Post-progression survival is highly linked to overall survival in patients with non-small-cell lung cancer harboring sensitive EGFR mutations treated with first-line epidermal growth factor receptor-tyrosine kinase inhibitors

Background In patients with epidermal growth factor receptor (EGFR)-mutated advanced non-small-cell lung cancer (NSCLC), epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) treatment has shown a good response. Subsequent treatments jeopardize the ability to determine the effect of first-line chemotherapy on overall survival (OS). Therefore, using patient-level data, we aimed to study the associations of progression-free survival (PFS) and post-progression survival (PPS) with OS after first-line EGFR-TKI treatment in patients with EGFR-mutated NSCLC. Methods Between November 2006 and December 2016, we analyzed 92 patients with EGFR-mutated NSCLC treated with first-line EGFR-TKI. The correlations of PFS and PPS with OS were analyzed for each patient. Results Spearman's rank correlation and linear regression analyzes showed that PPS correlated highly with OS (r = 0.85, P < 0.05, R-2 = 0.75), whereas PFS correlated weakly with OS (r = 0.76, P < 0.05, R-2 = 0.50). The best responses after first-line and second-line treatments were significantly associated with PPS. Conclusions PPS has a higher impact on OS than PFS in patients with EGFR-mutated NSCLC treated with first-line EGFR-TKIs. These outcomes suggest that the OS in this patient group may be affected by treatments following first-line chemotherapy; however, this remains to be verified in prospective trials.