CLINICAL STUDY/PATIENT STUDY Gamma Knife robotic microradiosurgery of pituitary adenomas invading the cavernous sinus: treatment concept and results in 89 cases Motohiro Hayashi • Mikhail Chernov • Noriko Tamura • Mariko Nagai • Shoji Yomo • Taku Ochiai • Kosaku Amano • Masahiro Izawa • Tomokatsu Hori • Yoshihiro Muragaki • Hiroshi Iseki • Yoshikazu Okada • Kintomo Takakura Received: 19 November 2009 / Accepted: 31 March 2010 / Published online: 22 April 2010 Ó Springer Science+Business Media, LLC. 2010 Abstract The objective of the present retrospective study was evaluation of results of ‘‘robotic microradiosurgery’’ of pituitary adenomas invading the cavernous sinus. Eighty- nine patients with such tumors underwent management using Leksell Gamma Knife model C with automatic posi- tioning system. There were 77 residual and 12 recurrent neoplasms. The applied radiosurgical treatment plan was based on the use of multiple isocenters, mainly of smaller size, which were positioned compactly within the border of the lesion with resultant improved dose homogeneity, increased average dose within the target, and sharp dose fall outside the treated volume. The marginal dose varied from 12 to 25 Gy (mean, 18.2 Gy) in non-functional pituitary adenomas (43 cases), and from 12 to 35 Gy (mean, 25.2 Gy) in hormone-secreting ones (46 cases). The length of follow- up after treatment ranged from 24 to 76 months (mean, 36 months). Control of the tumor growth was attained in 86 cases (97%), whereas actual shrinkage of the lesion was marked in 57 cases (64%). In 18 out of 46 secreting neo- plasms (39%), normalization of the excess of the pituitary hormone production was noted after radiosurgery. Treat- ment-associated morbidity was limited to transitory cranial nerve palsy in two patients (2%). No patient with either non- functional or hormone secreting tumor exhibited new pitu- itary hormone deficit after treatment. In conclusion, highly precise microanatomy-based Gamma Knife robotic micro- radiosurgery provides an opportunity for effective man- agement of pituitary adenomas invading the cavernous sinus with preservation of the adjacent functionally important neuronal structures. Keywords Automatic positioning system Á Cavernous sinus Á Gamma Knife radiosurgery Á Outcome Á Pituitary adenoma Introduction Stereotactic radiosurgery, particularly Gamma Knife radi- osurgery, is an approved management option for residual or recurrent pituitary adenomas [1–3]. According to most reports, the growth control of both non-functional and hormone-secreting tumors after treatment varies from 92 to 100% with significant proportion of lesions, which are actually undergoing prominent shrinking [2, 3]. Roughly, from one- to two-thirds of patients with secreting neo- plasms show normalization of the excess of pituitary hormone production after radiosurgery [1–3]. The treat- ment-associated morbidity is usually considered minimal, but could not be neglected. It is mainly related to new M. Hayashi (&) Á M. Chernov Á N. Tamura Á M. Nagai Á T. Ochiai Á K. Amano Á M. Izawa Á T. Hori Á Y. Muragaki Á H. Iseki Á Y. Okada Á K. Takakura Department of Neurosurgery, Neurological Institute, Tokyo Women’s Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan e-mail: GKRmoto@aol.com M. Hayashi Á M. Chernov Á S. Yomo Á Y. Muragaki Á H. Iseki Á K. Takakura Faculty of Advanced Techno-Surgery, Institute of Advanced Biomedical Engineering and Science, Tokyo Women’s Medical University, Tokyo, Japan M. Chernov Á H. Iseki Á K. Takakura International Research and Educational Institute for Integrated Medical Sciences (IREIIMS), Tokyo Women’s Medical University, Tokyo, Japan 123 J Neurooncol (2010) 98:185–194 DOI 10.1007/s11060-010-0172-2