A case report on a novel use of intraoperative Intrabeam™ radiation therapy for a recurrent malignant peripheral nerve sheath tumor with sciatic nerve involvement.

BACKGROUND: Malignant peripheral nerve sheath tumors (MPNST) are sarcomas that arise from peripheral nerves. They generally have a poor prognosis which is exacerbated by high local recurrence rates. This case report discusses the treatment of a patient with a MPNST with local recurrence. This case report is novel due to the use of intraoperative Intrabeam™ (Zeiss, Dublin, CA) radiation therapy use in the protection of neurovascular structures such as the sciatic nerve. CASE PRESENTATION: The patient was a 65-year-old male who noticed a right posterior thigh mass slowly increasing in size over two months. A planned positive margin wide-resection excision was performed due to sciatic nerve abutment. The mass was determined to be a MPNST via postoperative pathology with positive margins along the sciatic nerve. The patient began adjuvant radiation therapy to the upper and lower thigh fields over a period of three months. Thirty-two months later, the patient was found to have a hypermetabolic mass with venous congestion and hyperemia at the prior surgical site which was confirmed by core needle biopsy to be local recurrence of the MPNST. Re-excision of the tumor was planned and performed followed by intraoperative Intrabeam™ radiation therapy. At two years of follow-up, the patient was doing well with minimal pain in his right buttock region with no new or recurrent neurological deficits. Radiologic imaging was negative for local recurrence of the MPNST. CONCLUSION: We believe this case report demonstrates a novel treatment strategy for sarcoma management. The unique use of intraoperative Intrabeam™ radiation therapy, which had not previously been used for this indication, may be efficacious in cases involving neurovascular structures. In this case, focal radiation from the intraoperative Intrabeam™ radiation device was used in a way to affect the recurrent tumor yet protect the sciatic nerve.

Gamma Knife Radiosurgery for Arteriovenous Malformations Using a Four-Dimensional Dynamic Volume Computed Tomography Angiography Planning System as an Alternative to Traditional Catheter Angiogram.

Background Gamma knife radiosurgery (GKRS) remains a critical intervention in the long-term management of arteriovenous malformations (AVMs). For planning a treatment, identification of the nidus is essential, and it is dependent on high-resolution blood flow imaging, usually in the form of a traditional angiogram. The development of dynamic 320-slice computed tomography (CT) angiography has offered a noninvasive alternative to intra-arterial fluoroscopic imaging, and it is capable of providing equivalent temporal resolution. In this study, we describe the feasibility of using four-dimensional CT angiography (4D-CTA) in GKRS planning for AVM treatment and a comparative analysis with a traditional angiogram. Methods A retrospective review was performed on AVM patients treated via GKRS with a 4D-CTA prior to the day of treatment, on the day of treatment, or with a day-of-treatment angiogram. Treatment times, along with total times in the Leksell® coordinate frame G, were obtained from the medical records. The frame-on time was calculated by subtracting the treatment time from the total time starting from application to removal, and the statistical analysis was performed across groups using analysis of variance (ANOVA). All treatments were performed on the Perfexion™ model with a dynamic flow imaging procured via a 320-slice CT scanner or traditional angiography platform. Results Some 27 patients underwent a total of 29 GKRS procedures for AVM treatment at our institution between September 2011 and January 2017. Mean age at the time of treatment was 35.5 (6-65) years, and male:female ratio was 5:4. Some 12 patients had 4D-CTA performed prior to the day of treatment, eight patients had the same CTA completed after frame placement on the day of treatment, while seven patients underwent traditional angiography. The mean frame-on times of each group were 190, 336, and 426 minutes, respectively (p < 0.0001). No procedures were aborted based on the image quality. Conclusions 4D-CTA is an effective tool in identifying the AVM nidus for GKRS planning. These studies can be performed prior to the day of treatment, allowing for a significant reduction in frame-on time and eliminating the risk of angiogram complication on the day of GKRS.

A multispecialty pediatric neurovascular conference: a model for interdisciplinary management of complex disease.

INTRODUCTION: In 2013, our institution established a multidisciplinary pediatric neurovascular conference for coordination of care. Here, we review our initial experience. METHODS: Clinical and demographic data were obtained from medical records for patients presented to the pediatric neurovascular conference from April 2013 to July 2014. Patient descriptive characteristics were described by mean and standard deviation for continuous measures and by number and percent for categorical measures. Patients were secondarily stratified by lesion/disease type, and descriptive statistics were used to measure demographic and clinical variables. RESULTS: The pediatric neurovascular conference met 26 times in the study period. Overall, 75 children were presented to the conference over a 15-month period. The mean age was 9.8 (standard deviation, 6.3) years. There were 42 (56%) male patients. These 75 children were presented a total of 112 times. There were 28 (37%) patients with history of stroke. Complex vascular lesions were the most frequently discussed entity; of 62 children (83%) with a diagnosed vascular lesion, brain arteriovenous malformation (29%), cavernous malformation (15%), and moyamoya (11%) were most common. Most discussions were for review of imaging (35%), treatment plan formulation (27%), the need for additional imaging (25%), or diagnosis (13%). Standardized care protocols for arteriovenous malformation and moyamoya were developed. CONCLUSION: A multidisciplinary conference among a diverse group of providers guides complex care decisions, helps standardize care protocols, promotes provider collaboration, and supports continuity of care in pediatric neurovascular disease.

Survival benefit for early hormone ablation in biochemically recurrent prostate cancer.

PURPOSE: To determine whether early initiation of androgen ablation in patients with biochemically recurrent prostate cancer, but without clinically evident metastases, is associated with improved overall or disease-specific survival. To describe subgroups, based on PSA kinetics, which are most likely to benefit from early androgen ablation. MATERIALS AND METHODS: A retrospective cohort of 124 patients, who were definitively treated by external beam radiotherapy between 1988 and 1999, and subsequently received androgen ablation for biochemical (92 patients) or clinically metastatic (32 patients) failure, was reviewed. Median follow-up time was 6.2 years. Overall survival, disease-specific survival, and hormonal control were examined and compared for patients whose hormone ablation was started early (prostate-specific antigen [PSA] 7 months) or late in the course of their biochemical failure. RESULTS: All patients had biochemical response to hormone initiation, with a median PSA nadir of 0.05 ng/ml. Early initiation of hormone ablation resulted in statistically significant improvement in all outcome measures. Multivariate analysis indicated that PSA doubling time at hormone initiation was the most consistent predictor of outcome. The 5-year overall survival was 78% for patients whose androgen ablation was initiated at doubling time 7 months. Mean survival improved from 84.9 +/- 4.6 (doubling time 7). Survival for patients started on hormones with doubling time <5 months was similar to that of patients with clinical metastases. CONCLUSIONS: This survival benefit justifies the use of androgen ablation in patients whose doubling time approaches 7 months. A randomized trial is needed to confirm these findings, investigate potential benefit for patients with longer doubling times, and gather data on the morbidity of early hormone ablation, including quality of life issues.

MammoSite and interstitial brachytherapy for accelerated partial breast irradiation: factors that affect toxicity and cosmesis.

BACKGROUND: In interstitial brachytherapy (IB), cosmesis and toxicity correlate with volume of tissue irradiated, dose homogeneity index (DHI), and adjuvant doxorubicin/cyclophosphamide based chemotherapy (ACCT). MammoSite brachytherapy (MSB) irradiates smaller volumes than IB, and lower dose homogeneity does not appear to affect toxicity. However, clinical experience suggests that other factors may also play an important role in cosmesis and toxicity with MSB. We reviewed our prospectively maintained data base of women who underwent accelerated partial breast irradiation (APBI) to assess this issue. METHODS: Beginning in September 1995, 115 women were enrolled in a trial evaluating APBI as monotherapy after lumpectomy. The first 75 eligible patients received IB, and the most recent 28 eligible patients received MSB. All patients received 34 gray (Gy) in 10 twice-daily fractions through high-dose rate iridium-192 brachytherapy; 19% of patients in the IB group and 0% of patients in the MSB group received ACCT. RESULTS: At 1 year after treatment, MSB caused significantly less Grade 2-4 subcutaneous fibrosis (as graded by a radiation oncologist according to the Radiation Therapy Oncology Group/Eastern Cooperative Oncology Group system) compared with IB (10.7% vs. 32%; P = 0.04). However, when only ACCT-naïve patients in the IB group were compared with patients in the MSB group, this finding became nonsignificant. Among the patients who received MSB, significantly smaller volumes were irradiated, and the DHI was lower. CONCLUSIONS: Current studies suggest an improved toxicity profile with MSB compared with IB that is attributed to lower irradiated volumes with MSB. When only chemotherapy-naïve patients were compared, however, toxicity and cosmesis were found to be similar between MSB and IB, suggesting a more complex interplay between irradiated volumes, DHI, and chemotherapy. The relation of ACCT to toxicity in this scenario is intriguing and warrants further investigation.