PURPOSE:This study aimed to verify the contouring accuracy of the artificial intelligence (AI)-based auto-segmentation software Contour+ (MVision AI Oy, Helsinki, Finland) both quantitatively and visually, and to evaluate its clinical validity for the thoracic region in Japanese patients. METHODS:Ten thoracic radiotherapy cases with lung lesions were analyzed. Contour+ was used to automatically delineate both lungs, trachea, bronchus, esophagus, spinal cord, and heart. Three observers visually evaluated the auto-contours using a five-point scoring system, and the final manually corrected contours were used as the reference to calculate the dice similarity coefficient (DSC), Hausdorff distance (HD), and volume differences. RESULTS:In all cases, the AI auto-contours were evaluated as "clinically acceptable with minor modifications (score ≥3)," with an average score of 4.4. The mean DSC values were 1.00 for the lungs, 0.99 for the trachea, 0.91 for the bronchi, 0.86 for the esophagus, 0.99 for the spinal cord, and 0.99 for the heart, indicating high agreement. The mean HD values were 5.68 mm, 8.72 mm, and 3.30 mm for the bronchi, esophagus, and heart, respectively. The mean volume changes after manual correction were 4.02 cc for the bronchi, 2.55 cc for the esophagus, and 2.58 cc for the heart. CONCLUSION:AI-based auto-segmentation software Contour+ demonstrated high geometric agreement and clinical validity for major thoracic organs in Japanese patients, suggesting its potential to reduce the contouring workload and promote standardization in radiotherapy treatment planning.

PURPOSE:To develop an algorithm-based method for determining optimal gantry angle ranges in volumetric modulated arc therapy (VMAT) for liver cancer by minimizing the beam path length through normal liver. METHODS:Fifteen consecutive patients with primary liver cancer who had undergone stereotactic body radiotherapy (SBRT) were analyzed. The algorithm calculated the shortest beam paths between the liver surface and the target center from DICOM-based contours to determine feasible gantry-angle ranges. For each patient, three VMAT plans were generated: (1) an automated gantry-angle plan using the proposed method, (2) an expert manual plan, and (3) a novice manual plan. Plans were compared in terms of selected gantry angle ranges, liver path length, dose-volume parameters, and monitor units (MUs). Gantry angle range agreement between plans was evaluated using the Jaccard similarity coefficient. RESULTS:The automated plan achieved a mean normal liver path length of 35.0 ± 14.4 mm, comparable to the expert plan (34.6 ± 15.0 mm) and shorter than the novice plan (39.3 ± 15.2 mm), with no significant differences among the three plans (p > 0.05). The mean Jaccard similarity coefficients were 0.86 ± 0.10 (auto-expert) and 0.80 ± 0.12 (auto-novice), indicating closer agreement with expert plans. Dosimetric parameters and MUs were similar across all plans. CONCLUSIONS:The algorithmic approach provides a simple, quantitative, and reproducible method for determining gantry-angle ranges in liver VMAT. It effectively reproduces expert planner decision-making, reduces variability between planners, and has the potential to standardize gantry angle determination and streamline treatment planning.

This study evaluated the benefits of the ExacTrac system for non-coplanar beams in brain stereotactic radiotherapy (SRT) by comparing pre- and post-X-ray verification (XV) positioning data. Data from 62 patients undergoing brain SRT were analyzed, focusing on 151 non-coplanar beams. Patient positioning involved initial infrared marker alignment, followed by ExacTrac kV x-ray acquisition and 6D robotic couch adjustments. Patient positioning was corrected within a tolerance of 0.5 mm and 0.5° for translation and rotation, respectively. Pre and post-XV positioning data were compared at each planned couch angle. Results showed that 54% of non-coplanar beams had positioning errors exceeding the specified tolerances on the pre-XV. Significant differences were observed in translational and rotational corrections between pre- and post-XV positioning at each planned couch angle. These results demonstrate that XV at any each planned couch angle using the ExacTrac system significantly improves patient positioning accuracy in brain SRT.

Purpose: This study aimed to evaluate the effectiveness of knowledge-based planning (KBP) with additional multi-criteria optimization (MCO) for the volumetric modulated arc therapy (VMAT) of the larynx. Methods: Twenty previously treated VMAT was used to train the KBP model. A manual plan (MP) was created using 10 patients. The KBP was generated by a single optimization with no planner intervention during the optimization. An additional MCO was applied to KBP (KBP + MCO) to further improve the plan’s quality. All plans were normalized to the planning target volume (PTV) D50% (percentage of the volume receiving 50% of the prescribed dose). The PTV D95%, conformity index (CI), doses to the carotid artery (V10-50 Gy: absolute volume receiving 10–50 Gy), and maximum dose to the spinal cord were calculated for the three planning methods. Results: The average PTV D95% for MP, KBP, and KBP + MCO were 90.2%, 92.8%, and 94.1%, respectively. The average CI95% for KBP + MCO was 0.06 and 0.02 higher than that for MP and KBP, respectively. PTV and CI95% were not significantly different between the three planning methods (P > 0.05). KBP + MCO showed that the carotid artery for V10-30 Gy with MP was smaller than that for KBP, and there were no significant differences between V40 Gy and V50 Gy. The maximum dose to the spinal cord did not differ significantly among the three planning methods. Conclusions: KBP + MCO could improve dose sparing of the carotid artery while maintaining PTV coverage in laryngeal VMAT.

We evaluated the effects of different aperture shape controller (ASC) settings on the dose distribution and delivery efficiency of lung stereotactic body radiotherapy (SBRT) using volumetric modulated arc therapy (VMAT) with a 10 MV flattening filter-free (FFF) beam. Ten lung SBRT cases with breath-holding were retrospectively analyzed by comparing plans with no-ASC and those with 5 ASC settings (very low, low, moderate, high, and very high). The gross tumor volume (GTV) coverage: D98% (minimum dose to 98% of the volume), target conformity index (CI), gradient index (GI), D2cm (dose maximum at 2cm from the planning target volume), lung dose, monitor unit (MU), modulated complexity score for VMAT (MCSv), and delivery time were evaluated. Compared with the no-ASC setting, there were no significant differences in GTV coverage, GI, or D2cm in the different ASC settings. A very high ASC setting resulted in a slight increase in the mean lung dose metrics. On average, MU and delivery times were significantly reduced by approximately 200 MU and 5.0 s with very high ASC settings compared to the no-ASC setting. Plan complexity decreased as the ASC increased, with the very high ASC setting showing the highest MCSv values. This study suggests that the very high ASC setting may improve the delivery efficiency for lung SBRT using VMAT with the 10 MV FFF beam under breath-holding while maintaining comparable dose distributions and target coverage.

PURPOSE:The combination of 45 Gy accelerated hyperfractionated thoracic radiotherapy (AHF-TRT) and concurrent chemotherapy is the standard treatment for limited-stage small-cell lung cancer (LS-SCLC). However, the optimal dose and fractionation remain controversial. We herein report the long-term results of a phase II study investigating the utility of dose escalation to 54 Gy in AHF-TRT for LS-SCLC. METHODS AND MATERIALS:We enrolled patients with pathologically confirmed LS-SCLC. The radiation dose was 54 Gy, delivered in 36 fractions over 3.6 weeks. All patients were treated with 3D-CRT with multiple fields to reduce the elevated dose volume to the surrounding tissues. The chemotherapy regimens consisted of either cisplatin and etoposide or carboplatin and etoposide. All patients were evaluated for overall survival (OS), progression-free survival (PFS), and nonhematological toxicity. RESULTS:Between 2013 and 2019, 21 patients were enrolled in this study. All the patients were assessed for their response and toxicities. The median age was 70 years and 15 patients were male, while 6 were female. The median follow-up period of all patients was 57.3 months. The 2- and 5-year OS rates were 85.7% and 47.6% respectively. The 2- and 5-year PFS rates were 52.3% and 47.6% respectively. No patient experienced grade ≥ 3 nonhematological adverse effects either during treatment or in follow-up. CONCLUSIONS:In this phase II study, AHF-TRT of 54 Gy resulted in a good OS and PFS without increasing severe toxicities. These outcomes suggest that dose escalation to 54 Gy may be a promising radical treatment for LS-SCLC.

BACKGROUND: This study aimed to compare the treatment plan between free breathing (FB) and deep inspiration breath-hold (DIBH) in patients with left-sided breast cancer. We aimed to investigate the dose to the heart and left lung. MATERIALS AND METHODS: Fifty-five patients with left-sided breast cancer treated with three-dimensional conformal radiotherapy were retrospectively compared with those planned with FB and DIBH in terms of doses to the heart and left lung. The prescribed dose was 42.56 Gy which was delivered in 16 fractions. RESULTS: Compared with FB, DIBH effectively reduced the mean dose to the heart by an average of 55% (2.0 Gy vs. 0.9 Gy, p < 0.001). DIBH resulted in significantly greater left lung volumes, with an average of 74.7% (980.5 cc vs. 1713.0 cc, p < 0.001). The DIBH plan delivered a significantly lower relative volume to the left lung, with an average of 1.6% at V20Gy (11.7% vs. 10.1%, p < 0.001) but delivered a significantly higher absolute irradiated volume to the left lung at V20Gy, with an average of 45.9% (118.2 cc vs. 172.5 cc, p < 0.001). CONCLUSION: DIBH is an effective treatment technique for reducing the dose to the heart and the relative irradiated left lung volume for left-sided breast cancer, although the absolute irradiated left lung volume is increased.

PURPOSE:This study proposed a "2.5D gamma analysis" method for patient-specific quality assurance (PSQA) in volumetric modulated arc therapy (VMAT) using film measurements. METHODS:A custom-designed water phantom was used, consisting of a main body and an insert box, each with a wall thickness of 10 mm, and filled with water. The insert box contained a film holder designed to accommodate several radiochromic films. The holder consisted of four separate 2 mm-thick plates and a cover, allowing the positioning of one to five films. For consistency, three films were used per case, positioned at 0 and ± 2 mm. Quasi-volumetric data were generated from the measured Gafchromic film data at various positions using B-spline interpolation, producing additional data points at 0.5 mm intervals. Five spine SBRT cases were analyzed by comparing 2.5D and 2D gamma analyses using different criteria and dose thresholds. RESULTS:The 2.5D gamma analysis showed higher gamma pass rates compared to the 2D analysis, with an average gamma pass rate of 98.6 % for the 2.5D analysis and 87.4 % for the 2D analysis, using 3 %/1 mm gamma criteria with a 5 % dose threshold. This represented an 11.2 % point increase in the gamma pass rate. CONCLUSIONS:The 2.5D gamma analysis provided higher gamma pass rates than the 2D analysis for film measurements, providing increased confidence in the accuracy of the spine VMAT treatment plan.

PURPOSE:This study evaluated the accuracy of a commercial deep learning (DL)-based algorithm for segmenting the prostate, seminal vesicles (SV), and organs at risk (OAR) in patients with prostate cancer. METHODS:Ten patients with prostate cancer were selected to compare automated and manual segmentation. The prostate, SV, and OAR, including the bladder, rectum, left and right femoral heads, and penile bulb, were delineated and reviewed according to our institutional protocols by radiation oncologists. The CT and MR images were fused to the prostate, and the prostate and penile bulb were manually delineated on the CT and MR images. The remaining organs were delineated on the CT images without the MR images. MVision AI Contour+ was used to perform DL-based automated segmentation. The dice similarity coefficient (DSC) and 95% Hausdorff distance (HD95%) were evaluated for comparison with manual delineations. RESULTS:The mean DSC values for the prostate, SV, bladder, rectum, both femoral heads, and penile bulb were 0.86, 0.80, 0.96, 0.92, 0.97, and 0.64, respectively. The HD95% for all the organs was less than 3 mm. CONCLUSIONS:The commercial DL-based auto segmentation solution provided high-quality contours in patients with prostate cancer.

Purpose/Objective(s) Most respiratory-induced target motion data have been measured at only a few points, the centroid and the edge. Due to organ deformation, volumetric measurement is more appropriate than point measurement. Previously, we proposed a quantitative method to evaluate respiratory-induced organ motion using deformable image registration (DIR), called vector volume histogram (VVH). However, the process of VVH was very complicated and no one can use the VVH because the deformation vector field (DVF) was calculated on the treatment planning system (TPS) and the file format was converted by in-house software. We developed a volumetric quantitative evaluation user-friendly software to evaluate respiratory-induced organ motion using DIR. Materials/Methods The B-spline-based DIR algorithm was used to compute the DVF, which includes DVFLR (left-right), DVFAP (anterior-posterior), and DVFCC (cranio-caudal). The VVH function was written in Python. Two sets of images were required for DIR in the VVH software: a reference image set and a registered image set. The VVH was a calculation method similar to the dose volume histogram. In the VVH software, the user could change the result of the direction by selecting a combo box. Other features included a calculation index, changing the range of the x and y axes, a tracking bar, and exporting to a CSV file. A displaced target within a moving phantom was used to evaluate the performance of the VVH system. The 2 cm diameter target was systematically displaced 5, 10, 15, and 20 mm in the CC direction. To evaluate respiration-induced target motion, the VVH method was applied to the inhalation and exhalation phases of 4D CT scans in 5 patients with lung cancer. L5% (length at 5% volume) and L50% (length at 50% volume) were calculated to evaluate target motion. Target centroid was measured for comparison with VVH methods. Results In the phantom study, L5% and L50% were 5 mm versus 4.7 mm, 9.7 mm versus 10.3 mm, 14.7 mm versus 14.9 mm, and 19.7 mm versus 20.0 mm for displacements of 5, 10, 15, and 20 mm, respectively. In the patient study, the average difference between the L5% and L50% methods and the centroid methods was as follows: L5% and L50% were 0.2 mm versus 0.5 mm, 0.3 mm versus 0.6 mm, and 2.0 mm versus 0.8 mm in the LR, AP, and CC directions, respectively. Although it was difficult to decide which index to use, the centroid and L50% results were close. The performance of VVH depends on the accuracy of the DIR algorithm and the extent of anatomic changes. Conclusion The performance of the VVH software was demonstrated by verifying the phantom and the patient with tumor motion. The VVH software provided a volumetric quantitative assessment of respiratory-induced target motion, which in its clinical application can provide strategy-decision at the time of treatment planning.

PurposeLateral response artifact (LRA) is caused by the interaction between film and flatbed scanner in the direction perpendicular to the scanning direction. This can significantly affect the accuracy of patient-specific quality assurance (QA) in cases involving large irradiation fields. We hypothesized that by utilizing the central area of the flatbed scanner, where the magnitude of LRA is relatively small, the LRA could be mitigated effectively. This study proposes a practical solution using the image-stitching technique to correct LRA for patient-specific QA involving large irradiation fields.MethodsGafchromic (TM) EBT4 film and Epson Expression ES-G11000 flatbed scanner were used in this study. The image-stitching algorithm requires a spot between adjacent images to combine them. The film was scanned at three locations on a flatbed scanner, and these images were combined using the image-stitching technique. The combined film dose was then calculated and compared with the treatment planning system (TPS)-calculated dose using gamma analysis (3%/2 mm). Our proposed LRA correction was applied to several films exposed to 18 x 18 cm2 open fields at doses of 200, 400, and 600 cGy, as well as to four clinical Volumetric Modulated Arc Therapy (VMAT) treatment plans involving large fields.ResultsFor doses of 200, 400, and 600 cGy, the gamma analysis values with and without LRA corrections were 95.7% versus 67.8%, 95.5% versus 66.2%, and 91.8% versus 35.9%, respectively. For the clinical VMAT treatment plan, the average pass rate +/- standard deviation in gamma analysis was 94.1% +/- 0.4% with LRA corrections and 72.5% +/- 1.5% without LRA corrections.ConclusionsThe effectiveness of our proposed LRA correction using the image-stitching technique was demonstrated to significantly improve the accuracy of patient-specific QA for VMAT treatment plans involving large irradiation fields.

In this study, AHF-TRT of 54 Gy with concurrent PE- or CE-based regimens resulted in a good OS and PFS without increasing severe toxicity. Although this regimen needs to be evaluated in more patients to fully confirm its efficacy, these outcomes suggest that dose escalation to 54 Gy may be a promising radical treatment for LS-SCLC.

Purpose: This phase II study aimed to evaluate the efficacy and safety of hypofractionated involved-field radiation therapy (HypoFx-IFRT) in 2.5 Gy fractions and concurrent chemotherapy for locally advanced stage IIIA and B nonsmall cell lung cancer (LA-NSCLC) without prolonging treatment delivery time beyond 6 weeks. We analyzed the overall survival (OS), progression-free survival, and safety of the treatment. Methods and Materials: This prospective, single center, single-arm trial was initiated in 2010. All LA-NSCLC patients were treated with HypoFx-IFRT using 3-dimensional conformal radiation therapy. The median total dose of HypoFx-IFRT was 67.5 Gy (range, 60-70). Results: From December 2010 to October 2016, 36 patients were ultimately enrolled and evaluated. The trial closed early owing to slow accrual. The median follow-up duration was 50 months in all patients and 65 months in surviving patients. The 1-, 3-, and 5-year OS rates were 88.9% (95% confidence interval [CI], 78.6%-99.2%), 61.1% (95% CI, 45.2%-77.0%), and 54.1% (95% CI, 37.3%-70.9%), respectively. The median time for OS was not reached. The median time for progression-free survival was 10.7 months. The incidence rates of grade 3 radiation pneumonitis, esophagitis and esophageal stenosis were 8.3%, 2.8%, and 2.8%, respectively, and no acute or late toxicities of grade 4 or 5 were observed. Conclusions: This study indicated that HypoFx-IFRT with concurrent chemotherapy yielded an acceptable safety profile and might be beneficial in the survival outcomes of patients with LA-NSCLC. (C) 2020 American Society for Radiation Oncology. Published by Elsevier Inc. All rights reserved.

The combination of accelerated hyperfractionated thoracic radiotherapy (AHF-TRT) of 45 Gy and concurrent chemotherapy is the standard treatment for limited-stage small-cell lung cancer (LS-SCLC); however, the optimal dose and fractionation remains controversial. We herein report the results of a prospective preliminary study investigating the efficacy of dose escalation to 54 Gy in AHF-TRT for LS-SCLC. A total of 13 patients who were diagnosed to have LS-SCLC at our institution between 2013 and 2016 were enrolled in the present study. The radiation dose was 54 Gy in 36 fractions in 18 treatment days over 3.6 weeks. The chemotherapy regimens were either cisplatin and etoposide (PE) or carboplatin and etoposide (CE) regimens. AHF-TRT was given in 2 phases: patients initially received 36 Gy to the gross tumor plus uninvolved mediastinal nodes, followed by a boost to the gross tumor of 18 Gy. All patients were treated with three-dimensional conformal radiation therapy with multiple fields to reduce the dose volume delivered to the surrounding tissues, such as the lungs and esophagus, as much as possible. All patients were evaluated for their overall survival (OS), progression-free survival (PFS), and development of pneumonitis and esophagitis. The median follow-up for all patients was 35 months (range, 13-62), and that for surviving patients was 39 months (range, 30-62). The patterns of failure were locoregional-only recurrence in 0% (0 patients), both locoregional and distant in 7.7% (1 patient), and distant-only in 38.5% (5 patients). The 1-, 2-, and 3-year OS rates were 100%, 92.3%, and 72.5%, respectively, and the median OS has not yet been reached. The 1-, 2-, and 3-year PFS rates were 76.9%, 53.9%, and 53.9%, respectively, and the median PFS has not yet been reached. No patient experienced grade 3 or greater non-hematological adverse effects, such as esophagitis or pneumonitis, during treatment or follow-up. Grade 2 pneumonitis was observed in 2 patients (9%). Grade 2 esophagitis was observed in 21 patients (91%). In this study, AHF-TRT of 54 Gy with concurrent PE or CE regimens resulted in a better OS and PFS without an increase in the severity of toxicity. Although more studies in a larger number of patients are needed to fully evaluate the efficacy, these outcomes suggest that a dose escalation to 54 Gy may be a promising radical treatment for LS-SCLC.

In the present study, we evaluated the appropriate schedule of S-1 administration in combination with radiotherapy for T2N0 glottic cancer by investigating the safety and efficacy. Between 2007 and 2016 23 patients diagnosed with T2N0 glottic cancer and treated with chemoradiotherapy (CRT) were enrolled in this study. Sixteen patients were treated with daily administration of S-1 (80-120 mg/day) during the course of radiotherapy between March 2007 and June 2013. Briefly, they received the drug for 4 weeks followed by 2-week drug-free intervals, or for 2 weeks followed by 1-week drug-free intervals. The remaining 7 patients were treated with an alternate-day regimen (80 mg/day) intended to reduce severe mucositis between July 2013 and December 2016. Radiotherapy was given as a once-daily fraction at 2 Gy up to a total median dose of 70 Gy (range, 66-70). The rates of survival and local control were estimated by the Kaplan-Meier method, and the Log Rank test was used to evaluate the significance of the survival and local control. The CTCAE ver. 4.0 was used to grade toxicities, and the chi-squared test was used to compare the toxicity between the daily and alternate-day administration groups. The median follow-up of the daily and alternate-day administration groups was 76 months (range: 44-104 months) and 40 months (range: 14-50 months), respectively. One patient in the alternate-day administration group experienced local recurrence and underwent total laryngectomy at eight months after the completion of CRT. A comparison between the daily administration and alternate-day administration groups at 2 years showed that the overall survival rate was 100% vs. 100%, (p = 0.68), and the local control rate was 100% vs. 86% (p = 0.13). Grade 2+ mucositis was observed in 13 patients (81%) in the daily administration group and in 3 patients (43%) in the alternate-day administration group (p=0.0656). No Grade 3 mucositis was encountered in the alternate-day administration group. Opioid pain medication to reduce symptoms was used in 9 patients (69%) in the daily administration group and in 1 patient (14%) in the alternate-day administration group (p = 0.0618). An interruption of radiotherapy due to mucosal pain was carried out in 4 patients (25%) in the daily administration group and in no patients (0%) in the alternate-day administration group (p = 0.1455). Our results suggest that an alternate-day administration regimen of S-1 for CRT might reduce mucositis without compromising the therapeutic effectiveness compared to a daily administration regimen. CRT with alternate-day administration of S-1 may therefore be a viable standard treatment option for T2N0 glottic cancer.

The combination of accelerated hyperfractionated thoracic radiotherapy (AHF-TRT) and chemotherapy has been established as the current standard therapy for limited-stage small-cell lung cancer (LS-SCLC). Although 45 Gy in 30 fractions is commonly used for dose-fractionation, the optimal dose of AHF-RT remains unknown. In this study, we evaluated the efficacy on AHF-TRT of escalating the dose to 54 Gy. Between 2006 and 2012, 19 patients diagnosed with LS-SCLC and treated with AHF-TRT and chemotherapy were enrolled in this study. The chemotherapy regimens were cisplatin and etoposide (PE) or carboplatin and etoposide (CE). Nine patients treated between 2006 and 2010 were irradiated with 45 Gy in 30 fractions for 3 weeks. Ten patients treated between 2011 and 2012 were irradiated with 54 Gy in 36 fractions for 3 and a half weeks. AHF-RT was given in 2 phases: patients initially received 36 Gy to the gross tumor plus uninvolved mediastinal nodes, followed by a boost to the gross tumor of 9 or 18 Gy. All patients were treated with three-dimensional conformal radiation therapy with multiple fields to reduce the volume of the surrounding normal tissues, such as the esophagus, from receiving a high dose, as much as possible. Variables related to the survival were estimated by the Kaplan-Meier method, and the log rank test was used to evaluate the significance of the survival, using a p value of 0.05 to indicate significance. The CTCAE ver. 3.0 was used to grade toxicities. The median follow-up of the 45 and 54 Gy groups was 23.6 months (range: 6.3-93.7 months) and 46.1 months (range: 8.1-67.7 months), respectively. No significant differences between the two groups regarding the patient and tumor characteristics were noted. The median duration of AHF-TRT was 22 days (range: 19-27 days) in the 45 Gy group and 29 days (range: 23-30 days) in the 54 Gy group. Prophylactic cranial irradiation was administered to 4 patients (44%) in the 45 Gy group and 8 (80%) in the 54 Gy group. The median survival time (MST) was 23.6 months in the 45 Gy group and 41.5 months in the 54 Gy group. A comparison between the 45 and 54 Gy groups at 4 years showed that the overall survival rate was 22.2% vs. 50.0% (p = 0.1559), the progression-free survival (PFS) was 0% vs. 40.0% (p = 0.0191), the in-field progression-free survival (IFPFS) was 11.1% vs. 40.0% (p = 0.0318) and the distant metastasis-free survival (DMFS) was 0% vs. 50.0% (p = 0.0293), respectively. No Grade 3+ non-hematological adverse effects, such as acute esophagitis, pneumonitis or lung fibrosis, were encountered in either group. AHF-TRT at 54 Gy with concurrent PE or CE regimens significantly improved the PFS, IFPFS and DMFS without increasing the toxicity compared with 45 Gy. Although more patients with longer follow-up periods are needed to fully evaluate the usefulness and safety of this 9 Gy dose escalation, these outcomes suggest that increasing the dose to 54 Gy in AHF-TRT for LS-SCLC may be a promising modality for improving the treatment results.

PURPOSE:This phase II study aimed to evaluate the efficacy and safety of hypofractionated involved-field radiation therapy (HypoFx-IFRT) in 2.5 Gy fractions and concurrent chemotherapy for locally advanced stage IIIA and B nonsmall cell lung cancer (LA-NSCLC) without prolonging treatment delivery time beyond 6 weeks. We analyzed the overall survival (OS), progression-free survival, and safety of the treatment.METHODS AND MATERIALS:This prospective, single center, single-arm trial was initiated in 2010. All LA-NSCLC patients were treated with HypoFx-IFRT using 3-dimensional conformal radiation therapy. The median total dose of HypoFx-IFRT was 67.5 Gy (range, 60-70).RESULTS:From December 2010 to October 2016, 36 patients were ultimately enrolled and evaluated. The trial closed early owing to slow accrual. The median follow-up duration was 50 months in all patients and 65 months in surviving patients. The 1-, 3-, and 5-year OS rates were 88.9% (95% confidence interval [CI], 78.6%-99.2%), 61.1% (95% CI, 45.2%-77.0%), and 54.1% (95% CI, 37.3%-70.9%), respectively. The median time for OS was not reached. The median time for progression-free survival was 10.7 months. The incidence rates of grade 3 radiation pneumonitis, esophagitis and esophageal stenosis were 8.3%, 2.8%, and 2.8%, respectively, and no acute or late toxicities of grade 4 or 5 were observed.CONCLUSIONS:This study indicated that HypoFx-IFRT with concurrent chemotherapy yielded an acceptable safety profile and might be beneficial in the survival outcomes of patients with LA-NSCLC.