Abdelrahim, Maen

11177 Background: Early detection of recurrence after curative-intent treatment is a critical priority, traditional imaging often detects relapse when disease burden is high, potentially limiting treatment efficacy. ctDNA has emerged as an established prognostic biomarker for molecular residual disease (MRD) detection and early relapse. We performed a real-world meta-analysis on published datasets that utilized personalized, tumor-informed ctDNA testing to assess its performance across tumor types and clinical management approaches. Methods: Real-world studies published from December 2022 to December 2025 using the personalized, tumor-informed Signatera ctDNA assay (Natera, Inc.) were included. Eligibility required ctDNA assessment in the MRD (2–16 weeks post-surgery (histology dependent)/pre adjuvant therapy (ACT)) and/or surveillance (post-ACT/end of the MRD window if no ACT was given) settings, with outcomes stratified by ctDNA status and hazard ratios (HR) reported from univariable or time-dependent Cox regression analysis. Exclusions included: clinical trials, biobanks, metastatic disease treated with palliative intent, case reports, reviews, editorials, or commentaries. Clinical outcomes were harmonized into a composite event-free survival (EFS) endpoint (time to recurrence, progression, or death). Pooled HRs and 95% CIs were estimated using random and fixed effects models and heterogeneity between studies was assessed using the I 2 and Cochran’s Q test. Median lead time from ctDNA-positivity to radiographic or clinical recurrence was summarized when available. Results: We identified 18 eligible publications comprising 3,004 unique patients across 15 solid tumor types. During the MRD window, ctDNA positivity was associated with a significantly increased risk of an EFS event compared with ctDNA negativity (pooled HR: 8.15; 95% CI: 6.12–10.85, I 2 = 0.00%, P = 0.844, n = 13). During the surveillance window, inclusive of post-definitive treatment, ctDNA positivity conferred an even greater EFS risk (pooled HR: 18.30; 95% CI: 14.17–23.65, I 2 = 0%, P = 0.911 for heterogeneity, n = 16). Across studies, ctDNA detection during surveillance preceded radiographic or clinical recurrence by a median of 3.20 months (95% CI: 2.50-4.10, P < 0.0001, n = 10), although this varied substantially by study/tumor type (I 2 = 80.9%). Conclusions: In this pan-cancer real-world meta-analysis, ctDNA positivity assessed using a tumor-informed assay was highly prognostic following curative-intent therapy at all timepoints evaluated with low heterogeneity between studies. These findings support the broad clinical utility of tumor-informed ctDNA testing for post-treatment risk stratification and longitudinal disease monitoring across solid tumors.

PURPOSE Tumor treating fields (TTFields) use alternating electric fields to disrupt cancer cell proliferation. Feasibility of TTFields therapy with gemcitabine/nab-paclitaxel was previously demonstrated in patients with advanced pancreatic adenocarcinoma. PANOVA-3 was designed to confirm safety and efficacy of TTFields in patients with unresectable locally advanced pancreatic adenocarcinoma (LA-PAC). METHODS In this global phase III trial, 571 patients with newly diagnosed LA-PAC were randomly assigned to receive gemcitabine 1,000 mg/m 2 and nab-paclitaxel 125 mg/m 2 by intravenous infusion once a day on days 1, 8, and 15 of a 28-day cycle with or without TTFields. The primary end point was overall survival (OS). Secondary end points included progression-free survival (PFS), local PFS, pain-free survival, and overall response rate (ORR). Distant PFS was analyzed post hoc. RESULTS OS was significantly prolonged using TTFields with gemcitabine/nab-paclitaxel versus gemcitabine/nab-paclitaxel (median, 16.2 months [95% CI, 15.0 to 18.0] v 14.2 months [95% CI, 12.8 to 15.4]; hazard ratio [HR], 0.82 [95% CI, 0.68 to 0.99]; P = .039). PFS, local PFS, and ORR were not improved. Pain-free survival was significantly prolonged with TTFields with gemcitabine/nab-paclitaxel (median, 15.2 months [95% CI, 10.3 to 22.8] v 9.1 months [95% CI, 7.4 to 12.7]; HR, 0.74 [95% CI, 0.56 to 0.97]; P = .027), as was distant PFS (median, 13.9 months [95% CI, 12.2 to 16.8] v 11.5 months [95% CI, 10.4 to 12.9]; HR, 0.74 [95% CI, 0.57 to 0.96]; P = .022). Device-related skin adverse events (AEs) were experienced by 76.3% of patients. Most device-related skin AEs were mild to moderate, with 7.7% of patients reporting a grade 3 AE. CONCLUSION This study demonstrated significant OS, pain-free survival, and distant PFS benefits for TTFields with gemcitabine/nab-paclitaxel versus gemcitabine/nab-paclitaxel in patients with unresectable LA-PAC, with no additive systemic toxicity.

e16052 Background: Patients with esophageal squamous cell carcinoma (ESCC) who fail definitive treatment are candidates for second-line therapy. They often present with more aggressive disease and suboptimal responses to definitive treatments. In this individual patient-level meta-analysis, we aim to evaluate the efficacy of PD-1/PD-L1 inhibitors as second-line treatment in advanced ESCC. Methods: A systematic search of PubMed, Scopus, and Cochrane databases (December 5, 2024) identified randomized controlled trials (RCTs) comparing PD-1/PD-L1 inhibitors to chemotherapy as second-line treatment for advanced ESCC. Kaplan-Meier (KM) curves were reconstructed, and individual patient data (IPD) were extracted using R scripts. A patient-level meta-analysis was performed using the reconstructed IPDs and the Cox proportional hazards regression model. The Schoenfeld residuals test and Restricted Mean Survival Time (RMST) were also applied. The following R packages were used: MASS, Splines, survival, survRM2, survminer, and dbplyr . Results: Out of 3,930 records, five RCTs met the criteria: four phase 3 trials and one phase 2 trial (ORIENT-2), all were open-label, comparing PD-1 inhibitors to chemotherapy. Overall survival (OS) improved significantly with PD-1/PD-L1 inhibitors compared to chemotherapy (HR: 0.718, 95% CI: 0.650–0.793, p < 0.001). For patients with CPS ≥ 10, OS further improved (HR: 0.626, 95% CI: 0.446–0.878, p = 0.007), ), indicating an additional beneft in those with high PD-1 expression. The proportional hazards assumption was met for both OS and CPS ≥ 10 (Schoenfeld residuals test: p > 0.05). Progression-free survival (PFS) showed no significant difference (HR: 0.913, CI: 0.828–1.007, p = 0.069). However, the proportional hazards assumption was violated (Schoenfeld residuals test p < 0.001); therefore, these results should be interpreted with caution. PFS was further evaluated using RMST at 6, 12, 18, and 24 months. At 6 months, no significant difference was observed (RMST difference: -0.047, p = 0.593). However, PD-1 inhibitors showed significant differences at 12 months (0.37 months, p = 0.022), 18 months (0.74 months, p = 0.001), and 24 months (0.97 months, p < 0.001). Despite these significant differences, the magnitude of the difference is relatively small and may not be clinically meaningful. Conclusions: PD-1/PD-L1 inhibitors as second-line therapy improve overall survival in patients with advanced esophageal squamous cell carcinoma, compared to chemotherapy. However, the improvements in progression-free survival (PFS) were modest, and the clinical significance of these PFS benefits may be limited.