Worldwide Access to Stereotactic Radiosurgery.

Stereotactic radiosurgery is a safe and effective technology that can address a variety of neurosurgical conditions, but in many parts of the world, access remains an issue. Although the technology is increasingly available in the United States, Canada, Europe, and parts of Asia, poor access to central nervous system (CNS) imaging and inadequate treatment equipment in other parts of the world limit the availability of radiosurgery as a treatment option. In addition, epidemiologic data about cancer and CNS metastases in low-income countries are sparse and much less complete than in more developed countries, and the need for radiosurgery may be underestimated as a result. Current radiosurgical platforms can be expensive to install and require a substantial amount of personnel training for safe operation. Socioeconomic and political forces are relevant to limitations to and opportunities for improving access to care. Here we examine the current barriers to access and propose areas for future efforts to improve global availability of radiosurgery for neurosurgical conditions.

An overview of anti-epileptic therapy management of patients with malignant tumors of the brain undergoing radiation therapy.

As our surgical, radiation, chemotherapeutic and supportive therapies for brain malignancies improve, and overall survival is prolonged, appropriate symptom management in this patient population becomes increasingly important. This review summarizes the published literature and current practice patterns regarding prophylactic and perioperative anti-epileptic drug use. As a wide range of anti-epileptic drugs is now available to providers, evidence guiding appropriate anticonvulsant choice is reviewed. A particular focus of this article is radiation therapy for brain malignancies. Toxicities and seizure risk associated with cranial irradiation will be discussed. Epilepsy management in patients undergoing radiation for gliomas, glioblastoma multiforme, and brain metastases will be addressed. An emerging but inconsistent body of evidence, reviewed here, indicates that anti-epileptic medications may increase radiosensitivity, and therefore improve clinical outcomes, specifically in glioblastoma multiforme patients.

Predictors of acute toxicities during definitive chemoradiation using intensity-modulated radiotherapy for anal squamous cell carcinoma.

PURPOSE: To identify clinical and dosimetric factors associated with acute hematologic and gastrointestinal (GI) toxicities during definitive therapy using intensity-modulated radiotherapy (IMRT) for anal squamous cell carcinoma (ASCC). MATERIALS AND METHODS: We retrospectively analyzed 108 ASCC patients treated with IMRT. Clinical information included age, gender, stage, concurrent chemotherapy, mitomycin (MMC) chemotherapy and weekly hematologic and GI toxicity during IMRT. From contours of the bony pelvis and bowel, dose-volume parameters were extracted. Logistic regression models were used to test associations between toxicities and clinical or dosimetric predictors. RESULTS: The median age was 59 years, 81 patients were women and 84 patients received concurrent MMC and 5-fluorouracil (5FU). On multivariate analysis (MVA), the model most predictive of Grade 2 + anemia included the maximum bony pelvis dose (Dmax), female gender, and T stage [p = 0.035, cross validation area under the curve (cvAUC) = 0.66]. The strongest model of Grade 2 + leukopenia included V10 (percentage of pelvic bone volume receiving ≥ 10 Gy) and number of MMC cycles (p = 0.276, cvAUC = 0.57). The model including MMC cycle number and T stage correlated best with Grade 2 + neutropenia (p = 0.306, cvAUC = 0.57). The model predictive of combined Grade 2 + hematologic toxicity (HT) included V10 and T stage (p = 0.016, cvAUC = 0.66). A model including VA45 (absolute bowel volume receiving ≥ 45 Gy) and MOH5 (mean dose to hottest 5% of bowel volume) best predicted diarrhea (p = 0.517, cvAUC = 0.56). CONCLUSION: Dosimetric constraints to the pelvic bones should be integrated into IMRT planning to reduce toxicity, potentially reducing treatment interruptions and improving disease outcomes in ASCC. Specifically, our results indicate that Dmax should be confined to ≤ 57 Gy to minimize anemia and that V10 should be restricted to ≤ 87% to reduce incidence of all HT.