Abstract
BACKGROUND: The therapeutic advantage of radiotherapy (RT) as an adjunct to first-line immunotherapy and chemotherapy in patients with extensive-stage small cell lung cancer (ES-SCLC) remains unclear. This study aimed to elucidate the value of RT based on the first failure pattern of ES-SCLC. METHODS: In this study, we retrospectively analyzed ES-SCLC patients treated with first-line chemotherapy and immune checkpoint inhibitors (ICIs) at Shanghai Chest Hospital from August 2018 to October 2023. Our study recorded the first failure pattern in ES-SCLC, analyzed the main sites of disease progression, explored factors that may affect prognosis and estimated the value of RT in extending patient survival in the immunotherapy era. Key endpoints included the first failure pattern, progression-free survival (PFS) and overall survival (OS). RESULTS: Among 344 patients, 70 (20%) had local failure, 105 (31%) had distant failure, 69 (20%) experienced both types of failure, and 100 (29%) showed no disease progression. Disease progression occurred in 244 patients (71%). They were divided into two groups: 183 without pre-progression RT and 61 with pre-progression RT. In the non-pre-progression RT group, 55 patients (30%) had local failure, 72 patients (39%) had distant failure, and 56 patients (31%) had both. In the pre-progression RT group, 15 patients (25%) had local failure, 33 patients (54%) had distant failure, and 13 patients (21%) had both. Univariate and multivariate analyses identified RT as an independent prognostic factor for improved OS (P < 0.05). Subgroup analysis further confirmed these findings. Pre-progression RT was associated with superior PFS (P < 0.05). The median overall survival (mOS) was 20.1 months (95% confidence interval [CI]: 15.5-24.7 months) in the pre-progression RT group, compared to 13.4 months (95% CI: 13.4-19.2 months) in the non-pre-progression RT group. CONCLUSION: RT improved OS in these patients, and pre-progression RT improved PFS further. Pre-progression RT shows a trend toward OS benefit.