S792
Clinical - Lung
ESTRO 2026
Results: Treatment included SABR (54–60Gy/3–8fractions,20%), hypofractionated (55Gy/20fractions,66%), and conventional radiotherapy (60–66Gy/30– 33fractions,14%). 1026 (27%) had PCD, associated with a higher risk of CD (HR=3.4;p<0.001). Before weighting, cohort 1 was older, received chemotherapy less frequently, and had lower rates of nodal involvement (SMD up to 0.68). After IPTW, covariates were balanced (SMD<0.05). Over a median follow-up of 34 months (observed CD: 11%), the weighted 2-year cumulative incidence of CD was 5.8% for CAA-sparing versus 8.4%. In the weighted multivariable Fine–Gray model, there was a 23% lower hazard of CD in cohort 1 (adjusted HR 0.77,95% CI 0.61–0.98,p=0.03). Older age, male sex, chemotherapy, and PCD were associated with higher CD (Figure1). Sensitivity analyses using continuous and cubic-spline CAA dose confirmed the trend, with a non-linear dose–response (p<0.05) and risk rising steeply beyond 25Gy EQD2,alpha/beta=3 to the CAA.
Digital Poster 2516
Single-Fraction Stereotactic Body Radiotherapy for Localized Non-Small Cell Lung Cancer: Real-World Clinical Outcomes João Basílio, Tiago Figueiredo, Isabel Rodrigues, Susana Costa, João Lima, Rafael Matias, Joana Cardia Radiation Oncology, Portuguese Oncology Institute of Porto, Francisco Gentil, Porto, Portugal Purpose/Objective: Despite its logistical advantages, single-fraction SBRT remains less adopted than fractionated regimens due to concerns about toxicity and scarce real-world data. (1) The aim of this study was to report efficacy and safety outcomes of this regimen, delivered with curative intent for NSCLC, in a large real-world cohort. Material/Methods: A retrospective single-centre study included patients with primary NSCLC, treated between 2018 and 2022 with single-fraction SBRT (30 Gy) for curative intent. Treatments were planned with 4D CT and delivered using VMAT on a TrueBeam system (Varian), with image guidance through 4D CBCT and fluoroscopy. Toxicity was graded by CTCAE v5.0. Survival and recurrence outcomes were estimated using Kaplan– Meier analysis. Results: A total of 247 patients (264 lesions) were analysed. Median follow-up was 34 months (range 0.4–94.1). Median age was 73 years, and 76% were male. Most patients (74.9%) had an ECOG performance status < 2, while 25.1% had ECOG ≥ 2. Adenocarcinoma was the most frequent histology (79.2%), followed by squamous cell carcinoma (16.3%). Most lesions were peripheral (95.8%), and T1–T2 tumours predominated; the highest stage treated was T4N0M0 (stage IIIA), specifically T4 due to two ipsilateral nodules in different lobes. Median largest tumour diameter was 1.6 cm (range 0.5–4.0 cm). Median OS was 48.9 months (95% CI 39.2–58.6), with 1-, 2-, and 3-year rates of 87%, 73%, and 60%, respectively. Mean Locoregional Recurrence-Free Survival (LRRFS) and Local Recurrence-Free Survival (LRFS) were 76.5 months (95% CI 71.8–81.1) and 81.1 months (95% CI 77.0–85.3), with 3-year rates of 78% and 84%, respectively. The Kaplan–Meier curve for LRFS is shown in Figure 1. On univariate and multivariate analyses, ECOG ≥ 2 was the only independent predictor of poorer OS (HR 2.38, p < 0.001; Figure 2). No other clinicopathologic variable significantly influenced local or locoregional control. Treatment was well tolerated, with no grade ≥ 3 toxicity. Most frequent adverse event was radiation pneumonitis, predominantly grade 1, observed in 7.7% of patients, confirming an excellent safety profile.
Conclusion: In this real-world target-trial emulation, lower doses to the CAA were causally associated with reduced CD. This framework provides a robust basis for evaluating cardiac dose constraints and informs future prospective studies. A prospective CAA-sparing study is underway at our institution. References: doi:10.1001/jama.2022.21383 Keywords: target trial, cardiac-related events, emulation
Made with FlippingBook - Share PDF online