Repeat Gamma Knife Radiosurgery Research Articles

Salvage pemetrexed for brain metastases from ALK-positive lung cancer after Gamma Knife radiosurgery: illustrative case.

Systemic therapy for cancer treatment has improved, and therapeutic options for intracranial lesions are increasing. Combinations of treatment modalities are required in certain difficult cases. Gamma Knife radiosurgery (GKS) is effective for the treatment of brain metastases, especially for lesions that are inoperable because of their anatomical or functional location. The authors report a case of brain metastases in anaplastic lymphoma kinase (ALK)-positive lung adenocarcinoma initially treated with GKS followed by the combination of repeat GKS and ALK tyrosine kinase inhibitors (ALK-TKIs) for tumor recurrence. During the clinical course, acquired resistance to ALK-TKIs due to the long exposure period was suspected. After a great deal of thought and discussion with the oncologist responsible for the treatment of the pulmonary lesions, the authors successfully controlled the lesion for the next 17 months by salvage pemetrexed administration. This is the first report on the effectiveness of pemetrexed for recurrent brain metastasis from ALK-positive lung adenocarcinoma resistant to both radiosurgery and ALK inhibitors. Salvage pemetrexed showed a favorable therapeutic effect in this specific case.

Long-term outcomes of Gamma Knife radiosurgery in treating glossopharyngeal neuralgia.

Glossopharyngeal neuralgia (GPN) is an unusual disorder causing severe, brief pain episodes in the areas supplied by the glossopharyngeal nerve. Initial treatment involves medications like carbamazepine, but if these are ineffective or cause side effects, interventional pain management techniques or surgery may be considered. Gamma Knife radiosurgery is becoming popular in managing GPN due to its lower risk of complications than surgical interventions like microvascular decompression or rhizotomy. In this retrospective case series, we examined the outcomes of Gamma Knife radiosurgery in eight patients with GPN. The decision to utilize Gamma Knife radiosurgery was made following specific criteria, including failed surgical interventions, patient preference against surgery, or contraindications to surgical procedures. Patients were administered radiation doses within the range of 80 to 90 Gy, targeting either the cisternal glossopharyngeal nerve or glossopharyngeal meatus of the jugular foramen. Evaluations were conducted before the Gamma Knife radiosurgery; at 3, 6, and 12 months after Gamma Knife radiosurgery; and annually thereafter. Pain severity was assessed using the modified Barrow Neurological Institute scale grades, with patients achieving grade I-IIIa considered to have a good treatment outcome and grade IV-V to have a poor treatment outcome. Pain control and absence of radiosurgery-related complications were primary endpoints. The median age of the patients was 46.5 years, varying from 8 to 72 years. The median duration of pain was 32 months (range, 12-120 months). All patients, except one, were on polydrug therapy. All cases exhibited preoperative grade V pain. The median follow-up duration after Gamma Knife radiosurgery was 54.5 months, varying from 14 to 90 months. The overall clinical assessments revealed a gradual neurological improvement, particularly within the first 8.5 weeks (range, 1-12 weeks). The immediate outcomes at 3 months revealed that all patients (8/8, 100%) experienced pain relief, with 25% (2/8) achieving a medication-free status (Grade I). Three patients (37%) experienced a recurrence during the follow-up and were managed with repeat Gamma Knife radiosurgery (n = 2) and radiofrequency rhizotomy (n = 1). At the last follow-up, 88% (7/8) of patients had pain relief (Grades I-IIIa), with three (37%) achieving a medication-free status (Grade I). No adverse events or neurological complications occurred. The patient who underwent radiofrequency rhizotomy continued to experience inadequately controlled pain despite medication (Grade IV). Gamma Knife radiosurgery is a non-invasive, efficacious treatment option for idiopathic GPN, offering short- and long-term relief without permanent complications.

Repeat Gamma Knife radiosurgery for recurrent trigeminal neuralgia in patients with multiple sclerosis: a single-center retrospective study.

Gamma Knife radiosurgery (GKRS) has emerged as an effective treatment option for trigeminal neuralgia (TN) in patients with multiple sclerosis (MS). To date, the outcomes of repeat GKRS for patients with TN and MS with recurrent pain have been investigated in a few patients. This study aims to report the outcomes and predictive factors of pain reduction for MS patients undergoing repeat GKRS for recurrent TN. Eighteen patients with MS underwent repeat GKRS for recurrent TN. A retrospective chart review and telephone interviews were conducted to determine background medical history, dosimetric data, and outcomes of the procedure. Facial pain and sensory function were evaluated using the Barrow Neurological Institute (BNI) scales. Fifteen patients achieved a BNI pain score of IIIa or better, indicating pain reduction, within a median period of 21 days after repeat GKRS. The maximum dose for repeat GKRS ranged from 70 to 85 Gy. Pain recurred in 5 patients after a median period of 12 months after GKRS. Percentages of patients with pain reduction at 1, 2, 3, 5, and 7 years were 60%, 60%, 50%, 50%, and 50%, respectively. Older age at repeat GKRS predicted sustained pain reduction (P = 0.01). Seven patients developed facial sensory disturbances, which were bothersome in two patients. Repeat GKRS may be used as an effective treatment modality for prolonging the duration of pain reduction time in patients with MS and TN. After repeat GKRS, facial sensory disturbances are common; however, they are often not bothersome.

Post-operative gamma knife radiosurgery for WHO grade I intracranial meningiomas: A single-center, retrospective study.

To explore the results of the Gamma Knife radiosurgery (GKRS) for World Health Organization (WHO) grade I intracranial meningiomas after surgical resection. A total of 130 patients who were pathologically diagnosed as having WHO grade I meningiomas and who underwent post-operative GKRS were retrospectively reviewed in a single center. Of the 130 patients, 51 patients (39.2%) presented with radiological tumor progression with a median follow-up time of 79.7 months (ranging from 24.0 to 291.3 months). The median time to radiological tumor progression was 73.4 months (ranging from 21.4 to 285.3 months), whereas 1-, 3-, 5-, and 10-year radiological progression-free survival (PFS) was 100, 90, 78, and 47%, respectively. Moreover, 36 patients (27.7%) presented with clinical tumor progression. Clinical PFS at 1, 3, 5, and 10 years was 96, 91, 84, and 67%, respectively. After GKRS, 25 patients (19.2%) developed adverse effects, including radiation-induced edema (n = 22). In a multivariate analysis, a tumor volume of ≥10 ml and falx/parasagittal/convexity/intraventricular location were significantly associated with radiological PFS [hazard ratio (HR) = 1.841, 95% confidence interval (CI) = 1.018-3.331, p = 0.044; HR = 1.761, 95% CI = 1.008-3.077, p = 0.047]. In a multivariate analysis, a tumor volume of ≥10 ml was associated with radiation-induced edema (HR = 2.418, 95% CI = 1.014-5.771, p = 0.047). Of patients who presented with radiological tumor progression, nine were diagnosed with malignant transformation. The median time to malignant transformation was 111.7 months (ranging from 35.0 to 177.2 months). Clinical PFS after repeat GKRS was 49 and 20% at 3 and 5 years, respectively. Secondary WHO grade II meningiomas were significantly associated with a shorter PFS (p = 0.026). Post-operative GKRS is a safe and effective treatment for WHO grade I intracranial meningiomas. Large tumor volume and falx/parasagittal/convexity/intraventricular location were associated with radiological tumor progression. Malignant transformation was one of the main cause of tumor progression in WHO grade I meningiomas after GKRS.

Radiation-Induced Changes Associated with Obliteration of Brain AVMs after Repeat Radiosurgery.

Radiation-induced changes can occur after stereotactic radiosurgery for brain AVMs, potentially causing symptomatic complications. We evaluated the incidence of such changes and the efficacy of repeat gamma knife radiosurgery for incompletely obliterated AVMs. We retrospectively evaluated 150 patients who underwent gamma knife radiosurgery for AVMs between 2002 and 2020; twenty-five underwent further radiosurgical procedures for incompletely obliterated AVMs. We recorded the median margin doses at the first (median, 20 Gy; range, 12-23 Gy; AVM volume, 0.026-31.3 mL) and subsequent procedures (median, 18 Gy; range, 12-23 Gy; AVM volume, 0.048-9.2 mL). After the first treatment, radiologic radiation-induced changes developed in 48 (32%) patients, eight of whom had symptomatic changes. After repeat gamma knife radiosurgery, 16 of 25 patients achieved complete AVM obliteration (64%). The development of radiation-induced changes after the first treatment was significantly associated with successful obliteration by subsequent radiosurgery (OR = 24.0, 95% CI 1.20-483, P = .007). Radiation-induced changes occurred in only 5 (20%) patients who underwent a second gamma knife radiosurgery, one of whom experienced transient neurologic deficits. Between the first and repeat gamma knife radiosurgery procedures, there was no significant difference in radiologic and symptomatic radiation-induced changes (P = .35 and P = 1.0, respectively). Radiation-induced changes after the first gamma knife radiosurgery were associated with AVM obliteration after a repeat procedure. The risk of symptomatic radiation-induced changes did not increase with retreatment. When the first procedure fails to achieve complete AVM obliteration, a favorable outcome can be achieved by a repeat gamma knife radiosurgery, even if radiation-induced changes occur after the first treatment.

Tumor Control and Hearing Preservation After Gamma Knife Radiosurgery for Vestibular Schwannomas in Neurofibromatosis Type 2—A Retrospective Analysis of 133 Tumors

This study was conducted with the aim to estimate long-term tumor control and hearing preservation rates in patients with neurofibromatosis 2 (NF2)-related vestibular schwannoma (VS), document retreatment success rate, and assess the associated predictive factors. This was a retrospective analysis of patients with NF2-associated VS who underwent Gamma Knife radiosurgery (GKRS) between 2009 and 2020 and had a minimum follow-up of 1 year. Loss of tumor control was defined as greater than 10% increase in volume in more than one follow-up imaging or the need for retreatment in the form of repeat GKRS or surgery. The Kaplan-Meier method was used to evaluate actuarial tumor control and hearing preservation rates. In total, 85 patients with 133 VSs were included in the study. The mean age was 29.8 years. In total, 57 tumors showed tumor regression, 35 showed stable disease, and 23 progressed in size at last follow up. Actuarial tumor control rates after 1, 3, 5, and 9 years were 95%, 79%, 75%, and 55%, respectively, with overall tumor control rate being 85%. Hearing worsened in 39 patients, and facial nerve dysfunction occurred in 4 patients. Five tumors underwent retreatment with GKRS at a median duration of 27.6 months (19-36 months) following the first GKRS. This is the largest radiosurgical series of NF2-associated VS reported to date. GKRS provides a high rate of long-term local tumor control with a low risk of neurologic deprivation for patients with these tumors. The need for retreatment with GKRS, although low, is associated with good tumor control and lesser complications.

Letter to the Editor: The Role of Modern Simulation Techniques in Neurovascular Surgery Training

Trigeminal neuralgia (TN) in patients with multiple sclerosis (MS) is a challenging condition to manage that is treated with Gamma Knife radiosurgery (GKRS). The aim of this report is to assess the safety, efficacy, and durability of GKRS for the treatment of TN in patients with MS. Our findings are compared with those of the existing literature and discussed.We retrospectively reviewed all patients at our institution who underwent GKRS for the treatment of TN secondary to MS and had 1 or more years of follow-up. Preoperative and postoperative pain intensities and facial numbness were evaluated with the Barrow Neurological Institute scores. Durability of successful pain relief was statistically evaluated with Kaplan–Meier analysis. The prognostic role of perioperative factors was investigated and analyzed using Cox proportional hazards regression.There were 29 patients with MS-TN who underwent GKRS at our institution. Two patients underwent bilateral treatment. Four patients underwent repeat GKRS for pain recurrence. The median period of follow-up assessment was 33 months. Rates of reasonable pain reduction at 1, 3, and 5 years were 70%, 57%, and 57% respectively. All patients who underwent repeat GKRS had durable pain reduction. No prognostic factor for successful pain reduction was found.Our study shows that GKRS for the treatment of TN secondary to MS is a safe and effective procedure in controlling pain in the short term but often fails to provide long-term pain control. GKRS can be safely repeated to prolong the time of pain reduction.

Characteristic of Tumor Regrowth After Gamma Knife Radiosurgery and Outcomes of Repeat Gamma Knife Radiosurgery in Nonfunctioning Pituitary Adenomas.

ObjectiveThis study aimed to report the characteristic of tumor regrowth after gamma knife radiosurgery (GKRS) and outcomes of repeat GKRS in nonfunctioning pituitary adenomas (NFPAs).Design and MethodsThis retrospective study consisted of 369 NFPA patients treated with GKRS. The median age was 45.2 (range, 7.2–84.0) years. The median tumor volume was 3.5 (range, 0.1–44.3) cm3.ResultsTwenty-four patients (6.5%) were confirmed as regrowth after GKRS. The regrowth-free survivals were 100%, 98%, 97%, 86% and 77% at 1, 3, 5, 10 and 15 year, respectively. In multivariate analysis, parasellar invasion and margin dose (<12 Gy) were associated with tumor regrowth (hazard ratio [HR] = 3.125, 95% confidence interval [CI] = 1.318–7.410, p = 0.010 and HR = 3.359, 95% CI = 1.347–8.379, p = 0.009, respectively). The median time of regrowth was 86.1 (range, 23.2–236.0) months. Previous surgery was associated with tumor regrowth out of field (p = 0.033). Twelve patients underwent repeat GKRS, including regrowth in (n = 8) and out of field (n = 4). Tumor shrunk in seven patients (58.3%), remained stable in one (8.3%) and regrowth in four (33.3%) with a median repeat GKRS margin dose of 12 (range, 10.0–14.0) Gy. The actuarial tumor control rates were 100%, 90%, 90%, 68%, and 68% at 1, 3, 5, 10, and 15 years after repeat GKRS, respectively.ConclusionsParasellar invasion and tumor margin dose (<12 Gy) were independent risk factors for tumor regrowth after GKRS. Repeat GKRS might be effective on tumor control for selected patients. For regrowth in field due to relatively insufficient radiation dose, repeat GKRS might offer satisfactory tumor control. For regrowth out of field, preventing regrowth out of field was the key management. Sufficient target coverage and close follow-up might be helpful.

Gamma Knife Radiosurgery for the Treatment of Trigeminal Neuralgia in Patients with Multiple Sclerosis: A Single-Center Retrospective Study and Literature Review

Trigeminal neuralgia (TN) in patients with multiple sclerosis (MS) is a challenging condition to manage that is treated with Gamma Knife radiosurgery (GKRS). The aim of this report is to assess the safety, efficacy, and durability of GKRS for the treatment of TN in patients with MS. Our findings are compared with those of the existing literature and discussed. We retrospectively reviewed all patients at our institution who underwent GKRS for the treatment of TN secondary to MS and had 1 or more years of follow-up. Preoperative and postoperative pain intensities and facial numbness were evaluated with the Barrow Neurological Institute scores. Durability of successful pain relief was statistically evaluated with Kaplan-Meier analysis. The prognostic role of perioperative factors was investigated and analyzed using Cox proportional hazards regression. There were 29 patients with MS-TN who underwent GKRS at our institution. Two patients underwent bilateral treatment. Four patients underwent repeat GKRS for pain recurrence. The median period of follow-up assessment was 33 months. Rates of reasonable pain reduction at 1, 3, and 5 years were 70%, 57%, and 57% respectively. All patients who underwent repeat GKRS had durable pain reduction. No prognostic factor for successful pain reduction was found. Our study shows that GKRS for the treatment of TN secondary to MS is a safe and effective procedure in controlling pain in the short term but often fails to provide long-term pain control. GKRS can be safely repeated to prolong the time of pain reduction.

Gamma Knife radiosurgery for bilateral trigeminal neuralgia

OBJECTIVEA small subset of patients with trigeminal neuralgia (TN) will experience bilateral symptoms. Treatment in these patients is controversial because the population is heterogeneous and patients may have nonvascular etiologies of their pain. This study reports treatment outcomes in the largest cohort of patients with bilateral TN who have undergone Gamma Knife radiosurgery (GKRS) to date.METHODSA retrospective chart review identified 51 individual nerves in 34 patients with bilateral TN who were treated with GKRS at the authors’ institution between 2001 and 2015, with 12 nerves in 11 patients undergoing repeat GKRS for recurrent or persistent symptoms. Long-term follow-up was obtained by telephone interview. Pain outcomes were measured using the Barrow Neurological Institute (BNI) pain scale, with BNI IIIb or better considered a successful treatment.RESULTSThere was sufficient follow-up to determine treatment outcomes for 48 individual nerves in 33 patients. Of these nerves, 42 (88%) achieved at least BNI IIIb pain relief. The median duration of pain relief was 1.9 years, and 1-, 3-, and 5-year pain relief rates were 64%, 44%, and 44%, respectively. No patients experienced bothersome facial numbness, and 1 case of anesthesia dolorosa and 2 cases of corneal dryness were reported. Patients with a history of definite or possible multiple sclerosis were significantly more likely to experience BNI IV–V relapse. There was no statistically significant difference in treatment outcomes between patients in this series versus a large cohort of patients with unilateral TN treated at the authors’ institution. There was sufficient follow-up to determine treatment outcomes for 11 individual nerves in 10 patients treated with repeat GKRS. Ten nerves (91%) improved to at least BNI IIIb after treatment. The median duration of pain relief was 2.8 years, with 1-, 3-, and 5-year rates of pain relief of 79%, 53%, and 53%, respectively. There was no statistically significant difference in outcomes between initial and repeat GKRS. One case of bothersome facial numbness and 1 case of corneal dryness were reported, with no patients developing anesthesia dolorosa with retreatment.CONCLUSIONSGKRS is a safe, well-tolerated treatment for patients with medically refractory bilateral TN. Efficacy of treatment appears similar to that in patients with unilateral TN. GKRS can be safely repeated in this population if necessary.

Long-Term Outcomes of Gamma Knife Radiosurgery for Cystic Vestibular Schwannomas

Vestibular schwannomas (VSs) can either be solid or contain variable amounts of cystic components. It has been established that gamma knife radiosurgery (GKRS) is an effective treatment modality for solid VSs. However, in the case of cystic VS, given the somewhat unpredictable growth of the cystic portion of these tumors, microsurgery has often been preferred to GKRS in the management of cystic VS. However, to date, a relative paucity of data evaluating the outcomes after GKRS for cystic VS has been available. In the present study, we reviewed our experience treating cystic VSs with GKRS and evaluated the results. The data from patients with a diagnosis of cystic VS who had undergone GKRS from 1999 to 2018 were analyzed. Only those patients who had undergone GKRS as the initial treatment of cystic VSs were included in the present study. Patients who had undergone previous surgical treatment were excluded. The cystic VSs were divided into intratumoral and peritumoral cysts. A total of 24 patients were enrolled in the present study. The mean age was 60.8 ± 2.4 years (range, 38-82 years). The mean follow-up period was 55.8 ± 8.1 months (range, 8-145 months). Of the 24 patients, 11 were men. The control rate after GKRS for cystic VSs was 75%. The 5-year progression-free rate was 70%. Six patients had presented with an increasing lesion size after GKS. Of these 6 patients, 2 underwent surgical treatment and 1 underwent repeat GKRS. No statistically significant differences were found between the control rate and cystic type (P= 0.093). The results from the present study have demonstrated that GKRS is an effective treatment modality for cystic VSs.

RADI-14. FRAMELESS STEREOTACTIC RADIOSURGERY ON THE GAMMA KNIFE ICON: EARLY EXPERIENCE FROM 42 PATIENTS WITH BRAIN METASTASES

BACKGROUND: The Gamma Knife (GK) Icon uses a Cone-Beam CT (CBCT) scanner and an infrared camera system to support the delivery of frameless radiosurgery. There are limited data on patients treated with frameless GK radiosurgery (GKRS) for brain metastases. OBJECTIVE: To describe the early experience, process, technical details, and short-term outcomes with frameless GKRS for brain metastases at our institution. METHODS: We describe our patient selection and workflow for frameless GKRS in detail. Because of the short interval of follow-up, we provide crude rates of local control. RESULTS: 42 patients had a total of 96 brain metastases. Median age was 69. 77 intact lesions were treated definitively, 18 cavities postoperatively, and 1 had GKRS for recurrence after resection. 11 patients underwent repeat GKRS to the same area. Median dose was 20Gy in 1 fraction (range: 14–21), 24Gy in 3 fractions (range: 19.5–27), and 25Gy in 5 fractions (Range: 25–30). Median treatment time was 23.7 minutes (Range: 7.3 – 85.5). 29 patients had a follow-up MRI in our records after completing GKRS. Median follow-up time was 105 days (Range: 16 – 314). 16 local recurrences (LR) were identified in 9 patients. An additional 6 patients had distant brain recurrence without LR. Crude mean time between GKRS and LR was 101 days (range 44–161 days). There were 6 patients with grade 1, 3 with grade 2, 2 with grade 3, and 1 with grade 4 toxicity. We found an improvement in workflow and a greater number of patients eligible for GKRS due to the ability to fractionate treatments. CONCLUSION: We report a large cohort of consecutive patients with brain metastases treated with frameless GKRS. We look forward to studies with longer follow-up to provide valuable data on clinical outcomes and to further our understanding of the radiobiology of hypofractionation in the brain.

Repeat Gamma Knife radiosurgery versus microvascular decompression following failure of GKRS in trigeminal neuralgia: a systematic review and meta-analysis.

Gamma Knife radiosurgery (GKRS) has emerged as a promising treatment modality for patients with classical trigeminal neuralgia (TN); however, considering that almost half of the patients experience post-GKRS failure or lesion recurrence, a repeat treatment is typically necessary. The existing literature does not offer clear evidence to establish which treatment modality, repeat GKRS or microvascular decompression (MVD), is superior. The present study aimed to compare the overall outcome of patients who have undergone either repeat GKRS or MVD after failure of their primary GKRS; the authors do so by conducting a systematic review and meta-analysis of the literature and analysis of data from their own institution. The authors conducted a systematic review and meta-analysis of the PubMed, Cochrane Library, Web of Science, and CINAHL databases to identify studies describing patients who underwent either repeat GKRS or MVD after initial failed GKRS for TN. The primary outcomes were complete pain relief (CPR) and adequate pain relief (APR) at 1 year. The secondary outcomes were rate of postoperative facial numbness and the retreatment rate. The pooled data were analyzed with R software. Bias and heterogeneity were assessed using funnel plots and I2 tests, respectively. A retrospective analysis of a series of patients treated by the authors who underwent repeat GKRS or MVD after post-GKRS failure or relapse is presented. A total of 22 studies met the selection criteria and were included for final data retrieval and meta-analysis. The search did not identify any study that had directly compared outcomes between patients who had undergone repeat GKRS versus those who had undergone MVD. Therefore, the authors' final analysis included two groups: studies describing outcome after repeat GKRS (n = 17) and studies describing outcome after MVD (n = 5). The authors' institutional study was the only study with direct comparison of the two cohorts. The pooled estimates of primary outcomes were APR in 83% of patients who underwent repeat GKRS and 88% of those who underwent MVD (p = 0.49), and CPR in 46% of patients who underwent repeat GKRS and 72% of those who underwent MVD (p = 0.02). The pooled estimates of secondary outcomes were facial numbness in 32% of patients who underwent repeat GKRS and 22% of those who underwent MVD (p = 0.11); the retreatment rate was 19% in patients who underwent repeat GKRS and 13% in those who underwent MVD (p = 0.74). The authors' institutional study included 42 patients (repeat GKRS in 15 and MVD in 27), and the outcomes 1 year after retreatment were APR in 80% of those who underwent repeat GKRS and 81% in those who underwent MVD (p = 1.0); CPR was achieved in 47% of those who underwent repeat GKRS and 44% in those who underwent MVD (p = 1.0). There was no difference in the rate of postoperative facial numbness or retreatment. The current meta-analysis failed to identify any superiority of one treatment over the other with comparable outcomes in terms of APR, postoperative facial numbness, and retreatment rates. However, MVD was shown to provide a better chance of CPR compared with repeat GKRS.

Personalized repeat Gamma Knife Radiosurgery treatment in patients with recurrent refractory trigeminal neuralgia

Objective: To analyze the prognosis and untoward effect in recurrent refractory trigeminal neuralgia (RRTN) patients who underwent repeat Gamma Knife Radiosurgery treatment (GKRS) retrospectively, and to summarize the experience of repeat Gamma Knife Radiosurgery treatment of recurrent refractory trigeminal neuralgia. Methods: RRTN patients who treated with repeat GKRS during 1998.8.1 to 2014.10.1 in Gamma Knife treatment Center of the Fifth Affiliated Hospital of Zhengzhou University were involved. The factors influencing long-term prognosis and facial numbness adverse reactions were statistically analyzed. Results: Therapeutic dose was an independent factor that influence long-term prognosis of RRTN patients. Therapeutic dose was a dangerous factor that influence long-term facial numbness. Interval time between twice GKRS treatment was a favorable factor for facial numbness. Long-term prognosis of repeat GKRS treatment was positively correlated with therapeutic dose. Untoward effect of facial numbness after repeat GKRS treatment was positively correlated with therapeutic dose and negatively correlated with interval time between twice GKRS treatment. Conclusions: Repeat GKRS for RRTN patients is safe and effective, but personalized treatment plan should be given according to the patient's own condition.

Stereotactic Radiosurgery for Multiple Sclerosis Associated Trigeminal Neuralgia

Trigeminal neuralgia in the setting of multiple sclerosis (MS-TN) is a challenging condition to manage and frequently does not respond as well to medications or surgical intervention when compared with classic TN. Gamma Knife radiosurgery (GKRS) is a commonly used treatment modality for these patients, however, data regarding the efficacy of this treatment is limited. Here we report a large single institution retrospective analysis for MS-TN treated with GKRS. A retrospective review of our GKRS database was performed to identify patients with MS-TN treated with GKRS between 2001 and 2016. Seventy-seven cases of unilateral MS-TN (UMSTN) in 74 patients were treated with GKRS at our institution between 2001 and 2016. Background medical history, treatment outcomes and complications, and dosimetric data were obtained by retrospective chart reviews and telephone interviews. Time-to-failure outcomes were estimated using the Kaplan-Meier method. Cox proportional hazards methods were used to estimate the hazard ratios (HR) associated with patient and treatment-related variables for time-to-failure outcomes. Seventy-four of 77 cases of UMSTN had sufficient follow up to determine BNI pain score outcomes. Three patients had both nerves treated. Sixty-one out of 74 cases (82%) of UMSTN achieved BNI IIIb or better pain relief following initial GKRS, with 18 cases (24%) achieving BNI I pain relief. Median time to BNI IIIb pain relief was 1.8 weeks. At a median follow up of 2.5 years, the estimated median duration of BNI IIIb pain relief after initial GKRS was 1.1 years. Estimated rates of pain relief at 1, 3 and 5 years were 51%, 37%, and 27% respectively. Three cases (4.1%) developed bothersome numbness and three cases (4.1%) developed ipsilateral corneal anesthesia, although none experienced vision loss. No patients experienced anesthesia dolorosa. Thirty-seven of the original 77 cases of UMSTN were treated with repeat GKRS after initial treatment failure. Of 35 patients with sufficient follow up to determine pain outcomes, 30 (86%) achieved BNI IIIb or better pain relief, with 12 (34%) achieving BNI I following repeat GKRS. Median time to BNI IIIb pain relief was 4.5 weeks. At a median follow up of 2.3 years from repeat GKRS, the median duration of BNI IIIb pain relief after repeat GKRS was 2.8 years. Estimated rates of pain relief at 1 and 3 years were 67% and 49% respectively. One case (2.9%) developed bothersome numbness after repeat GKRS, and three cases (8.6%) developed new ipsilateral corneal anesthesia, but none reported vision loss. No patients developed anesthesia dolorosa. Patients with episodic pain were more likely to achieve a good pain outcome after repeat GKRS than those with atypical symptoms (HR 10.51, p = 0.03). GKRS is a viable, well tolerated treatment option for patients with MS-TN. More durable relief is often achieved with a second application of GKRS. Patients with episodic pain are more likely to have successful second procedure.

203 Treatment Options Following Failed Gamma Knife Radiosurgery in Trigeminal Neuralgia

Abstract INTRODUCTION Primary treatment of trigeminal neuralgia with gamma knife radiosurgery (GKRS) is an accepted and effective modality, but is associated with a significant failure rate. Many of the patients ultimately require additional treatment for adequate pain relief. The present paper discusses the long term outcome of this group of patients who are treated with either repeat GKRS or microvascular decompression (MVD) as a secondary procedure. METHODS Using the retrospective database, the clinical data was analyzed of the patients who underwent GKRS at our institute between January 2000 and June 2016. The initial GKRS plan included median prescription dose of 80 Gy at a single iso-center using 4 mm collimator. The patients who did not improve after initial therapy and maximal medication dosage were offered either repeat radiosurgery or MVD. Repeat radiosurgery included a similar plan but a reduced median prescription dose of 40 Gy. Long term pain relief was measured using Marseille's score. Multiple factors including demographic factors, the type of pain, post GKRS facial numbness, treatment interval were analyzed to predict association with the final outcome. RESULTS &gt;In the study preriod, a total of 198 patients underwent GKRS for trigeminal neuralgias. Among these patients 42 (21.2%) patients had treatment failure and required additional treatment. The median interval of subsequent interventions was 16 months (range 2 months to 154 months). Six patients (14.2%) required repeat treatment after 5 years of initial treatment. Out of 42 failed GKRS patients, 15 (35.7%) underwent repeat radiosurgery and 27 (64.3%) underwent MVD. The mean follow up duration was 4.3 years. Overall, 34 patients (81%) improved and had adequate pain relief (Marseille's score III or better) after the second procedure. The rate of adequate pain relief after repeat GKRS and microvascular decompression were 86.6% and 77.7% respectively (P = 0.68). Univariate analysis failed to reveal any significant predictor for pain relief after second treatment. CONCLUSION Repeat GKRS and MVD both are valid treatment options after failed initial radiosurgery, with no difference in long term outcome. Unless specifically indicated, repeat GKRS being noninvasive, may be considered over microvascular decompression.

Follow-up results of brain metastasis patients undergoing repeat Gamma Knife radiosurgery.

OBJECTIVE Stereotactic radiosurgery (SRS) without upfront whole-brain radiotherapy (WBRT) has influenced recent treatment recommendations for brain metastasis patients. However, in brain metastasis patients who undergo SRS alone, new brain metastases inevitably appear with relatively high incidences during post-SRS follow-up. However, little is known about the second SRS results. The treatment results of second SRS were retrospectively reviewed, mainly for newly developed or, uncommonly, for recurrent brain metastases in order to reappraise the efficacy of this treatment strategy with a special focus on the maintenance of neurological status and safety. METHODS This was an institutional review board-approved, retrospective cohort study that used a prospectively accumulated database, including 3102 consecutive patients with brain metastases who underwent SRS between July 1998 and June 2015. Among these 3102 patients, 859 (376 female patients; median age 64 years; range 21-88 years) who underwent a second SRS without WBRT were studied with a focus on overall survival, neurological death, neurological deterioration, local recurrence, salvage SRS, and SRS-induced complications after the second SRS. Before the second SRS, the authors also investigated the clinical factors and radiosurgical parameters likely to influence these clinical outcomes. For the statistical analysis, the standard Kaplan-Meier method was used to determine post-second SRS survival and neurological death. A competing risk analysis was applied to estimate post-second SRS cumulative incidences of local recurrence, neurological deterioration, salvage SRS, and SRS-induced complications. RESULTS The post-second SRS median survival time was 7.4 months (95% CI 7.0-8.2 months). The actuarial survival rates were 58.2% and 34.7% at 6 and 12 months after the second SRS, respectively. Among 789 deceased patients, the causes of death could not be determined in 24 patients, but were confirmed in the remaining 765 patients to be nonbrain diseases in 654 (85.5%) patients and brain diseases in 111 (14.5%) patients. The actuarial neurological death-free survival rates were 94.4% and 86.6% at 6 and 12 months following the second SRS. Multivariable analysis revealed female sex, Karnofsky Performance Scale score of 80% or greater, better modified recursive partitioning analysis class, smaller tumor numbers, and higher peripheral dose to be significant predictive factors for longer survival. The cumulative incidences of local recurrence were 11.2% and 14.9% at 12 and 24 months after the second SRS. The crude incidence of neurological deterioration was 7.1%, and the respective cumulative incidences were 4.5%, 5.8%, 6.7%, 7.2%, and 7.5% at 12, 24, 36, 48, and 60 months after the second SRS. SRS-induced complications occurred in 25 patients (2.9%) after a median post-second SRS period of 16.8 months (range 0.6-95.0 months; interquartile range 5.6-29.3 months). The cumulative incidences of complications were 1.4%, 2.0%, 2.4%, 3.0%, and 3.0% at 12, 24, 36, 48, and 60 months after the second SRS, respectively. CONCLUSIONS Carefully selected patients with recurrent tumors-either new or locally recurrent-are favorable candidates for a second SRS, particularly in terms of neurological status maintenance and the safety of this treatment strategy.

BMET-37. RADIOSURGICAL TREATMENT FOR ELDERLY PATIENTS WITH BRAIN METASTASES

This study was designed to investigate the treatment results of Gamma Knife radiosurgery (GKRS) for elderly patients (age ≥65) with brain metastases and the relevant factors associated with survival. We retrospectively analyzed the data of 106 patients treated with GKRS for 1 to 15 brain metastases. The median age at the time of treatment was 72 years (65~86), and the median Karnofsky performance status score was 90 (50~100). The most common primary tumor site was the lungs (n =86). The mean lesion volume was 2 cc (0.001~41.2). A median prescription dose of 20 Gy was delivered to the median 50 % isodose line. The median overall survival time was 5.8 ± 1.0 months. During the median follow-up duration of 5.6 ± 1.1 months (0.2~54), 85 patients died of primary cancer progression, and 1 died of uncertain cause. Twenty-two patients underwent repeat GKRS or whole brain radiation therapy for newly developed or progressive brain metastases. Among various factors, primary tumor control (p = 0.001, HR: 0.215, 95% CI: 0.116~0.398) and female (p < 0.001, HR: 0.521, 95% CI: 0.330~0.822) were significant favorable factors for survival after univariate and multivariate analysis. The median survival time of patients with controlled primary tumor vs. uncontrolled was 33.9 ± 12.0 vs. 4.0 ± 0.5 months, and the median survival time of female patients vs. male patients was 14.6 ± 4.1 vs. 4.2 ± 0.6 months. GKRS for elderly patients with brain metastases appears to provide outcomes comparable to younger patients. According to our results, we suggest that radiosurgical treatment should be recommended to female patients with brain metastases when their primary cancer is controlled, even when they are aged 65 years or more. Age should not be an impediment to treatment in this selected group.

Repeat Gamma-Knife Radiosurgery for Refractory or Recurrent Trigeminal Neuralgia with Consideration About the Optimal Second Dose

To investigate adequate radiation doses for repeat Gamma Knife radiosurgery (GKS) for trigeminal neuralgia in our series and meta-analysis. Fourteen patients treated by ipsilateral repeat GKS for trigeminal neuralgia were included. Median age of patients was 65 years (range, 28-78), the median target dose, 140-180). Patients were followed a median of 10.8 months (range, 1-151) after the second gamma-knife surgery. Brainstem dose analysis and vote-counting meta-analysis of 19 studies were performed. After the second gamma-knife radiosurgeries, pain was relieved effectively in 12 patients (86%; Barrow Neurological Institute Pain Intensity Score I-III). Post-gamma-knife radiosurgery trigeminal nerve deficits were mild in 5 patients. No serious anesthesia dolorosa was occurred. The second GKS radiation dose ≤ 60 Gy was significantly associated with worse pain control outcome (P = 0.018 in our series, permutation analysis of variance, and P = 0.009 in the meta-analysis, 2-tailed Fisher's exact test). Cumulative dose ≤ 140-150 Gy was significantly associated with poor pain control outcome (P = 0.033 in our series and P = 0.013 in the meta-analysis, 2-tailed Fisher's exact test). A cumulative brainstem edge dose >12 Gy tended to be associated with trigeminal nerve deficit (P = 0.077). Our study suggests that the second GKS dose is a potentially important factor.

Repeat Radiosurgery for Trigeminal Neuralgia.

Repeat Gamma Knife radiosurgery (GKRS) is an established option for patients whose pain has recurred after the initial procedure, with reported success rates varying from 68% to 95%. Predictive factors for response to the repeat GKRS are ill-defined. This cohort study aimed to report the outcomes and factors predictive of success for patients who have undergone repeated GKRS for trigeminal neuralgia at Wake Forest University Baptist Medical Center. Between 1999 and 2013, 152 patients underwent repeat GKRS at Wake Forest, 125 of whom were available for long-term follow-up. A retrospective chart review and telephone interviews were conducted to determine background medical history, dosimetric data, outcomes, and adverse effects of the procedure. Eighty-four percent of patients achieved at least Barrow Neurological Institute (BNI) IIIb pain relief, with 46% achieving BNI I. The 1-, 3-, and 5-year rates of BNI I pain relief were 63%, 50%, and 37%, respectively. The 1-, 3-, and 5-year rates of BNI IIIb or better pain relief were 74%, 59%, and 46%, respectively. One patient experienced bothersome numbness and 2 patients developed anesthesia dolorosa. The dominant predictive factors for pain relief were facial numbness after the first GKRS and a positive pain response to the first GKRS. Repeat GKRS is an effective method of treating recurrent trigeminal neuralgia. Patients who have facial numbness after the first treatment and a positive pain response to the first GKRS are significantly more likely to respond well to the second treatment.