Determinants of high sessile serrated lesion detection: Role of faecal occult blood test and colonoscopy quality indicators

Table 1 Recent Australian studies reporting the sessile serrated lesion detection and similar metrics

Ref.	Study focus	Number of colonoscopies	Colonoscopist		SSL-DR
			Specialty	Number	Rate	Value
Zhang et al[1], 2023	SSLDRs prevalence	21903	NR	NR	SSL-DR	24.0%
Haga et al[2], 2022	Rural QI performance	1674	GP	3	CSSDR	14.2%
					PSDR	16.0%
Watson et al[10], 2023	Rural QI performance	3497	GS	24	CSSDR	5.4%
			GS Reg	12
Wong et al[11], 2020	Withdrawal times	1579	GS	NR	SSL-DR	5.4%
Zorron Cheng Tao Pu et al[21], 2019	Specialty and time of day	2657	GE	9	SSL-DR	7.1%
			Surgeons	6		4.9%
Wong et al[36], 2017	Age in years, < 50 vs ≥ 50	2013	NR	NR	SSL-DR	3.1%
Bettington et al[17], 2017	SSL prevalence	707	GE	1	SSL-DR	19.8%
Kumbhari et al[25], 2013	Caucasian vs Asian	1000	GE	1	SSL-DR	5.3%

Rates are reported for all indications. For simplicity, only the lead author is listed in the “Study” column. In some Australian studies, the sessile serrated lesion (SSL) detection rate was not always directly reported, and a review of the number of colonoscopies and patients with SSLs was required. Some studies reported alternative metrics, such as the clinically significant serrated polyp detection rate and proximal serrated polyp detection rate, and the SSL detection rate could not be determined from supplementary tables. SSLDs: Sessile serrated lesion detection rate; NR: Not reported; QI: Quality indicator; GP: General practitioner; GE: Gastroenterologists; GS: General surgeons; GS Reg: General surgical registrars; SSL-DR: Sessile serrated lesion detection rate; CSSDR: Clinically significant serrated polyp detection rate; PSDR: Proximal serrated polyp detection rate.

Table 2 Special definitions and data transformations

Characteristic	Terms	Explanation
Variables	Indication	For the purpose of this study, each colonoscopy was assigned only a single indication using a hierarchical coding system, with the following priority order: (1) Clinical symptoms; (2) FOBT (+); (3) Surveillance (previous patient); (4) Surveillance (new patient); and (5) Screening
	Bowel preparation status	Boston Bowel Preparation Scores were collated into three broad groups: Inadequate (BBPS ≤ 5), adequate (BBPS 6 or 7), good (BBPS 8 or 9)
	Serrated polyposis syndrome status	This variable amalgates the distinction between those with SPS diagnosed in a previous colonscopy and those with SPS diagnosed from the present colonoscopy. It represents whether SPS classified as present or absent
Polypectomy quality indicators	Polypectomy rate	The proportion of colonoscopies during which at least one polypectomy was performed
	ADR	The proportion of colonoscopies during which at least one conventional adenomatous polyp, (tubular adenomas, tubulovillous adenomas, or villous adenomas) was detected. Excludes malignancies
	ASLDR	The proportion of colonoscopies during which at least one serrated lesion was detected
	SPDR	The proportion of colonoscopies during which at least one SSL/dSSL or TSA is detected. Excludes HPs
	PSDR SDR	The propotion of colonoscopies during which at least one of any serrated lesion (HP, SSL, dSSL, or TSA) is detected proximal to the border between the descending and sigmoid colon
	SSL-DR	The proportion of colonoscopies during which at least one SSL, dSSL is detected

FOBT (+): Faecal occult blood test positive; BBPS: Boston bowel preparation scale; SPS: Serrated polyposis syndrome; SSL: Sessile serrated lesion; dSSL: Dysplastic sessile serrated lesion; ADR: Adenoma detection rate; ASLDR: Any serrated lesion detection rate; SPDR: Serrated polyp detection rate; PSDR: Proximal serrated detection rate; TSA: Traditional serrated adenoma; SSL-DR: Sessile serrated lesion detection rate; SDR: Serrated detection rate; HP: Hyperplastic polyp.

Table 3 Patient demographics and colonoscopy characteristics, n (%)

Characteristic	SSL detections		Overall (n = 1450)	Respective SSL-DRs, %
	None (n = 1005)	At least one (n = 445)
Age at colonoscopy
mean ± SD	66.6 ± 13.2	66.7 ± 13.3	66.6 ± 13.2	N/A
Median (minimum-maximum)	68.8 (17.0-93.5)	69.8 (16.3-92.2)	69.2 (16.3-93.5)	N/A
Patient sex
Male	408 (40.6)	182 (40.9)	590 (40.7)	30.8
Female	597 (59.4)	263 (59.1)	860 (59.3)	30.6
Indication
Clinical symptoms	317 (31.5)	102 (22.9)	419 (28.9)	24.3
FOBT (+)	58 (5.8)	42 (9.4)	100 (6.9)	42.0
Surveillance (previous patient)	541 (53.8)	251 (56.4)	792 (54.6)	31.7
Surveillance (new patient)	45 (4.5)	29 (6.5)	74 (5.1)	39.2
Screening	44 (4.4)	21 (4.7)	65 (4.5)	32.3
Bowel preparation status
Inadequate (BBPS ≤ 5)	58 (5.8)	11 (2.5)	69 (4.8)	15.9
Adequate (BBPS 6 or 7)	311 (30.9)	128 (28.8)	439 (30.3)	29.2
Good (BBPS 8 or 9)	636 (63.3)	306 (68.8)	942 (65.0)	32.5
Serrated polyposis syndrome diagnosis
Absent	959 (95.4)	377 (84.7)	1336 (92.1)	28.2
Prior	46 (4.6)	58 (13.0)	104 (7.2)	55.8
New	0 (0)	10 (2.2)	10 (0.7)	100.0
Inflammatory bowel disease
Absent	959 (95.4)	437 (98.2)	1396 (96.3)	31.3
Present	46 (4.6)	8 (1.8)	54 (3.7)	14.8
Endoscopist
1	857 (85.3)	397 (89.2)	1254 (86.5)	31.6
2	148 (14.7)	48 (10.8)	196 (13.5)	24.5
Intubation depth
Terminal ilium	992 (98.7)	443 (99.6)	1435 (99.0)	30.9
Caecum	3 (0.3)	2 (0.4)	5 (0.3)	40.0
Not to caecum	7 (0.7)	0 (0)	7 (0.5)	0.0
No comment	3 (0.3)	0 (0)	3 (0.2)	0.0
Colonoscopy occurrences in 2023
Sole colonoscopy	996 (99.1)	442 (99.3)	1438 (99.2)	30.7
First colonoscopy	9 (0.9)	3 (0.7)	12 (0.8)	25.0

FOBT (+): Faecal occult blood test positive; SSL: Sessile serrated lesion; SSL-DR: Sessile serrated lesion detection rate; N/A: Not applicable.

Table 4 Polypectomies by location and findings, n (%)

Finding	Location										Overall (n = 3749)
	Caecum (n = 385)	Ascending colon (n = 740)	Hepatic flexure (n = 45)	Transverse colon (n = 1371)	Splenic flexure (n = 5)	Descending colon (n = 298)	Sigmoid colon (n = 722)	Rectosigmoid junction (n = 6)	Rectum (n = 175)	Unknown (n = 2)
Normal	54 (14.0)	117 (15.8)	2 (4.4)	206 (15.0)	0 (0)	25 (8.4)	52 (7.2)	0 (0)	6 (3.4)	0 (0)	462 (12.3)
TA	211 (54.8)	427 (57.7)	32 (71.1)	660 (48.1)	1 (20.0)	124 (41.6)	318 (44.0)	1 (16.7)	44 (25.1)	0 (0)	1818 (48.5)
TVA	16 (4.2)	9 (1.2)	1 (2.2)	11 (0.8)	1 (20.0)	3 (1.0)	34 (4.7)	1 (16.7)	11 (6.3)	0 (0)	87 (2.3)
HP	14 (3.6)	31 (4.2)	3 (6.7)	163 (11.9)	1 (20.0)	66 (22.1)	168 (23.3)	2 (33.3)	89 (50.9)	1 (50.0)	538 (14.4)
SSL	85 (22.1)	141 (19.1)	6 (13.3)	303 (22.1)	2 (40.0)	68 (22.8)	135 (18.7)	0 (0)	23 (13.1)	0 (0)	763 (20.4)
dSSL	1 (0.3)	1 (0.1)	0 (0)	8 (0.6)	0 (0)	2 (0.7)	2 (0.3)	0 (0)	0 (0)	0 (0)	14 (0.4)
TSA	0 (0)	0 (0)	0 (0)	1 (0.1)	0 (0)	2 (0.7)	3 (0.4)	1 (16.7)	0 (0)	0 (0)	7 (0.2)
Malignancy	0 (0)	5 (0.7)	0 (0)	1 (0.1)	0 (0)	0 (0)	2 (0.3)	1 (16.7)	1 (0.6)	0 (0)	10 (0.3)
Inadequate sample	4 (1.0)	9 (1.2)	1 (2.2)	18 (1.3)	0 (0)	8 (2.7)	8 (1.1)	0 (0)	1 (0.6)	0 (0)	49 (1.3)
Lost	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	1 (50.0)	1 (0.0)

Normal: Reflects samples within normal limits; TA: Tubular adenoma; TVA: Tubulovillous adenoma; HP: Hyperplastic polyp; SSL: Sessile Serrated lesion; dSSL: Dysplastic sessile serrated lesion; TSA: Traditional serrated adenoma; Malignancy: Encompasses cancerous findings; Inadequate sample; Samples insufficient for histological assessment, for example, acellular samples or those with only faecal matter; Lost: Reflects samples that were lost in the handling process and were not received for histopathological assessment.

Table 5 Polypectomy and detection rates by indication

Indication	Proportions (%)
	Polypectomy rate	ADR	ASLDR	PSDR	SPDR	SSL-DR
Overall (n = 1450)	83.66	57.03	48	37.1	30.97	30.69
Clinical symptoms (n = 419)	75.1	51.31	39.38	29.83	24.34	24.34
FOBT (+) (n = 100)	90	81	58	43	43	42
Surveillance (previous patient) (n = 792)	86.49	56.19	49.62	38.64	31.94	31.69
Surveillance (new patient) (n = 74)	87.84	63.51	55.41	45.95	39.19	39.19
Screening (n = 65)	89.23	60	60	46.15	33.85	32.31

FOBT (+): Faecal occult blood test positive; Polypectomy rate: The proportion of colonoscopies during which at least one polypectomy was performed; ADR: Adenoma detection rate; ASLDR: Any serrated lesion detection rate; SPDR: Serrated polyp detection rate; PSDR: Proximal serrated detection rate; SSL-DR: Sessile serrated lesion detection rate.

Table 6 Polypectomy and detection rates by indication

Comparisons	Statistics
	OR	95%CI	P value
Indication
FOBT (+)/clinical symptoms	2.299	1.203-4.396	0.004a
Surveillance (previous patient)/clinical symptoms	1.229	0.829-1.824	0.610
FOBT (+)/surveillance (previous patient)	1.870	1.02-3.43	0.039a
Surveillance (new patient)/clinical symptoms	1.898	0.912-3.953	0.120
FOBT (+)/surveillance (new patient)	1.211	0.508-2.888	0.975
Surveillance (new patient)/surveillance (previous patient)	1.544	0.767-3.108	0.437
Screening/clinical symptoms	1.386	0.625-3.073	0.797
FOBT (+)/screening	1.659	0.656-4.194	0.570
Screening/surveillance (previous patient)	1.128	0.52-2.444	0.993
Surveillance (new patient)/screening	1.370	0.51-3.679	0.909
Bowel preparation status
Adequate/inadequate	2.578	1.119-5.939	0.021a
Good/inadequate	2.430	1.082-5.458	0.027a
Adequate /good	1.061	0.748-1.504	0.917
Serrated polyposis syndrome status (grouped diagnoses)
SPS diagnosis (new or prior)/SPS absent	3.723	2.473-5.606	< 0.001a
Inflammatory bowel disease status
IBD absent/IBD present	2.332	1.073-5.065	0.032a
Endoscopist
Endoscopist 1/endoscopist 2	1.43	1.01-2.02	0.043a
Patient sex
Male/female	1.021	0.805-1.296	0.861

^aP values < 0.05.

Comparisons are made such that all odds ratios are greater than 1 for ease of interpretation odds ratios > 1 for ease of interpretation. OR: Odds ratio; CI: Confidence interval; FOBT (+): Faecal occult blood test positive; IBD: Inflammatory bowel disease.