Yong Hwy Kim

Differentiating radiation necrosis from tumor recurrence in high-grade gliomas: assessing the efficacy of 18F-FDG PET, 11C-methionine PET and perfusion MRI.

PURPOSE The authors analyzed the characteristics of perfusion magnetic resonance imaging (MRI), (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET) and (11)C-methionine (MET) PET to compare the efficacies of these modalities in making the distinction between radiation necrosis and tumor recurrence of high-grade glioma. PATIENTS AND METHODS Ten patients were evaluated with dynamic susceptibility contrast perfusion MRI, (11)C-MET PET and (18)F-FDG PET to visualize gadolinium-enhanced lesions during the post-radiation follow-up period. In the perfusion MRI, four regions of interest (ROIs) were identified and average values were calculated. A reference ROI of the same size was defined in the contralateral white matter to obtain the relative cerebral blood volume (rCBV). After coregistering the PET images with the MRI, we measured the maximum uptake values of the lesion and of the contralateral cerebral white matter as reference area to calculate the L(max)/R(max) ratio. RESULTS The rCBV was higher in the recurrence group than in the necrosis group (p=0.010). There was no difference between groups in terms of the L(max)/R(max) ratio as derived from the (18)F-FDG and (11)C-MET PET. CONCLUSION A quantitative rCBV as calculated from a perfusion MRI scan might be superior to the L(max)/R(max) ratio as derived from (18)F-FDG and (11)C-MET PET in order to distinguish a recurrence of high-grade glioma from radiation necrosis.

Long-Term Outcome of Gamma Knife Radiosurgery for Treatment of Typical Trigeminal Neuralgia

PURPOSE To analyze the long-term outcomes of patients with typical trigeminal neuralgia treated with gamma knife radiosurgery (GKRS). PATIENTS AND METHODS A total of 62 consecutive patients with typical trigeminal neuralgia were treated with GKRS between 1998 and 2004. Of the 62 patients, 2 were lost to follow-up; the remaining 60 patients were followed for >12 months. The mean prescribed maximal dose was 79.7 Gy (range, 75-80), using a 4-mm shot. RESULTS Of the 60 patients, 48 were followed for >4 years. An additional 3 patients, followed for <4 years, experienced recurrent pain after a favorable initial response and were incorporated into the long-term response analysis. Of these 51 patients (mean age, 61 +/- 11 years; 37 women [72.5%]; and mean follow-up duration, 58 +/- 14 months), 46 (90.2%) responded to GKRS, as demonstrated by an improvement in their Barrow Neurological Institute pain intensity score. Of the 46 patients, 24 (52.2%) had pain recurrence. The actuarial recurrence-free survival rate was 84.8%, 76.1%, 69.6%, 63.0%, and 45.8% at 1, 2, 3, 4, and 5 years after radiosurgery, respectively. Patient age >70 years correlated with a favorable outcome in terms of pain recurrence after radiosurgery (hazard ratio, 0.125; 95% confidence interval, 0.016-0.975; p = .047) on multivariate analysis. CONCLUSION GKRS seems to be an effective treatment modality for patients with typical trigeminal neuralgia considering the initial response rate; however, fewer than one-half of patients might continue to benefit from GKRS after long-term follow-up. Elderly patients might be good candidates for radiosurgery considering the long-term durability of efficacy.

Hearing Outcomes After Stereotactic Radiosurgery for Unilateral Intracanalicular Vestibular Schwannomas: Implication of Transient Volume Expansion

PURPOSE We evaluated the prognostic factors for hearing outcomes after stereotactic radiosurgery (SRS) for unilateral sporadic intracanalicular vestibular schwannomas (IC-VSs) as a clinical homogeneous group of VSs. METHODS AND MATERIALS Sixty consecutive patients with unilateral sporadic IC-VSs, defined as tumors in the internal acoustic canal, and serviceable hearing (Gardner-Roberson grade 1 or 2) were treated with SRS as an initial treatment. The mean tumor volume was 0.34±0.03 cm3 (range, 0.03-1.00 cm3), and the mean marginal dose was 12.2±0.1 Gy (range, 11.5-13.0 Gy). The median follow-up duration was 62 months (range, 36-141 months). RESULTS The actuarial rates of serviceable hearing preservation were 70%, 63%, and 55% at 1, 2, and 5 years after SRS, respectively. In multivariate analysis, transient volume expansion of ≥20% from initial tumor size was a statistically significant risk factor for loss of serviceable hearing and hearing deterioration (increase of pure tone average≥20 dB) (odds ratio=7.638; 95% confidence interval, 2.317-25.181; P=.001 and odds ratio=3.507; 95% confidence interval, 1.228-10.018; P=.019, respectively). The cochlear radiation dose did not reach statistical significance. CONCLUSIONS Transient volume expansion after SRS for VSs seems to be correlated with hearing deterioration when defined properly in a clinically homogeneous group of patients.

Central neurocytoma: long-term outcomes of multimodal treatments and management strategies based on 30 years' experience in a single institute.

BACKGROUND A thorough investigation of the long-term outcomes of central neurocytoma (CN) after different treatments is required to establish optimal management strategies. OBJECTIVE We retrospectively reviewed the long-term clinical outcomes of patients with CN according to various treatments and suggest treatment strategies based on 30 years of experience in a single institution. METHODS Fifty-eight consecutive patients with CN were treated at our institution between 1982 and 2008. Patient demographics, overall survival, local control rates according to multimodal treatments, and functional outcomes were evaluated. The mean clinical and radiological follow-up periods were 119 months (range, 18-304 months) and 98 months (range, 13-245 months), respectively. RESULTS The initial treatment modality was classified into 4 subgroups: operation only (34 patients), operation followed by radiation therapy (7 patients) or radiosurgery (7 patients), and radiosurgery alone (10 patients). The actuarial overall survival was 91% at 5 years and 88% at 10 years. The actuarial overall survival and local tumor control rate did not differ significantly according to the various treatments and the initial extent of the surgical resection. However, functional outcomes, such as the postoperative seizure outcome at the last follow-up, differed according to the surgical approach. CONCLUSION The long-term clinical outcomes of CN after multimodal treatment seem to be excellent. Our study suggests that treatment strategies for CN should focus on the patients quality of life, as well as on tumor control, because of the benign nature of CN.

Early Significant Tumor Volume Reduction After Radiosurgery in Brain Metastases From Renal Cell Carcinoma Results in Long-Term Survival

PURPOSE To retrospectively evaluate survival of patients with brain metastasis from renal cell carcinoma (RCC) after radiosurgery. PATIENTS AND METHODS Between 1998 and 2010, 46 patients were treated with radiosurgery, and the total number of lesions was 99. The mean age was 58.9 years (range, 33-78 years). Twenty-six patients (56.5%) had a single brain metastasis. The mean tumor volume was 3.0 cm(3) (range, 0.01-35.1 cm(3)), and the mean marginal dose prescribed was 20.8 Gy (range, 12-25 Gy) at the 50% isodose line. A patient was classified into the good-response group when the sum of the volume of the brain metastases decreased to less than 75% of the original volume at a 1-month follow-up evaluation using MRI. RESULTS As of December 28, 2010, 39 patients (84.8%) had died, and 7 (15.2%) survived. The overall median survival time was 10.0 ± 0.4 months (95% confidence interval, 9.1-10.8). After treatment, local tumor control was achieved in 72 (84.7%) of the 85 tumors assessed using MRI after radiosurgery. The good-response group survived significantly longer than the poor-response group (median survival times of 18.0 and 9.0 months, respectively; p = 0.025). In a multivariate analysis, classification in the good-response group was the only independent prognostic factor for longer survival (p = 0.037; hazard ratio = 0.447; 95% confidence interval, 0.209-0.953). CONCLUSIONS Radiosurgery seems to be an effective treatment modality for patients with brain metastases from RCC. The early significant tumor volume reduction observed after radiosurgery seems to result in long-term survival in RCC patients with brain metastases.

Papillary tumor of pineal region presenting with leptomeningeal seeding

Papillary tumor of the pineal region (PTPR) is a recently recognized and rare pineal tumor, presenting as a solitary mass with or without hydrocephalus. Here, we report a case of c‐Kit expressing PTPR with leptomeningeal seeding. A 39‐year‐old woman presented with a 1‐month history of headache and decreased visual acuity. MRI showed a large, 4 cm‐diameter solid and cystic enhancing mass at the pineal region with associated ventriculomegaly. Smaller nodular lesions were also found at the pituitary stalk and bilateral internal acoustic canal (IAC). The leptomeninges were noted to be enhanced with gadolinium. Endoscopic third ventriculostomy and partial resection were performed. The specimen was small in quantity but nonetheless, revealed the typical features of PTPR, which were tumor cells with vacuolated cytoplasm forming a pseudopapillary architecture. The tumor cells were diffusely immunoreactive for vimentin, INI‐1 and c‐Kit, focally immunoreactive for neuronal specific enolase (NSE) and S100 protein but negative for cytokeratin, epithelial membrane antigen (EMA), synaptophysin and GFAP. Ultrastructurally, the tumor cells revealed variably‐sized cytoplasmic vacuoles, intermediate filaments and villous cytoplasmic membrane. With these features, a diagnosis of PTPR was rendered. The lesions at the pineal gland and bilateral IAC were irradiated through gamma knife radiosurgery and a decrease in size of the lesions was noted on follow‐up MRI. However, soon after, other lesions were also noted to develop along the adjacent sites. The case presented is proof that PTPR can disseminate to other sites distant from the original lesion. This case was a c‐kit expressing PTPR, which might represent the more primitive nature of this tumor. Ultrastructural examination is useful to differentiate PTPR from other tumors of the pineal gland in addition to immunohistochemistry.

Radiosurgery for Atypical and Anaplastic Meningiomas: Histopathological Predictors of Local Tumor Control

Objectives: We investigated the radiosurgical outcomes of patients with nonbenign meningiomas retrospectively and sought to identify prognostic factors for local tumor control after radiosurgery with an emphasis on histopathology. Methods: Between 1998 and 2010, 35 patients with 49 atypical or anaplastic meningiomas were treated with radiosurgery. The mean tumor volume and marginal irradiation dose were 3.5 cm3 (range 0.3–25.3) and 16 Gy (range 12–21), respectively. Results: The actuarial local tumor control rates for patients with atypical meningiomas at 1, 2 and 3 years after radiosurgery were 78, 53 and 36%, respectively, whereas those for anaplastic meningiomas were 35% at 1 year and 10% at 2 years. Multivariate analysis revealed that the mitotic count (≤8 per 10 high-power fields; HPF) and the MIB-1 proliferation marker labeling index (LI; ≤8%) were significant favorable prognostic factors for the radiosurgical outcomes of patients with nonbenign meningiomas (p = 0.014 and p = 0.012, respectively). Conclusions: Radiosurgery could be a treatment option for patients with atypical meningiomas, but more aggressive treatments are needed for those with anaplastic meningiomas. Histopathological factors such as mitotic count and MIB-1 LI are significant prognostic factors for the radiosurgical outcomes of patients with nonbenign meningiomas and should be considered before radiosurgery.

Feasibility of Endoscopic Endonasal Approach for Recurrent Pituitary Adenomas after Microscopic Trans-Sphenoidal Approach

Objective The surgical approach for recurrent pituitary adenoma after trans-sphenoidal approach (TSA) is challenging. We report the outcomes of the endoscopic TSA for recurrent pituitary adenoma after microscopic TSA. Methods From February 2010 to February 2013, endoscopic TSA was performed for removal of 30 recurrent pituitary adenomas after microscopic TSA. Twenty-seven (90%) patients had a clinically non-functioning pituitary adenoma. Twenty-four (80%) patients suffered from a visual disturbance related to tumor growth. The clinical features and surgical outcomes were retrospectively analyzed for the ophthalmological, endocrinological, and oncological aspects. Results The mean tumor volume was 11.7 cm3, and gross total resection was achieved in 50% of patients. The volumetric analysis based on the postoperative MR showed that the mean extent of resection rates were 90%. Vision was improved in 19 (79%) of 24 patients with visual symptoms, and endocrinological cure was achieved in all of three functioning pituitary adenomas; however, the post-operative follow-up endocrinological examination revealed a new endocrinological deficit in one patient. Two patients required antibiotics management for post-operative meningitis. Conclusion The endoscopic TSA can be an effective treatment option for recurrent pituitary adenoma after microscopic TSA with acceptable outcome.

Is It Effective to Raise the Irradiation Dose from 80 to 85 Gy in Gamma Knife Radiosurgery for Trigeminal Neuralgia

Objective: In order to assess the effect of raising gamma knife radiosurgery (GKS) doses from 80 to 85 Gy for the treatment of trigeminal neuralgia (TN), the authors analyzed the outcomes of GKS in each group. Patients and Methods: The authors retrospectively collected follow-up data of 104 GKS procedures conducted for TN. Doses of 80 and 85 Gy were prescribed for 60 and 44 patients, respectively. The target was 2–4 mm anterior to the junction of the trigeminal nerve and pons. Outcomes were quantified based on facial pain levels and classified using the Barrow Neurological Institute scale. Results: Actuarial rates of a favorable pain control outcome at 1 and 3 years after GKS were 75.0 and 61.2% for 80 Gy and 65.9 and 60.3% for 85 Gy. Post-GKS facial sensory loss developed in 20.6%. There was no statistically significant difference in pain control rate between the two groups. Time to maximal pain relief was shorter in the 85-Gy group. Protracted morbidity before GKS was a favorable prognostic factor of pain control in a multivariate analysis. Conclusion: According to our finding that 85 Gy brought more rapid clinical improvement without causing more complications, 85 Gy seems to be preferable to 80 Gy, but prospective randomized trials are mandatory to get a more definite conclusion on the optimal dose for GKS of TN.

Brain Metastasis from Renal Cell Carcinoma

Renal cell carcinoma (RCC) is one of primary cancers which metastasis to the brain frequently, although RCC accounts for only 1% of all cancer. The metastatic tumor from RCC has the propensity of intratumoral hemorrhage and relatively massive surrounding edema compared with other metastatic tumors. These characteristics make an emphasis on the surgical resection in the management of metastatic tumor. However, the surgery is not always possible due to the characteristics of tumor and patient. The outcome of conventional whole brain radiotherapy is unsatisfactory due to the resistant feature of RCC to the radiation, although it plays an important role in other malignancies. The stereotactic radiosurgery (SRS) including various modalities have showed the excellent outcomes in the control of tumor itself and surrounding edema. The repeatability of SRS is also attractive merit, because the new brain metastasis can be encountered in anytime regardless of the first-line treatment modalities. A few adverse effects following SRS have been reported however, incidence and severity could be acceptable without severe morbidity. Therefore, SRS must be emphasized in the management of brain metastasis from RCC and individual various combined treatment strategies could be suggested.