Results of Definitive (Chemo)radiotherapy Using Computed Tomography-based Brachytherapy for Cervical Cancer.

Background/aim: Concurrent cisplatin-based chemoradiotherapy (CCRT) is the standard treatment for locally advanced cervical cancer. Especially, CCRT with magnetic resonance imaging (MRI) or computed tomography-based image-guided brachytherapy (CT-based 3D-IGBT) for cervical cancer has resulted in good LC rates. However, progression-free survival (PFS) and overall survival (OS) rates for locally advanced cervical cancer are still low and could be improved.

Learning curve of lung dose optimization in intensity-modulated radiotherapy for locally advanced non-small cell lung cancer.

Background: Intensity-modulated radiotherapy (IMRT) has been increasingly used for patients with locally advanced non-small cell lung cancer (LA-NSCLC). However, there are some barriers to implementing IMRT for LA-NSCLC, including the complexity of treatment plan optimization. This study aimed to evaluate the learning curve of lung dose optimization in IMRT for LA-NSCLC and identify the factors that affect the degree of achievement of lung dose optimization.

Optimal Number of Needle Applicators Inserted in Combined Intracavitary and Interstitial Brachytherapy for Cervical Cancer.

Background/aim: Combined intracavitary and interstitial brachytherapy (IC/IS-BT) is an effective treatment for extensive and bulky cervical cancer. However, the optimum number of interstitial needle applicators ("needles") inserted in IC/IS-BT can be difficult to determine. To examine the number of needles required for adequate dose coverage of cervical tumors, we retrospectively analyzed IC/IS-BT plans.

Safety and Efficacy of Palliative Radiotherapy (25 Gy × 5 Fractions) for Symptomatic Pelvic Tumors.

Background/aim: Palliative radiotherapy is one of the effective treatments for pelvic tumors with bleeding or pain. In this study, we evaluated the safety and efficacy of palliative radiotherapy (RT) for symptomatic pelvic tumors when delivered as 25 Gy in 5 fractions.

Patients And Methods: We retrospectively analyzed 34 patients (gynecological cancer: n=14, rectal cancer: n=5, metastatic pelvic bone tumor: n=7, metastatic pelvic lymph node tumor: n=5, synovial sarcoma of the pelvis: n=1, prostate cancer: n=1, and urothelial cancer: n=1), who were treated between July 2016 and July 2021.

Simple method for evaluating achievement degree of lung dose optimization in individual patients with locally advanced non-small cell lung cancer treated with intensity modulated radiotherapy.

Background: In this study, we developed a simple method for evaluating achievement degree of lung dose optimization in individual patients with locally advanced non-small cell lung cancer (NSCLC) treated with intensity modulated radiotherapy (IMRT).

Methods: Data of 28 patients with stage IIB to IIIC NSCLC were retrospectively analyzed. All patients were treated with IMRT and a simulated three-dimensional conformal radiotherapy (3D-CRT) plan created for them.

Results of computer tomography-based adaptive brachytherapy in combination with whole-pelvic- and central-shielding-external beam radiotherapy for cervical cancer.

Purpose: To evaluate treatment results and investigate predictors of local control.

Methods And Materials: In this retrospective study of 236 patients with cervical cancer, we administered CT-based adaptive brachytherapy (BT) in combination with whole- pelvic (WP)- and central shielding (CS)- external beam radiotherapy (EBRT) with or without chemotherapy. The study cohort comprised patients with cervical cancer treated with definitive radiotherapy (RT) or concurrent chemoradiotherapy between June 2013 and March 2019.

High-dose stereotactic body radiotherapy using CyberKnife® for stage I peripheral lung cancer: a single-center retrospective study.

Background: This retrospective study was performed to evaluate the efficacy and toxicity of high-dose stereotactic body radiotherapy (SBRT) using a CyberKnife® for patients with stage I peripheral non-small cell lung cancer (NSCLC).

Methods: Ninety-six patients with stage I peripheral NSCLC who were treated with SBRT using a CyberKnife® from August 2010 to June 2019 were identified and included in this study. Local control (LC), local progression-free survival (LPFS), progression-free survival (PFS), overall survival (OS), and late toxicity were evaluated.

A 54 Gy in three fractions of stereotactic body radiotherapy using CyberKnife for T1b-2aN0M0 pathologically confirmed non-small cell lung cancer.

Objective: Optimal dose-fractionation regimen of stereotactic body radiotherapy for peripheral early-stage non-small cell lung cancer remains unclear. We retrospectively investigated outcomes of stereotactic body radiotherapy using CyberKnife at 54 Gy in three fractions in 26 patients (median age: 76 years) with pathologically confirmed T1b-T2aN0M0 non-small cell lung cancer.

Methods: A 54 Gy in three fractions was prescribed to cover the 99% of gross tumor volume.

Feasibility of intensity modulated radiotherapy with involved field radiotherapy for Japanese patients with locally advanced non-small cell lung cancer.

The feasibility of intensity modulated radiotherapy (IMRT) with involved field radiotherapy (IFRT) for Japanese patients with locally advanced non-small cell lung cancer (LA-NSCLC) remains unclear. Here we reviewed our initial experience of IMRT with IFRT for Japanese patients with LA-NSCLC to evaluate the feasibility of the treatment. Twenty LA-NSCLC patients who were treated with IMRT with IFRT during November 2019 to October 2020 were retrospectively analyzed.

Time Dependence of Intra-fractional Motion in Spinal Stereotactic Body Radiotherapy.

Background/aim: Positional uncertainty in spinal stereotactic body radiotherapy (SBRT) may cause fatal error, therefore, we investigated the intra-fractional spinal motion during SBRT and its time dependency.

Patients And Methods: Thirty-one patients who received SBRT using CyberKnife were enrolled in the study. 2D kV X-ray spine images in two directions were taken before and during treatment.

Incidence and risk factors for pneumonitis among patients with lung cancer who received immune checkpoint inhibitors after palliative thoracic radiotherapy.

The aim of this study is to analyze the incidence and risk factors for pneumonitis when immune checkpoint inhibitors (ICIs) are combined with palliative thoracic radiotherapy (RT) for lung cancer. We retrospectively evaluated 29 patients with lung cancer who received ICIs after palliative thoracic RT (30 Gy in 10 fractions). Their ICIs were pembrolizumab (n = 17), nivolumab (n = 8) and atezolizumab (n = 4).

Effect of durvalumab on local control after concurrent chemoradiotherapy for locally advanced non-small cell lung cancer in comparison with chemoradiotherapy alone.

Background: Durvalumab after concurrent chemoradiotherapy (CCRT) for locally advanced non-small cell lung cancer (LA-NSCLC) has been found to significantly improve overall survival (OS). However, the effect of durvalumab on local control remains unclear. Here, we evaluated the effect of the durvalumab on local control in comparison with the clinical result of patients treated with CCRT alone.

Results of definitive radiotherapy with concurrent chemotherapy for maxillary sinus carcinomas with neck lymph node metastasis.

The purpose of this study was to describe the results of definitive radiotherapy (RT) with concurrent chemotherapy for maxillary sinus carcinomas (MSCs) with neck lymph node metastasis to clarify its limitation. Local control (LC), progression-free survival (PFS) and overall survival (OS) rates were calculated using the Kaplan-Meier method and were compared between subgroups using the log rank test. Toxicity was classified using common terminology criteria of adverse events version 5.

Plan-Optimization Method for Central-shielding Pelvic Volumetric-modulated Arc Therapy for Cervical Cancer.

Aim: To establish a method of plan optimization in pelvic volumetric-modulated arc therapy (VMAT) for cervical cancer using the central-shielding (CS) principle.

Patients And Methods: We created external beam VMAT plans for eight cases with non-bulky stage I-IIb using the CS principle based on the Japanese standard guideline. Clinical target volumes (CTVs) for whole-pelvis (WP) irradiation were created using published guidelines, and CTVs for CS irradiation were created by subtracting the uterus corpus and 4 cm-wide regions centered at the cervix and vagina from the CTVs for WP irradiation.

Development of an HDR-BT QA tool for source position verification.

Purpose: This study aimed to develop a high-dose-rate brachytherapy (HDR-BT) quality assurance (QA) tool for verification of source positions, and to report on its effectiveness.

Methods: We fabricated a cuboid phantom measuring 30 × 30×3 cm with spaces to embed Fletcher-Williamson tandem and ovoid applicators. Lead-based, cylindrically shaped radiopaque markers, which scatter radiation and blacken the Gafchromic RTQA2 films placed on the applicators, were inserted into the phantom to determine the applicator tip and reference source positions.

Stereotactic body radiation therapy using CyberKnife for T1N0M0 lung cancer patients with severe pulmonary dysfunction.

We retrospectively investigated the efficacy and safety of stereotactic body radiotherapy (SBRT) for T1N0M0 lung cancer using CyberKnife (CK) among 13 patients with severe pulmonary dysfunction which was defined as forced expiratory volume in 1 s (FEV1.0) of <1 L. The prescribed dose was 54 Gy in 3 fractions but adjusted for some patients if their tumors were in close proximity to the organs at risk (54 Gy/3 fractions: n = 11; 50 Gy/5 fractions: n = 1; 60 Gy/8 fractions: n = 1).

Stereotactic Body Radiotherapy for Pulmonary Oligometastasis from Colorectal Cancer.

Background/aim: A retrospective study was conducted to evaluate the safety and efficacy of stereotactic body radiotherapy (SBRT) for pulmonary oligometastasis from colorectal cancer (CRC).

Patients And Methods: Patients with pulmonary oligometastasis from CRC who were treated with SBRT between April 2010 and October 2018 were enrolled in this study. All patients underwent SBRT using Cyberknife® with a dose of 54-60 Gy in 3 fractions to 99% of the clinical target volume.

Estimation of the cable effect in megavoltage photon beam by measurement and Monte Carlo simulation.

Purpose: Ionization chambers are widely used for dosimetry with megavoltage photon beams. Several properties of ionization chambers, including the cable effect, polarity effect, and ion recombination loss, are described in standard dosimetry protocols. The cable effect is categorized as the leakage current and Compton current, and careful consideration of these factors has been described not only in reference dosimetry but also in large fields.

Incidence and dose-volume relationship of radiation pneumonitis after concurrent chemoradiotherapy followed by durvalumab for locally advanced non-small cell lung cancer.

Background And Purpose: We investigated the incidence and dose-volume relationships of radiation pneumonitis (RP) after concurrent chemoradiotherapy (CCRT) followed by durvalumab for locally advanced non-small-cell lung cancer (LA-NSCLC).

Materials And Methods: We retrospectively analyzed records of 36 patients with LA-NSCLC who underwent CCRT followed by durvalumab. Incidence of RP was analyzed for correlations with clinical factors and dose-volume parameters of lung in radiotherapy.

Pattern of Local Failure and its Risk Factors of Locally Advanced Non-small Cell Lung Cancer Treated With Concurrent Chemo-radiotherapy.

Background/aim: The treatment outcome of locally advanced non-small cell lung cancer (LA-NSCLC) has been improved over the past years but local failure is still common for these patients. The purpose of this study is to analyze the pattern of local failure and its risk factor of concurrent chemo-radiotherapy (CCRT) for locally advanced LA-NSCLC.

Patients And Methods: We evaluated 77 patients treated with CCRT for LA-NSCLC from July 2007 to December 2017 at our institution.

Dose-volume parameters and local tumor control in cervical cancer treated with central-shielding external-beam radiotherapy and CT-based image-guided brachytherapy.

Definitive radiotherapy for cervical cancer consists of external-beam radiotherapy (EBRT) and brachytherapy. In EBRT, a central shield (CS) reduces the dose to the rectum and bladder. The combination of whole-pelvic (WP)- and CS-EBRT and brachytherapy is the standard radiotherapy protocol in Japan.

Dosimetric comparison of three-dimensional conformal radiotherapy versus volumetric-arc radiotherapy in cervical cancer treatment: applying the central-shielding principle to modern technology.

This study evaluated the feasibility of applying volumetric-arc radiotherapy (VMAT) in standard curative radiotherapy for non-bulky cervical cancer using the central-shielding principle. Whole-pelvis irradiation of 20 Gy and central-shielding pelvis irradiation of 30 Gy, both in 2 Gy fractions, were created using 3D conformal radiotherapy (3DCRT) with a standard midline block or VMAT. Composite dose distributions and DVH parameters were compared first in a simple phantom model and then in 10 clinical cases of Stage I-II cervical cancer.

Changes in deviation of absorbed dose to water among users by chamber calibration shift.

Purpose: The JSMP01 dosimetry protocol had adopted the provisional Co calibration coefficient [Formula: see text], namely, the product of exposure calibration coefficient N and conversion coefficient k . After that, the absorbed dose to water D  standard was established, and the JSMP12 protocol adopted the [Formula: see text] calibration. In this study, the influence of the calibration shift on the measurement of D among users was analyzed.