A preliminary study on the timing of radiotherapy for chemoimmunotherapy in oligometastatic non-small-cell lung cancer with negative driver genes.

Abstract

e20084 Background: Local radiotherapy (LRT) is reported to provide durable local and distant disease control for oligometastatic non-small cell lung cancer (NSCLC) in accumulating evidence, but research on the optimal initial time point remains scarce. We conducted a study to preliminarily evaluate the timing of radiotherapy for chemoimmunotherapy in Oligometastatic Non-small-cell lung cancer with negative driver genes. Methods: 50 patients diagnosed with Oligometastatic Non-small-cell lung cancer with negative driver genes who were treated with chemoimmunotherapy and radiotherapy were retrospectively recruited between January 2018 and October 2023. They were divided into two groups: one early to initiate radiotherapy group (≤2 cycles of immunotherapy, EAR group) and one deferred radiotherapy group (>2 cycles of immunotherapy, DEF group). The clinical efficacy and adverse reactions were compared between the two groups. Progression-free survival (PFS) and overall survival (OS) were evaluated by Kaplan-Meier curves, the Cox proportional hazard model was used to find out predictors of PFS and OS. Results: The tumor control rates had no significance was observed when comparing these two groups (50.0% and 26.9%, respectively, p = 0.093). The PFS in the RAE group was significantly higher than that in the DEF group (median PFS: 12.2 months vs 5.3 months, P<0.05). The OS in two groups were no significance (median OS: 20.5months vs 23.1months, P>0.05). The results of the Cox multivariate regression analysis revealed that the number of metastatic lesions and organs were independent prognostic factors for PFS. The number of metastatic lesions and organs, maintain therapy were independent predictors associated with OS. All patients well tolerated the treatments. Conclusions: Early initiation of local radiotherapy resulted in better PFS and no significant increase in adverse reactions was observed.