e12511 Background: Left-sided breast cancer radiotherapy poses a significant challenge in balancing target coverage with the sparing of critical cardiac substructures. RapidArc Dynamic (RAD) is a novel hybrid technique that integrates the continuous arc delivery of volumetric modulated arc therapy (VMAT) with the fixed-beam modulation of intensity modulated radiotherapy (IMRT) through strategic gantry pauses and dynamic collimator rotation. This study aims to evaluate the dosimetric performance of RAD, benchmarking it against IMRT and VMAT, with a specific focus on cardiac substructure sparing and normal tissue complication probability (NTCP). Methods: Twenty patients with left-sided breast cancer treated with post-mastectomy adjuvant radiotherapy were retrospectively enrolled. For each patient, RAD (2 partial arcs with 6 gantry pauses), IMRT (9 fields), and VMAT (5 partial arcs) plans were generated with a prescription of 50 Gy in 25 fractions. Dosimetric metrics, plan complexity, and conformity index were analyzed, and NTCP values were calculated using the Lyman-Kutcher-Burman (LKB) model for multiple endpoints. Results: RAD demonstrated significantly lower (P < 0.05) doses to the heart, left lung, and spinal cord compared to both IMRT and VMAT. Specifically, RAD achieved superior sparing of the left anterior descending coronary artery (LAD) and left ventricle (LV), reducing mean and maximum doses significantly compared to competing modalities. While VMAT resulted in a higher low-dose bath to the contralateral breast, RAD successfully mitigated this issue, delivering significantly lower contralateral doses. Furthermore, RAD yielded significantly lower predicted NTCPs for cardiac perfusion defects, LA major adverse cardiac events, and pulmonary pneumonitis compared to IMRT and VMAT. Conclusions: RAD offers a feasible and effective alternative for left-sided chest radiotherapy, providing an optimal balance between high dose conformity and superior ipsilateral organ sparing. By significantly reducing doses to critical cardiac substructures and minimizing predicted complications, RAD may reduce the risk of late toxicity in breast cancer survivors.

Background Left-sided breast cancer radiotherapy poses a challenge in balancing target coverage with the sparing of critical cardiac substructures. A novel hybrid technique - RapidArc Dynamic (RAD) - integrated continuous arc delivery of volumetric modulated arc therapy (VMAT) with fixed-beam modulation of intensity modulated radiotherapy (IMRT) through strategic gantry pauses and dynamic collimator rotation. Purpose This study aims to evaluate the dosimetric performance of RAD, benchmarking it against IMRT and VMAT, with a specific focus on cardiac substructure sparing and normal tissue complication probability (NTCP). Methods Twenty patients with left-sided breast cancer treated with post-mastectomy adjuvant radiotherapy were retrospectively enrolled. For each patient, three plans (RAD, IMRT, and VMAT) were generated with a prescription of 50 Gy in 25 fractions. RAD plans utilized a “balanced” optimization strategy combining static ports and dynamic arcs with strategic gantry pauses to enhance modulation. Dosimetric metrics were analyzed for the planning target volume (PTV) and organs at risk (OARs). NTCP values were calculated using the Lyman-Kutcher-Burman (LKB) model for multiple endpoints. Results RAD demonstrated significantly lower dose metrics for the heart, left lung, and spinal cord compared to both IMRT and VMAT (P < 0.05). Specifically, RAD achieved superior sparing of the left anterior descending coronary artery (LAD) and left ventricle (LV), reducing mean and maximum doses significantly compared to competing modalities. While VMAT provided better conformity than IMRT, it resulted in a higher low-dose bath to the contralateral breast. Radiobiological modelling demonstrated that RAD successfully mitigated this issue, delivering significantly lower contralateral doses than VMAT. RAD yielded significantly lower predicted NTCPs for cardiac perfusion defects, LA major adverse cardiac events, and pulmonary pneumonitis compared to IMRT and VMAT. Conclusion RAD offers a feasible and effective alternative for left-sided chest radiotherapy, providing an optimal balance between high dose conformity and superior organ sparing.

Abstract Background: Patients with advanced esophageal squamous cell carcinoma (ESCC) face a poor prognosis and limited options after first-line therapy failure. This study aims to evaluate the efficacy and safety of camrelizumab combined with chemotherapy as a second-line treatment in patients who with or without prior immunotherapy exposure. Method: This single-center, multi-cohorts, phase II exploratory clinical trial enrolled patients with locally recurrent or metastatic ESCC who had either failed or were intolerant to first-line treatment. Patients were stratified into two cohorts: those who had previously received immunotherapy (Cohort 1) and those who had not (Cohort 2). All patients received camrelizumab (Q3W, up to 2 years) combined with nab-paclitaxel or fluorouracil based chemotherapy (Q3W, 4-6 cycles).The primary endpoint was progression-free survival (PFS). Results: Between May 2021 and September 2025, 40 patients were enrolled, with 20 patients in each cohort. The median age was 67 years in Cohort 1 and 66 years in Cohort 2.The median age was 67 years in Cohort 1 and 66 years in Cohort 2. The cohorts comprised 18 (90%) and 15(75%) males;15(75%) and 15(75%) with an ECOG performance status of 1; 10% and 15% with pulmonary metastases; and 55% and 45% with lymph node metastases, respectively. According to RECIST 1.1, among the 15 and 18 evaluable patients in Cohorts 1 and 2, the objective response rate (ORR) was 33.3% and 50.0%, and the disease control rate (DCR) was 93.3% and 88.9%, respectively. The median progression-free survival (mPFS) was 4.5 months(95%CI 2.13-6.8 ) in Cohort 1 and 9.5 months(95%CI 2.7-16.4 ) in Cohort 2. The median overall survival(mOS) was not reached.The most common adverse events (AEs) were lymphocyte count decreased (90% and 75%), anemia (85% and 70%), and decreased neutrophils (50% and 40%), which were grade 1-3. No grade 4 or 5 AEs occurred.The most common immune-related AEs (irAEs) was reactive cutaneous capillary endothelial proliferation(64.% and 57.1%), which was grade 1-2 in all cases. Conclusion: Camrelizumab combined with chemotherapy showed good antitumor efficacy and safety in advanced ESCC as second-line treatment, regardless of whether the patients have previously received immunotherapy. Citation Format: Linlin Wang, Bingjie Fan, Bing Zou, Aiqin Gao, Shijiang Wang, Chunni Wang, Qian Shao, Yishan Yu, Hong Zhao, Jinzhi Wang, Yan Yi, Qingxi Yu. Exploratory study of camrelizumab combined with chemotherapy as second-line treatment for advanced esophageal squamous cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 6487.

BACKGROUND:Thoracic SMARCA4-deficient undifferentiated tumor (SMARCA4-UT) is a newly defined type of epithelial tumor in the 2021 World Health Organization (WHO) fifth edition classification of thoracic tumors, with a low incidence. Currently, its treatment and prognosis remain unclear. Pathologically, it can be distinguished from SMARCA4-deficient non-small cell lung cancer (SMARCA4-dNSCLC) based on histological morphology and immunohistochemistry, yet whether there are differences in their clinical features, sensitivity to radiotherapy, and prognosis remains unknown. This study aimed to analyze the clinical characteristics of patients with SMARCA4-UT and SMARCA4-dNSCLC and to identify prognostic factors. METHODS:A retrospective analysis was performed on pathologically confirmed SMARCA4-UT and SMARCA4-dNSCLC patients with complete follow-up data who were admitted to Shandong First Medical University Affiliated Tumor Hospital from June 2022 to February 2025. The differences in clinicopathological characteristics and imaging findings between the two groups were statistically analyzed, and the impacts of surgery, radiotherapy, immunotherapy, and clinicopathological factors on the prognosis of patients in both groups were assessed. RESULTS:A total of 27 SMARCA4-UT patients and 40 SMARCA4-dNSCLC patients were enrolled. Both groups showed similar biological characteristics in terms of gender, age, smoking history, tumor size, symptoms, stage, presence of pleural metastasis, neutrophil-to-lymphocyte ratio (NLR), and systemic immune-inflammation index (SII). However, there were differences in the predilection sites: SMARCA4-UT occurred more frequently in the mediastinal pleura (22.22%) and right lower lobe (25.93%), while SMARCA4-dNSCLC occurred more frequently in the right upper lobe (25.00%) and left upper lobe (22.50%) (P<0.05). Furthermore, SMARCA4-UT more often presented with local invasion into adjacent structures and more extensive lymph node metastasis (proportion with metastasis in ≥5 lymph node stations: 55.56% vs 27.50%). Both types showed high sensitivity to radiotherapy, with a 6-month local control rate (LCR) of 84.62% vs 83.33% after radiotherapy; the objective response rate (ORR) of immunotherapy was 91.67% vs 68.18% (P>0.05). Regarding survival, the two groups did not show significant differences in progression-free survival (PFS) or overall survival (OS). Cox multivariate regression analysis indicated that surgery could improve the prognosis of both types, while a high NLR (≥3.57) was a predictor of poor prognosis. CONCLUSIONS:SMARCA4-UT and SMARCA4-dNSCLC share similar clinical characteristics and survival outcomes, with minor differences in local invasion, mediastinal lymph node metastasis, and primary tumor location. Surgery improved survival in both groups. Although both tumor types exhibited high sensitivity to radiotherapy, this did not translate into a significant survival benefit for the patients. Pretreatment NLR is a potential prognostic indicator.

Background and purposeTo investigate the dynamic changes in cardiac enzymes, high-sensitivity troponin T (hs-TnT), pro-brain natriuretic peptide (pro-BNP) and left ventricular ejection fraction (LVEF) during radiotherapy (RT) and 6 months after RT for oesophageal squamous cell carcinoma (ESCC) in the middle and lower locations and to analyse the correlations between these indicators and cardiac radiation dosimetry parameters.MethodsFor 35 patients with ESCC in the middle and lower locations receiving radical concurrent chemoradiotherapy (cCRT), intensity-modulated RT was performed at 1.8 Gy or 2.0 Gy per day, and the totle dose was 50.4 Gy or 60 Gy. Serum creatine kinase (CK), creatine kinase isoenzyme (CK-MB), lactate dehydrogenase (LDH), alpha-hydroxybutyrate dehydrogenase (α-HBDH), hs-TnT, pro-BNP and LVEF were measured before, during, and at the end of RT and 1, 3 and 6 months after RT, and correlations of these indicators with mean heart dose (MHD) and heart V5-V50 were analysed.Resultshs-TnT during, at the end and 6 months after RT for oesophageal cancer showed increasing trends, however, LVEF showed a downward trend. pro-BNP showed an increasing trend during RT and gradually returned to normal after RT. CK and CK-MB showed decreasing trends during RT and continued until one month after RT and then gradually returned to normal. Compared with the low-dose group (MHD < 2000 cGy), the high-dose group (MHD ≥ 2000 cGy) had larger increases in hs-TnT and pro-BNP, a more significant decrease in LVEF, and a longer recovery time for these indicators. MHD and V35 were positively correlated with dynamic changes in hs-TnT.ConclusionsCardiac injury caused by cCRT for ESCC in the middle and lower locations led to increased hs-TnT and pro-BNP levels and a decrease in LVEF in the early stage of treatment, effects that were more pronounced in the high-dose group. MHD and V35 may be potential indicators to predict the degree of cardiac damage. hs-TnT and pro-BNP are sensitive indicators reflecting cardiac injury in RT for oesophageal cancer. Continuous dynamic monitoring of these markers can provide a reference for cardiac protection in clinical RT.

Background and Purpose:This study aimed to investigate inter-/intra-observer delineation variability in GTVs of primary esophageal carcinomas (ECs) based on planning CT with reference to different combinations of diagnostic multimodal images from endoscopy/EUS, esophagography and FDG-PET/CT.Materials and Methods:Fifty patients with pathologically proven thoracic EC who underwent diagnostic multimodal images before concurrent chemoradiotherapy were enrolled. Five radiation oncologist independently delineated the GTVs based on planning CT only (GTVC), CT combined with endoscopy/EUS (GTVCE), CT combined with endoscopy/EUS and esophagography (X-ray) (GTVCEX), and CT combined with endoscopy/EUS, esophagography, and FDG-PET/CT (GTVCEXP). The intra-/inter-observer variability in the volume, longitudinal length, generalized CI (CIgen), and position of the GTVs were assessed.Results:The intra-/inter-observer variability in the volume and longitudinal length of the GTVs showed no significant differences (p>0.05). The mean intra-observer CIgen values for all observers was 0.73 ± 0.15. The mean inter-observer CIgen values for the four multimodal image combinations was 0.67 ± 0.11. The inter-observer CIgen for the four combined images was the largest, showing significant differences with those for the other three combinations. The intra-observer CIgen among different observers and inter-observer CIgen among different combinations of multimodal images showed significant differences (p<0.001). The intra-observer CIgen for the senior radiotherapists was larger than that for the junior radiotherapists (p<0.001).Conclusion:For radiation oncologists with advanced medical imaging training and clinical experience, using diagnostic multimodal images from endoscopy/EUS, esophagography, and FDG-PET/CT could reduce the intra-/inter-observer variability and increase the accuracy of target delineation in primary esophageal carcinomas.

Objective:To investigate the effectiveness of abdominal compression in tumor motion and the target volume, and analyze the suitable margins of planning target volume (PTV) for patients treated with lung-SBRT based on 4DCT.Methods:Patients diagnosed with peripheral pulmonary tumor were enrolled. The patients were divided into the whole group, upper-middle-lobe group (group A) and the lower-lobe group (group B). Each patient underwent 3DCT, 4DCT with abdominal compression (4DCT com) and 4DCT with free breath (4DCT free) scans. The GTVs were delineated and IGTVs on these images. PTV MIP 5 mm, PTV MIP 4 mm, PTV MIP 3 mm were constructed with a 5, 4, 3 mm margin in left-right (LR), anterior-posterior (AP) directions and cranial-caudal (CC) directions. Results:The median motion vector with compression reduced by 30.92% in whole group, increased by 3.42% in group A and reduced by 18.80% in group B, respectively. And there were no significant differences of TMA LR, TMA AP, TMA CC and motion vector by the Wilcoxon test ( P>0.05). The median sizes of IGTV MIP com , IGTV MIP free and IGTV10 com, IGTV10 free were 4.01, 5.36 cm 3and 6.59, 7.65 cm 3, with statistically significant difference ( Z=-3.45, -3.14, P<0.01). The median ratio of DI of IGTV CBCT com in PTV MIP 5 mm, PTV MIP 4 mm and PTV MIP 3 mm≥95% was 100%, 100% and 83.33%, respectively. Conclusions:The patients′ respiratory pattern changed with abdominal compression and abdominal compression is useful in reducing the size of IGTV MIP and IGTV10, which could reduce the target volume and protect the normal tissue. Adding a 4 mm margin to IGTV MIP com based on 4DCT account for respiration in SBRT is a tendency for precise radiotherapy.

目的 探讨同步加量调强放疗(SIB-IMRT)联合多西他赛顺铂(DP)治疗颈段和胸中上段食管癌疗效,并评估其可行性.方法 选择2009-05-01-2012-07-31山东省肿瘤医院行放化疗治疗的食管癌患者23例,其中肿瘤位于颈段3例,胸上段13例,胸中段7例;肿瘤长度2.5～10 cm,中位长度5.5 cm.放疗采用SIB-IMRT(PTV-G 60.2 Gy/28次;PTV-C 50.4 Gy/28次),放疗同时联合DP方案化疗,共完成2个周期.生存分期采用Kaplan-meier曲线描述,并行Log-rank检验.影响生存单因素分析采用Cox回归.结果 23例患者均坚持至同步放化疗结束.Ⅲ/Ⅳ度骨髓抑制发生率34.8％(8/23),Ⅲ/Ⅳ度急性放射性食管炎发生率30.4％(7/23).1年内3例出现食管瘘.近期疗效评估:完全缓解(CR)7例(30.4％),部分缓解(PR)9例(39.1％),疾病稳定(SD)5例(21.7％),疾病进展(PD)2例(8.7％),近期疾病控制率91.3％(21/23).中位生存时间30个月,1、2、3和5年总生存率(OS)分别为78％、57％、35％和25％.根据近期疗效的不同进一步对比OS,CR患者具有更好的生存情况(χ2=11.641,P=0.009).多因素分析显示,病变位置(HR=0.367,95％CI为0.157～0.859,P=0.021)及近期疗效(HR=3.401,95％CI为1.797～6.436,P<0.001)与生存相关,胸段食管癌预后好于颈段食管癌,近期疗效好的患者OS更高.结论 SIB-IMRT联合DP方案化疗治疗颈段和胸中上段食管鳞癌,近期疗效CR患者具有更好的生存情况.急性毒副作用主要表现为血液学毒性和放射性食管炎,但食管瘘发生率较高,因此具体的分割模式和病例的选择需进一步探讨.

CT is the most commonly used method to stage esophageal cancer (EC). However, the reported CT T-staging criteria for EC are controversial. To determine and validate the optimal esophageal wall thickness (EWT) threshold on CT to distinguish lesions with different T stages in esophageal squamous cell carcinoma (ESCC) patients. One thousand, one hundred-two consecutive patients with histopathologically confirmed ESCC between July 2014 and April 2020 were retrospectively reviewed. All patients underwent a preoperative CT examination and surgical treatment. The maximal EWT of the lesions on CT was measured. Patients were divided into pT1, pT2, pT3 and pT4 subgroups according to the pathologic stage. We employed the support vector machine, where linear kernels were leveraged to determine the optimal threshold to classify samples with different T stages. 90% of samples from each subgroup were randomly selected as the training set, while the remainder comprised the testing set. The mean EWTs of the pT1, pT2, pT3 and pT4 subgroups were 4.9 ± 2.6 mm, 8.1 ± 2.3 mm, 12.4 ± 3.6 mm, and 18.6 ± 4.4 mm, respectively. Differences in the EWT between the four subgroups or between adjacent subgroups were significant (p < 0.001), and esophageal wall became thicker with increasing pT stage. We utilized MATLAB 2020a to implement the SVM model and ran the code 10 times. The accuracy of the model was 60.29 ± 2.33%. The thresholds between samples from pT1/pT2, pT2/pT3 and pT3/pT4 lesions were 5.5 ± 0.3 mm, 10.8 ± 0.8 mm and 15.9 ± 0.5 mm, respectively. Possibility of predicting T stage of ESCC by EWT on CT scans was limited to 60% by model examination with large sample size.

Abstract Background This study aimed to investigate the effect of abdominal compression on tumour motion and target volume and to determine suitable planning target volume (PTV) margins for patients treated with lung stereotactic body radiotherapy (SBRT) based on four-dimensional computed tomography (4DCT). Methods Twenty-three patients diagnosed to have a peripheral pulmonary tumour were selected and divided into an all lesions group (group A), an upper middle lobe lesions group (group B), and a lower lobe lesions group (group C). Two 4DCT scans were performed in each patient, one with and one without abdominal compression. Cone beam computed tomography (CBCT) was performed before starting treatment. The gross target volumes (GTVs) were delineated and internal gross target volumes (IGTVs) were defined. IGTVs were generated using two methods: (1) the maximum intensity projections (MIPs) based on the 4DCT were reconstructed to form a single volume and defined as the IGTVMIP and (2) GTVs from all 10 phases were combined to form a single volume and defined as the IGTV10. A 5-mm, 4-mm, and 3-mm margin was added in all directions on the IGTVMIP and the volume was constructed as PTVMIP5mm, PTVMIP4mm, and PTVMIP3mm. Results There was no significant difference in the amplitude of tumour motion in the left–right, anterior–posterior, or superior-inferior direction according to whether or not abdominal compression was applied (group A, p = 0.43, 0.27, and 0.29, respectively; group B, p = 0.46, 0.15, and 0.45; group C, p = 0.79, 0.86, and 0.37; Wilcoxon test). However, the median IGTVMIP without abdominal compression was 33.67% higher than that with compression (p = 0.00), and the median IGTV10 without compression was 16.08% higher than that with compression (p = 0.00). The median proportion of the degree of inclusion of the IGTVCBCT in PTVMIP5mm, PTVMIP4mm, and PTVMIP3mm ≥ 95% was 100%, 100%, and 83.33%, respectively. Conclusions Abdominal compression was useful for reducing the size of the IGTVMIP and IGTV10 and for decreasing the PTV margins based on 4DCT. In IGTVMIP with abdominal compression, adding a 4-mm margin to account for respiration is feasible in SBRT based on 4DCT.

Background The application of delayed-enhancement magnetic resonance (DE-MR) simulation imaging in lumpectomy cavity (LC) delineation for prone radiotherapy in patients with an invisible seroma or a low seroma clarity score (SCS) after breast-conserving surgery (BCS) based on deformable image registration (DIR) was assessed. Methods Twenty-six patients who were suitable for radiotherapy in prone positions after BCS were enrolled, and both computed tomography (CT) and DE-MR simulation scans were acquired. The LC delineated based on titanium surgical clips on CT images was denoted as LC CT . The LC delineated based on the signal of cavity boundaries on fat-suppressed T2-weighted imaging (T2WI) and multiphase delayed-enhancement T1-weighted imaging (DE-T1WI), which was performed at 2 min, 5 min and 10 min postinjection, were denoted as LC T2 , LC 2T1 , LC 5T1 and LC 10T1 , respectively. Afterwards, DIR was performed to compare the volumes and locations of the LCs with MIM software. The generalized conformity index (CIgen) of inter (intra) observer (Inter-CIgen and Intra-CIgen) was also used to explore the inter(intra) observer variation for LC delineation on each image modality. Results LC CT –LC 10T1 provided the best conformal index (CI) and degree of inclusion (DI), increasing by 2.08% and 4.48% compared to LC CT –LC T2 , 11.36% and 2.94% for LC CT –LC 2T1 , and 8.89% and 7.69% for LC 5T1 –LC CT , respectively. The center of mass (COM) of LC CT –LC 10T1 decreased by 17.86%, 6.12% and 13.21% compared with that of LC CT –LC T2 , LC CT –LC 2T1 and LC CT –LC 5T1 , respectively. The agreement of LC delineation was strongest for 10th min DE-TIWI (coefficient of variation, COV = 2.30%, Inter-CIgen = 87.06%, Intra-CIgen = 92.64%). Conclusion For patients with a low SCS (SCS ≤ 2) after BCS, it is feasible to contour the LC based on prone DE-MR simulation images. Furthermore, the LC derived from prone DE-T1WI at 10 min was found to be most similar to that derived from prone CT simulation scans using titanium surgical clips regardless of the volume and location of the LC. Inter (intra) variability was minimal for the delineation of the LC based on 10th min DE-TIWI.

BackgroundClinically, many esophageal cancer patients who planned for radiation therapy have already undergone diagnostic Positron-emission tomography/computed tomography (PET/CT) imaging, but it remains unclear whether these imaging results can be used to delineate the gross target volume (GTV) of the primary tumor for thoracic esophageal cancer (EC).MethodsSeventy-two patients diagnosed with thoracic EC had undergone prior PET/CT for diagnosis and three-dimensional CT (3DCT) for simulation. The GTV3D was contoured on the 3DCT image without referencing the PET/CT image. The GTVPET-ref was contoured on the 3DCT image referencing the PET/CT image. The GTVPET-reg was contoured on the deformed registration image derived from 3DCT and PET/CT. Differences in the position, volume, length, conformity index (CI), and degree of inclusion (DI) among the target volumes were determined.ResultsThe centroid distance in the three directions between two different GTVs showed no significant difference (P > 0.05). No significant difference was found among the groups in the tumor volume (P > 0.05). The median DI values of the GTVPET-reg and GTVPET-ref in the GTV3D were 0.82 and 0.86, respectively (P = 0.006). The median CI values of the GTV3D in the GTVPET-reg and GTVPET-ref were 0.68 and 0.72, respectively (P = 0.006).ConclusionsPET/CT can be used to optimize the definition of the target volume in EC. However, no significant difference was found between the GTVs delineated based on visual referencing or deformable registration whether using the volume or position. So, in the absence of planning PET–CT images, it is also feasible to delineate the GTV of primary thoracic EC with reference to the diagnostic PET–CT image.

Objective: To investigate the effect of anatomic and technical parameters on the incidental internal mammary lymph node (IMN) irradiation (IIMNI) dose among postmastectomy patients. Methods: We retrospectively delineated the IMN on planning CT images from 138 patients who had undergone postmastectomy radiotherapy (PMRT). We analyzed the IIMNI dose coverage and its relationship with anatomic and technical parameters. Results: The IIMNI mean dose was 32.85 ± 9.49 Gy, and 10 of 138 patients (7.25%) treated with PMRT received ≥45 Gy. In univariate analysis, the body weight, body mass index, body surface area, thoracic transverse diameter (DT), ratio of DT to the thoracic anteroposterior diameter (DAP)(RT/AP), planning target volume of IMN (PTVIMN) included in PTV (IMNin) and the ratio of IMNin to PTVIMN (RIMNin) and PTV posterior border were the parameters affecting IIMNI dose. In multivariate analysis, body weight, RT/AP, and RIMNin were correlative factors that affected IIMNI dose. Conclusions: For patients who underwent PMRT without IMN irradiation (IMNI), there was a wide variety in IIMNI doses. A minority of patients had adequate IIMNI dose coverage, and the higher IIMNI doses were associated with the less body weights and more RIMNin.

Objective:To assess the feasibility of delayed-enhancement MRI in contouring the lumpectomy cavity (LC) for patients with invisible seroma or a low cavity visualization score (CVS≤2) in the excision cavity after breast-conserving surgery (BCS).Methods:Twenty-six patients with stage T 1-2N 0M 0 who underwent prone radiotherapy after BCS were recruited. The LC delineated on CT simulation images was denoted as LC CT. The LCs delineated on T 2WI, as well as on different delayed phases (2-, 5-and 10-minute) of delayed-enhancement T 1WI were defined as LC T2, LC 2T1, LC 5T1 and LC 10T1, respectively. Subsequently, the volumes and locations of the LCs were compared between CT simulation images and different sequences of MR simulation images using deformable image registration. Results:The volumes of LC T2, LC 2T1, LC 5T1 and LC 10T1 were all larger than that of LC CT. A statistical significance was found between the volume of LC CT and those of LC 2T1 or LC 5T1, respectively (both P<0.05). The conformal index (CI), degree of inclusion (DI), dice similarity coefficient (DSC) and the distance between the center of mass of the targets (COM) of LC CT-LC 10T1 were better than those of LC CT-LC T2, LC CT-LC 2T1 and LC CT-LC 5T1, however, there was no statistical difference among them (all P>0.05). Conclusions:It is feasible to delineate the LC based on prone delayed-enhancement MR simulation images in patients with low CVS after BCS. Meanwhile, the LCs derived from prone delayed-enhancement T 1WI of 10-minute are the most similar with those derived from prone CT simulation scans using titanium clips, regardless of the volumes and locations of LCs.

Objective:To compare positional and volumetric differences between the gross target volumes (GTV) delineated on three-dimensional CT (3D-CT) referencing 18F-FDG PET/CT and the GTV on the deformed image derived from 3D-CT and 18F-FDG PET/CT for primary thoracic esophageal cancer (EC). Methods:Seventy-two patients underwent chemoradiotherapy were enrolled. All the patients sequentially underwent 18F-FDG PET/CT scans for diagnosis and 3D-CT scans for simulation. The GTV 3D was delineated on 3D-CT without referencing 18F-FDG PET/CT. The GTV PET-ref was delineated on 3D-CT referencing 18F-FDG PET/CT. The GTV PET-regwas delineated on the deformed image derived from 3D-CT and 18F-FDG PET/CT by MIM deformable registration software. The differences in position, volume, length, conformity index (CI), and degree of inclusion (DI) of target volumes were compared, respectively. Results:The median volume of GTV 3D, GTV PET-ref, GTV PET-reg were 44.90, 40.36 and 41.15 cm 3, respectively. There was no statistical difference between the volumes of any two targets. The mean lengths of GTV 3D, GTV PET-ref, GTV PET-reg were 8.54, 9.29 and 8.38 cm, respectively. The length of GTV PET-ref was longer than that of GTV 3D ( t=2.134, P<0.05). The median DIs of GTV PET-ref, GTV PET-regin GTV 3D were 0.86, 0.82( Z=-2.741, P<0.05), and that of GTV 3D in GTV PET-ref, GTV PET-reg were 0.87, 0.84 ( Z=-1.429, P<0.05). The median CIs of GTV 3D in GTV PET-ref and GTV PET-reg were 0.72, 0.68 ( Z=2.756, P<0.05), and the difference was significant. The CIs of GTV 3D and GTV PET-ref, GTV 3D and GTV PET-reg, GTV PET-ref and GTV PET-reg had significant negative correlation with the distance of target centers. Conclusions:There was no significant difference between GTV contoured on three-dimensional CT (3D-CT) referencing 18F-FDG PET/CT and the GTV on the deformed image derived from 3D-CT and 18F-FDG PET/CT either in volume size or in spatial position. Therefore, it is recommended that radiation oncologists can refer to the recent diagnostic PET/CT when delineating the gross target volume for primary thoracic esophageal cancer.

Objective:To explore the interobserver variabilities in the delineation of the target volume using simulation three-dimensional computed tomography (3DCT) between the supine and prone positions for external-beam partial breast irradiation (EB-PBI) after breast-conserving surgery (BCS).Methods:Twenty-seven breast cancer patients who were scheduled to receive EB-PBI after BCS from July 2016 to April 2017 were enrolled in this study. All patients underwent axial 3DCT simulation scanning in the supine and prone positions during free breathing. Based on two different simulation 3DCT acquired, the gross target volume (TB) formed by using surgical clips and the clinical target volume (CTV) were delineated by five radiologists using specific guidelines. The following parameters including the target volume, coefficient of variations (COV) and matching degree (MD) were calculated to analyze the interobserver variability. Twenty-seven breast cancer patients who were scheduled to receive EB-PBI after BCS from July 2016 to April 2017 were enrolled in this study.Results:Whether in the supine or prone position, the interobserver variabilities for TB and CTV were statistically significant ( P<0.001, P=0.001, P<0.001, P=0.001). And the intersection of CTV in the prone position was 5.79 cm 3 greater than that in the supine position ( P=0.011). The interobserver variability of COV CTV in the prone positionwas significantly lower than that in the supine position ( P=0.014). And the interobserver variabilities of MDTB TB and MDTB CTV in the prone positionwere statistically greater than those in the supine position, respectively ( P<0.001, P= 0.001). Conclusions:When delineating the target volume of EB-PBI in the prone position, the interobsever variability can be reduced compared with that in the supine position. Hence, it is more reasonable to carry out EB-PBI in the prone position in free breathing.

Purpose: Mapping the distribution of internal mammary sentinel lymph nodes (IM-SLNs) presented on single photon emission computed tomography in conjunction with computed tomography (SPECT/CT) images to explore the value of IM-SLN to guide tailored clinical target volume (CTV) delineation of postoperative prophylactic IMNI.Materials and methods: Ninety-seven patients who underwent preoperative lymphoscintigraphy by SPECT/CT and had imaging of IM-SLN were selected in this study. The imaging IM-SLNs on SPECT/CT of eligible patients were projected onto corresponding anatomical positions of a representative axial CT image. The IMN CTVs were delineated on the representative axial CT images according to the Radiation Therapy Oncology Group (RTOG) and Danish Breast Cancer Cooperative Group (DBCG) guideline, and defined as CTVRTOG and CTVDBCG. The location of the IM-SLNs was compared with the RTOG and DBCG guidelines of IMN target volume delineations, respectively. The intercostal space distribution of IM-SLNs was recorded. The distances from the CTVRTOG and CTVDBCG to the IM-SLNs were measured, respectively.Results: The total number of imaging IM-SLNs was 136. IM-SLNs were mostly found in the first intercostal space (40.4%), with 30.2, 24.3, 4.4, and 0.7% of IM-SLNs in the second, third, fourth, and fifth intercostal space, respectively. The average distance from the edge of the CTVRTOG and the edge of CTVDBCG to the central points of the IM-SLNs was 4.10 mm (SD, 3.3 mm) and 1.60 mm (SD, 2.6 mm), respectively (t = 16.640, P = 0.000). The average distance from the edge of CTVRTOG and the edge of CTVDBCG to the lateral border IM-SLN was 6.40 mm (SD, 3.5 mm) and 3.34 mm (SD, 3.3 mm), respectively (t = 19.815, P = 0.000). Only 18.4% of IM-SLN central points were included in the CTVRTOG, and 60.3% of IM-SLN central points were included in the CTVDBCG. When covering 90 and 100% of the IM-SLN center points, the CTVRTOG needs to expand 8 and 15 mm, respectively, and the CTVDBCG needs to expand 5 and 13 mm, respectively.Conclusion: Neither the RTOG nor DBCG consensus guideline about the delineation of IMN CTV was sufficient to cover 90% of IM-SLNs. For 90% coverage of IM-SLN central points, CTVRTOG needed to be expanded by 8 mm, and CTVDBCG needed to be expanded by 5 mm.

Background: The study aimed to compare normal oesophageal wall thickness based on 3-dimensional computed tomography (3DCT), 4-dimensional computed tomography (4DCT) and cone beam computed tomography (CBCT). Methods: Contrast-enhanced 3DCT, 4DCT, and CBCT scans were acquired from 50 patients with lung cancer or metastatic lung cancer. The outer oesophageal wall was manually contoured on each 3DCT, the maximum intensity projection of 4DCT (4DCT MIP ) the end expiration phase of 4DCT (4DCT 50 ) (the end expiration phase of 4DCT) and the CBCT data sets. The average wall thicknesses were measured (defined as R 3DCT , R 50 , R MIP , and R CBCT ). Results: Whether for thoracic or for intra-abdominal segments, there were no significant differences between R 3DCT and R 50 , but significant differences between R 3DCT and R MIP , R 3DCT and R CBCT . For upper and middle oesophagus, R CBCT were larger than R MIP . There was no significant difference between upper and middle segments on 3DCT, 4DCT, and CBCT. Intra-abdominal oesophageal wall thickness was greater than that of thoracic oesophagus. There were no differences between upper and lower, and middle and lower oesophagus on CBCT. Conclusion: Our findings indicate normal oesophageal wall thickness differed along the length of oesophagus whatever it was delineated on 3DCT, 4DCT (4DCT 50 and 4DCT MIP ) or CBCT. It is reasonable to use uniform criterion to identify normal esophageal wall thickness when delineating gross tumor volume on 3DCT and 4DCT 50 , the same is true of delineating internal gross tumor volume on 4DCT MIP or CBCT images for lower and intra-abdominal oesophagus. But, in spite of using contrast-enhanced scanning, relatively blurred boundary on the CBCT images is noteworthy, especially for upper and middle thoracic esophagus.

BACKGROUNDTo study the effects and adverse reactions of different doses and fractionated radiotherapies on non-epidermal growth factor receptor (EGFR) mutant lung adenocarcinoma patients with multiple brain metastases.METHODSIn total, 80 patients eligible for inclusion were randomly divided into 4 groups. Group A included whole brain radiotherapy (WBRT) alone 300 cGy/fraction ×10 fractions, at a total dose of 3,000 cGy. Group B included WBRT alone 180 cGy/fraction ×22 fractions, at a total dose of 3,960 cGy. Group C included intracranial metastases radiotherapy alone 250 cGy/fraction ×22 fractions at a total dose of 5,500 cGy. Group D included the whole brain + intracranial metastases group (SIB group) whole brain 180 cGy/fraction ×22 fractions intracranial metastases 250 cGy/fraction ×22 fractions, at a total dose 3,960 cGy, 5,500 cGy, respectively.RESULTSThe median survival time of intracranial disease-free survival (IPFS) in group A, group B, group C, and group D was 6, 9, 8, and 13 months, respectively (P=0.000). The median overall survival (OS) time was 16, 24.5, 24, and 30 months, respectively (P=0.150). There was a significant difference in IPFS between different doses and fractionated radiotherapies, but there was no difference in OS. Multivariate analysis showed that the radiotherapy dose of intracranial metastases was positively correlated with IPFS and OS. The incidence rate of adverse reaction of memory decline in 0.5, 1, and 2 years in group A, group B, group C, and group D was respectively 10.0%, 15.0%, 5.0%, and 15.0% (P=0.006); 20.0%, 45.0%, 30.0%, and 60.0% (P=0.000); 10.0%, 20.0%, 35.0%, and 65.0% (P=0.000). The incidence rates of memory decline in the groups of WBRT were significantly more increased than in the non-WBRT group.CONCLUSIONSRadiotherapy is effective for multiple brain metastases of lung adenocarcinoma, the increase of radiotherapy dose can improve IPFS and OS, and the adverse reaction of memory decline after WBRT is increased but tolerable. Therefore, WBRT and simultaneous integrated boost (SIB) radiotherapy of intracranial metastases is recommended for multiple brain metastases of non-EGFR-mutant lung adenocarcinoma.

Objective To detect the changes of heart volume during concurrent chemoradiotherapy for esophageal cancer based on repeated enhanced 4DCT. Methods Patients with squamous cell esophageal cancer underwent repeated enhanced 4DCT and 3DCT scans before and after 10, 20 and 30 fractions of radiotherapy, respectively. The heart was contoured on 3DCT, end expiratory (EE) and maximum intensity projection (MIP) of 4DCTimages. The changes in theheart volume, blood pressure and heart rate were statistically compared at different time points. Results A total of forty-six patients completed 4 fractions of 3DCT and enhanced 4DCT scans. Compared with the initial values, the heart volume was significantly decreased by 3.27%, 4.45% and 4.52% after 10 fractions of radiotherapy, and reduced by 6.05%, 5.64% and 4.51% following 20 fractions of radiotherapy on 3DCT, EE and MIP, respectively (P=0.000-0.027). The heart volume after 30 fractions of radiotherapy did not significantly differ from the initial volume (P>0.05). After radiotherapy, there was a significant decrease inboth systolic and diastolic blood pressure (P=0.000 and P=0.009) and a significant increase in the heart rate (P=0.001) compared with those measured before radiotherapy. Conclusions Enhanced 4DCT scan can clearly reflect the changes of heart volume throughout concurrent chemoradiotherapy. The heart volume starts to shrink during the early stage of radiotherapy and continue to decrease until the middle-and late-stage, whereas it restores to the initial volume after radiotherapy. Simultaneously, blood pressure declines and heart rate is accelerated during radiotherapy. Key words: Esophageal neoplasm/concurrent chemoradiotherapy; Tomography, X-ray computed, four-dimensional; Heart volume