Diffusivity metrics alterations three months after GammaKnife radiosurgery for trigeminal neuralgia may predict pain relief.

Objectives: Early identification of patients who will experience delayed-onset pain relief after GKRS for trigeminal neuralgia (TN) will allow optimal patient management, and avoidance of unnecessary procedures. A non-invasive tool to identify late responders to GKRS is currently unavailable. We sought to evaluate MRI based diffusivity metrics obtained at the 3-month post-GKRS time point as predictors of treatment response. Methods: Pre-procedural and 3-month post-procedural 3T MRI examinations were obtained in 43 patients with TN. Diffusion tensor metrics including axial diffusivity (AD), radial diffusivity (RD), and fractional anisotropy (FA) were extracted from the bilateral trigeminal nerve intra-pontine fibers, cisternal radiosurgical targets (or corresponding contralateral nerve segments), and non-targeted cisternal nerve segments. A favorable treatment response was defined as pain intensity on the Barrow Neurological Institute (BNI) scale of I-II at last follow-up. Pain relief and treatment response at last follow-up were examined for correlation with the 3-month post-GKRS diffusivity metrics. Results: At a median clinical follow-up of 5 months (range 0.5 to 24.5 months), all patients who did not experience pain relief at last follow-up had significantly reduced cisternal AD values (p=0.04) at the 3-month brain Diffusion Tensor image. In patients with classic TN, reduced mean cisternal AD (p=0.032), RD (p=0.026), and FA (p=0.042) values at the 3-month DTI follow-up were associated with BNI >2 at last follow-up. In addition, decreased mean cisternal AD (p=0.036), RD (p=0.029), and FA (p=0.037) were noted in patients with classic TN that failed to achieve a decrease of 2 points on the BNI scale at last follow-up. Conclusion: Alterations of diffusivity metrics on the treated trigeminal nerve 3 months after GKRS for classic TN significantly correlated with no response to GKRS at last follow-up. Further studies to clarify the value of DTI as a non-invasive tool to predict response to treatment in patients with TN managed with GKRS are warranted.

Stereotactic radiosurgery for craniopharyngiomas.

BACKGROUND: The management of craniopharyngiomas is challenging, usually requiring multidisciplinary care. We evaluated the long-term clinical and radiologic outcomes of Gamma Knife radiosurgery (GKRS) for craniopharyngiomas. METHODS: This retrospective study involved patients managed with GKRS for a craniopharyngioma during the period of 1989 to 2019. Patient clinical and radiologic data, tumor characteristics, and procedural details were analyzed. RESULTS: Thirty-eight consecutive patients (24 males; mean patient age at GKRS = 30.82 years [SD ± 20.45 years]) were treated with GKRS for craniopharyngioma. Overall survival rates at 5 and 10 years were 84.1% and 80.1%, respectively. Progression-free survival at 5 years was 48.1%, and, at 10 years, it was 29.8%. Risk factors for post-GKRS clinical deterioration were increasing number of isocenters used (p = 0.04 (HR1.32, CI 1-1.73)), increasing margin dose [p = 0.02 (HR1.52, CI 1.31-1.84)], and maximum dose > 35 Gy [p = 0.002 (HR1.35, CI 1.11-1.63)]. CONCLUSION: Stereotactic radiosurgery (SRS) appears a safe and effective management option in selected craniopharyngioma patients. Increasing margin dose and maximum dose > 35 Gy are associated with an increased risk for post-SRS neurologic deficit. Further, well-designed studies are necessary to determine the optimal timing and SRS parameters and to identify which patients with craniopharyngioma will benefit the most from SRS.

Diffusivity Metrics Three Months After Upfront Gamma Knife Radiosurgery for Trigeminal Neuralgia May Be Correlated with Pain Relief.

BACKGROUND: Gamma Knife radiosurgery (GKRS) is a safe and effective treatment option for trigeminal neuralgia (TN). However, there is no objective, noninvasive tool to identify nonresponders or late responders to GKRS and to facilitate longitudinal patient management. We hypothesized that diffusivity metrics obtained 3 months after GKRS may correlate with response to treatment. METHODS: Sixteen patients with TN treated with GKRS underwent preprocedural and 3-month postprocedural 3-T magnetic resonance imaging of the brain. Diffusion tensor metrics of axial diffusivity, radial diffusivity, and fractional anisotropy were extracted from the pontine segments, the root entry zones, and the distal cisternal segments of both trigeminal nerves. Diffusivity metrics at the 3-month post-GKRS time point were compared with pain relief at last follow-up. Favorable response to GKRS was defined as pain intensity of I-III on the Barrow Neurological Institute scale. RESULTS: The median clinical follow-up was 11 months (range 3-18 months). Patients with favorable response to GKRS at last follow-up had lower mean fractional anisotropy values at the pontine segment (P = 0.04) and increased mean radial diffusivity values at the root entry zones (P = 0.032) of the treated trigeminal nerve on the 3-month diffusion tensor imaging sequences as compared with the nonresponders. CONCLUSIONS: Diffusivity metrics changes on the treated trigeminal nerve at the 3-month time point after GKRS for TN correlated with pain relief at last follow-up. Further, well-designed studies are warranted to establish the clinical application of diffusion tensor imaging as a noninvasive, prognostic tool in patients with TN managed with GKRS.

Stereotactic radiosurgery before bilateral adrenalectomy is associated with lowered risk of Nelson's syndrome in refractory Cushing's disease patients.

BACKGROUND: Nelson's syndrome is a rare but challenging sequelae of Cushing's disease (CD) after bilateral adrenalectomy (BLA). We sought to determine if stereotactic radiosurgery (SRS) of residual pituitary adenoma performed before BLA can decrease the risk of Nelson's syndrome. METHODS: Consecutive patients with CD who underwent BLA after non-curative resection of ACTH secreting pituitary adenoma and had at least one follow-up visit after BLA were studied. Nelson's syndrome was diagnosed based on the combination of rising ACTH levels, increasing volume of the pituitary adenoma and/or hyperpigmentation. RESULTS: Fifty patients underwent BLA for refractory CD, and 43 patients (7 men and 36 women) had at least one follow-up visit after BAL. Median endocrine, imaging, and clinical follow-up were 66 months, 69 months, and 80 months, respectively. Nine patients (22%) were diagnosed with the Nelson's syndrome at median time after BLA at 24 months (range: 0.6-119.4 months). SRS before BLA was associated with reduced risk of the Nelson's syndrome (HR = 0.126; 95%CI [0.022-0.714], p=0.019), while elevated ACTH level within 6 months after BLA was associated with increased risk for the Nelson's syndrome (HR = 9.053; 95%CI [2.076-39.472], p=0.003). CONCLUSIONS: SRS before BLA can reduce the risk for the Nelson's syndrome in refractory CD patients requiring BLA and should be considered before proceeding to BLA. Elevated ACTH concentration within 6 months after BLA is associated with greater risk of the Nelsons' syndrome. When no prior SRS is administered, those with a high ACTH level shortly after BLA may benefit from early SRS.

Quality-of-life trajectories after stereotactic radiosurgery for brain metastases.

OBJECTIVE: Quality of life (QOL) is an important endpoint measure of cancer treatment. The authors' goal was to evaluate QOL trajectories and prognostic value in cancer patients treated with stereotactic radiosurgery (SRS) for brain metastases. METHODS: Patients who underwent Gamma Knife radiosurgery (GKRS) between January 2016 and November 2019 were prospectively evaluated for QOL using the EQ-5D-3L questionnaire before SRS and at follow-up visits. Only patients who had pre-SRS and at least 1 post-SRS QOL assessment were considered. RESULTS: Fifty-four cancer patients underwent 109 GKRS procedures. The first post-SRS visit was at a median of 2.59 months (range 0.13-21.08 months), and the last post-SRS visit was at 14.72 months (range 2.52-45.21 months) after SRS. There was no statistically significant change in the EQ-5D index score (p = 0.539) at the first compared with last post-SRS visit. The proportion of patients reporting some problems on the EQ-5D dimension of self-care increased during the course of follow-up from 9% (pre-SRS visit) to 18% (last post-SRS visit; p = 0.03). The proportion of patients reporting problems on the EQ-5D dimensions of mobility, usual activities, pain/discomfort, and anxiety/depression remained stable during the course of follow-up (p ≥ 0.106). After adjusting for clinical variables, a higher recursive partitioning analysis (RPA) class (i.e., worse prognostic category) was independently associated with greater odds for EQ-5D index score deterioration (p = 0.050). Upfront whole-brain radiation therapy predicted deterioration of the EQ-5D self-care (p = 0.03) and usual activities (p = 0.024) dimensions, while a greater number of lesions predicted deterioration of the EQ-5D anxiety/depression dimension (p = 0.008). A lower pre-SRS EQ-5D index was associated with shorter survival independently from clinical and demographic variables (OR 18.956, 95% CI 2.793-128.64; p = 0.003). CONCLUSIONS: QOL is largely preserved in brain metastasis patients treated with SRS. Higher RPA class, upfront whole-brain radiation therapy, and greater intracranial disease burden are independent predictors of post-SRS QOL deterioration. Worse pre-SRS QOL predicts shorter survival. Assessment of QOL is recommended in brain metastasis patients managed with SRS.

Impact of Integral Dose on the Maintenance of Pain Relief in Patients with Idiopathic Trigeminal Neuralgia Treated with Upfront Gamma Knife Radiosurgery.

BACKGROUND: Integral dose (ID) defined as the product of mean dose and target volume, is a measure of the absorbed radiation energy. OBJECTIVE: To evaluate the effect of ID on the duration of pain relief after primary Gamma knife stereotactic radiosurgery (GKSRS) in trigeminal neuralgia. PATIENTS AND METHODS: A total of 78 patients who achieved initial pain response of I-III on the Barrow Neurological Institute Pain Scale (BNI-PS) following primary GKSRS for idiopathic trigeminal neuralgia were included in this study. A Cox regression model was used to compute the prognostic factor with respect to the ID within the 50% isodose line. Facial pain relief maintenance interval was defined as time interval between the day of improved BNI-PS grade and pain level back to the BNI-PS IV or V. The median duration of follow-up was 42 months (range 6-108 months). RESULTS: After the initial GKSRS, patients achieved pain relief at a median of 0.5 months (range, 7 days to 6 months); 28 patients developed recurrence of pain. There was a positive correlation between the pain relief maintenance and increasing ID within 50% isodose line (hazard ratio 1.85, P = 0.04) on multivariable Cox-regression analysis. Using logistic regression analysis, we found that ID was not predictive of developing post-stereotactic radiosurgery hypoesthesia (P = 0.64, hazard ratio 1.057). CONCLUSIONS: Stereotactic radiosurgery can be individualized based on trigeminal nerve morphology to achieve durable pain relief in patients with trigeminal neuralgia. ID calculation aids in planning an optimal radiation dose based on the nerve morphology to provide durable pain relief of idiopathic trigeminal neuralgia.