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Protection From Colorectal Cancer After Colonoscopy: A Population-Based, Case–Control Study

Hermann Brenner, MD, MPH; Jenny Chang-Claude, PhD; Christoph M. Seiler, MD, MSc; Alexander Rickert, MD; and Michael Hoffmeister, PhD
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From German Cancer Research Center and University Clinic Heidelberg, University of Heidelberg, Heidelberg, Germany, and University Hospital Mannheim, Mannheim, Germany.

Acknowledgment: The authors thank Ute Handte-Daub for her excellent technical assistance. They are grateful to the study participants and the interviewers who collected the data. The authors also thank the following hospitals and cooperating institutions that recruited patients for this study: Chirurgische Universitätsklinik Heidelberg, Klinik am Gesundbrunnen Heilbronn, Sankt Vincentiuskrankenhaus Speyer, Sankt Josefskrankenhaus Heidelberg, Chirurgische Universitätsklinik Mannheim, Diakonissenkrankenhaus Speyer, Krankenhaus Salem Heidelberg, Kreiskrankenhaus Schwetzingen, Sankt Marien- und Sankt Annastiftkrankenhaus Ludwigshafen, Klinikum Ludwigshafen, Stadtklinik Frankenthal, Diakoniekrankenhaus Mannheim, Kreiskrankenhaus Sinsheim, Klinikum am Plattenwald Bad Friedrichshall, Kreiskrankenhaus Weinheim, Kreiskrankenhaus Eberbach, Kreiskrankenhaus Buchen, Kreiskrankenhaus Mosbach, Enddarmzentrum Mannheim, Kreiskrankenhaus Brackenheim, and Cancer Registry of Rhineland-Palatinate in Mainz.

Grant Support: By the German Research Council (BR 1704/6-1, BR 1704/6-3, BR 1704/6-4, and CH 117/1-1) and the German Federal Ministry of Education and Research (01KH0404 and 01ER0814).

Potential Conflicts of Interest: Disclosures can be viewed at www.acponline.org/authors/icmje/ConflictOfInterestForms.do?msNum=M10-1362.

Reproducible Research Statement:Study protocol and data set: Not available. Statistical code: Available by request from and written agreement with Dr. Brenner (e-mail, h.brenner@Dkfz-Heidelberg.de).

Requests for Single Reprints: Hermann Brenner, MD, MPH, Division of Clinical Epidemiology and Aging Research, German Cancer Research Center, Im Neuenheimer Feld 280, D-69120 Heidelberg, Germany; e-mail, h.brenner@Dkfz-Heidelberg.de.

Current Author Addresses: Drs. Brenner and Hoffmeister: Division of Clinical Epidemiology and Aging Research, German Cancer Research Center, Im Neuenheimer Feld 280, D-69120 Heidelberg, Germany.

Dr. Chang-Claude: Division of Cancer Epidemiology, Unit of Genetic Epidemiology, German Cancer Research Center, Im Neuenheimer Feld 280, D-69120 Heidelberg, Germany.

Dr. Seiler: Department of General, Visceral, and Trauma Surgery, University Clinic Heidelberg, University of Heidelberg, Im Neuenheimer Feld 110, D-69120 Heidelberg, Germany.

Dr. Rickert: Department of Surgery, University Hospital Mannheim, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, D-68167 Mannheim, Germany.

Author Contributions: Conception and design: H. Brenner, J. Chang-Claude, C.M. Seiler, M. Hoffmeister.

Analysis and interpretation of the data: H. Brenner, C.M. Seiler, M. Hoffmeister.

Drafting of the article: H. Brenner.

Critical revision of the article for important intellectual content: H. Brenner, J. Chang-Claude, C.M. Seiler, M. Hoffmeister.

Final approval of the article: H. Brenner, J. Chang-Claude, C.M. Seiler, M. Hoffmeister.

Provision of study materials or patients: A. Rickert.

Statistical expertise: H. Brenner.

Obtaining of funding: H. Brenner, J. Chang-Claude.

Administrative, technical, or logistic support: C.M. Seiler, M. Hoffmeister.

Collection and assembly of data: H. Brenner, C.M. Seiler, M. Hoffmeister.

Ann Intern Med. 2011;154(1):22-30. doi:10.7326/0003-4819-154-1-201101040-00004
Text Size: A A A

Background: Colonoscopy with detection and removal of adenomas is considered a powerful tool to reduce colorectal cancer (CRC) incidence. However, the degree of protection achievable in a population setting with high-quality colonoscopy resources remains to be quantified.

Objective: To assess the association between previous colonoscopy and risk for CRC.

Design: Population-based case–control study.

Setting: Rhine-Neckar region of Germany.

Patients: A total of 1688 case patients with colorectal cancer and 1932 control participants aged 50 years or older.

Measurements: A detailed lifetime history of CRC risk factors and preventive factors, including history and results of previous colonoscopies, and of medical data obtained by self-reports and medical records. Odds ratios of CRC associated with colonoscopy in the preceding 10 years were estimated, after adjustment for sex, age, education level, participation in a general health screening examination, family history of CRC, smoking status, body mass index, and use of nonsteroidal anti-inflammatory drugs or hormone replacement therapy.

Results: Overall, colonoscopy in the preceding 10 years was associated with 77% lower risk for CRC. Adjusted odds ratios for any CRC, right-sided CRC, and left-sided CRC were 0.23 (95% CI, 0.19 to 0.27), 0.44 (CI, 0.35 to 0.55), and 0.16 (CI, 0.12 to 0.20), respectively. Strong risk reduction was observed for all cancer stages and all ages, except for right-sided cancer in persons aged 50 to 59 years. Risk reduction increased over the years in both the right and the left colon.

Limitation: The study was observational, with potential for residual confounding and selection bias.

Conclusion: Colonoscopy with polypectomy can be associated with strongly reduced risk for CRC in the population setting. Aside from strong risk reduction with respect to left-sided CRC, risk reduction of more than 50% was also seen for right-sided colon cancer.

Primary Funding Source: German Research Council and German Federal Ministry of Education and Research.




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Submit a Comment/Letter
In Response
Posted on February 17, 2011
Richard Babb
No Affiliation
Conflict of Interest: None Declared

Brenner and colleagues in a population based case controlled community study from Germany (1) found that colonoscopy in the preceding 10 years reduced the overall risk of colorectal cancer (CRC) by 77%; they noted a protective effect of 84% for left sided disease and 56% for the more proximal colon. As noted by Dr Weinberg in his accompanying editorial (2) "these results offer reassurance that colonoscopy can provide substantial protection against right and left sided CRC. Both Brenner et al and Weinberg make the point of our goals are to have programs for prevention and early detection to decrease incidence and mortality.

In a true US community setting, the Palo Alto Medical Foundation with 350 doctors and 11 endoscopists, all Board Certified Gastroenterologists, has just completed a quality assurance and quality improvement review of over 15000 colonoscopies done in 2007 and 2008. The results and observations confirm the opinions of Brenner et al and Dr Weinberg and are worthwhile to share. We did not look at prior colonoscopy histories in those with 10 year followups but 16% of the patients had an indication for an adenoma followup.

The incidence of CRC in Santa Clara County, CA, according to to the NCI and CDC CRC statistics is one of the lowest in the more densely populated areas of the state. With 70 CRCs in two years our incidence numbers with our patient population is 74% less than the low incidence of the county, a reflection of 25 years of attention to early detection and prevention. A surprise was finding that 20% of the CRCs occurred in patients 50 and younger. Seven women and seven men, 75% were left sided in this group. In the rest of the population, ages 51 to 91, 29 of the CRCs were right sided and 27 left sided.

With the authors as well as others (3) emphasis on qualified endoscopists doing the procedures for maximal benefits, we evaluated the metrics of our endoscopists. Cecal intubation, over 98 percent of the time. Adenoma detection rate for the entire population; 36.3% am and 36% pm. The withdrawal times in all cases were longer than 6 minutes with 26% being 6-8 minutes and the rest longer.

In summary, we agree with the authors that in community settings colonoscopy done with well trained endoscopists can significantly reduce the incidence and there by the mortality from CRCs and is as effective in decreasing risk from right sided cancers as it is from left sided malignancies.

Richard Babb,MD Brian Paaso,MD Brennan Scott,MD


1) Benner,H, Chang-Claude,J, Seiler,CM, Rickert,A, Hoffmeister,M. Protection from Colorectal Cancer after colonoscopy. A population-based, case control study. Ann Intern Med. 2011;154:22-30. [PMID: 21200035]

2) Weinberg,DS. Colonoscopy: what does it take to get in "right"? Ann Intern Med. 2011:154:68-69. [PMID: 21200044]

3)Hewett,DG,Kail,CJ,Rex,DK. Does Colonoscopy Work. Journal of the National Comprehensive Cancer Network. 2010;8:67-77. [PMID:20064290]

Conflict of Interest:

None declared

Submit a Comment/Letter

Summary for Patients

Protection Against Colorectal Cancer With Colonoscopy

The full report is titled “Protection From Colorectal Cancer After Colonoscopy. A Population-Based, Case–Control Study.” It is in the 4 January 2011 issue of Annals of Internal Medicine (volume 154, pages 22-30). The authors are H. Brenner, J. Chang-Claude, C.M. Seiler, A. Rickert, and M. Hoffmeister.


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