Article
Volume changes of vestibular schwannoma after robotic stereotactic radiosurgery
Volumenveränderungen von Vestibularisschwannomen nach robotischer stereotaktischer Radiochirurgie
Search Medline for
Authors
-
Daniel Rueß
- Universitätsklinikum Köln, Klinik für Stereotaxie und funktionelle Neurochirurgie, Köln, Deutschland
-
Betina Schuetz
- Universitätsklinikum Köln, Klinik für Stereotaxie und funktionelle Neurochirurgie, Köln, Deutschland
-
Harald Treuer
- Universitätsklinikum Köln, Klinik für Stereotaxie und funktionelle Neurochirurgie, Köln, Deutschland
-
Martin Kocher
- Universitätsklinikum Köln, Klinik für Stereotaxie und funktionelle Neurochirurgie, Köln, Deutschland
-
Maximilian I. Ruge
- Universitätsklinikum Köln, Klinik für Stereotaxie und funktionelle Neurochirurgie, Köln, Deutschland
| Published: | June 4, 2021 |
|---|
Outline
Text
Objective: Different responses of volume can be observed after stereotactic radiosurgery (SRS) for vestibular schwannomas (VS) ranging from decrease, stability or increase of volume. The latter makes the differentiation between pseudoprogression and recurrence of VS after SRS difficult. Since only scarce data are available for robotic SRS with Cyberknife® we evaluated the course of volume changes during follow-up.
Methods: We included all patients with unilateral VS who underwent single fraction robotic SRS with a minimum follow-up of 24 months. Tumor volumes (TV) were measured on T1-weighted contrast enhanced images pre and post SRS every six months within the first year and then annually until last follow-up.
To classify different volume variations during follow-up volume changes of more or less than 10% of pre SRS TV were noted. A cox regression analysis was carried out to identify risk factors for changes in TV.
Results: Overall 63 patients with a median initial TV of 1.1 ml (0.1 – 8.6) matches the inclusion criteria. The median follow-up was 37 months (24-76). We observe different types of volume patterns: (1) partial response (62%, n=39), (2) stable disease (8%, n=5) and (3) a variable course of TV during follow-up encompassing increase followed by decrease (22%, n=14) or continuous increase followed by stable disease (8%, n=5). None of the patients requires further treatment.
Nor patient related parameters (tumor volume, age) neither radiation associated parameters (coverage, nCi, prescription dose, maximal dose) influenced the course of post SRS volume changes.
Conclusion: Volume regression after SRS for VS is observed in the majority of cases. However, there are cases of volume increase after SRS which require an extended observation period to differentiate between pseudoprogression and recurrence.
