Unconventional therapies and cancer

In their recent letter, David Warr and Ian Tannock question the conclusion that evidence concerning the efficacy of hydrazine sulfate in the management of cancer is "uncertain."1 They argue that the presence of 3 negative double-blind randomized trials published in peer-reviewed journals should lead to only one reasonable verdict: ineffective. Finally, they conclude that the reviewers who compiled the information used in the articles did not use conventional rules for ranking evidence.

We would like to assure them that the reviewers (including one of us), as well as the Management Committee of the Canadian Breast Cancer Research Initiative (CBCRI), which commissioned the original reviews, are very aware of the importance of well-designed randomized controlled trials in generating reliable and generalizable research findings. However, the use of a randomized controlled trial design does not automatically confer credibility on research findings. Equally, the publication of a study in a peer-reviewed journal may add weight to the evidence, but it does not mean that readers should suspend their own judgement about the quality of the study.[2, 3]

Our review of the hydrazine sulfate trials raised concerns about the selection of study subjects, the application of the intervention, the presence of confounders and the analysis of the outcomes. These concerns were reinforced by our review of additional material pertaining to an investigation into the conduct of the hydrazine sulfate trials, which was being carried out by the US General Accounting Office. On the basis of that material, it was entirely reasonable to conclude that the evidence for and against the efficacy of hydrazine sulfate was uncertain.4

The CBCRI is a partnership of several organizations, including the Medical Research Council of Canada and Health Canada. Although it is independent from each of these partners, it benefits from their expertise and operates to the same high standards. The CBCRI embarked on its review of some alternative therapies following discussions of its Management Committee. This committee monitored the preparation of bibliographies and acknowledged the expertise, effort and care brought to the difficult task of reviewing the available data. The CBCRI considers that the resulting annotated bibliographies, as well as the summaries produced for CMAJ,[4–9] have proved helpful to researchers, clinicians and patients. It remains committed to supporting high-quality research into a broad range of issues that face breast cancer patients and the cancer-control community. It does this through a process of open-minded, rigorous and fair general competition for research funds, and through a small number of carefully selected targeted activities.

The CBCRI is pleased to stand by its record.