P49.01 Drug Holiday Based on Minimal Residual Disease Status After Local Therapy Following EGFR-TKI Treatment for Patients With Advanced NSCLC

Local consolidative therapy (LCT)has been confirmed to improve the overall survival of patients with non-small cell lung cancer (NSCLC) receiving targeted and continuation target is currently recommended. it unknown whether could benefit from holiday if no visible lesions negative minimal residual disease (MRD) after LCT. Detection ctDNA in periphery blood was performed identify MRD EGFR mutant oligo-residual EGFR-TKIs were ceased for who met criteria: (1) imagery surgery; (2) MRD; (3) normal serum carcinoembryonic antigen (CEA); (4) asymptomatic. Negative defined as driver genes or a maximum one cancer-related gene detected. Follow-up would be done every three months retreated If any above drug criteria missed. This study exploring part CTONG 1602 (NCT03046316), which approved by Research Ethics Committee Guangdong General Hospital&Guangdong Academy Medical Sciences. 38 stage IIIB IV NSCLC screened LCT following between June 2019 February 2021. Except 2 positive MRD, 36 criteria. 7 refused participation. For 29 enrolled median duration front-line treatment EGFR-TIKs 298 days (0-1699 days). The 117 (5-434 Eleven (37.9%) at least issue during follow-up 165 (55-434 days), six them presented lesions, five relapsed previous sites (2 lung, 3 brain), patient new site (brain). all these (100%) responsive EGFR-TKI retreatment. other (EGFR mutation) and/or increased levels CEA again retreatment, two them(P02 P13) therefore gained second holiday(Fig 1). Drug based on status feasible treated basis Brain metastases higher risk recurrence holiday.