National Comprehensive Cancer Network (NCCN) Central Nervous System (CNS) Guidelines recommend utilizing next-generation sequencing (NGS) to enable comprehensive genomic profiling (CGP) as standard of care for molecular characterization of CNS malignancies. The restrictive nature of the blood–brain barrier (BBB) makes plasma-based liquid biopsy an ineffective alternative, however cerebrospinal fluid (CSF)–based liquid biopsy offers a minimally invasive alternative for genomic assessment. This study aimed to evaluate the clinician perspective of clinical utility of Belay’s CSF-based genomic assay, Summit 2.0, and to assess how clinicians use test results in routine clinical practice.
Methods
Clinical utility was assessed using clinician-reported survey responses from cases where Belay Summit 2.0 testing was ordered for patients with known or suspected CNS disease. Survey questions evaluated indications for testing, test positivity, impact on clinical decision-making, report clarity, and perceived overall utility.
Results
The survey response rate was 52% (95 surveys sent). Among 49 surveyed cases, 74% yielded positive genomic findings. Clinicians most frequently ordered testing to address diagnostic uncertainty or inform clinical management, with treatment selection as a less frequent primary indication. Clinical utility was reported in 86% of cases including those with negative findings, of which some results were useful for confirming existing diagnoses or management strategies. Clinicians also reported high confidence in the clarity and usability of test reports.
Conclusion
Clinician-reported outcomes indicate that Belay Summit 2.0 CSF-based genomic testing influenced clinical decision-making, including treatment selection, diagnostic clarification, confirmation of expected diagnoses, and care planning and provides meaningful information that supports diagnostic evaluation and management of CNS tumors.
Figure 1: Overview of Belay Summit 2.0 results for 49 cerebrospinal fluid (CSF) specimens. (A) Primary tumors accounted for 37% of specimens (gray), while 63% were metastatic specimens (black), distributed across positive and negative results. (B) Distribution of positive and negative Belay Summit 2.0 results among suspected primary or metastatic central nervous system (CNS) disease, stratified by tissue of origin.
Figure 2: Clinical use and impact of Belay Summit 2.0 CSF liquid biopsy testing. (A) Geographical representation of survey respondents. (B) Reported indications for ordering Belay Summit 2.0 testing, including diagnostic uncertainty (n = 27), clinical management (n = 24), treatment selection (n = 16), and disease monitoring (n = 7). (C) Proportion of cases in which Belay Summit 2.0 results influenced clinical decision-making (86%), did not influence decisions (8%), or had an uncertain impact (6%). (D) Reported clinical impact among cases in which test results influenced care, including treatment guidance (n = 22), patient or caregiver decision-making (n = 21), prognostic information (n = 18), definitive diagnosis (n = 17), confirmation of expected diagnosis (n = 15), referral to another specialty (n = 7), changes to therapy planning (n = 7), additional diagnostic testing (n = 3), and avoidance of biopsy or surgery (n = 1). (E) Reported reasons for lack of or uncertainty in clinical impact were most commonly attributed to unclear or uninformative results.
Figure 3: Clinician-reported clinical utility and report clarity of Belay Summit 2.0 (A) Clinician responses regarding the clinical utility of Belay Summit 2.0 testing, categorized as Neutral (n = 5; 1 negative, 4 positive cases), Agree (n = 6; 1 negative, 5 positive cases), and Strongly Agree (n = 38; 11 negative, 27 positive cases). (B) Clinician responses regarding clarity and understandability of Belay Summit 2.0 test reports, categorized as Neutral (n = 1, negative case), Agree (n = 11; 4 negative, 7 positive), Strongly Agree (n = 34; 8 negative, 26 positive), and no response (n = 3, positive cases). (C) Clinician responses regarding likelihood of ordering the test again, with 47 clinicians responding “Yes” (96%) and 2 clinicians provided no response.
