3637 - Local-Regional Control In LA-NSCLC Treated with Concurrent Chemoradiation with and without Consolidative Durvalumab: A Retrospective Analysis Using Both Proton and Photon Therapy
Presenter(s)
E. Thompson1, C. Centeno1, B. Adair1, A. Acevedo1, M. Pasli1, C. G. Morris1, S. Jean-Baptiste2, A. N. De Leo1, and T. Biswas1; 1Department of Radiation Oncology, University of Florida College of Medicine, Gainesville, FL, 2Department of Radiation Oncology, University of Florida College of Medicine, Jacksonville, FL
Purpose/Objective(s): The PACIFIC trial established the standard of care using consolidative durvalumab after concurrent chemoradiation in locally advanced non-small cell lung cancer (LA-NSCLC). While it showed improvement in progression free survival and overall survival (OS), the effect of consolidative durvalumab on local-regional control (LRC) was not reported. We aim to evaluate LRC with and without consolidative durvalumab in LA-NSCLC patients treated with proton (PT) and photon radiation therapy (XRT).
Materials/Methods: Two hundred and seventy patients with stage IIB-IIIC LA-NSCLC were identified between 2012-2024 at our institution. Patients were included if received conventional fractionated dose radiation therapy with chemotherapy. Patient, tumor, and treatment information including age, sex, histology, TNM stage, smoking status, radiation dose, use of durvalumab and radiation modality were collected. Survival outcomes were computed using Kaplan-Meier method.
Results: Of the 270, 189 (70%) received XRT and 81 (30%) received PT. Median follow-up was 1.5 years (range, 0.1-13.2), and the median follow-up time among the 92 living patients was three years. Fifty-eight patients received consolidative durvalumab (21%). PT had a higher proportion of patients receiving doses >60 Gy compared to XRT. Patients who received durvalumab demonstrated a trend toward improved LRC, but this trend was not statistically significant (81% [95% confidence interval {CI} 68–92%] vs 71% [95% CI 65–78%]; p=0.08). Durvalumab cohort trended toward improved cause-specific survival (77% [95% CI 65–88%] vs 61% [95% CI 54–68%]; p=0.06) and improved 5-year freedom from metastases that was statistically significant (67% [95% CI 55–79%] vs 51% [95% CI 44–58%]; p=0.02). OS at five years was 40% with durvalumab and 29% without (p=0.3126). The 5-year LRC rates were similar between XRT and PT (74% [95% CI 67–80%] vs 75% [95% CI 64–84%]; p=0.55). Smoking status was significant for LRC with non-smokers having improved LRC of 88% (95% CI 68-98%) at five years vs 61% among current smokers (p=0.01). On univariable analysis, OS was significantly associated with T stage, overall stage, and histology (p=0.0001, p=0.0001, and p=0.003, respectively). There was no difference in freedom from metastasis, LRC, and OS between PT and XRT.
Conclusion: This is one of the largest series exploring LRC with and without durvalumab in LA-NSCLC, including patients treated with PT. While LRC was improved with durvalumab, it was not statistically significant. Consolidative durvalumab was significantly associated with improved freedom from distant metastases. Our findings support the use of consolidative durvalumab following chemoradiotherapy regardless of radiation modality, and radiation remains critical in LRC.