We thank our correspondents for their interest in our work and for their comments.
We agree with Rohde that the positive predictive value and the numbers needed to screen can be additional useful measures and that they underline the importance of screening colonoscopy we described in our article.
We correctly presented uptake rates as annual participation rates. On the basis of these it is obviously possible to calculate approximate projections for longer time periods. However, these are subject to uncertainties since, epidemiologically speaking, what’s under discussion is not a closed cohort. Whether the projection for 8 years as suggested by Schuster is the most sensible variant requires further discussion. In view of the 10-year screening intervals that are foreseen for screening colonoscopy, a 10-year projection would better reflect total uptake rates.
Our large studies, in which we collected detailed information on screening colonoscopy participants’ medical histories and reasons for participating (1, 2) showed that the reasons for conducting screening colonoscopy mentioned by Hedemann may apply indeed, but only in a small minority of cases. And even if the offer of screening colonoscopy would only result in additional “indicated” colonoscopies being conducted, then this would also be a “positive side effect” associated with the screening offer.
Wenderlein points out an important issue—namely, the role of gynecologists in bowel cancer screening. A large proportion of tests for fecal occult blood —for whose effectiveness there is substantially more evidence (3) than for the rectal-digital examinations he cites—are being conducted in the setting of gynecological screenings.
Mühlhauser points to her own work in her letter, where she discusses criteria for compiling patient information on cancer screening examinations. She claims these to be the standard for communicating the results of cancer screening examinations and that they could be adapted for scientific studies. We thank the author for pointing this out; however, we intentionally based the presentation of our results on clearly defined study objectives and internationally established standards for scientific publications. The additional information that Mühlhauser is asking for was not the focus of our study. Furthermore, it would be possible to estimate the requested data only on the basis of far reaching additional assumptions, whose detailed presentation and discussion would not have made sense, nor even been possible, within the word limit imposed by Deutsches Ärzteblatt. With regard to serious complications we’d like to draw attention to page 757 of our article.
Prof. Dr. med. Hermann Brenner*
Dr. rer. soc. Lutz Altenhofen
Dr. sc. hum. Michael Hoffmeister
*Abteilung Klinische Epidemiologie und Alternsforschung
Bergheimer Str. 20
69115 Heidelberg, Germany
Conflict of interest statement
The authors of all contributions declare that no conflict of interest exists according to the guidelines of the International Committee of Medical Journal Editors.
|1.||Hundt S, Haug U, Brenner H: Comparative evaluation of immunochemical fecal occult blood tests for colorectal adenoma detection. Ann Intern Med 2009;150:162–9. MEDLINE|
|2.||Brenner H, Tao S, Haug U: Low-dose aspirin use and performance of immunochemical fecal occult blood tests. JAMA 2010; 304: 2513–20. MEDLINE|
|3.||Hewitson P, Glasziou P, Watson E, Towler B, Irwig L: Cochrane systematic review of colorectal cancer screening using the fecal occult blood test (hemoccult): an update. Am J Gastroenterol. 2008; 103: 1541–9. MEDLINE|
|4.||Brenner H, Altenhofen L, Hoffmeister M: Eight years of colonoscopic bowel cancer screening in Germany: Initial findings and projections, Dtsch Arztebl Int 2010; 107(43): 753–60. VOLLTEXT|