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We sincerely appreciate the comments of Bleijenbert et al regarding our study. However, we would like to specify some of these comments. Bleijenbert et al point out potential differences in indications between serrated polyposis syndrome (SPS) and multiple serrated polyps (MSP) patients as a putative cause for the high rate of colorectal cancer (CRC) between these last cases. Although not reported in the manuscript, no differences in the indication for colonoscopy were found between SPS and MSP patients. Specifically regarding the indication of a positive fecal immunochemical test from a CRC screening program, it is important to remark that none of the included patients in this study came from CRC screening programs, because at the time of patients’ inclusion in this study (2008 and 2009), population CRC screening programs using fecal immunochemical testing were not yet available in Spain. Some pilot programs started in some Spanish regions in 2004 and 20051Garcia M. et al.Eur J Cancer Prev. 2012; 21: 42-45Crossref PubMed Scopus (12) Google Scholar not affecting the participant centers in the EPIPOLIP registry. It is likely that the greater proportion of adenomas found in the MSP group is exclusively due to the selection criteria chosen for defining this group. Bleijenbert et al also argue a potential overrepresentation of SPS patients with lower CRC risk, such as patients fulfilling the World Health Organization (WHO) criterion 3 or smokers. This could be theoretically correct, because the criteria for selecting patients in this study requires to have ≥10 polyps, potentially limiting representation of patients fulfilling the WHO criterion 1, with only few and large right-sided serrated polyps. However, in all the previously reported series,2Guarinos C. et al.World J Gastroenterol. 2012; 18: 2452-2461Crossref PubMed Scopus (49) Google Scholar the majority of SPS patients are those who fulfil the WHO criterion 3, with MSP throughout the colon. However, in a previous study,3Guarinos C. et al.Clin Gastroenterol Hepatol. 2013; 11: 705-711Abstract Full Text Full Text PDF PubMed Scopus (35) Google Scholar in which we described our SPS cohort, 30% of our patients fulfil criterion 1 of WHO, a proportion similar to that found in other series. Finally, regarding smokers, minimal and nonsignificant differences in the proportion of smokers were found, as can be seen in Table 1. Therefore, it does not look like as an overrepresentation of lower risk SPS patients could be found in our cohort. Another doubt reported by Bleijenberg et al is about potential differences in the time interval between colonoscopies in the SPS and MSP groups, as well as possible differences in quality of baseline colonoscopies. Unfortunately, we cannot provide these data. We recognize the retrospective design of our study as a limitation, but given that there are no differences in the number of surveillance colonoscopies between the groups, it would not be very likely to have such a differences in the interval between colonoscopies. Also, we do not expect to see differences in the quality of baseline colonoscopies. Finally, we completely agree about the need for prospective studies aimed at defining SPS better. Based on our results, patients with MSP represent a population at risk for CRC, and surveillance strategies should be developed. We feel that studies like this are revealing the lack of evidences for the selection of patients for special surveillance. Research in this field is urgent, because without robust evidence, recommendations remain weak. With a rare disease, it is necessary for different research groups interested in SPS to pool their efforts, looking for evidence to redefine the current WHO criteria identifying patients at a really increased risk of CRC that can be appropriately protected with surveillance colonoscopy. Multiple Serrated Polyps and Serrated Polyposis Syndrome: Equally Hazardous?GastroenterologyVol. 153Issue 6PreviewSerrated polyposis syndrome (SPS) is perhaps the least understood and most prevalent polyposis syndrome currently known and is associated with an increased prevalence of colorectal cancer (CRC).1,2 In screening populations, prevalence rates of up to 1:127 are reported.3 Little is known about the pathophysiology, but likely a combination of genetic and environmental factors (most notably smoking) lies at the heart of this disease.1,2 The limited understanding of the syndrome’s etiology has led to the use of clinical diagnostic criteria, which were arbitrarily defined by the World Health Organization (WHO). Full-Text PDF