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PQA 01 - PQA 01 Lung Cancer/Thoracic Malignancies and Diversity, Equity and Inclusion in Healthcare Poster Q&A

2040 - Clinical Efficacy of Postoperative Radiotherapy for High-Risk Locoregional Recurrence in Patients with Completely Resected Pathologic Stage IIIA(N2) Non-Small Cell Lung Cancer: A Propensity Score-Matc

Sunday, September 29, 2024
2:45 PM – 4:15 PM ET
Location: Hall C

Screen: 10

    Presenter(s)

  • Wen Feng, MD

    Shanghai Chest Hospital Shanghai Jiao Tong University
    Shanghai, Shanghai

S. Zhang1, R. Hou1, X. Cai2, J. Liu1, W. Yu1, Q. Zhang2, J. Guo1, Z. Zhu3, W. Feng4, and X. Fu2; 1Department of Radiation Oncology, Shanghai Chest Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China, 2Department of Radiation Oncology, Shanghai Chest Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China, 3Department of Radiation Oncology, Fudan University Shanghai Cancer Center, Shanghai, China, 4Department of Radiation Oncology, Shanghai Chest Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China

Purpose/Objective(s): Two recent Phase III studies showed no survival benefit from postoperative radiotherapy (PORT) in completely resected stage IIIA(N2) non-small cell lung cancer (NSCLC), suggesting a need for more precise PORT application. Based on our prior work establishing patient stratification by locoregional recurrence (LRR) risk, we conducted a propensity score-matched (PSM) analysis to assess whether PORT provided survival benefits for the high-risk LRR group.

Materials/

Methods: We conducted a prospective, randomized clinical trial from June 2016 at 5 hospitals to explore the optimal timing of PORT in a high-LRR-risk group of patients with completely resected pathologic stage IIIA(N2) NSCLC. Patients were randomly assigned to receive early or late PORT following the institutional CTV guideline, in addition to four cycles of chemotherapy. To assess the value of PORT for high-LRR-risk patients, entire patients in this trial were selected as the PORT cohort for analysis. In addition, we identified high-risk IIIA(N2) patients without PORT in a retrospective cohort from our institution, which served as the non-PORT cohort. A PSM analysis was conducted to compare survival endpoints between the two cohorts, including overall survival (OS), disease-free survival (DFS), locoregional recurrence-free survival (LRFS), and distant metastasis-free survival (DMFS).


Results: Between June 2016 and January 2022, 132 patients were included in the prospective clinical trial, serving as the PORT cohort. The median follow-up was 49.3 months (range, 8.8-100.2). The 3-year-OS rate was 83.2% and 3-year-DFS rate was 35.0%. PORT was well-tolerated, with only 3 patients (2.3%) experiencing grade 3 radiation pneumonitis. 10 patients did not receive planned PORT, leaving 122 patients serving as the per-protocol (PP) population. For 132 intention-to-treat patients, a PSM analysis was performed with the high-risk non-PORT cohort (n=307), and 130 patients in each group were successfully matched. Results suggested a clinical benefit of PORT with LRFS (3-year-LRFS, 77.6% for PORT vs 57.3% for non-PORT; p=0.00014), DFS (3-year-DFS, 35.2% for PORT vs 28.6% for non-PORT; p=0.038), and OS (3-year-OS, 83.0% for PORT vs 60.7% for non-PORT; p=0.00017), while there was no difference in DMFS (p=0.17). PSM analysis was also conducted for 122 PP patients, yielding consistent results with improved LRFS (p=0.00028), DFS (p=0.027), and OS (p<0.0001), and no difference in DMFS (p=0.16).


Conclusion: According to our PSM analysis, PORT could considerably enhance local control and even DFS, and should thus be considered for completely resected pathologic stage IIIA(N2) NSCLC patients at high risk of LRR. Multi-dimensional data should be used in future research to pinpoint more precise patient subgroups that benefit from PORT, and prospective trials should be planned and undertaken to validate these results. (NCT02974426)