Correspondence
Colonoscopy Screening for Detection of Advanced Neoplasia
N Engl J Med 2007; 356:632-634February 8, 2007
- Article
To the Editor:
In the cross-sectional study of the detection of advanced neoplasia during colorectal-cancer screening, Regula et al. (Nov. 2 issue)1 observed that Polish men were more than twice as likely as Polish women to have advanced neoplasia. Although they controlled for age and family history, the authors did not examine lifestyle factors known to be associated with colorectal neoplasia.
Clinical studies have consistently shown that current and former smokers have significantly higher rates of colorectal neoplasia than nonsmokers. Results from screening populations have shown that smoking may be at least as potent a risk factor as family history of colorectal cancer.2,3
In Poland, men were nearly twice as likely as women to smoke cigarettes during most of the last decade.4 In addition, a study of Polish patients with lung cancer showed that men had more pack-years of smoking than women did.5 We believe that this sex difference in tobacco exposure, coupled with the importance of smoking as a risk factor for colorectal neoplasia, warrants its consideration as a confounding factor that may explain the sex disparity observed in this trial.
5 ReferencesMichael W. Latreille, B.S.
Joseph C. Anderson, M.D.
State University of New York at Stony Brook, Stony Brook, NY 11794-8173
jcanderson@notes.cc. sunysb. edu 1
Regula J ,Rupinski M ,Kraszewska E , et al. Colonoscopy in colorectal-cancer screening for detection of advanced neoplasia. N Engl J Med 2006;355:1863-1872
Full Text | Web of Science | Medline2
Anderson JC ,Attam R ,Alpern Z , et al. Prevalence of colorectal neoplasia in smokers. Am J Gastroenterol 2003;98:2777-2783
CrossRef | Web of Science | Medline3
Lieberman DA ,Prindiville S ,Weiss DG ,Willett W . Risk factors for advanced colonic neoplasia and hyperplastic polyps in asymptomatic individuals. JAMA 2003;290:2959-2967
CrossRef | Web of Science | Medline4
WHO Regional Office for Europe. Tobacco control database: country profiles — smoking prevalence in adults (%) in Poland. Geneva: World Health Organization, 2006. (Accessed January 18, 2007, at http://data.euro.who.int/tobacco/Default.aspx?TabID=2404.)
5
Radzikowska E ,Glaz P ,Roszkowski K . Lung cancer in women: age, smoking, histology, performance status, stage, initial treatment and survival: population-based study of 20 561 cases. Ann Oncol 2002;13:1087-1093
CrossRef | Web of Science | Medline
To the Editor:
Regula et al. found that the number of men 40 to 49 years of age who needed to be screened to detect one advanced colorectal neoplasm (the number needed to screen) was similar to that of women 50 to 54 years of age. This finding is reasonable, since the ratio of the incidence of colorectal cancer for men to that for women in the 40-to-49-year age group in Warsaw is 1.4.
The authors suggest modifying the current screening recommendations for colorectal cancer, perhaps by using their “numbers needed to screen” data. We believe a more comprehensive approach, with additional risk factors included, should be taken. Tobacco and alcohol use are recognized risk factors for colorectal adenomatous polyps1 and cancer2,3 and could explain the higher prevalence of neoplasia observed in men. Giovannucci et al. previously suggested lowering the age threshold for colorectal screening among long-term smokers.2
Prognostic models have been developed to assess the individual risk of certain forms of cancer.4 A similar risk model for colorectal cancer, which could include information on risk factors such as age, sex, family history, body-mass index, diet, smoking status, alcohol consumption, and previous bowel disease, would be a useful tool for defining the ideal target population for colorectal-cancer screening.
4 ReferencesPatrick Maisonneuve, Eng.
European Institute of Oncology, 20141 Milan, Italy
patrick.maisonneuve@ieo. it Albert B. Lowenfels, M.D.
New York Medical College, Valhalla, NY 105951
Martinez ME ,McPherson RS ,Annegers JF ,Levin B . Cigarette smoking and alcohol consumption as risk factors for colorectal adenomatous polyps. J Natl Cancer Inst 1995;87:274-279
CrossRef | Web of Science | Medline2
Giovannucci E ,Rimm EB ,Stampfer MJ , et al. A prospective study of cigarette smoking and risk of colorectal adenoma and colorectal cancer in U.S. men. J Natl Cancer Inst 1994;86:183-191
CrossRef | Web of Science | Medline3
Cho E ,Smith-Warner SA ,Ritz J , et al. Alcohol intake and colorectal cancer: a pooled analysis of 8 cohort studies. Ann Intern Med 2004;140:603-613
Web of Science | Medline4
Gail MH ,Brinton LA ,Byar DP , et al. Projecting individualized probabilities of developing breast cancer for white females who are being examined annually. J Natl Cancer Inst 1989;81:1879-1886
CrossRef | Web of Science | Medline
To the Editor:
Regula et al. speculate about why their study yielded a lower-than-expected prevalance of advanced neoplasia. Perhaps the explanation is that only 29.8% of their patients received intravenous sedation. A colonoscopy in an unsedated patient is not a pleasant experience. An unsedated patient would certainly be less likely to tolerate a complete examination; this is probably reflected in the lower-than-expected cecal intubation rate in their study. In the United States, intravenous sedation is now routinely used, and one should therefore exercise great caution in extrapolating the findings of this study to the United States, as well as to other countries where sedation is the norm.
Stephen M. Picca, M.D.
Nassau University Medical Center, East Meadow, NY 11554
eesp@aol.com Author/Editor Response
Latreille and Anderson suggest that the higher rate of detection of advanced neoplasia in men than in women during colonoscopic screening in our study was due to sex differences in tobacco exposure. This may be true — it has been suggested that smoking is related to colorectal adenomatous polyps and cancer, although the data are not sufficient to call the relationship causal.1 Furthermore, smoking may be associated with lifestyle patterns that may be linked to colorectal neoplasia, (i.e., low fiber intake, high alcohol and fat intake, and low levels of physical activity). There may also be other factors that decrease the risk in women, including the presence of sex hormones. Our study was not designed to investigate the influence of smoking or other lifestyle factors, and we can neither reject nor confirm the suggestion of Latreille and Anderson. However, the fact remains that the numbers needed to screen to detect advanced neoplasia were significantly lower for men than for women. A similar finding was reported in studies conducted in the United States.2,3
We agree with Maisonneuve and Lowenfels that there are more complex prognostic models to assess the individual risk of cancer, but in our opinion, they are not ideal to guide practical recommendations for mass screening, because reliable data on factors such as smoking and drinking habits and especially diet are difficult to obtain.
Picca suggests that only colonoscopy with sedation is an acceptable screening tool and links the lower-than-expected prevalence of advanced adenoma in our study to the fact that the majority of screened patients (70.2%) underwent examination without sedation. However, the cecal intubation rate, an important measure of the quality of colonoscopy, was 91.1%, which is only slightly lower than the expected rate of 95% for an expert colonoscopist. Although this might have affected the rate of adenoma detection, the effect could not have been large. On the other hand, screening on a mass scale cannot be limited to expert centers. Other factors have an established effect on the rate of adenoma detection, including the colonoscope withdrawal time, the quality of bowel preparation, and the adequacy of training.4,5 Sedation is helpful mainly during colonic intubation; its role during withdrawal of the colonoscope, a phase vital for adenoma detection, is certainly much less important. We are not aware of any study indicating that the rate of adenoma detection in the colonic segments examined can be influenced by sedation, if the cecal intubation rate remains the same.
5 ReferencesJaroslaw Regula, M.D.
Marcin Polkowski, M.D.
Eugeniusz Butruk, M.D.
Maria Sklodowska-Curie Memorial Cancer Center, 02-784 Warsaw, Poland
jregula@coi.waw. pl 1
Department of Health and Human Services. The health consequences of smoking: a report of the Surgeon General. Atlanta: Centers for Disease Control and Prevention, 2004.
2
Imperiale TF ,Wagner DR ,Lin CY ,Larkin GN ,Rogge JD ,Ransohoff DF . Risk of advanced proximal neoplasms in asymptomatic adults according to the distal colorectal findings. N Engl J Med 2000;343:169-174
Full Text | Web of Science | Medline3
Schoenfeld P ,Cash B ,Flood A , et al. Colonoscopic screening of average-risk women for colorectal neoplasia. N Engl J Med 2005;352:2061-2068
Full Text | Web of Science | Medline4
Barclay RL ,Vicari JJ ,Doughty AS ,Johanson JF ,Greenlaw RL . Colonoscopic withdrawal times and adenoma detection during screening colonoscopy. N Engl J Med 2006;355:2533-2541
Full Text | Web of Science | Medline5
Hoff G ,Bretthauer M ,Huppertz-Hauss G , et al. The Norwegian Gastronet project: continuous quality improvement of colonoscopy in 14 Norwegian centres. Scand J Gastroenterol 2006;41:481-487
CrossRef | Web of Science | Medline
