91%), tumor size (869 studies, 29.32%) and safety (547 studies, 18.45%). Completeness and adequacy of reporting appeared to improve with time.
The authors of this paper drew the following conclusion: data from controlled clinical studies of TCM therapies in cancer treatment is substantial, and different therapies are applied either as monotherapy or in combination with conventional medicine. Reporting of controlled clinical studies should be improved based on the CONSORT and TREND Statements in future. Further studies should address the most frequently used TCM therapy for common cancers and outcome measures should address survival, relapse/metastasis and quality of life.
Almost 3000 controlled clinical trials! This number is likely to impress many people – unless, of course, one knows that the quality of these studies is dismal. Interestingly, no formal assessment of study quality was included in this analysis. But it was mentioned that only 63 of these trials reported patient-blinding, and only 5 were deemed to be “relatively well designed” by the authors of this paper (who, incidentally, are strong proponents of TCM).
What I find the most interesting aspect of this article is the fact that the authors fail to mention how many of the studies reported a positive result – in a way, they don’t need to: there is plenty of evidence to show that virtually all of the Chinese studies of TCM are positive. In my view, this invalidates this body of evidence completely.
Analysis like the present one tend to lead us up the garden path. They suggest that there is a realistic hope for effective new treatments hidden in this difficult to access, large amount of data. This might lead other researchers to try to replicate some of the original studies. I fear that they would be wasting their time. From all I know, they are irreproducible.