P2.01-049 Long Progression Free Survival and Overall Survival in Advanced NSCLC Patients with EGFR Mutation and Complete Response with TKI Treatment

Abstract

Lung cancer is the first cause of death by cancer worldwide. Around 70% of patients are diagnosed in advances stages. The EGFR mutations (EGFRmut) are present in 15-20% of cases of lung adenocarcinoma. Most frequent mutations are exon 19 deletions and L858R (90%); in those patients, the TKI treatments have higher response rates (RR) and longer progression free survival (PFS) compared versus chemotherapy. However, the longtime OS is low and the complete responses (CR) are achieved in 1-3% only. Nevertheless, contributing factors to long term survival are still unclear. Our objective was to describe long PFS and OS associated factors in patients with TKI treatment. We analyzed patients with EGFRmut NSCLC, who received TKI between 2011 and 2017 in the Thoracic Tumors Clinic at Instituto Nacional de Cancerologia, Mexico. EGFR mutational test was performed by RT-PCR (SCORPION/ARMS therascreen). We search factors associated with CR and Major responses (MR; defined as tumor size reduction >80%) and correlated with PFS and OS. One-hundred sixty patients were analyzed. Median age was 62y (SD ±12.8), female 66%, never smoking 82%, adenocarcinoma 98%, exon 19 deletions 60.6% and L858R 34.4%, uncommon mutations 5%. The RR were 56.3%; 12/160 (7.5%) patients had CR (Group1), 16/160 (10%) patients had MR and received local control with Radiotherapy (Group2) and 132/160 (82.5%) had non-CR without radiotherapy (Group3). In the total population PFS and OS was 15months (CI95% 8.2-21.9mo) and 27.9mo (21.8-32.2mo) respectively; in group3 PFS/OS was 8.77 (CI95% 7.66-9.88mo)/24.7mo (CI95% 20.8-28.8mo); in Group1 PFS/OS was 38.7mo (CI 95% 35.7-41.6)/47.8mo (CI95% 40.1-55.5mo) and Group2 PFS/OS 28.1mo (0.43-56.4mo)/OS 36.1mo (CI95% 11.6-60.7mo). We found significant differences in PFS and OS compared group1 vs Group3 (p=0.003 and p=0.0001, respectively) and Group2 vs group3 (p=0.009 and 0.007, respectively). Was not significant differences in PFS/OS between Group1 vs Group2 (p=0.09/0.9, respectively). All patients with CR are alive, except one patient who died due to pneumoniae. In the multivariate analysis were not found association with CR and TKI or mutation subtype (Exon 19 vs L858R). Patients treated with TKI who reach CR or MR followed by local control with radiotherapy have longer PFS and OS. These findings support the importance to optimize TKI treatment, in order to achieve CR as well as the importance of local control in residual lesions to improve survival outcomes.