Rebuttal: Should Canadians be offered systematic screening for colorectal cancer?

Forty years ago, the World Health Organization adopted 10 principles to guide screening for chronic disease, including cancer.1 These principles have remained the criterion standard for the practice of screening. In line with the philosophy of the organization for which he works, Dr Pineau invokes 5 of these principles to justify screening for colorectal cancer (CRC). Unfortunately, he makes no mention of the reasons why screening for CRC is incompatible with at least 5 of these 10 principles.

It is high time that Canadian doctors rid themselves of erroneous beliefs about screening, particularly cancer screening. First of all, it is because screening always does harm that it must be based on scientific knowledge rather than on the conclusions of consensus conferences that are influenced by all sorts of considerations that have nothing to do with protection of public health.2 And it is because screening always does harm that, before we turn screening into a public health program, we must determine that the potential benefits of such a program are substantially greater than the harm it will certainly inflict. Screening for CRC still has not proven that its contribution to public health warrants the creation of a public health program, regardless of what the directors of the Canadian Cancer Society say.3

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