Trends over 18 months in the utilization of ctDNA monitoring assays for solid tumor patients in US clinical practice.

Abstract

e23135 Background: Circulating tumor DNA (ctDNA) monitoring assays are increasingly incorporated into treatment planning, yet optimal patient selection and clinical utility across stages remain under evaluation. This study assessed oncologist awareness, adoption patterns, decision drivers and perceptions related to ctDNA monitoring in solid tumors. Methods: Three online surveys of 150 oncologists were conducted in April 2024, October 2024, and April 2025. Respondents reported retrospective use of ctDNA monitoring for early- and late-stage NSCLC, breast, colorectal, prostate, and bladder cancers. Analyses examined overall and segment-level trends by practice setting, experience, region, preferred assay, and patient caseload. A sum-of-ranks method quantified assay selection drivers. Results: Across all waves, oncologists reported ordering similar numbers of ctDNA monitoring tests for early- and late-stage patients. Testing volume was highest in NSCLC (4–6 tests/month), colorectal cancer (5 tests/month), and breast cancer (5–6 tests/month). Respondents anticipated increasing use by 4–5 tests within one year and 5–6 within two years. Clinical performance consistently ranked as a primary assay selection factor (W1: 347; W3: 367), while supporting clinical data was most influential in Wave 2 (377). Quantitative ctDNA availability and report clarity increased in importance, whereas KOL recommendations declined. Physicians report a positive attitude towards ctDNA cancer monitoring, with 81% (95% CI 75–87) agreeing that “The use of ctDNA cancer monitoring really excites me.” Many express interest in increasing their knowledge of ctDNA cancer monitoring (74%, 95% CI 67–817) and believe that ctDNA monitoring brings comfort and reassurance for their patients (71%, 95% CI 64–78). However, physicians are split in their preference between tissue-informed and tissue-naïve ctDNA approaches, with 57% (95% CI 49–65) agreeing more with “I believe tissue-informed ctDNA assays are better,” while 40% (95% CI 32–48) agree more with “I believe tissue-naïve ctDNA assays are better.” Conclusions: Oncologists demonstrate sustained and growing interest in ctDNA monitoring to guide patient management, with expected increases in utilization. Despite adoption, many clinicians continue to seek clarity on optimal use and the impact of ctDNA monitoring on patient outcomes. Agreement with statements on ctDNA cancer monitoring. Statements Agree (6-7), % of respondents (N=150) 95% CI (%) Complements other monitoring approaches 80% 74%-86% Would like to know more 68% 61%-76% Would like to do more ctDNA monitoring 64% 56%-72% Provides objective insights 68% 61%-76% More informed treatment decisions 60% 52%-68% Others think highly of 49% 41%-47% Able to effectively interpret and act on results 54% 46%-62% Better than other monitoring approaches 42% 34%-50% Could replace scans 36% 28%-44%