[Association between different EGFR mutation status and survival in pemetrexed-based chemotherapy for advanced non-small cell lung cancer].

OBJECTIVE: To explore the association between different epidermal growth factor receptor (EGFR) mutation status and survival in pemetrexed-based chemotherapy for advanced non-small-cell lung cancer (NSCLC).

METHODS: A retrospective cohort study was performed to assess 146 patients with advanced NSCLC at Cancer Institute/Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College. The first-line regimens included pemetrexed based chemotherapy (pemetrexed first-line therapy group, n = 79), pemetrexed based chemotherapy plus pemetrexed maintenance chemotherapy (pemetrexed maintenance therapy group, n = 38) and pemetrexed based chemotherapy plus tyrosine kinase inhibitors (TKI) maintenance therapy (TKI maintenance therapy group, n = 29). Median progression-free survival (PFS) was determined.For comparison, median PFS was evaluated for EGFR-positive,EGFR-negative versus EGFR mutation unknown NSCLC patients in first-line pemetrexed therapy and pemetrexed maintenance therapy groups.

RESULTS: The median PFS was 4.6 (95%CI: 2.8-6.4), 9.8 (95%CI: 6.1-13.5) and 14.5 (95%CI: 11.8-17.2) months in pemetrexed first-line therapy, pemetrexed maintenance therapy and TKI maintenance therapy groups respectively (P = 0.000). No difference existed in PFS for pemetrexed first-line therapy group with a median PFS of 5.2 (95%CI: 2.8-7.7), 4.0 (95%CI: 0-10.8) and 4.6 (95%CI: 3.4-5.8) months respectively (P = 0.661). Among EGFR-positive,EGFR-negative and EGFR mutation status unknown patients in pemetrexed maintenance therapy group, the median PFS was 8.5 (95%CI: 4.0-13.1), 12.6 (95%CI: 11.6-13.7) and 8.0 (95%CI: 5.8-10.3) months with no significant statistical difference (P = 0.468).

CONCLUSIONS: No significant difference exists in survival between different EGFR mutation status for pemetrexed based first-line chemotherapy. And TKI maintenance therapy is associated with better survival than pemetrexed maintenance therapy regardless of EGFR status.