ESTRO 2024 - Abstract Book

S1644

Clinical - Lung

ESTRO 2024

Results:

The analysis included 1505 NSCLC-SIII patients from 35 DROs from Spain.

Their average age was 67.1 years, with 75.9% being men. Most (89.6%) had an ECOG Status of 0-1, and 92.9% had a current or former history of tobacco exposure. Of these, 9.6% underwent surgery (primarily lobectomy for 126 patients), 57.9% received cCRT, typically with a mean total dose of 60.2 Gy administered using the VMAT technique (77.8%). 73.6% received a platinum doublet-based chemotherapy regimen. About 22.5% experienced treatment interruptions (average duration of 2 days), with 2.3% receiving compensation. 390 patients (25.91%) received immunotherapy (IT) maintenance with durvalumab, following the PACIFIC schedule. The IT was well-tolerated: 27 patients of the IT cohort (6.9%) developed CTCAE Grade >3 pneumonitis.Other G3 toxicities different than pneumonitis were developed by 28 patients (7.2%), The median overall survival (MOS) was 26 months (ranging from 9.4 to Not Reached). There was a statistically significant difference when stratifying by IT, with a MOS of 40 months (ranging from 22.1 to Not Reached) in the IT maintenance cohort compared to 19.4 months (ranging from 7.1 to 58.1) in the non-IT cohort. Differences were also noted in Progression-Free Survival (PFS), with a median PFS of 20.8 months (ranging from 9.6 to Not Reached) in the IT cohort versus 8.4 months (ranging from 3.1 to 25.1) in the non-IT cohort. These differences remained significant in a multivariable model (OS: HR 0.45 [CI 0.36-0.56], p<0.001; PFS: HR 0.5 [CI 0.42-0.59], p<0.001). Significant differences in OS were also observed when stratifying by age, with a MOS of 32.1 months (ranging from 11.2 to Not Reached) in patients younger than 65 years versus 21.6 months (ranging from 7.9 to 58.1) in older patients. Improved MOS was also seen in the female cohort (38.2 months [ranging from 11.4 to Not Reached]) compared to the male cohort (23.5 months [ranging from 9.0 to 23.5]). PFS showed differences in favor of females (median PFS 13.1 months [ranging from 4.3 to Not Reached] vs. 10.2 months [ranging from 4.1 to 27.9]). In multivariable analysis, differences in age (OS: HR 1.01 [CI 1.00-1.02], p<0.001) and tumor stage (Stage IIIC OS: HR 1.70 [CI 1.31-2.21], p<0.001; PFS: HR 1.67 [CI 1.34-2.09], p<0.001) remained significant. Cancer relapsed in 53.8% of the cohort, with the majority experiencing distant metastasis (CNS [9.8%], bone [7.8%], and lung [7.2%]). Our national population-based study aims to identify strengths and weaknesses in the management of stage III NSCLC (Non-Small Cell Lung Cancer) in DROs in Spain. The treatment of this tumoral stage aligns with international guidelines and expert recommendations. Adherence to concurrent chemoradiotherapy (cCRT) has improved compared to previously published data in other population-based studies, with over 57% of patients following this regimen. However, there is plenty of room for improvement, and this study serves as a starting point for coordinating national efforts towards it. The oncological outcomes are consistent with the information found in the literature. Regarding severe pneumonitis, our study reflects slightly higher figures than those reported in the original PACIFIC trial, although they are favorable compared to those obtained in real-world studies and elderly patients. This circumstance will be developed in further publications. Conclusion:

This is the first multicenter study by Spanish DRO regarding the management of stage III NSCLC.