The role of salvage stereotactic radiosurgery for tumor progression following incomplete microsurgical resection of vestibular schwannoma.
Abstract
[OBJECTIVE] Stereotactic radiosurgery (SRS) has long been used for the management of vestibular schwannoma (VS). While the use of SRS as a primary or adjuvant modality for VS has been extensively studied, more effort is needed to clarify the outcomes of SRS as a salvage approach after tumor progression following incomplete resection of VS. The objective of this study was to determine the safety and efficacy of salvage SRS for tumor progression after incomplete resection of VS and to elucidate the factors influencing tumor control and freedom from additional treatment (FFAT).
[METHODS] Patients with VS who underwent incomplete microsurgical resection followed by salvage SRS for tumor progression were retrospectively reviewed. A total of 64 patients were identified and analyzed. The median patient age at time of SRS was 51.5 years, and 30 (46.9%) patients were males. The median marginal dose was 12.5 Gy at a median isodose of 50%.
[RESULTS] The 10- and 15-year tumor control rates following salvage SRS were 87.5% (95% CI 76.8-94.4) and 84.4% (95% CI 73.1-92.2), respectively, while the 10- and 15-year FFAT rates were 95.3% (95% CI 86.9-99.0) and 92.2% (95% CI 82.7-97.4), respectively. No factors were significantly associated with tumor control or FFAT in the Cox proportional hazards model. The median time between microsurgical resection and salvage SRS was 38.8 months. Following SRS, the primary complication was worsening or new-onset trigeminal neuropathy (n = 10 [15.6%]). Worsening hearing, measured using Gardner-Robertson class, was reported in 9 cases (14.1%).
[CONCLUSIONS] Salvage SRS is a safe and effective modality for long-term tumor control and FFAT in VS patients whose tumors progress after initial incomplete microsurgical resection.
[METHODS] Patients with VS who underwent incomplete microsurgical resection followed by salvage SRS for tumor progression were retrospectively reviewed. A total of 64 patients were identified and analyzed. The median patient age at time of SRS was 51.5 years, and 30 (46.9%) patients were males. The median marginal dose was 12.5 Gy at a median isodose of 50%.
[RESULTS] The 10- and 15-year tumor control rates following salvage SRS were 87.5% (95% CI 76.8-94.4) and 84.4% (95% CI 73.1-92.2), respectively, while the 10- and 15-year FFAT rates were 95.3% (95% CI 86.9-99.0) and 92.2% (95% CI 82.7-97.4), respectively. No factors were significantly associated with tumor control or FFAT in the Cox proportional hazards model. The median time between microsurgical resection and salvage SRS was 38.8 months. Following SRS, the primary complication was worsening or new-onset trigeminal neuropathy (n = 10 [15.6%]). Worsening hearing, measured using Gardner-Robertson class, was reported in 9 cases (14.1%).
[CONCLUSIONS] Salvage SRS is a safe and effective modality for long-term tumor control and FFAT in VS patients whose tumors progress after initial incomplete microsurgical resection.