Shinya Hayashi

Incidence of Brain Atrophy and Decline in Mini-Mental State Examination Score After Whole-Brain Radiotherapy in Patients With Brain Metastases: A Prospective Study

PURPOSE To determine the incidence of brain atrophy and dementia after whole-brain radiotherapy (WBRT) in patients with brain metastases not undergoing surgery. METHODS AND MATERIALS Eligible patients underwent WBRT to 40 Gy in 20 fractions with or without a 10-Gy boost. Brain magnetic resonance imaging or computed tomography and Mini-Mental State Examination (MMSE) were performed before and soon after radiotherapy, every 3 months for 18 months, and every 6 months thereafter. Brain atrophy was evaluated by change in cerebrospinal fluid-cranial ratio (CCR), and the atrophy index was defined as postradiation CCR divided by preradiation CCR. RESULTS Of 101 patients (median age, 62 years) entering the study, 92 completed WBRT, and 45, 25, and 10 patients were assessable at 6, 12, and 18 months, respectively. Mean atrophy index was 1.24 +/- 0.39 (SD) at 6 months and 1.32 +/- 0.40 at 12 months, and 18% and 28% of the patients had an increase in the atrophy index by 30% or greater, respectively. No apparent decrease in mean MMSE score was observed after WBRT. Individually, MMSE scores decreased by four or more points in 11% at 6 months, 12% at 12 months, and 0% at 18 months. However, about half the decrease in MMSE scores was associated with a decrease in performance status caused by systemic disease progression. CONCLUSIONS Brain atrophy developed in up to 30% of patients, but it was not necessarily accompanied by MMSE score decrease. Dementia after WBRT unaccompanied by tumor recurrence was infrequent.

Impact of [11C]Methionine Positron Emission Tomography for Target Definition of Glioblastoma Multiforme in Radiation Therapy Planning

PURPOSE The purpose of this work was to define the optimal margins for gadolinium-enhanced T(1)-weighted magnetic resonance imaging (Gd-MRI) and T(2)-weighted MRI (T(2)-MRI) for delineating target volumes in planning radiation therapy for postoperative patients with newly diagnosed glioblastoma multiforme (GBM) by comparison to carbon-11-labeled methionine positron emission tomography ([(11)C]MET-PET) findings. METHODS AND MATERIALS Computed tomography (CT), MRI, and [(11)C]MET-PET were separately performed for radiation therapy planning for 32 patients newly diagnosed with GBM within 2 weeks after undergoing surgery. The extent of Gd-MRI (Gd-enhanced clinical target volume [CTV-Gd]) uptake and that of T(2)-MRI of the CTV (CTV-T(2)) were compared with the extent of [(11)C]MET-PET (CTV--[(11)C]MET-PET) uptake by using CT--MRI or CT--[(11)C]MET-PET fusion imaging. We defined CTV-Gd (x mm) and CTV-T(2) (x mm) as the x-mm margins (where x = 0, 2, 5, 10, and 20 mm) outside the CTV-Gd and the CTV-T(2), respectively. We evaluated the relationship between CTV-Gd (x mm) and CTV-- [(11)C]MET-PET and the relationship between CTV-T(2) (x mm) and CTV-- [(11)C]MET-PET. RESULTS The sensitivity of CTV-Gd (20 mm) (86.4%) was significantly higher than that of the other CTV-Gd. The sensitivity of CTV-T(2) (20 mm) (96.4%) was significantly higher than that of the other CTV-T(2) (x = 0, 2, 5, 10 mm). The highest sensitivity and lowest specificity was found with CTV-T(2) (x = 20 mm). CONCLUSIONS It is necessary to use a margin of at least 2 cm for CTV-T(2) for the initial target planning of radiation therapy. However, there is a limit to this setting in defining the optimal margin for Gd-MRI and T(2)-MRI for the precise delineation of target volumes in radiation therapy planning for postoperative patients with GBM.

Clinical comparison of positional accuracy and stability between dedicated versus conventional masks for immobilization in cranial stereotactic radiotherapy using 6-degree-of-freedom image guidance system-integrated platform

PURPOSE To compare the positioning accuracy and stability of two distinct noninvasive immobilization devices, a dedicated (D-) and conventional (C-) mask, and to evaluate the applicability of a 6-degrees-of-freedom (6D) correction, especially to the C-mask, based on our initial experience with cranial stereotactic radiotherapy (SRT) using ExacTrac (ET)/Robotics integrated into the Novalis Tx platform. MATERIALS AND METHODS The D- and C-masks were the BrainLAB frameless mask system and a general thermoplastic mask used for conventional radiotherapy such as whole brain irradiation, respectively. A total of 148 fractions in 71 patients and 125 fractions in 20 patients were analyzed for the D- and C-masks, respectively. For the C-mask, 3D correction was applied to the initial 10 patients, and thereafter, 6D correction was adopted. The 6D residual errors (REs) in the initial setup, after correction (pre-treatment), and during post-treatment were measured and compared. RESULTS The D-mask provided no significant benefit for initial setup. The post-treatment median 3D vector displacements (interquatile range) were 0.38 mm (0.22, 0.60) and 0.74 mm (0.49, 1.04) for the D- and C-masks, respectively (p<0.001). The post-treatment maximal translational REs were within 1 mm and 2 mm for the D- and C-masks, respectively, and notably within 1.5 mm for the C-mask with 6D correction. The pre-treatment 3D vector displacements were significantly correlated with those for post-treatment in both masks. CONCLUSIONS The D-mask confers positional stability acceptable for SRT. For the C-mask, 6D correction is also recommended, and an additional setup margin of 0.5 mm to that for the D-mask would be sufficient. The tolerance levels for the pre-treatment REs should similarly be set as small as possible for both systems.

Palliative external-beam radiotherapy for bone metastases from hepatocellular carcinoma

The incidence of bone metastases (BMs) from hepatocellular carcinoma (HCC) is relatively low compared to those of other cancers, but it has increased recently, especially in Asian countries. Typically, BMs from HCC appear radiologically as osteolytic, destructive, and expansive components with large, bulky soft-tissue masses. These soft-tissue masses are unique to bone metastases from HCC and often replace the normal bone matrix and exhibit expansive growth. They often compress the peripheral nerves, spinal cord, or cranial nerves, causing not only bone pain but also neuropathic pain and neurological symptoms. In patients with spinal BMs, the consequent metastatic spinal cord compression (MSCC) causes paralysis. Skull base metastases (SBMs) with cranial nerve involvement can cause neurological symptoms. Therefore, patients with bony lesions often suffer from pain or neurological symptoms that have a severe, adverse effect on the quality of life. External-beam radiotherapy (EBRT) can effectively relieve bone pain and neurological symptoms caused by BMs. However, EBRT is not yet widely used for the palliative management of BMs from HCC because of the limited number of relevant studies. Furthermore, the optimal dosing schedule remains unclear, despite clinical evidence to support single-fraction radiation schedules for primary cancers. In this review, we outline data describing palliative EBRT for BMs from HCC in the context of (1) bone pain; (2) MSCC; and (3) SBMs.

Impact of respiratory motion on breast tangential radiotherapy using the field-in-field technique compared to irradiation using physical wedges

Abstract Background. This study aimed to evaluate whether the field-in-field (FIF) technique was more vulnerable to the impact of respiratory motion than irradiation using physical wedges (PWs). Patients and methods. Ten patients with early stage breast cancer were enrolled. Computed tomography (CT) was performed during free breathing (FB). After the FB-CT data set acquisition, 2 additional CT scans were obtained during a held breath after light inhalation (IN) and light exhalation (EX). Based on the FB-CT images, 2 different treatment plans were created for the entire breast for each patient and copied to the IN-CT and EX-CT images. The amount of change in the volume of the target receiving 107%, 95%, and 90% of the prescription dose (V107%, V95%, and V90%, respectively), on the IN-plan and EX-plan compared with the FB-plan were evaluated. Results. The V107%, V95%, and V90% were significantly larger for the IN-plan than for the FB-plan in both the FIF technique and PW technique. While the amount of change in the V107% was significantly smaller in the FIF than in the PW plan, the amount of change in the V95% and V90% was significantly larger in the FIF plan. Thus, the increase in the V107% was smaller while the increases in the V95% and V90% were larger in the FIF than in the PW plan. Conclusions. During respiratory motion, the dose parameters stay within acceptable range irrespective of irradiation technique used although the amount of change in dose parameters was smaller with FIF technique.

Dosimetric comparison of 2.5 mm vs. 3.0 mm leaf width micro-multileaf collimator-based treatment systems for intracranial stereotactic radiosurgery using dynamic conformal arcs: implications for treatment planning

PurposeThe objective of our study was to explore any significant dosimetric differences between different leaf width (3.0 mm vs. 2.5 mm) micro-multileaf collimator (mMLC)-based treatment systems for intracranial stereotactic radiosurgery using dynamic conformal arcs (DCAs).Materials and methodsThe systems included a 3 mm leaf width mMLC (m3) mounted on a nondedicated linac, and the Novalis Tx system with an integrated 2.5 mm width mMLC (HD120). Thirty plans for brain metastases were replanned for both systems using a uniform method for target definition and treatment planning for baseline comparison.ResultsThe target coverage values for the 80% isodose surface (IDS) and the D95 values in the HD120 plans were significantly lower than those for the m3 plans. The ratios of lower isodose volumes to the target for the HD120 were smaller than those for the m3. When a 1 mm leaf margin was added to the HD120 plans, these differences were reversed, but statistically significant differences were still observed.ConclusionSignificant dosimetric differences were observed between these systems. Different planning methods are required for the two systems to attain similar target coverage values with selected IDS, which can be achieved by adjusting the leaf margin with 0.1 mm increments or isocenter dose settings.

Pretreatment maximum standardized uptake value on 18F-fluorodeoxyglucose positron emission tomography is a predictor of outcome for stage I non-small cell lung cancer after stereotactic body radiotherapy

Stereotactic body radiotherapy (SBRT) is commonly considered an important treatment option for patients with stage I non‐small cell lung cancer (NSCLC) who have contraindications for surgery or refuse surgery. Many studies have reported that the maximum standardized uptake value (SUVmax) on 18F‐fluorodeoxyglucose positron emission tomography (FDG‐PET) of the primary tumor has prognostic value for resected NSCLC. The purpose of this study was to determine whether SUVmax is a predictor of disease‐free survival (DFS) in patients with stage I NSCLC after SBRT.

Imaging characteristics of local recurrences after stereotactic body radiation therapy for stage I non-small cell lung cancer: Evaluation of mass-like fibrosis.

This study aimed to evaluate stereotactic body radiation therapy (SBRT) in patients with stage I non‐small cell lung cancer (NSCLC) in terms of radiation‐induced changes and computed tomography (CT) features of local recurrence by 18F‐fluorodeoxyglucose positron emission tomography (18F‐FDG‐PET).

Comparison of urethral diameters for calculating the urethral dose after permanent prostate brachytherapy.

PurposeNo studies have yet evaluated the effects of a dosimetric analysis for different urethral volumes. We therefore evaluated the effects of a dosimetric analysis to determine the different urethral volumes.MethodsThis study was based on computed tomography/magnetic resonance imaging (CT/MRI) combined findings in 30 patients who had undergone prostate brachytherapy. Postimplant CT/MRI scans were performed 30 days after the implant. The urethra was contoured based on its diameter (8, 6, 4, 2, and 0 mm). The total urethral volume—in cubic centimeters [UrV150/200(cc)] and percent (UrV150%/200%), of the urethra receiving 150% or 200% of the prescribed dose—and the doses (UrD90/30/5) in Grays to 90%, 30%, and 5% of the urethral volume were measured based on the urethral diameters.ResultsThe UrV150(cc) and UrD30 were statistically different between the of 8-, 6-, 4-, 2-, and 0-mm diameters, whereas the UrD5 was statistically different only between the 8-, 6-, and 4-mm diameters. Especially for UrD5, there was an approximately 40-Gy difference between the mean values for the 8- and 0-mm diameters.ConclusionWe recommend that the urethra should be contoured as a 4- to 6-mm diameter circle or one side of a triangle of 5–7 mm. By standardizing the urethral diameter, the urethral dose will be less affected by the total urethral volume.

A phase II study of nab-paclitaxel plus carboplatin in combination with thoracic radiation in patients with locally advanced non–small-cell lung cancer

We investigated the efficacy and safety of albumin-bound paclitaxel (nab-PTX) and carboplatin (CBDCA) with concurrent radiotherapy for unresectable locally advanced non–small-cell lung cancer (NSCLC). Patients with Stage III NSCLC and an Eastern Cooperative Oncology Group performance status of 0 or 1 were eligible. Concurrent chemoradiotherapy consisted of weekly administration of nab-PTX (40 mg/m2) plus CBDCA (area under the plasma concentration time curve (AUC) 2) and thoracic radiotherapy (60 Gy/30 fractions) for a total of 6 weeks. After concurrent chemoradiotherapy, patients received an additional two cycles of consolidation phase chemotherapy that consisted of 4-week cycles of nab-PTX (100 mg/m2 on Days 1, 8 and 15)/CBDCA (AUC 5 mg/ml/min on Day 1). Response was evaluated in accordance with the Response Evaluation Criteria in Solid Tumors. Progression-free survival and overall survival were estimated using the Kaplan–Meier method. Toxicity was graded using the National Cancer Institute Common Terminology Criteria for Adverse Events. A total of 10 patients were enrolled in this trial between September 2013 and January 2014 from three institutes. The overall response rate was 40.0% and the median progression-free survival was 6.7 months. Treatment-related death occurred in two patients. Grade 2 or worse severe radiation pneumonitis was observed in all three patients that had the volume of lung receiving at least 20 Gy (V20) >30%. The results of this study indicate that no further investigation is warranted into nab-PTX and CBDCA with concurrent thoracic radiation for Stage III NSCLC with V20 > 30% due to severe toxicity.