Clin Endosc > Volume 51(4); 2018 > Article
Kim and Chang: How to Detect Sessile Serrated Adenoma/Polyps
See “Endoscopic Features of Mucous Cap Polyps: A Way to Predict Serrated Polyps” by Brian T. Moy, Faripour Forouhar, Chia-Ling Kuo, et al., on page 368-374.
Interval colorectal cancer (CRC) is defined as CRC diagnosed after a negative screening or surveillance colonoscopy (no cancer detection) and before the next recommended follow-up examination [1]. It has been generally accepted that most CRCs are derived from adenomatous polyps. Therefore, if an adenomatous polyp is detected and removed during a regular colonoscopy, the development of CRC can be prevented. Actually, previous studies have shown that the colonoscopic removal of adenomatous polyps reduces the mortality from CRC [2]. However, interval CRCs have been consistently reported in patients who have undergone a complete colonoscopy [3,4].
There are several explanations for the development of interval CRCs including: missed lesions, new lesions, and incomplete resected lesions [5]. Recent studies have reported that interval CRCs exhibit some characteristics such as a predominant proximal location, association with the CpG island methylator phenotype (CIMP), and microsatellite instability [5,6]. Further, these characteristics of interval CRCs overlap with sessile serrated adenomas/polyps (SSA/Ps). In recent years, there has been a growing interest in SSA/Ps.
Although only 20% of serrated polyps are SSA/Ps, SSA/Ps are considered more important than the other serrated polyps due to their malignant potential. SSA/Ps have been recognized as precursors of CIMP-positive and BRAF mutant CRCs that are often associated with microsatellite instability [7,8]. Unfortunately, the diagnosis of SSA/Ps is easy to miss due to their indistictive endoscopic morphologies. According to recent studies, the detection of SSA/Ps correlates with the gastroenterologist’s experience and skills [9]. Therefore, it is crucial to know about the endoscopic features of SSA/Ps. Previous studies have reported that SSA/Ps exhibit presence of several endoscopic characteristics such as a mucous cap, a rim of debris or bubbles, an alteration of the contour of a mucosal fold, the obscuring of an underlying submucosal vessel, a nodular surface and a dome-shaped protuberance [10,11]. Following analysis of 158 SSPs, Tadepalli et al. reported that a mucous cap (63.9%) and peripheral rim (51.9%) were the most common characteristics of SSPs; further, these chracteristics showed a remarkable positive association with SSPs (odds ratio [OR] 3.8, p=0.0002) [10]. Murakami et al. showed that 95%–100% of SSA/Ps with or without dysplasia had a mucous cap [12].
In a current issue of Clinical endoscopy, Moy et al. investigated whether a mucous- capped polyp, one of the most common endoscopic features of SSA/Ps, can predict the presence of serrated polyps [13]. They examined the endoscopic features of 147 mucous-capped polyps to determine if they could predict SSA/Ps. Among these, there were 127 (86%) serrated polyps (right-sided hyperplastic polyps, SSA/Ps, or traditional serrated adenomas), and only 43 (29%) SSA/Ps [13]. To find the predictive features of SSA/Ps, they also evaluated other endoscopic characteristics of mucous- capped polyps such as polyp size (≥10 mm), the distinct border, elevation, rim of debris, location, varicos vessels, nodular surface and alterations in the fold contour. It was observed that 39 polyps of 43 SSA/Ps (91%) and 56 polyps of 104 non SSA/Ps (54%) were combined with varicos vessels, and these results were found to be statistically significant (adjusted OR, 10.75; p=0.000). Based on these findings, the researchers concluded that mucous- capped polyps are more likely to be serrated polyps and the presence of a mucous cap combined with varicous vessels was a significant predictor for SSA/Ps.
This study revealed some interesting results; however, these results should be interpreted with caution.
Although previous studies have shown that most SSA/Ps had a mucous cap, this study demonstrated that most mucous-capped polyps were unfortunatly not SSA/Ps (43/147, 29%). Additionaly, while most mucous- capped SSA/Ps had varicous vessels (39/43, 91%), the percentage of SSA/Ps among mucous- capped polyps with varicous vessels was only 41% (39/95). Therefore, it is insufficient to conclude that the combind presence of a mucous cap and varios vessels is a predictor for SSA/Ps. Additionally, there exists a possibility that further analysis according to the number of morphological characteristics of mucous capped polyps would provide more information and better predictability for SSA/Ps.
Recent studies have attempted to identify the morphological characteristics of SSA/Ps using several advanced imaging techniques such as narrow band imaging (NBI), image enhanced endoscopy or autofluorescence imaging [7,14]. According to a recent meta-analysis, most of studies conducted using NBI and NBI proved to have a higher sensitivity for detecting SSA/Ps compared to other endoscopic imaging techniques [15]. However, the sensitivity of NBI for detecting SSA/Ps has shown variations, depending on the endoscopic features. For example, indistinct borders (OR, 3.7) and a cloud-like surface (OR, 2.65) were found to be associated with SSA/Ps on high-resolution white light, whereas on an NBI, a cloud-like surface (OR, 4.91), indistinctive borders (OR, 2.38) and dark spots inside the crypts (OR, 2.05) were correlated with SSA/Ps [11].
Based on current studies, there are no clear and definite endoscopic features to predict serrated lesions, especially SSA/Ps. However, in general practice, it is paramount to make efforts not to miss the serrated polyps. This can be accomplished by gaining an in-depth knowledge of the several endoscopic characteristics of serrated polyps and conducting a meticulous examination of the bowel mucosa.

NOTES

Conflicts of Interest:The authors have no financial conflicts of interest.

REFERENCES

1. Sanduleanu S, le Clercq CM, Dekker E, et al. Definition and taxonomy of interval colorectal cancers: a proposal for standardising nomenclature. Gut 2015;64:1257–1267.
crossref pmid
2. Zauber AG, Winawer SJ, O’Brien MJ, et al. Colonoscopic polypectomy and long-term prevention of colorectal-cancer deaths. N Engl J Med 2012;366:687–696.
crossref pmid pmc
3. Richter JM, Campbell EJ, Chung DC. Interval colorectal cancer after colonoscopy. Clin Colorectal Cancer 2015;14:46–51.
crossref pmid
4. Brenner H, Chang-Claude J, Seiler CM, Hoffmeister M. Interval cancers after negative colonoscopy: population-based case-control study. Gut 2012;61:1576–1582.
crossref pmid
5. Adler J, Robertson DJ. Interval colorectal cancer after colonoscopy: exploring explanations and solutions. Am J Gastroenterol 2015;110:1657–1664; quiz 1665.
crossref pmid pdf
6. Samadder NJ, Curtin K, Tuohy TM, et al. Characteristics of missed or interval colorectal cancer and patient survival: a population-based study. Gastroenterology 2014;146:950–960.
crossref pmid
7. Tanaka Y, Yamano HO, Yamamoto E, et al. Endoscopic and molecular characterization of colorectal sessile serrated adenoma/polyps with cytologic dysplasia. Gastrointest Endosc 2017;86:1131–1138; e4.
crossref pmid
8. Thorlacius H, Takeuchi Y, Kanesaka T, Ljungberg O, Uedo N, Toth E. Serrated polyps - a concealed but prevalent precursor of colorectal cancer. Scand J Gastroenterol 2017;52:654–661.
crossref pmid
9. Li D, Woolfrey J, Jiang SF, et al. Diagnosis and predictors of sessile serrated adenoma after educational training in a large, community-based, integrated healthcare setting. Gastrointest Endosc 2018;87:755–765; e1.
crossref pmid
10. Tadepalli US, Feihel D, Miller KM, et al. A morphologic analysis of sessile serrated polyps observed during routine colonoscopy (with video). Gastrointest Endosc 2011;74:1360–1368.
crossref pmid
11. Hazewinkel Y, López-Cerón M, East JE, et al. Endoscopic features of sessile serrated adenomas: validation by international experts using high-resolution white-light endoscopy and narrow-band imaging. Gastrointest Endosc 2013;77:916–924.
crossref pmid
12. Murakami T, Sakamoto N, Ritsuno H, et al. Distinct endoscopic characteristics of sessile serrated adenoma/polyp with and without dysplasia/carcinoma. Gastrointest Endosc 2017;85:590–600.
crossref pmid
13. Moy BT, Forouhar F, Kuo CL, Devers TJ. Endoscopic features of mucous cap polyps: a way to predict serrated polyps. Clin Endosc 2018;51:368–374.
crossref pmid pmc pdf
14. Singh R, Zorrón Cheng Tao Pu L, Koay D, Burt A. Sessile serrated adenoma/polyps: where are we at in 2016? World J Gastroenterol 2016;22:7754–7759.
crossref pmid pmc
15. Parikh ND, Chaptini L, Njei B, Laine L. Diagnosis of sessile serrated adenomas/polyps with image-enhanced endoscopy: a systematic review and meta-analysis. Endoscopy 2016;48:731–739.
crossref pmid pdf
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