Clinical Impact of Post-Progression Survival on Overall Survival in Elderly Patients with Non-Small-Cell Lung Cancer Harboring Sensitive EGFR Mutations Treated with First-Line EGFR Tyrosine Kinase Inhibitors.

BACKGROUND/AIMS: More than 50% of patients with lung cancer are aged > 65 years, and non-small-cell lung cancer (NSCLC) accounts for 85% of all cases of lung cancer among both elderly and adult patients. Subsequent therapies confound the capability to discern the effect of first-line chemotherapy on overall survival (OS). Therefore, using individual-level data, our study aimed to determine the relationships of progression-free survival (PFS) and post-progression survival (PPS) with OS after first-line epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) treatment in elderly patients with NSCLC harboring sensitive EGFR mutations.

METHODS

Between April 2008 and December 2015, we analyzed 68 elderly patients with NSCLC harboring sensitive EGFR mutations and treated with first-line EGFR-TKI. The relationships of PFS and PPS with OS were analyzed at an individual level.

RESULTS

Linear regression analysis showed that PPS was more closely associated with OS (R2 = 0.54) than PFS was (R2 = 0.48). Best response at first-line treatment, performance status at the end of first-line treatment, and administration of EGFR-TKI rechallenge were significantly correlated with PPS.

CONCLUSIONS

PPS has a stronger impact on OS than PFS does in elderly patients with NSCLC harboring sensitive EGFR mutations and treated with first-line EGFR-TKI. These results indicate that OS in this patient population may be influenced by treatments subsequent to first-line chemotherapy; however, this remains to be verified in prospective studies.