Ahluwalia, M.

TPS10628 Background: Despite advances in cancer treatment, a lack of established population-level cancer screening strategies for early detection across cancer types contributes to cancer-related mortality. Emerging MCED liquid biopsy tests represent a screening approach with potential to enable detection of multiple malignancies at earlier stages in the disease process. We previously showed that an initial classifier based on a genome-wide methylome enrichment platform detected 12 cancer types, including early-stage, low-shedding tumors (Park et al. AACR 2023. Abs 1030). However, clinical performance of the platform has not been evaluated prospectively. Thus, the CAMPERR study (NCT05366881) was designed to train and validate a cell-free methylated DNA immunoprecipitation and high throughput sequencing (cfMeDIP-seq)-based test for detection and differentiation of 20 pre-selected cancer types, representing 93% of annual cancer incidence and 88% of annual cancer deaths. Longitudinal follow-up for a subset of participants with lung cancer will enable training and validation for MRD-based recurrence prognostication. Methods: This case-control study is enrolling participants with 20 different pre-specified cancer types (n=2400) and those without known cancer (n=3900). Eligible participants are ≥40 years of age and not receiving treatment for cancer at the time of enrollment or taking any demethylating/hypomethylating agents. Cases include individuals with newly diagnosed (≤120 days), untreated cancer or recurrence of a cancer originally diagnosed >5 years ago. Cancers of interest are stage I-IV bladder, brain, breast, cervical, colorectal, endometrial, esophageal, gastric, head and neck, hepatobiliary, leukemia, lung, lymphoma, multiple myeloma, ovarian, pancreatic, prostate, renal, sarcoma, and thyroid. Participants with stage I-III lung cancer will have clinical follow-up and blood draws after completion of first-line treatment, every 3 mo for the first year thereafter, and every 6 mo for an additional 2 years. Eligible control participants have not been diagnosed with invasive cancer in the last 5 years and will have clinical follow-up ≥12 mo from enrollment to evaluate cancer status. Liquid biopsy results will not be returned to clinicians or participants. The primary objective is cancer detection. Secondary objectives include detection of specific cancer types, identification of the tissue of origin, and prognostication of clinical outcomes (eg, recurrence-free survival, overall survival). CAMPERR is currently enrolling at 15 sites. As of December 3, 2025, 2108 of 2400 cancer cases have been enrolled, including prostate (n=225), lung (n=216), colorectal (n=211), breast (n=193), and pancreatic (n=192); controls are fully enrolled. Clinical trial information: NCT05366881 .

e14017 Background: The role of stereotactic radiosurgery (SRS) is well established in the setting of one to four brain metastases (BM), offering effective control with reduced neurocognitive toxicity compared with whole-brain radiotherapy (WBRT). However, for patients with five or more BM, the optimal radiation strategy remains uncertain, and comparative outcome data are limited. We performed a systematic review and meta-analysis to compare overall survival (OS) between SRS and WBRT in patients with ≥ 5 BM. Methods: A systematic review was conducted to identify comparative studies of SRS versus WBRT in patients with ≥5 brain metastases. Retrospective and prospective studies reporting median OS with available cohort sizes were included. Comparative survival was summarized using pooled ratios of median survival within a random-effects meta-analytic framework. Results: Five comparative studies were included, comprising 226 patients treated with SRS and 261 treated with WBRT, including both retrospective and prospective cohorts. Sample-size–weighted summary (with reported medians) showed median OS was 8.1 months with SRS and 7.7 months with WBRT. Pooled analysis demonstrated no significant difference in OS between treatment strategies (ratio of median survival, 1.03; 95% CI, 0.73–1.46; p = 0.81). Conclusions: Among patients with ≥5 BM, SRS and WBRT were associated with comparable OS. These data suggest that OS alone may not guide treatment choice in this population, emphasizing the importance of careful patient selection. As focal therapies are increasingly incorporated into clinical practice for patients with higher intracranial disease burden, prospective, multi-institutional randomized clinical trials are needed to better define optimal management strategies. Summary of included studies reporting median overall survival (OS). Study Study Design SRS (n) WBRT (n) Median OS in SRS cohort (months) Median OS in WBRT cohort (months) Kim et al., 2009 Retrospective 29 39 5.6 7.2 Mizuno et al., 2019 Retrospective 24 20 7.3 7 .2 Li et al., 2020 Prospective, randomized 35 34 7.8 8.9 Bodensohn et al., 2023 Prospective, non-randomized 40 70 10.4 6.5 Aizer et al., 2025 Prospective, randomized 98 98 8.3 8.5

e14016 Background: Postoperative stereotactic radiosurgery (SRS) is utilized following resection of brain metastases (BM), however use is limited by target delineation uncertainty and an increased risk of leptomeningeal disease (LMD). Preoperative SRS allows for precise targeting and is being increasingly utilized in treatment paradigms of resectable BM. Reported outcomes across studies are promising and there are several phase 3 trials which are underway. Therefore, we pooled multiple studies and conducted a meta-analysis to estimate 1-year local control (LC), LMD incidence, and overall survival (OS) following single-fraction preoperative SRS for resectable BM. Methods: We systematically searched PubMed, Embase, and Scopus to identify studies of single-fraction preoperative SRS for resectable BM. For each cohort, data for 1-year LC, 1-year LMD, and 1-year OS, along with corresponding sample sizes, were extracted. A proportion-based meta-analysis was performed to derive pooled estimates and 95% confidence intervals (CIs), with between-study heterogeneity quantified using I². Results: Ten studies published between 2016 and 2025, including both prospective trials and retrospective cohorts, met the inclusion criteria. There were 617 patients treated with single-fraction preoperative SRS. The median age was 60.8 years (range 58-65 years), and the median prescribed dose was 15.8 Gy (range 14.5-17.0 Gy). The pooled 1-year LC rate was 81.9% (95% CI, 76.9-85.9; I² = 43.4%). The pooled 1-year incidence of LMD was 4.6% (95% CI, 2.8-7.4; I² = 0%), and the pooled 1-year OS rate was 60.2% (95% CI, 55.5-64.8; I² = 0%). Sensitivity analyses showed stable pooled estimates, with no single study driving the results. Conclusions: Single-fraction preoperative SRS is associated with low rates of LMD and acceptable LC and OS. In the context of historically reported postoperative SRS outcomes, these results suggest that preoperative SRS represents a promising strategy in selected patients. Randomized trials are needed to define the comparative role and optimal patient selection for preoperative SRS, with ongoing studies (NCT05341739, NCT03741673) expected to clarify its role in the management of resectable BM. Study characteristics and reported outcomes of single-fraction preoperative SRS for BM. Study Study design Number of patients Median age (years) Median dose (Gy) 1-year LTC (%) 1-year LMD (%) 1 year OS (%) Agarwal, 2024 Trial 47 59 NR NR 4.8 NR Higazy, 2025 Trial 35 61 17 82 2.86 NR Li, 2022 Retrospective 24 64 NR 87.6 NR NR Mallela, 2024 Retrospective 26 64.5 NR 77.2 NR NR Murphy, 2024 Trial 35 63 NR 76.6 NR 59 Patel, 2018 Retrospective 12 57.5 NR 49.1 10 74.1 Patel, 2016 Retrospective 66 58.2 14.5 84.1 3.2 NR Prabhu, 2025 Retrospective 124 NR 17 87.2 1.7 64.5 Prabhu, 2025 Retrospective 183 NR 15 86.4 7.3 58.1 Prabhu, 2020 Retrospective 65 NR NR 77.1 4.2 56.3

2028 Background: Patients with EGFR-mutated non–small cell lung cancer (NSCLC) frequently develop BM, and CNS progression is a common mode of failure on earlier-generation EGFR tyrosine kinase inhibitors (TKIs). After TKI failure in the setting of BM, optimal next-line systemic therapy remains uncertain, particularly regarding the comparative effectiveness of targeted escalation, immunotherapy (IO)-based regimens, and chemotherapy. Methods: We conducted a retrospective cohort study using the TriNetX Global Collaborative Network. We identified EGFR-mutated NSCLC patients treated with first- or second-generation EGFR TKIs who subsequently developed metachronous BM and initiated next-line systemic therapy between 2015 and 2025. Patients with leptomeningeal disease prior to earlier-generation TKI exposure were excluded. Treatment strategies were categorized as targeted escalation with osimertinib, IO-based therapy (immune checkpoint inhibitor with or without chemotherapy), or chemotherapy alone. The index date was defined as initiation of next-line systemic therapy. Propensity score matching was performed for pairwise comparisons. The primary endpoint was overall survival (OS) at 180 days. Restricted mean survival time (RMST) through 181 days was evaluated as a sensitivity analysis. Baseline covariate balance after matching was assessed using standardized mean differences, with values <0.10 indicating adequate balance. Results: After propensity score matching with adequate baseline balance, osimertinib was associated with significantly lower 180-day mortality compared with chemotherapy (24.5% vs 33.2%; hazard ratio [HR] 0.69, 95% CI 0.47–1.00). Comparisons between osimertinib and IO-based therapy showed numerically lower 180-day mortality with osimertinib (26.0% vs 32.6%; HR 0.79, 95% CI 0.54–1.15), but this difference did not reach statistical significance. Similarly, IO-based therapy was not associated with a statistically significant survival advantage compared with chemotherapy alone (31.7% vs 37.5%; HR 0.78, 95% CI 0.58–1.06). RMST analyses for death over 181 days were directionally consistent with hazard ratio–based results, with modest, non-significant differences in mean survival time. Conclusions: In EGFR-mutated NSCLC patients with metachronous brain metastases after earlier-generation TKI failure, targeted escalation with osimertinib was associated with significantly lower 180-day mortality compared with chemotherapy. IO-based approaches demonstrated intermediate, directionally favorable but non-significant outcomes relative to both osimertinib and chemotherapy. These real-world findings support guideline recommendations prioritizing next-generation TKIs and help inform systemic treatment sequencing in a CNS-enriched population where prospective data remain limited.

2036 Background: Patients with oncogene-driven metastatic non–small cell lung cancer (NSCLC) treated with CNS-penetrant tyrosine kinase inhibitors (TKIs) frequently develop brain metastases (BM) while continuing targeted therapy, and outcomes of adding local CNS-directed therapy in this setting are not well defined. We evaluated outcomes associated with local CNS therapy after post-TKI BM diagnosis. Methods: We conducted a retrospective cohort study using the TriNetX Global Collaborative Network. Adults with NSCLC treated with osimertinib or lorlatinib who subsequently had a coded diagnosis of BM (ICD-10 C79.31) at least 1 month after TKI initiation and evidence of continued TKI use were included. Patients were stratified by receipt of CNS-directed local therapy (SRS/SBRT or neurosurgery) within 3 months of the index BM diagnosis versus no local therapy. The primary outcome was all-cause mortality within 180 days of the index event. Secondary outcomes included hospitalization and systemic corticosteroid use. Cohorts were balanced using 1:1 propensity score matching on demographics, comorbidities, extracranial disease, laboratory values, and TKI exposure. Survival analyses were performed, and proportional hazards assumptions were validated using Schoenfeld residuals (p>0.05). Results: Among 1,157 eligible patients, 1,053 matched pairs were generated. Within 180 days of the index brain metastasis diagnosis, mortality was lower among patients who received local CNS therapy compared with those who did not (10.9% vs 18.1%), corresponding to a hazard ratio (HR) for death of 0.54 (95% CI 0.43–0.68; p<0.001). Survival probabilities at 180 days were 88.7% in the local therapy cohort and 80.2% in the no local therapy cohort. Hospitalization within 180 days occurred in 20.3% of patients receiving local therapy and 22.4% of those without local therapy (p=0.24), with a nonsignificant trend toward delayed hospitalization (HR 0.84, 95% CI 0.69–1.01). Systemic corticosteroid use was common and similar between groups (61.3% vs 59.4%; p=0.40), with no significant difference in time to steroid initiation. In an osimertinib-only sensitivity analysis, 180-day mortality was 10.5% among patients receiving local CNS therapy compared with 19.4% among those without local therapy (HR 0.48, 95% CI 0.37–0.61; p<0.001). Conclusions: In this multi-institutional real-world cohort of patients with NSCLC receiving osimertinib or lorlatinib who developed BM, receipt of local CNS-directed therapy within 3 months was associated with lower 6-month mortality compared with continuation of targeted therapy alone, with consistent findings in an osimertinib-only sensitivity analysis. These results suggest a potential survival benefit of local CNS intervention in selected patients, while acknowledging residual confounding related to intracranial disease burden and clinical indication.