Sidney Winawer and Ann Zauber state that no cardiopulmonary deaths occurred after the 13 000 colonoscopies in the Minnesota trial.1 However, it is not known how many patients may have suffered a cardiovascular event related to colonoscopy that may have contributed to death at a later time. As summarized by Atkin,2 the reduction in deaths from colorectal cancer in the Minnesota trial in the screened group was precisely offset by an increase in mortality from cardiac ischemia; similarly, an increase in cardiovascular deaths in the screened group more than offset any reduction in deaths from colorectal cancer in the study from the Danish center of Funen.3 The contribution of ischemic cardiovascular events to the overall increase in noncolorectal cancer mortality reported in the study from Nottingham is unknown.4
Signature
Prasad Koduri
Department of Medicine Cook County Hospital Chicago, Ill.
References
- 1.Winawer SJ, Zauber AG. Rebuttal [editorial]. CMAJ 2000;163(5):547. [PMC free article] [PubMed]
- 2.Atkin WS. Screening for colectoral cancer; the heart of the matter. Gut 2000;45:480-1. [DOI] [PMC free article] [PubMed]
- 3.Kronborg O, Fenger O, Olsen J, Jorgensen OD, Sondergaard O. Randomized study of screening for colorectal cancer with faecal-occult-blood test. Lancet 1996;348:1467-71. [DOI] [PubMed]
- 4.Hardcastle JD, Chamberlain JO, Robinson MHE, Moss SM, Amar SS, Balfour TW, et al. Randomised controlled trial of faecal-occult-blood screening for colorectal cancer. Lancet 1996;348:1472.-1. [DOI] [PubMed]