Reirradiation using helical tomotherapy-based hypofractionated stereotactic radiotherapy for 19 brain metastases after the second recurrence of distant brain failure: a case report and literature review.

Background: A definitive optimal oncologic care regimen for recurrent multiple brain metastases (BMs) has yet to be established, and the accrual of high-quality evidence pertaining to helical tomotherapy-based stereotactic radiotherapy (HT-SRT) in patients with BMs is needed. Case Description: We treated a 64-year-old male smoker initially diagnosed with non-small cell lung cancer (NSCLC) with BMs, and the initial schedule involved administering linear accelerator-based hypofractionated stereotactic radiotherapy (Linac-HSRT) targeting 6 intracranial lesions. Further chemotherapy was declined due to intolerance after one cycle of paclitaxel-albumin/carboplatin. Distant brain failure (DBF) and extracranial progression emerged 3 months subsequent to the initial SRT, and helical tomotherapy-based hypofractionated stereotactic radiotherapy (HT-HSRT) was replanned to 4 BMs, while helical tomotherapy-based intensity-modulated radiotherapy was employed for the extracranial lesions. Nevertheless, reirradiation with hippocampal-sparing HT-HSRT and simultaneous memantine approach were imminently delivered for confirmed DBF, as 19 newly identified intact intracranial lesions were observed at 5 months posttreatment. As assessed by the Hopkins Verbal Learning Test Revised Total Recall test, neither severe symptomatic radionecrosis (RN) nor neurocognitive dysfunction has manifested thus far, representing a survival period of 20.5 months. In the literature review, SRT delivery schedule to BMs, strategies for managing recurrent BMs and addressing RN, along with 6 summarized published studies of HT-SRT for BM were discussed. Conclusions: We posit that the administration of repeated SRT for recurrent BMs in a short-term interval may be viable, yet randomized, robust analyses are imperative to ascertain the potential benefits of HT-SRT in preserving neurocognition and confirm the efficacy of memantine and hippocampal avoidance during SRT.