Zella, Julia

5624 Background: Endometrial cancer (EC) is the most common gynecologic cancer and abnormal uterine bleeding (AUB) is the predominant presenting symptom. While <10% of AUB represents underlying EC, endometrial sampling is currently required to rule out EC. To develop an alternative, non-invasive rule-out strategy, we aimed to refine a previously reported EC-associated methylated DNA marker (MDM) panel in vaginal swabs. Methods: Patients ≥18 years old with AUB who met ACOG recommendations for endometrial sampling and those undergoing a hysterectomy for biopsy-proven EC or atypical hyperplasia (AH) were prospectively enrolled in a multicenter cohort study. A vaginal fluid specimen was collected via swab by a provider during a speculum exam. DNA was extracted from samples and bisulfite treated, followed by a target and signal amplification method to detect 8 previously identified MDMs. The cross-validated EC classification model used the mean of standardized MDMs. Clinical classification of benign endometrium (BE), EC, and AH was based on central pathology review. EC diagnoses were based on hysterectomy specimens. Endometrioid and mucinous constituted type 1 EC; serous, carcinosarcoma, clear cell, and mixed histology ECs were collectively analyzed as type 2. Results: Of 693 participants enrolled, 670 were evaluable with valid results: 524 in the AUB cohort and 146 in the suspected EC cohort. Within the AUB cohort, 16 had EC or AH. The final analysis cohort included 508 BE, 156 EC, and 6 AH. Of the evaluable participants 20% identified as Black, 3% Asian or Pacific Islander, 75% White, and 3% Other; 7% reported Hispanic ethnicity. Median age was 66 and 50 years for EC and BE AUB, respectively; 80% of those with EC and 43% with benign AUB reported being postmenopausal. Among participants with EC, 102 (65%), 17 (11%), 30 (19%), 6 (4%) were stage I, II, III, and IV, respectively; one EC was unstaged. Type 2 EC accounted for 42 (27%) of all EC cases. A 4-MDM panel yielded an AUC of 0.97 (0.96-0.99, 95% CI) for EC; models with 5-8 MDMs gave identical performance. All-stage EC sensitivity was 97, 97, 96, 95, and 92% at specificities ranging from 75, 80, 85, 90, and 95%, respectively. At the 85% (82-88%) specificity threshold, sensitivities across EC stage, type, and age were consistently high (Table). Sensitivity for AH was 33% (10-70%). Conclusions: An MDM panel demonstrated high sensitivity for EC across stage and EC type, supporting the potential for a non-invasive vaginal swab-based test to rule out EC. Future studies are necessary to finalize the panel and algorithm, prior to validating the test. Clinical trial information: NCT06294886 . EC Sensitivity (%, 95% CI) at 85% Specificity All Stages (n=156)* 96 (92-98) Stage I (n=102) 94 (88 - 97) II (n=17) 100 (82 - 100) III (n=30) 100 (89 - 100) IV (n=6) 100 (61 - 100) Type 1 (n=114) 95 (89 - 98) 2 (n=42) 100 (92 -100) Age ≤ 66 yrs (n=86) 95 (89 - 98) > 66 (n=70) 97 (90 - 99) *n=1 EC was un-staged.

Abstract Background and Aims The FDA-approved multitarget stool-DNA [mt-sDNA] test is a successful colorectal cancer [CRC] screening tool in average-risk individuals but is not indicated for patients with inflammatory bowel disease [IBD]. We determined the performance of the mt-sDNA assay without the haemoglobin component [mt-sDNAHgb-] in patients with IBD, while measuring sensitivity for colorectal cancer and advanced colorectal neoplasia [ACRN]. Methods This was a multi-centre, proof-of-concept investigation in persons aged 18–84 years with a diagnosis of IBD, or primary sclerosing cholangitis [PSC] with IBD. Enrolment occurred between March 2013 and May 2016. Stool was tested with the mt-sDNA molecular markers only, minus the immunochemical haemoglobin component. Results The analysis set contained 355 samples. The median age was 52 [range 39–62] years, 45.6% were female and 93% were White. Two-thirds [63%] had ulcerative colitis [UC] and 10.1% had PSC/IBD. Colonoscopy revealed cancer in 8.5% [N = 30], advanced precancerous lesions [APLs] in 9.3% [N = 33] and non-advanced precancerous lesions in 7.6% [N = 27], and three-quarters [74.7%, N = 265] had negative findings. mt-sDNAHgb- sensitivity was 73.3% for any stage cancers, and 76.2% for ACRN. Sensitivity was highest for IBD-associated high-grade dysplasia at 100% and 84.6% for IBD-associated low-grade dysplasia ≥1 cm. The test showed higher sensitivity and lower specificity in UC than in Crohn’s disease. Increasing inflammation score was associated with a significant decrease in mt-sDNAHgb- test score [ = 0.028] amongst neoplasia-negative individuals, but not in patients with ACRN. Conclusions These data highlight the potential of multitarget stool-DNA marker testing as an important addition to colorectal cancer surveillance by complementing colonoscopic evaluations in IBD patients.