Abstract 7406: Noncontrast screening whole body MRI with diffusion-weighted imaging for multi cancer detection: a retrospective case series study

Abstract Introduction: Single-cancer screening (SCS) methods improve survival in some cancers but miss ∼70% of cancer deaths from unscreened cancers. Multi-Cancer Detection (MCD) strategies aim to broaden early detection. We evaluate the MCD yield of screening WB-MRI (sWB-MRI) in a real-world clinical setting. Methods: In this retrospective single-center study, we reviewed sWB-MRI cases from 2022 with 12 months follow-up, excluding active cancer patients. The noncontrast, multiparametric sWB-MRI with Diffusion-Weighted-Imaging (1.5T) covered head to ankles. Radiologists provided structured reports for primary care physician (PCP) review. Follow-up data was gathered through direct-to-patient phone calls, focusing on capturing any interval history of biopsy and histopathologic outcomes. Results: Of 1, 011 subjects (52% male, mean age 56 ± 28 years, median follow-up 14 ± 2 months), indications included proactive health (64%), general concerns (18%), and specific symptoms (18%). 9 radiologists reported the scans, with 5 reporting 90% (12%, 15%, 15%, 16%, & 32%). Results were reviewed with PCPs in 92.3% of cases. sWB-MRI led to targeted Tissue Sampling (TS) in 50 cases (4.9%). To isolate simple diagnostic-motivated TS (dTS) for further focused analysis, we excluded TS from clinically-indicated procedures beyond simple diagnostics: dTS = 41 (4.0%). Histopathology-confirmed Cancer Detection Percentages (CDP) with 95% CI were: Overall sWB-MRI CDP (O-CDP) = 2.2% (1.37-3.28%); dTS CDP = 51% (35-67%). O-CDP by age (# subjects, CDP %): <35 years (36, 0), 35-49 years (288, 1.4), 50-64 years (393, 2.6), 65-79 years (265, 3.0), >79 years (29, 0). Two false negatives (0.2%) were breast cancers. Of 22 detected cancers, 64% were retrospectively estimated localized, 36% regional/distant. 86% of cancers detected occurred in patients who did not indicate specific symptoms for their sWB-MRI reason. Of sWB-MRI detected cancer, 68% lacked SCS methods, while 32% had SCS options. Non-cancer clinically significant diagnoses (CSDs) included benign masses, aneurysms, liver disease, and pneumonia, prompting clinical action. Study limitations included reliance on patient-reported outcomes and lack of comprehensive medical records, limiting analysis of intermediate diagnostics and follow-up testing. Conclusions: sWB-MRI prompted pathologically-proven cancer diagnoses across diverse anatomical regions, including those outside standard SCS coverage. Prospective studies involving standardized sWB-MRI reporting frameworks (such as ONCO-RADS), larger cohorts, and designs that capture comprehensive intermediate diagnostic processes and long-term health outcomes, are essential to refine protocols and assess clinical validity (e.g., sensitivity, specificity, predictive values) and utility (e.g., patient outcomes, healthcare system impact). Citation Format: Candace Westgate, Rebecca Nayeri, Madhurima Datta, Jeffrey Venstrom, Rodrigo S. Pompa, Pratik Shingru, Saqib Basar, Sam Hashemi, Yosef Chodakiewitz. Noncontrast screening whole body MRI with diffusion-weighted imaging for multi cancer detection: a retrospective case series study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 7406.