Proton versus photon craniospinal irradiation for adult medulloblastoma: A dosimetric, toxicity, and exploratory cost analysis.

Background: This study aimed to determine whether proton craniospinal irradiation (CSI) decreased the dose to normal tissue and resulted in less toxicity than photon CSI for adult patients. Methods: This single-institution retrospective analyzed differences in radiation doses, acute toxicity, and cost between proton and CSI for adult medulloblastoma patients. Results: Of 39 total patients, 20 were treated with photon CSI prior to 2015, and 19 were treated with proton CSI thereafter. Median age was 28 years (range 18-66). The molecular subtype was most commonly sonic hedgehog (68%). Patients most commonly received 36 Gy CSI in 20 fractions with a boost to 54-55.8 Gy (92%). Proton CSI delivered significantly lower mean doses to cochleae, lacrimal glands, lens, parotid glands, pharyngeal constrictors, esophagus, lungs, liver, and skin (all P < .001). Patients receiving proton CSI had significantly lower rates of acute dysphagia of any grade (5% versus 35%, P = .044) and decreased median weight loss during radiation (+1.0 versus -2.8 kg, P = .011). Weight loss was associated with acute hospitalization (P = .009). Median follow-up was 2.9 and 12.9 years for proton and photon patients, respectively, limiting late toxicity and outcome comparisons. At the last follow-up, 5 photon patients had died (2 of progressive disease, 3 without recurrence ages 41-63) and 21% had experienced major cardiovascular events. At 10 years, 89% were alive and 82% were recurrence free. Conclusions: This study demonstrates dosimetric improvements with proton CSI, potentially leading to decreased acute toxicity including dysphagia and weight loss during treatment.

Insurance correlates with improved access to care and outcome among glioblastoma patients.

Background: The current standard of care for glioblastoma (GBM) constitutes maximal safe surgical resection, followed by fractionated radiation and temozolomide. This treatment regimen is logistically burdensome, and in a health care system in which access to care is variable, there may be patients with worsened outcomes due to inadequate access to optimal treatment. Methods: The National Cancer Database was queried for patients with diagnoses of GBM in 2006-2014. Patients were grouped according to insurance status: private insurance, Medicare, Medicaid, or uninsured. Treatments provided (surgery, radiation, and chemotherapy) were compared between groups in univariate and multivariable logistic regression analysis. Results: A total of 61614 patients were analyzed. Compared with private insurance, the odds of surgery for Medicaid and uninsured patients were 0.72 (95% CI: 0.66-0.79) and 0.77 (95% CI: 0.69-0.87), respectively (P < 0.001). The multivariable odds of receiving radiotherapy were 0.91 (95% CI: 0.86-0.96), 0.62 (95% CI: 0.57-0.68), and 0.47 (95% CI: 0.43-0.52) for Medicare, Medicaid, and uninsured patients, respectively (all P < 0.001). In addition, the odds of receiving chemotherapy were 0.94 (95% CI: 0.89-0.99), 0.53 (95% CI: 0.49-0.57), and 0.41 (95% CI: 0.38-0.46) for Medicare, Medicaid, and uninsured patients, respectively (all P < 0.001). Conclusion: Insurance status and type of insurance coverage appear to impact treatments rendered for GBM, independently of other variables. Furthermore, we find that such differential access to care significantly impacts survival. Ensuring adequate access to care for all patients with diagnoses of glioblastoma is critical to optimize survival, especially as therapies continue to advance.

Detection of neuronal loss using T(1rho) MRI assessment of (1)H(2)O spin dynamics in the aphakia mouse.

The loss of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNc) is well characterized in Parkinson's disease (PD). Recent developments in magnetic resonance imaging (MRI) techniques have provided the opportunity to evaluate for changes in cellular density. Longitudinal relaxation measurements in the rotating frame (T(1rho)) provide a unique magnetic resonance imaging contrast in vivo. Due to the specificity of T(1rho) to water-protein interactions, the T(1rho) MRI method has strong potential to be used as a non-invasive method for quantification of neuronal density in the brain. Recently introduced adiabatic T(1rho) magnetic resonance imaging mapping methods provide a tool to assess molecular motional regimes with high sensitivity due to utilization of an effective magnetic field sweep during adiabatic pulses. In this work, to investigate the sensitivity of T(1rho) to alterations in neuronal density, adiabatic T(1rho) MRI measurements were employed in vivo on Pitx3-homeobox gene-deficient aphakia mice in which the deficit of DA neurons in the SNc is well established. The theoretical analysis of T(1rho) maps in the different areas of the brain of aphakia mouse suggested variation of the (1)H(2)O rotational correlation times, tau(c). This suggests tau(c) to be a sensitive indicator for neuronal loss during neurological disorders. The results manifest significant dependencies of the T(1rho) relaxations on the cell densities in the SNc, suggesting T(1rho) MRI method as a candidate for detection of neuronal loss in neurological disorders.