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Hearing preservation after gamma knife stereotactic radiosurgery of vestibular schwannoma
Author(s) -
Paek Sun Ha,
Chung HyunTai,
Jeong Sang Soon,
Park ChulKee,
Kim ChaeYong,
Kim Jeong Eun,
Kim Dong Gyu,
Jung HeeWon
Publication year - 2005
Publication title -
cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.052
H-Index - 304
eISSN - 1097-0142
pISSN - 0008-543X
DOI - 10.1002/cncr.21190
Subject(s) - medicine , radiosurgery , schwannoma , vestibular system , gamma knife , acoustic neuroma , cochlear nerve , surgery , hearing loss , audiology , radiation therapy , cochlea
BACKGROUND To evaluate the hearing preservation rate and to determine its prognostic factors after gamma knife (GK) stereotactic radiosurgery (SRS) in patients with vestibular schwannoma, the authors used a prospective study design to analyze these patients. METHODS Between December 1997 and January 2002, 25 patients with vestibular schwannoma with serviceable hearing were enrolled in the current study. The median tumor volume was 3.0 cc (0.16–9.1 cc). The prescription dose was 12.0 ± 0.7 gray at an isodose line of 49.8 ± 1.1%. The tumor control rate and complications were evaluated by focusing on hearing preservation and its prognostic factors. RESULTS Based on radiologic study, the tumor control rate was 92% during the median follow‐up period of 45 months. The trigeminal and facial nerve preservation rates were 95% and 100%, respectively. Thirteen (52%) of the 25 patients preserved serviceable hearing and 9 (36%) patients retained their pre‐GK G‐R grade levels after GK SRS. However, 16 patients showed hearing deterioration > 20 dB within 3–6 months and this trend continued for 24 months after the treatment. The maximum radiotherapy dose delivered to the cochlear nucleus was the single, significant prognostic factor of hearing deterioration. CONCLUSIONS The authors concluded that a more sophisticated strategy to prevent hearing deterioration during the first 6 months post‐GK SRS is necessary to improve long‐term hearing preservation. Cancer 2005. © 2005 American Cancer Society.