Background: This study aimed to evaluate the differences in common types of epidermal growthfactor receptor (EGFR) mutations in non-small cell lung cancer (NSCLC) with brain metastasis (BM) treated using linear accelerator-based stereotactic radiosurgery (SRS) and fractionated stereotactic radiotherapy (fSRT). Methods: Between January 2011–December 2023, among 294 consecutive patients with BMfrom NSCLC, 84 patients with EGFR-mutated NSCLC were enrolled in this study. Results: The median follow-up time after SRS/fSRT was 20.1 months (range: 0.6–109.7months), while the median overall survival (mOS) after SRS/fSRT was 25.1 months (95% confidence interval [CI]: 18.4–33.5 months). The mOS after initial treatment for NSCLC was 56.2 months (95% CI:41.7–77.0 months). The mOS after SRS/fSRT in 34 patients with exon 19 deletions and 45 patients with exon 21 mutations with L858R was 20.4 months (95% CI: 13.6–55.9 months) and 28.5 months (95% CI: 16.2–33.5). The two groups showed no difference in the mOS. In univariate analyses using the Cox proportional hazards model, no prognostic factors associated with prolonged survival were identified except for good pretreatment Karnofsky Performance Status score and no prior tyrosine kinase inhibitor use before SRS/fSRT in EGFR-mutated NSCLC. There was no difference in both distant failure and local control in the two groups. Conclusion The difference in survival between EGFR subtypes (exon 21 L858R mutations vs.exon 19 deletion) was not observed after SRS/fSRT in NSCLC.

Lenalidomide (LD) was reported to increase the risk of thromboembolism when it was used along with dexamethasone (DEX). Prophylactic administration of antithrombotic drugs against thromboembolism has been recommended for proper use of LD, but none of the recommendation is stated in the package insert. The purpose of this study was to elucidate the usage of acetylsalicylic acid (ASA) for lenalidomide medication in patients withmultiple myeloma. We used the MDV analyzer to investigate clinical data retrospectively. The investigation period was from October 1, 2016 to September 30, 2017. Subjects were outpatients aged 20 years or older who were recorded in clinical data as multiple myeloma. There were 7,590 outpatients with multiple myeloma. They were divided into 4 groups by the combined use situation of LD and DEX: LD/DEX non-use group (n＝5,462), DEX alone group (n＝632),LD alone group (n＝203), and LD/DEX together group (n＝1,293), respectively. The prevalence rate of thromboembolism was 7.3% in the DEX alone group and 16.9% in the LD/DEX together group (p＜0.0001). Among the LD/DEX together group, ASA was prescribed at 63.6% in the group without thromboembolism (n＝1,074). The prevalence rate of thromboembolism was higher in the LD/DEX combined group than in the DEX alone group. Considering these findings, risk management for thromboembolism caused by administration of antithrombotic drugs should be considered. It is necessary to create more evidence concerning the necessity of administration of antithrombotic drug in combination with LD/DEX medication.