EGFR-TKI after disease progression with central nervous system metastasis in advanced non-small cell lung cancer with EGFR mutations.
e19083 Background: Several retrospective studies have reported that continued treatment with EGFR-TKI after developing progressive disease (PD) by RECIST improved survival compared to TKI-free treatment in NSCLC patients with EGFR mutations. However, it is unclear which patients would benefit from EGFR-TKI after PD. We hypothesized that patients with CNS progression only, without systemic deterioration, would show a good prognosis with EGFR-TKI after PD. Methods: In order to clarify the survival benefits in patients treated by EGFR-TKI after developing PD, particularly patients with CNS metastasis alone, NSCLC patients with EGFR mutations who were treated with EGFR-TKI and showed progression were analyzed retrospectively. The patients were categorized into two groups: patients continuing with EGFR-TKI treatment after progression (continuation group) and patients switched to chemotherapy or BSC (discontinuation group). Patients were also classified into two groups by site of progression: patients who showed deterioration involving only CNS metastasis (CNS group) and patients who showed progression of the primary lesion, lymph nodes, bone, liver, adrenal glands, CNS, or other sites (systemic group). Differences in post-EGFR-TKI progression survival (PPS) and overall survival were compared between the groups. Results: A total of 75 patients, including 54 women, 56 never smokers, 73 patients with adenocarcinomas, and 57 patients with good PS (0, 1), were analyzed. There were 40 patients with deletions in exon 19, 29 patients with L858R, and 6 with minor mutations. The continuation group (n=36) had a significantly longer PPS than the discontinuation group (n=39) (16.2 m vs. 8.5 m, p<0.01). Although it was not significant, the CNS group (n=14) showed longer PPS than the systemic group (n=61) (17.3 m vs. 9.2 m, p=0.10). The PPS of 9 patients (continuation and CNS groups) was 21.0 m, while PPS of 34 patients (discontinuation and systemic group) was 7.2 m. Conclusions: In this retrospective analysis, continued treatment with EGFR-TKI after PD resulted in longer PPS. A prospective study of patients with progression involving only CNS metastasis treated with EGFR-TKI is needed.