Dose escalation of Fractionated Stereotactic Radiotherapy (FSRT) for brain metastases from non-small cell lung cancer: protocol of a phase I study

Background: About half of lung cancer patients are found to have brain metastasis during the course of the disease. Fractionated stereotactic radiotherapy (FSRT) is a reliable treatment for patients with localized brain metastases. However, there is currently controversy over the prescription doses of FSRT. The aim of this study is to determine maximum tolerated dose of FSRT for brain metastasis from non-small cell lung cancer. Methods This study is a prospective mono-center phase I dose escalation trial which will recruit patients with brain metastases from non-small cell lung cancer receiving FSRT in 5 fractions. A standard 3 + 3 statistical design was employed. The dose escalation consists of 7 cohorts. FSRT will starting at 6 Gy × 5 fractions (dose level 1). The highest dose level will be 10 Gy × 5 fractions. The primary objective of this study is to determine the maximum tolerated dose. Secondary outcomes include acute and late toxicities following FSRT, intracranial progression-free survival (iPFS) and overall survival (OS). Discussion Since the prescription dose of FSRT treatment for patients with localized brain metastases are still unknow, we conducted a Phase I study to determine the maximum tolerated dose of FSRT for limited brain metastases. This trial protocol has been approved by the Ethics committee of Hangzhou cancer hospital. The ethics number is HZCH-2022 #124. This study was registered at ClinicalTrials.gov on 10/20/2022 (NCT05588206).