OBJECTIVES: This study aims to examine whether advanced non-small cell lung cancer (NSCLC) patients without epidermal growth factor receptor (EGFR) or anaplastic lymphoma kinase (ALK) mutations have different prognoses and treatment patterns between de novo patients who are directly diagnosed with stage Ⅲb–Ⅳ disease and relapsed/progressed patients.

METHODS: This retrospective cohort study analyzed data from the South Korean National Health Insurance Review and Assessment claims database from 2013 to 2020. We identified adult patients with stage Ⅲb–Ⅳ NSCLC initiating first-line palliative therapy between 2015 and 2019. Patients who have been treated with EGFR or ALK tyrosine kinase inhibitors were excluded. Overall survival (OS) from the date of initiating first-line therapy and time to next treatment (TTNT) for first- and second-line therapy of de novo and relapsed/progressed patients were estimated using the Kaplan-Meier method. The top five most frequent regimens were described in both groups of patients for first- and second-line therapies.

RESULTS: Of 14,726 patients with stage Ⅲb–Ⅳ NSCLC without EGFR or ALK mutations, 12,804 (86.9%) were de novo patients and 1,922 (13.1%) were relapsed/progressed patients. The median OS in the de novo group was 11.0 versus 14.6 months in the relapsed/progressed group (p < 0.001). The median TTNT for first-line therapy (6.42 versus 7.61 months, p< 0.001) and second-line therapy (3.91 versus 4.29 months, p= 0.02) were shorter in the de novo group than relapsed/progressed group. The most preferred first- and second-line therapies were paclitaxel+platinum (34.2% versus 24.8%) and docetaxel (18.7% versus 18.2%) in both groups of patients, respectively.

CONCLUSIONS: De novo patients had poorer OS and TTNT after initiation of palliative therapy versus relapsed/progressed patients. These findings suggest that stage of disease at the time of the initial diagnosis should be considered in observational studies and clinical trials as a prognostic factor.