To investigate the outcome of linac-based fractionated stereotactic radiotherapy over the last 10 years for intracranial skull base benign meningiomas in patients who were inoperable, who had residual tumors with some components of high mitotic index after surgery and who experienced relapse of the tumor. Twenty-seven patients with intracranial skull base benign meningiomas treated with fractionated stereotactic radiotherapy were retrospectively reviewed. Twenty-seven cases were diagnosed as benign meningiomas on pathological (17 cases) or radiological (10 cases) examination. The median follow-up time was 90 months after initial treatment and 63 months after fractionated stereotactic radiotherapy. The median biological equivalent dose calculated using an α/β ratio of 2.0 Gy was 82.0 Gy (range, 60–106 Gy). The 5-year overall survival was 95.7 (95% confidence interval: 87.3–100)% after initial treatment and 96.2 (88.8–100)% after fractionated stereotactic radiotherapy. The 5-year overall survival and local control rate of patients who received fractionated stereotactic radiotherapy alone were both 100%. The 5-year progression-free survival and local control rate after fractionated stereotactic radiotherapy were all 100% with a tumor volume of <9.1 cc and 68.2 (37.2–99.2) and 75.8 (45.2–100)% for the tumors 9.1 cc, respectively. The difference was significant in progression-free survival (P = 0.022) and local control rate (P = 0.044). The local control rate was significantly worse in patients who received fractionated stereotactic radiotherapy for relapsed tumors (P = 0.01). No late radiation damage was observed in the follow-up period. The long-term outcome suggests that fractionated stereotactic radiotherapy is a safe and effective treatment for intracranial skull base benign meningioma, especially for those who have tumors <9.1 cc or would receive fractionated stereotactic radiotherapy with or without surgery as the initial treatment.

Background: In-room cone-beam computerized tomography (CBCT) imaging is a promising method to reduce setup errors, especially in organs such as the bladder that often have large intrafractional variations due to organ movement. CBCT image quality is limited by low contrast and imaging artifacts, but few data have been reported about inter-observer variability of bladder boundary delineation on CBCT. The aim of this work was to analyze and evaluate the inter-observer contouring uncertainties of bladder boundary delineation on CBCT images in a prospective fashion. Methods: Five radiation oncologists contoured 10 bladders using the CBCT datasets of consecutive 10 patients (including 4 females) who were irradiated to the pelvic region. Prostates were also contoured in male patients. Patients who had had prostatectomy were excluded. The coefficient of variation (COV), conformity index (CI_gen), and coordinates of center-of-mass (COM) of the bladder and prostate were calculated for each patient. Results: The mean COV for the bladder and prostate was 0.08 and 0.20, respectively. The mean CI_gen of the bladder and prostate was 0.81 and 0.66, respectively. The root mean square (RMS) of the inter-observer standard deviation (σ) of the COM displacement in the left-right (LR) and anterior-posterior (AP) direction was 0.79, 0.87 and 0.54 for the bladder and 0.63, 0.99 and 1.72 for the prostate. Regarding the mean COV and CI_gen for the bladder, the differences between males and females were not significant. Conclusions: Inter-observer variability for bladder delineation on CBCT images was substantially small regardless of gender. We believe that our results support the applicability of CBCT in adaptive radiotherapy for bladder cancer.

Olfactory neuroblastoma (ONB) is a rare tumor originating from olfactory epithelium. Here we retrospectively analyzed the long-term treatment outcomes and toxicity of radiotherapy for ONB patients for whom computed tomography (CT) and three-dimensional treatment planning was conducted to reappraise the role of radiotherapy in the light of recent advanced technology and chemotherapy. Seventeen patients with ONB treated between July 1992 and June 2013 were included. Three patients were Kadish stage B and 14 were stage C. All patients were treated with radiotherapy with or without surgery or chemotherapy. The radiation dose was distributed from 50 Gy to 66 Gy except for one patient who received 40 Gy preoperatively. The median follow-up time was 95 months (range 8–173 months). The 5-year overall survival (OS) and relapse-free survival (RFS) rates were estimated at 88% and 74%, respectively. Five patients with stage C disease had recurrence with the median time to recurrence of 59 months (range 7–115 months). Late adverse events equal to or above Grade 2 in CTCAE v4.03 were observed in three patients. Multimodal therapy including radiotherapy with precise treatment planning based on CT simulation achieved an excellent local control rate with acceptable toxicity and reasonable overall survival for patients with ONB.

Background: Radiotherapy for brain tumors can induce cognitive decline, yet most studies examine white matter (WM) damage six months post-treatment, overlooking early microstructural changes. This study investigated whether early WM changes, as measured by diffusion tensor imaging (DTI) histogram and texture features, can predict later cognitive deficits. Methods: Nineteen adults with brain metastases underwent DTI before and immediately after radiotherapy. Ten features—eight histogram-based and two texture-based—were extracted from normal-appearing WM of major DTI indices. Changes (Δ) in these features, if any, were analyzed via multiple linear regression, correlating them with cognitive performance at four months after therapy. Results: Out of 40 features, four exhibited significant post-radiotherapy changes. These were the mean (AD_mean) and skewness (AD_skewness) of axial diffusivity and the kurtosis of mean diffusivity (MD_kurtosis) and radial diffusivity (RD_kurtosis). Regression identified ΔAD_mean (β = −3.303 × 10⁴, p = 0.002) as negatively and ΔAD_skewness (β = 4.642, p = 0.006) and ΔRD_kurtosis (β = −1.505, p = 0.027) as positively associated with semantic fluency. Conclusions: Early WM microstructural disruptions—particularly axonal damage and heterogeneous injury—correlate with declines in semantic fluency. DTI histogram and texture features may be promising as early non-invasive biomarkers for cognitive risk following radiotherapy.