Correspondence
Capsule Endoscopy versus Colonoscopy
N Engl J Med 2009; 361:1608-1610October 15, 2009
- Article
To the Editor:
The article by Van Gossum et al. (July 16 issue)1 and the corresponding editorial by Bretthauer2 describe a low sensitivity of colon capsule endoscopy as compared with colonoscopy for the detection of advanced neoplasia. The overall rate of detection of advanced neoplasia in a screening program depends not only on accuracy, but also on patients' adherence to the procedure.3 Colonoscopy has consistently been associated with a disappointing adherence rate of less than 30% in screening programs,4,5 so that, at best, 30% of the prevalent advanced neoplasia will be diagnosed. Assuming a 73% sensitivity for the detection of advanced neoplasia with the use of capsule endoscopy, a greater than 41% adherence rate would be sufficient to identify more than 30% of the overall advanced neoplasia present in the population. Therefore, the unanswered question does not appear to be whether a noninvasive test may achieve the same accuracy as an invasive one, but whether the increase in the rate of adherence that may be achieved with the use of a noninvasive test (in patients who are unwilling to undergo colonoscopy) will overcome its expected lower accuracy.
5 ReferencesCesare Hassan, M.D.
Angelo Zullo, M.D.
Nuovo Regina Margherita Hospital, Rome, Italy
cesareh@hotmail.com 1
Van Gossum A ,Munoz-Navas M ,Fernandez-Urien I , et al. Capsule endoscopy versus colonoscopy for the detection of polyps and cancer. N Engl J Med 2009;361:264-270
Full Text | Web of Science | Medline2
Bretthauer M . The capsule and colorectal-cancer screening -- the crux of the matter. N Engl J Med 2009;361:300-301
Full Text | Web of Science | Medline3
Hassan C ,Zullo A ,Winn S ,Morini S . Cost-effectiveness of capsule endoscopy in screening for colorectal cancer. Endoscopy 2008;40:414-421
CrossRef | Web of Science | Medline4
Segnan N ,Senore C ,Andreoni B , et al. Comparing attendance and detection rate of colonoscopy with sigmoidoscopy and FIT for colorectal cancer screening. Gastroenterology 2007;132:2304-2312
CrossRef | Web of Science | Medline5
Brenner H ,Hoffmeister M ,Brenner G ,Altenhofen L ,Haug U . Expected reduction of colorectal cancer incidence within 8 years after introduction of the German screening colonoscopy programme: estimates based on 1,875,708 screening colonoscopies. Eur J Cancer 2009;45:2027-2033
CrossRef | Web of Science | Medline
To the Editor:
The trial comparing capsule endoscopy with optical colonoscopy for the detection of polyps and cancers seems disappointing. However, two points warrant further discussion. First, the investigators used colonoscopy as the standard for comparison; however, some lesions detected by capsule endoscopy might be missed by colonoscopy.1 Even with back-to-back colonoscopies, a significant proportion of adenomas could not be seen.2 Second, since colonoscopy is an invasive, uncomfortable procedure with a finite risk of complications,3 the aim of introducing capsule endoscopy is to obviate the need for colonoscopy. Therefore, the high negative predictive values for the detection of polyps (86.0% and 93.0%) and an even higher value in patients with good or excellent cleanliness of the colon (90% in polyps ≥6 mm) cannot be overlooked. This fact may justify the usefulness and applicability of capsule endoscopy in screening for colorectal cancer. Nevertheless, all screening tools should be tested in randomized, comparative trials.
3 ReferencesChing-Sheng Hsu, M.D.
Buddhist Tzu Chi General Hospital, Taipei, TaiwanJia-Horng Kao, M.D., Ph.D.
National Taiwan University Hospital, Taipei, Taiwan
kaojh@ntu.edu. tw 1
Schoofs N ,Deviere J ,Van Gossum A . PillCam colon capsule endoscopy compared with colonoscopy for colorectal tumor diagnosis: a prospective pilot study. Endoscopy 2006;38:971-977
CrossRef | Web of Science | Medline2
Rex DK ,Cutler CS ,Lemmel GT , et al. Colonoscopic miss rates of adenomas determined by back-to-back colonoscopies. Gastroenterology 1997;112:24-28
CrossRef | Web of Science | Medline3
Bretthauer M . The capsule and colorectal-cancer screening -- the crux of the matter. N Engl J Med 2009;361:300-301
Full Text | Web of Science | Medline
Author/Editor Response
Indeed, although the sensitivity of colon capsule endoscopy for detecting polyps that were 6 mm in size or bigger was 64% as compared with colonoscopy in our study, the negative predictive value for the detection of such lesions was 86% in the global population and reached 94% in the group of patients with a good-to-excellent colon preparation. In our study, colon capsule endoscopy detected significant findings in 12 patients, whereas colonoscopy was normal. Although a second colonoscopy was not part of the protocol, we were informed that a second colonoscopy confirmed the presence of a lesion in three of four patients in whom we received the data.
Hassan and Zullo point out an important feature of a screening program — that is, the adherence of the population to such a program. This adherence can be highly dependent on the acceptability of the screening method.
The capsule, which is a minimally invasive method, has the potential to increase compliance with screening in patients who decline or are unable to undergo colonoscopy. The cost of the method should also be considered.
The results that we obtained in this multicenter trial and the relevant comments raised in the two letters provide support for the need for future trials with potentially better colon preparation as well as technical improvements of the second-generation colon capsule.
André Van Gossum, M.D.
Jacques Devière, M.D.
Erasme University Hospital, Brussels, Belgium
andre.vangossum@erasme. ulb. ac. be Author/Editor Response
Hsu and Kao present negative predictive values for the colon capsule. Positive and negative predictive values vary with the prevalence of the target disease in the study sample. Since the prevalence of colorectal lesions reported in the study by Van Gossum et al. was considerably higher than what can be expected in a screening population, sensitivity and specificity are more appropriate measures of test performance in the study by Van Gossum and colleagues.
As Hassan and Zullo point out, good adherence of the target population is a prerequisite for the success of any screening program. Colon capsule endoscopy is less invasive than colonoscopy. However, bowel cleansing is a major barrier to adherence to colonoscopy screening, and colon capsule endoscopy requires a more extensive bowel-cleansing regimen than colonoscopy. Therefore, higher compliance associated with the use of the capsule as compared with colonoscopy may be questionable. Studies comparing compliance rates for colonoscopy versus colon capsule endoscopy in screening populations are therefore important. The adherence rate associated with screening colonoscopy was shown to be low in an Italian study,1 as Hassan and Zullo indicate. In Germany, the cumulative compliance rate associated with the colonoscopy-based screening program is increasing with each year the program exists, and it is currently estimated to be 40% among women and 30% among men (in a population younger than 70 years of age). In the United States, adherence to colonoscopy-based screening has been steadily increasing during recent years and was already exceeding 45% of the target population in 2005.2 In Norway, a population-based study of colonoscopy-based screening indicated 71% compliance.3
3 ReferencesMichael Bretthauer, M.D., Ph.D.
Oslo University Hospital Rikshospitalet, Oslo, Norway1
Segnan N ,Senore C ,Andreoni B , et al. Comparing attendance and detection rate of colonoscopy with sigmoidoscopy and FIT for colorectal cancer screening. Gastroenterology 2007;132:2304-2312
CrossRef | Web of Science | Medline2
Shapiro JA ,Seeff LC ,Thompson TD ,Nadel MR ,Klabunde CN ,Vernon SW . Colorectal cancer test use from the 2005 National Health Interview Survey. Cancer Epidemiol Biomarkers Prev 2008;17:1623-1630
CrossRef | Web of Science | Medline3
Thiis-Evensen E ,Hoff GS ,Sauar J ,Langmark F ,Majak BM ,Vatn MH . Population-based surveillance by colonoscopy: effect on the incidence of colorectal cancer. Scand J Gastroenterol 1999;34:414-420
CrossRef | Web of Science | Medline
- Citing Articles (2)
Citing Articles
1
Francesco Perri, Angelo Iacobellis, Marco Gentile, Emanuele Tumino, Angelo Andriulli. (2010) The intelligent, painless, “germ-free” colonoscopy: A Columbus’ egg for increasing population adherence to colorectal cancer screening?. Digestive and Liver Disease 42:12, 839-843
CrossRef2
Cristiano Spada, Cesare Hassan, Riccardo Marmo, Lucio Petruzziello, Maria Elena Riccioni, Angelo Zullo, Paola Cesaro, Julia Pilz, Guido Costamagna. (2010) Meta-analysis Shows Colon Capsule Endoscopy Is Effective in Detecting Colorectal Polyps. Clinical Gastroenterology and Hepatology 8:6, 516-522.e8
CrossRef
