Risk in primary care of colorectal cancer from new onset rectal bleeding: 10 year prospective study

Sir,
More than 300 years ago, John Locke warned of the effects of the misuse of
language: “… the errors and obscurity, the mistakes and confusion that is
spread in the world by an ill use of words…” [1] If the evidence of the
article by du Toit et al. [2] is anything to go by, the philosopher’s
message appears to be in need constant reinforcement.

The context is set by the title of their paper which explicitly
refers to “colorectal cancer”. [2] However, the conclusion of the abstract
– later repeated in the discussion and the summary box – is that one in
ten patients aged 45 years or more with new onset rectal bleeding had
“colonic neoplasm” or “colorectal neoplasia”. Although less than 6% of
patients had cancer, substituting the combined figure for both cancer and
adenomas yields a more impressive “one in ten”. But, in their eagerness to
present their results in the best light, du Toit et al. simply end up by
being misleading. And, the proof of this is in the very same edition of
the BMJ. Weller, [3] in the accompanying leading article, stated that “The
study found that about one in 10 patients with new onset rectal bleeding
had cancer”. This is obviously untrue. If a reviewer, whose job it is to
study the paper in question carefully, can make such a mistake, then
questions must be raised about the way in which du Toit et al. presented
their data.

References

[1] Locke J. An Essay Concerning Human Understanding, 1690. Book III,
Chapter XI.

[2] Du Toit J, Hamilton W, Barraclough K. Risk in primary care of
colorectal cancer from new onset rectal bleeding: 10 year prospective
study. BMJ 2006;333;69-70.

[3] Weller D. Colorectal cancer in primary care. BMJ 2006; 333;54-5.

Competing interests:
None declared