Stereotactic irradiation of the resection cavity after surgical resection of brain metastases – when is the right timing?

Abstract

Purpose: This study aimed to evaluate whether an early beginning of the adjuvant stereotactic radiotherapy after macroscopic complete resection of 1–3 brain metastases is essential or whether longer intervals between surgery and radiotherapy are feasible.

Material and methods: Sixty-six patients with 69 resection cavities treated with HFSRT after macroscopic complete resection of 1–3 brain metastases between 2009 and 2016 in our institution were included in this study. Overall survival, local recurrence and locoregional recurrence were evaluated depending on the time interval from surgery to the start of radiation therapy.

Results: Patients that started radiotherapy within 21 days from surgery had a significantly decreased OS compared to patients treated after a longer interval from surgery (p < .01). There was no significant difference between patients treated ≥ 34 and 22–33 days from surgery (p = .210). In the univariate analysis, local control was superior for patients starting treatment 22–33 days from surgery compared to a later start (p = .049). This effect did not prevail in a multivariate model. There was no significant difference between patients treated within 21 days and patients treated more than 33 days after surgery (p = .203). Locoregional control was not influenced by RT timing (p = .508).

Conclusion: A short delay in the start of radiotherapy does not seem to negatively impact the outcome in patients with resected brain metastases. We even observed an unexpected reduction in OS in patients treated within 21 days from surgery. Further studies are needed to define the optimal timing of postoperative radiotherapy to the resection cavity.

Acknowledgments

The authors thank our team of technicians for excellent patient care.

Disclosure statement

Sophia Scharl received a travel grant from Mundipharma GmbH and NovoCure Ltd.; Christoph Straube received a scholarship from Medac GmbH, received a travel grant from NovoCure Ltd.; Bernhard Meyer work as consultants for BrainLab and Nexstim; Claus Zimmer has served on scientific advisory boards for Philips and Bayer Schering; serves as co-editor on the Advisory Board of Clinical Neuroradiology; has received speaker honoraria from Bayer-Schering and Philips and has received research support and investigator fees for clinical studies from Biogen Idec, Quintiles, MSD Sharp & Dome, Boehringer Ingelheim, Inventive Health Clinical UK Ltd., Advance Cor, Brainsgate, Pfizer, Bayer-Schering, Novartis, Roche, Servier, Penumbra, WCT GmbH, Syngis, SSS International Clinical Research, PPD Germany GmbH, Worldwide Clinical Trials Ltd., Phenox, Covidien, Actelion, Medivation, Medtronic, Harrison Clinical Research, Concentric, Penumbra, Pharmtrace, Reverse Medical Corp., Premier Research Germany Ltd., Surpass Medical Ltd. and GlaxoSmithKline; Stephanie E. Combs has served on Advisory Board of Bristol-Myers-Squibb (BMS); Advisory board and Speaker’s Bureau for BrainLab; Advisory Board of Roche, Daiichi Sankyo and Varian Medical Systems. Has received Speakers Honoraria from BrainLab, Tomotherapy, Dr. Sennewald, BMS, Varian Medical Systems, Elekta, Novocure and Medac GmbH. The remaining authors declare no competing financial interest.