Long-term survival in small-cell lung cancer patients: Extension of the SMALLBRAIN study.

Abstract

e20605 Background: Long-term survivors of metastatic Small Cell Lung Carcinoma (SCLC) with overall survival (OS) greater than 12 months are not frequent and have not been deeply studied. Therefore, we conducted the descriptive study SMALLBRAIN to characterize these patients with central nervous system metastases (mCNS), since at least a 20% of SCLC patients has mCNS at the diagnosis. The survival results were reported at the NCCN 2022 Annual Conference, showing no statistically significant survival difference between presenting mCNS at diagnosis or later and no correlation between the mCNS volume and OS. After these results, we have extended our study to metastatic SCLC patients without mCNS to analyze possible differences. Methods: We carried out a systematic search for metastatic SCLC patients with OS > 12 diagnosed and first treatment between January 2016 and April 2020 in our academic medical center in Spain, we excluded those with missing data. The included patients were classified in 3 cohorts: COHORT NA: Stage III at diagnosis with metastatic progression and no mCNS. COHORT NB: Stage IV patients without mCNS. COHORT Y: mCNS during the course of the disease, regardless of onset time. The number of treatment lines received and the survival were analyzed using Kaplan-Meier and multi-variable Cox proportional hazard analysis. Results: A total of 45 patients met study criteria (NA = 5, NB = 11 and Y = 29). The female - male ratio was of 1:3.14 for cohort Y and 1:2.2 for all the patients without mCNS (NA+NB), not statistically significant. The median OS was 24.9 months for cohort NA (range 16 – 64.83), 21.4 months for NB (range 12.30 – 31.83) and 18.6 months for Y (range 12.67 – 60.83), not statistically significant. Only three patients are currently alive, two from cohort NA and one from Y. The median of treatment lines was 3 for all the cohorts with a maximum of 8 for one patient in cohort Y. Best responses were two complete response with later progression in one patient from cohort NA and one from NB. Best response of cohort Y was a partial response. Conclusions: No statistically significant differences were found regarding survival or treatment lines between the population of long-term survivors of metastatic SCLC with and without mCNS. Their infrequency with few living individuals makes their characterization a challenge. These patients are also highly complex, more than 50% received at least 3 lines of treatment. Future research should explore the possibility of extracting long-term SCLC survivors from existing cancer registries of different countries. [Table: see text]