2522 - Efficacy and Safety of Thoracic Radiotherapy in Untreated Metastatic Pulmonary Large-Cell Neuroendocrine Carcinoma: A Multicenter Retrospective Analysis
Presenter(s)
H. Yang1,2, B. Li3, T. Dong4, C. Jiang5, J. Yu6, and L. Wang7; 1Shandong Cancer Hospital and Institute, Shandong First Medical University, Shandong Academy of Medical Sciences, Jinan, Shandong, China, 2Shandong First Medical University, Shandong Academy of Medical Sciences, Jinan, Shandong, China, 3Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, Shandong, China, 4Department of Obstetrics and Gynecology, Qilu Hospital of Shandong University, Jinan, Shandong, China, 5Department of Otorhinolaryngology & Head and Neck Surgery, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, China, 6Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences Department of Radiation Oncology, Jinan, Shandong, China, 7Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, China, Jinan, Shandong, China
Purpose/Objective(s):
Pulmonary large-cell neuroendocrine carcinoma (LCNEC) is a rare and aggressive cancer with a poor prognosis and limited treatment options. Among the patterns of escalation after first-line treatment, the progression of primary site and regional lymph nodes accounted for a significant proportion. The role of first-line thoracic radiotherapy (TRT) in advanced LCNEC remains uncertain. This study aimed to evaluate the efficacy and safety of TRT combined with systematic therapy in previously-untreated patients with metastatic LCNEC.Materials/Methods:
This retrospective study included treatment-naïve patients with metastatic LCNEC treated with or without thoracic radiotherapy. Fractionation schemes of TRT included conventional fractionation radiotherapy (30–60 Gy, once daily; 1.5–2.5 Gy/fraction), hyperfractionation radiotherapy (45 Gy, twice daily; 1.5 Gy/fraction), or hypofractionation radiotherapy (30 Gy, once daily; 3 Gy/fraction). Data from electronic health records of three hospitals, spanning from September 2018 to October 2024, were analyzed. Outcomes including progression-free survival (PFS), overall survival (OS), objective response rate (ORR), disease control rate (DCR) and safety were assessed for both groups.Results: Among the 94 enrolled patients, 26 were allocated to TRT group and 68 were allocated to non-TRT group. Up to December 31,2024, the median PFS (mPFS) was 10.0months (95% CI,8.3-11.8) in the TRT group, compared to 4.5 months (95% CI, 3.5-5.5) in the non-TRT group (hazard ratio [HR], 0.407; 95% CI, 0.245–0.675;p<0.001). The median OS was 28.4 months (95% CI, 4.9-52.0) in the TRT group, compared to 12.3 months (95% CI,7.6-17.0) in the non-TRT group (HR, 0.487; 95% CI, 0.259-0.917; p=0.009). The ORRs were 76.9% in the TRT group and 39.7% in the non-TRT group, and the DCRs were 100% and 75.0%, respectively. Regarding safety, no significant increase of any grades adverse event (AE) and grade = 3 AE was observed for patients receiving TRT. No patient exhibited grade 5 AE.
Conclusion: The addition of thoracic radiotherapy at first line was associated with superior PFS, and significantly improved OS for advanced LCNEC, which could be a feasible treatment option for LCNEC patients.