A0168 - Serrated Polyps in Patients With Positive FIT or Mt-sDNA, or Colonoscopy Only: Data From the New Hampshire Colonoscopy Registry

Sunday, October 23, 2022

5:00 PM – 7:00 PM ET

Location: Crown Ballroom

Has Audio

Presenting Author(s)

JA

Joseph C. Anderson, MD

Physician
Dartmouth
Hanover, NH

Award: Presidential Poster Award

Joseph C. Anderson, MD¹, Christina Robinson, MS², William Hisey, MSc¹, Paul Limburg, MD, MPH³, Bonny Kneedler, MS⁴, Lynn F. Butterly, MD⁵
¹Dartmouth, Hanover, NH; ²Dartmouth Hitchcock, Lebanon, NH; ³Mayo Clinic, Rochester, MN; ⁴Exact Sciences, Madison, WI; ⁵Dartmouth Hitchcock, Hanover, NH

Introduction: Use of fecal immunochemical testing (FIT) or multi-target stool-based DNA tests (mt-sDNA) for initial colorectal cancer (CRC) screening increases polyp yield at colonoscopy. Polyps are resected during colonoscopy, preventing CRC. Serrated polyps, including sessile serrated polyps (SSPs), traditional serrated adenomas (TSAs) and hyperplastic polyps (HPs), progress to CRC through methylation, and may account for up to 30% of all CRC. FIT detects blood in the stool, and is more sensitive at detecting large (> 1 cm) adenomas than serrated polyps, which are less likely to bleed. In addition to detecting blood, mt-sDNA detects methylated DNA, and has been found more effective than FIT at detecting serrated polyps. We investigated the yield of serrated polyps in colonoscopies after FIT+ or mt-sDNA+ and in those with no preceding positive stool test in the population-based New Hampshire Colonoscopy Registry (NHCR).

Methods: Data from Exact Sciences Laboratories identified NHCR patients with a positive mt-sDNA test resulting from routine care (8/2015-12/2020). We compared NHCR patients with colonoscopy after an mt-sDNA+ or FIT+ test to those with colonoscopy only during the same period. Outcomes were clinically relevant serrated polyps (CRSPs: all SSPs and TSAs, and large (≥ 1 cm) HPs). A logistic regression model predicting CRSP adjusted for age, sex, BMI, presence of large (> 1 cm) adenomas and smoking.

Results: In our sample of 560 mt-sDNA+ patients, 414 FIT+ patients, and 59,438 with screening colonoscopy only, mt-sDNA+ was more likely to yield CRSPs than FIT+ or colonoscopy only (p < 0.0001). When stratifed by large adenomas, nearly 1 in 5 (18.0%) mt-sDNA+ patients had CRSPs with no large adenomas as compared to 1 in 10 (9.9%) FIT+ and 8% of colonoscopy only patients. A regression model showed that mt-sDNA+ patients were nearly 3 times as likely (OR 2.86, 95% CI 2.19 – 3.69) and FIT+ patients 1.5 times as likely (1.52, 1.05-2.14) to have CRSP as colonoscopy only patients.

Discussion: At follow-up colonoscopy, mt-sDNA+ tests had a higher yield of CRSPs than FIT+ or colonoscopy only, both with and without synchronous large adenomas. Given the importance of the serrated pathway and the increased CRC risk associated with CRSPs, these data have significant implications for CRC screening.

Table 1. Clinically relevant serrated polyps (CRSPs: all SSPs & TSAs, HPs ≥1 cm) at colonoscopy in patients with mt-sDNA⁺, FIT⁺ and colonoscopy only, stratified by large (≥1 cm) adenomas

Colonoscopy Findings	mt-sDNA⁺ (N = 560)		FIT⁺ (N = 414)		Colonoscopy Only (N = 59,438)		P-Value
	N	%	N	%	N	%	All groups	mt-sDNA⁺ vs FIT⁺
CRSP	118	21.1	47	11.4	5126	8.7	< 0.0001	< 0.0001
No CRSP	442	78.9	367	88.6	54,242	91.4	< 0.0001	< 0.0001

CRSPS and Large Adenomas
							< 0.0001	< 0.0001
Large adenoma & CRSP	17	3.0	6	1.5	385	0.7
Large adenoma & no CRSP	86	15.4	56	13.5	2421	4.1
CRSP & no large adenoma	101	18.0	41	9.9	4741	8.0
No large adenoma or CRSP	356	63.6	311	75.1	51821	87.3

Table: Table 1. Clinically relevant serrated polyps (CRSPs: all SSPs & TSAs, HPs ≥1 cm) at colonoscopy in patients with mt-sDNA+, FIT+ and colonoscopy only, stratified by large (≥1 cm) adenomas

Disclosures:

Joseph Anderson indicated no relevant financial relationships.

Christina Robinson: Exact Science – Grant/Research Support.

William Hisey: Exact Sciences – Grant/Research Support.

Paul Limburg: Exact Sciences – Consultant, Dr. Limburg serves as Chief Medical Officer for Exact Sciences through a contracted services agreement with Mayo Clinic. Dr. Limburg and Mayo Clinic h, Royalties, Stock-publicly held company(excluding mutual/index funds).

Bonny Kneedler: Exact Sciences – Employee.

Lynn Butterly: Exact Sciences – Grant/Research Support.

Joseph C. Anderson, MD¹, Christina Robinson, MS², William Hisey, MSc¹, Paul Limburg, MD, MPH³, Bonny Kneedler, MS⁴, Lynn F. Butterly, MD⁵. A0168 - Serrated Polyps in Patients With Positive FIT or Mt-sDNA, or Colonoscopy Only: Data From the New Hampshire Colonoscopy Registry, ACG 2022 Annual Scientific Meeting Abstracts. Charlotte, NC: American College of Gastroenterology.