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  • Author or Editor: Isaac Yang x
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Michael E. Sughrue, Rajwant Kaur, Martin J. Rutkowski, Ari J. Kane, Gurvinder Kaur, Isaac Yang, Lawrence H. Pitts and Andrew T. Parsa

Object

With limited studies available, the correlation between the extent of resection and tumor recurrence in vestibular schwannomas (VSs) has not been definitively established. In this prospective study, the authors evaluated 772 patients who underwent microsurgical resection of VSs to analyze the association between total tumor resection and the tumor recurrence rate.

Methods

The authors selected all cases from a prospectively collected database of patients who underwent microsurgical resection as their initial treatment for a histopathologically confirmed VS. Recurrence-free survival was analyzed using Kaplan-Meier analysis. The authors studied the impact of possible confounders such as patient age and tumor size using stepwise Cox regression to calculate the proportional hazard ratio of recurrence while controlling for other cofounding variables.

Results

The authors analyzed data obtained in 571, 89, and 112 patients in whom gross-total, near-total, and subtotal resections, respectively, were performed. A gross-total resection was achieved in 74% of the patients, and the overall recurrence rate in these patients 8.8%. There was no significant relation between the extent of resection and the rate of tumor recurrence (p = 0.58). As expected, the extent of resection was highly correlated with patient age, tumor size, and surgical approach (p < 0.0001). Using Cox regression, the authors found that the approach used did not significantly affect tumor control when the extent of resection was controlled for.

Conclusions

While complete tumor removal is ideal, the results presented here suggest that there is no significant relationship between the extent of resection and tumor recurrence.

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Michael E. Sughrue, Isaac Yang, Seunggu J. Han, Derick Aranda, Ari J. Kane, Misha Amoils, Zachary A. Smith and Andrew T. Parsa

Object

While many studies have been published outlining morbidity following radiosurgical treatment of vestibular schwannomas, significant interpractitioner and institutional variability still exists. For this reason, the authors conducted a systematic review of the literature for non-audiofacial-related morbidity after the treatment of vestibular schwannoma with radiosurgery.

Methods

The authors performed a comprehensive search of the English-language literature to identify studies that published outcome data of patients undergoing radiosurgery treatment for vestibular schwannomas. In total, 254 articles were found that described more than 50,000 patients and were analyzed for satisfying the authors' inclusion criteria. Patients from these studies were then separated into 2 cohorts based on the marginal dose of radiation: ≤ 13 Gy and > 13 Gy. All tumors included in this study were < 25 mm in their largest diameter.

Results

A total of 63 articles met the criteria of the established search protocol, which combined for a total of 5631 patients. Patients receiving > 13 Gy were significantly more likely to develop trigeminal nerve neuropathy than those receiving < 13 Gy (p < 0.001). While we found no relationship between radiation dose and the rate of developing hydrocephalus (0.6% for both cohorts), patients with hydrocephalus who received doses > 13 Gy appeared to have a higher rate of symptomatic hydrocephalus requiring shunt treatment (96% [> 13 Gy] vs 56% [≤ 13 Gy], p < 0.001). The rates of vertigo or balance disturbance (1.1% [> 13 Gy] vs 1.8% [≤ 13 Gy], p = 0.001) and tinnitus (0.1% [> 13 Gy] vs 0.7% [≤ 13 Gy], p = 0.001) were significantly higher in the lower dose cohort than those in the higher dose cohort.

Conclusions

The results of our review of the literature provide a systematic summary of the published rates of nonaudiofacial morbidity following radiosurgery for vestibular schwannoma.

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Michael E. Sughrue, Rajwant Kaur, Ari J. Kane, Martin J. Rutkowski, Isaac Yang, Lawrence H. Pitts, Tarik Tihan and Andrew T. Parsa

Object

Vestibular schwannomas (VSs) are benign lesions with an unpredictable natural history. Perhaps the greatest barrier to predicting which patients need treatment is our poor understanding of how these tumors cause hearing loss in the first place. In this case-control study, the authors investigated the relationship between preoperative hearing loss and histological changes such as intratumoral microhemorrhage and extensive fibrosis.

Methods

From a prospectively collected database, the authors selected all patients with VS who had undergone microsurgical resection as their initial treatment for histopathologically confirmed VS. Histological specimens obtained in 274 of these patients were systematically reviewed by a blinded neuropathologist who graded the extent of microhemorrhage and fibrosis in these tumors. The effect of these variables on preoperative hearing loss was studied using binary logistic regression.

Results

On univariate analysis, patients with extensive intratumoral microhemorrhage or fibrosis (p < 0.0001), patients with larger tumors (p < 0.05), and patients 65 years of age or older (p < 0.05) were significantly more likely to have unserviceable hearing at the time of surgery. On multivariate analysis, only patients with extensive intratumoral microhemorrhage or fibrosis had an increased risk of having unserviceable hearing at the time of surgery (OR 3.72, 95% CI 1.3–10; p = 0.01). Older age and tumor size greater than 3 cm were not statistically significant risk factors for hearing loss, controlling for the effect of microhemorrhage and fibrosis.

Conclusions

In this study, the authors have demonstrated a correlation between the extent of nonneoplastic histological changes, such as microhemorrhage and fibrosis, and hearing loss. This alternate hypothesis has the potential to explain many of the exceptions to previously described mechanisms of hearing loss in patients with VS. The advent of high-resolution MR imaging technology to identify microhemorrhages may provide a method to screen for patients with VS at risk for hearing loss.

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Aaron J. Clark, Michael E. Ivan, Michael E. Sughrue, Isaac Yang, Derick Aranda, Seunggu J. Han, Ari J. Kane and Andrew T. Parsa

Object

Pineocytoma is a rare tumor, and the current literature on these tumors is primarily composed of case reports and small case series. Thus, recommendations on appropriate treatment of these tumors are highly varied. Therefore, the authors performed a systematic review of the literature on tumor control after surgery for pineocytoma to determine the relative benefits of aggressive resection and postoperative adjuvant radiotherapy.

Methods

A comprehensive search of the published English-language literature was performed to identify studies citing outcome data of patients undergoing surgery for pineocytoma. Determination of rates of progression-free survival (PFS) was performed using Kaplan-Meier analysis.

Results

Sixty-four articles met the criteria of the established search protocol, which combined for a total of 166 patients. Twenty-one percent of these patients had undergone a biopsy procedure, 38% had undergone subtotal resection (STR), 42% had undergone gross-total resection, and 28% were treated with radiation therapy. The 1- and 5-year PFS rates for the resection group versus the biopsy group were 97 and 90% (1 year), and 89 and 75% (5 years), respectively (p < 0.05, log-rank test). The 1- and 5-year PFS rates for the GTR group versus the group undergoing STR combined with radiation therapy were 100 and 94% (1 year), and 100 and 84% (5 years), respectively (p < 0.05, log-rank test). There was no significant difference in PFS for STR only compared with STR in addition to radiation therapy.

Conclusions

Gross-total resection is the ideal treatment for pineocytoma and might represent a cure for these lesions. When gross-total resection is not possible, adjuvant radiation therapy after STR is of questionable benefit for these patients.

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Oral Presentations

2010 AANS Annual Meeting Philadelphia, Pennsylvania May 1–5, 2010