A retrospective analysis of optimal timing of thoracic radiotherapy for driver gene-negative metastatic non-small cell lung cancer.

ABSTRACT

BACKGROUND: The optimal timing of thoracic radiotherapy (TRT) in driver-gene-negative metastatic non-small cell lung cancer (mNSCLC) patients was retrospectively investigated based on survival and safety profile. METHODS: The efficacy and safety data of driver-gene-negative mNSCLC patients treated with TRT during maintenance after first-line therapy was collected. Patients whose primary tumor and metastatic lesions remained no progression during maintenance and then received TRT were categorized as the NP (no progression) group, while patients who experienced slow progression during maintenance without reaching progressive disease and then received TRT were categorized as the SP (slow progression) group. The efficacy and adverse events of TRT were analyzed. RESULTS: In total, 149 driver-gene-negative mNSCLC patients treated with TRT during maintenance were enrolled into the study, with 119 in the NP group and 30 in the SP group. After a median follow-up of 30.83 (range 26.62-35.04) months, the median progression-free survival (PFS) in the NP group was 11.13 versus 9.53 months in the SP group (HR 0.599, p = 0.017). The median overall survival (OS) in the NP group was 32.27 versus 25.57 months in the SP group (HR 0.637, p = 0.088). The median PFS after radiotherapy (rPFS) was 6.33 versus 3.90 months (HR 0.288, p < 0.001). The adverse events were tolerable and manageable in both groups without significant difference (p > 0.05). CONCLUSION: The addition of TRT during the pre-emptive no progression phase was associated with a significantly longer PFS than during the delayed slow progression phase and had an acceptable safety profile. Our results might support the earlier initiation of TRT after induction therapy for some patients with driver-gene-negative mNSCLC.