Abstract
Prevalence and associations of sessile serrated polyps in a general colonoscopy population
Introduction and aims: Colorectal cancer (CRC) is a leading cause of cancer mortality in Australia. Most CRCs result from pre-existing adenomatous polyps and less commonly sessile serrated polyps (SSPs). While adenomatous polyps often have identifiable risk associations and have been the target of CRC prevention and screening programs, SSPs are more difficult to predict or detect using any screening modality or risk characterisation. Since the faecal immunochemical test (FIT) used in most bowel cancer screening programs with faecal occult blood testing (FOBT) has poor sensitivity for SSPs, good bowel preparation and quality colonoscopy are required to enhance detection. We examined the prevalence and associations of sessile serrated polyps in a general colonoscopy population. In Australia, the minimum standard expected by the Gastroenterological Society of Australia (GESA) for recertification includes a minimum SSP detection rate for screening colonoscopy in patients aged over 50 years while the cancer council set a target of at least 10%.
Methods: The electronic database of a hospital endoscopy service was interrogated to determine the polyp detection, and specifically the SSP detection rate of an unselected patient population undergoing colonoscopy over a 12-month period (1 January- 31 December 2018). Patients with inflammatory bowel disease were not excluded. Colonoscopy reports on all patients presenting for colonoscopy were examined for the key word polyp. The polyp histology was then reviewed to identify findings of SSPs. Patients with SSPs were characterised based on age, sex, ethnicity and indication for colonoscopy. The number of SSPs, size and location were recorded. Associations were sought between patient and SSP characteristics.
Results: Colonoscopy was performed on 3421 patients. Mean (standard deviation) age was 58(16) years, age range 18-93 years, and 47.5% male. Patients were predominantly Caucasian (95%). Amongst the patients, 1162 (33.9%) had polypectomy documented. SSPs were detected in 184 patients (5.4%) overall but 1 in 6 (15.8%) of histologically examined polyps were SSPs. There was no difference in sex between patients with SSPs (50.5% male). The median number of SSPs per patient was 1(range 1-20) and median (interquartile range) SSP size 5.0 (4.0-7.0) mm diameter. Two-thirds of the SSPs were located in or proximal to the transverse colon (proximal SSPs). Females had more proximal SSPs than males (73.6% vs. 59.1%, p=0.04). There was no difference in SSP count based on sex (1.6 SSPs per patient for males and females). However, the SSP count per colonoscopy was higher in patients aged under 50 years than those aged 50 years and over (2.1 vs. 1.5, p=0.04). Only 18% of patients with SSPs were having colonoscopy to investigate a positive FIT result.
Conclusions: In this general colonoscopy population the SSP detection rate is acceptable. The predominantly proximal distribution of SSPs underscores the need for quality colonoscopy, particularly in females. The fact that the SSP count per colonoscopy was higher in patients aged under 50 years with varied procedure indications, challenges the current paradigm of “average population risk” screening using FIT alone.
Introduction and aims: Colorectal cancer (CRC) is a leading cause of cancer mortality in Australia. Most CRCs result from pre-existing adenomatous polyps and less commonly sessile serrated polyps (SSPs). While adenomatous polyps often have identifiable risk associations and have been the target of CRC prevention and screening programs, SSPs are more difficult to predict or detect using any screening modality or risk characterisation. Since the faecal immunochemical test (FIT) used in most bowel cancer screening programs with faecal occult blood testing (FOBT) has poor sensitivity for SSPs, good bowel preparation and quality colonoscopy are required to enhance detection. We examined the prevalence and associations of sessile serrated polyps in a general colonoscopy population. In Australia, the minimum standard expected by the Gastroenterological Society of Australia (GESA) for recertification includes a minimum SSP detection rate for screening colonoscopy in patients aged over 50 years while the cancer council set a target of at least 10%.
Methods: The electronic database of a hospital endoscopy service was interrogated to determine the polyp detection, and specifically the SSP detection rate of an unselected patient population undergoing colonoscopy over a 12-month period (1 January- 31 December 2018). Patients with inflammatory bowel disease were not excluded. Colonoscopy reports on all patients presenting for colonoscopy were examined for the key word polyp. The polyp histology was then reviewed to identify findings of SSPs. Patients with SSPs were characterised based on age, sex, ethnicity and indication for colonoscopy. The number of SSPs, size and location were recorded. Associations were sought between patient and SSP characteristics.
Results: Colonoscopy was performed on 3421 patients. Mean (standard deviation) age was 58(16) years, age range 18-93 years, and 47.5% male. Patients were predominantly Caucasian (95%). Amongst the patients, 1162 (33.9%) had polypectomy documented. SSPs were detected in 184 patients (5.4%) overall but 1 in 6 (15.8%) of histologically examined polyps were SSPs. There was no difference in sex between patients with SSPs (50.5% male). The median number of SSPs per patient was 1(range 1-20) and median (interquartile range) SSP size 5.0 (4.0-7.0) mm diameter. Two-thirds of the SSPs were located in or proximal to the transverse colon (proximal SSPs). Females had more proximal SSPs than males (73.6% vs. 59.1%, p=0.04). There was no difference in SSP count based on sex (1.6 SSPs per patient for males and females). However, the SSP count per colonoscopy was higher in patients aged under 50 years than those aged 50 years and over (2.1 vs. 1.5, p=0.04). Only 18% of patients with SSPs were having colonoscopy to investigate a positive FIT result.
Conclusions: In this general colonoscopy population the SSP detection rate is acceptable. The predominantly proximal distribution of SSPs underscores the need for quality colonoscopy, particularly in females. The fact that the SSP count per colonoscopy was higher in patients aged under 50 years with varied procedure indications, challenges the current paradigm of “average population risk” screening using FIT alone.
Original language | English |
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Pages (from-to) | 233-233 |
Number of pages | 1 |
Journal | Journal of Gastroenterology and Hepatology |
Volume | 34 |
Publication status | Published - Sept 2019 |