Background and objective Transcription factor(TF)can bind specific sequences that either promotes or represses the transcription of target genes,and exerts important effects on tumorigenesis,migration,invasion.Staphylococcal nuclease-containing structural domain 1(SND1),which is a transcriptional co-activator,is considered as a promising target for tumor therapy.However,its role in lung adenocarcinoma(LUAD)remains unclear.This study aims to explore the role of SND1 in LUAD.Methods Data from The Cancer Genome Atlas(TCGA),Gene Expression Omnibus(GEO),Clinical Pro-teomic Tumor Analysis Consortium(CPTAC),and Human Protein Atlas(HPA)database was obtained to explore the associa-tion between SND1 and the prognosis,as well as the immune cell infiltration,and subcellular localization in LUAD tissues.Furthermore,the functional role of SND1 in LUAD was verified in vitro.EdU assay,CCK-8 assay,flow cytometry,scratch assay,Transwell assay and Western blot were performed.Results SND1 was found to be upregulated and high expression of SND1 is correlated with poor prognosis of LUAD patients.In addition,SND1 was predominantly present in the cytoplasm of LUAD cells.Enrichment analysis showed that SND1 was closely associated with the cell cycle,as well as DNA replication,and chro-mosome segregation.Immune infiltration analysis showed that SND1 was closely associated with various immune cell popula-tions,including T cells,B cells,cytotoxic cells and dendritic cells.In vitro studies demonstrated that silencing of SND1 inhib-ited cell proliferation,invasion and migration of LUAD cells.Besides,cell cycle was blocked at G,phase by down-regulating SND1.Conclusion SND1 might be an important prognostic biomarker of LUAD and may promote LUAD cells proliferation and migration.

Background and objective Lung cancer is a leading cause of cancer-related deaths.Non-small cell lung cancer(NSCLC)is the most common pathological subtype,with adenocarcinoma being the predominant type.FAT atypical cadherin 1(FAT1)is a receptor-like protein with a high frequency of mutations in lung adenocarcinoma.The protein encoded by FAT1 plays a crucial role in processes such as cell adhesion,proliferation,and differentiation.This study aims to investigate the expression of FAT1 in lung adenocarcinoma and its relationship with immune infiltration.Methods Gene expression levels and relevant clinical information of 513 lung adenocarcinoma samples and 397 adjacent lung samples were obtained through The Cancer Genome Atlas(TCGA)and Genotype-Tissue Expression(GTEx)data.The mRNA expression levels of the FAT1 gene in lung adenocarcinoma tissues were analyzed,along with its association with the prognosis of lung adenocarcinoma patients.Pathway enrichment analysis was conducted to explore the signaling pathways regulated by the FAT1 gene.Immu-noblotting was used to detect the differential expression of FAT1 in lung epithelial cells and various lung cancer cell lines,while immunohistochemistry was employed to assess FAT1 expression in lung cancer and adjacent tissues.Results FAT1 gene muta-tions were identified in 14%of lung adenocarcinoma patients.TCGA database data revealed significantly higher FAT1 mRNA expression in lung adenocarcinoma tissues compared to adjacent lung tissues.Kaplan-Meier analysis indicated lower survival rates in lung adenocarcinoma patients with higher FAT gene expression.Pathway enrichment analysis suggested the involve-ment of FAT1 in tumor development pathways,and its expression was closely associated with immune cell infiltration.Immu-nohistochemical validation demonstrated significantly higher expression of FAT1 in cancer tissues compared to adjacent lung tissues.Conclusion FAT1 mRNA is highly expressed in lung adenocarcinoma tissues,and elevated FAT1 mRNA expression is associated with poor prognosis in lung adenocarcinoma patients.FAT1 may serve as a potential biomarker for lung cancer.

Objective: To investigate the prospective effects of intake of each food group on the development of lung function of pupils,so as to provide theoretical basis for promoting the healthy development of lung function and preventing chronic respiratory diseases in Chinese children. Methods: A cluster stratified sampling method was used to select a total of 893 pupils in grades 2-5 from Chengdu in November 2021. Dietary data of respondents were collected using a food frequency questionnaire within the past year,then the food group intake was categorized into T1, T2 and T3 from low to high by the trichotomous method, and anthropometric measurements including lung capacity were obtained in 2022. Logistic regression models and test for trend were used to analyze the prospective effects of intake of each food group on lung function development of pupils. Results: Among male students, consumption of vegetables [118.6(50.5, 188.2)g/d] and milk and dairy products [200.0(73.3, 250.0)g/d] were higher in the excellent lung capacity group than in the non excellent lung capacity group [90.0(37.1, 192.9), and 178.6(35.7, 250.0)g/d],with statistically significant differences ( Z =-1.98, -2.24); among girls, the group with excellent lung capacity consumed less staple food [391.1(273.6, 511.4)g/d] than the group with non excellent lung capacity [407.4(309.5, 594.3)g/d], and the group with excellent lung capacity consumed more aquatic products [31.2(14.6, 69.8)g/d] and milk and dairy products [215.0(107.1, 250.1) g/d ] than that of the non excellent lung capacity [19.4(10.7, 58.3), 114.3(35.7, 250.0)g/d] ( Z =-2.01, -3.33, -5.10)( P < 0.05 ). After adjusting for energy, body mass index Z score(BMI Z ), mother s education level, averge family income monthly, whether presence of smokers in the living environment, and whether participation in physical activities during the past week, among male students, T3 group of vegetable intake ( OR =0.48, 95% CI = 0.27-0.86), T2 group of bean and soy product intake ( OR = 0.52 , 95% CI =0.27-0.96)，T2 and T3 groups of milk and dairy products intake (T2： OR =0.54, 95% CI =0.31-0.93; T3： OR = 0.52 , 95% CI =0.30-0.90) were negatively associated with non excellent lung capacity ( P <0.05). Among girls, T3 group of aquatic product intake( OR =0.52, 95% CI =0.28-0.97), T2 and T3 groups of milk and dairy product (T2: OR =0.44, 95% CI =0.25- 0.76 ;T3: OR =0.33, 95% CI =0.19-0.59) were negatively associated with nonexcellent lung capacity, whereas the T2 group of red meat intake ( OR =2.51, 95% CI =1.37-4.67) was positively associated with non excellent lung capacity. Non excellent lung capacity was found to be negatively associated with vegetable and milk and dairy product intake in boys by test for trend; in girls, milk and dairy products intake was negatively associated with non excellent lung capacity, whereas red meat intake was positively associated with non excellent lung capacity ( t =-1.13，-0.44；-3.03，1.95, P trend <0.05). Conclusions Milk and dariy products intakes reduce the risk of non excellent lung capacity in pupils, vegetables intakes reduce the risk of non excellent lung capacity in boys, and the intake of red meat increases the risk of non excellent lung capacity in girls. Promoting rational food choices is necessary for children to improve healthy lung development.

Objective:To analyze clinical efficacy of intensity-modulated chemoradiotherapy for patients with anal squamous cell carcinoma and identify prognostic factors.Methods:Clinical data of patients with anal squamous cell carcinoma who received intensity-modulated chemoradiotherapy in the Cancer Hospital of Chinese Academy of Medical Sciences from January 1, 2010 to January 1, 2022 were retrospectively analyzed. Regular follow-up was carried out. The main indexes included disease-free survival (DFS), locoregional failure-free survival (LRFFS) and overall survival (OS), and adverse reactions were recorded. The survival curve was delineated by Kaplan-Meier method and the influencing factors of survival were analyzed by Cox regression models.Results:A total of 65 patients were enrolled with 19 (29%) males and 46 (71%) females. According to the American Joint Committee on Cancer (AJCC) 7 th edition staging, there were 7 (11%), 28 (43%), 10 (15%), and 20 (31%) patients with stage I, II, IIIa, and IIIb, respectively. Before the chemoradiotherapy, 2 (3%) patients received chemotherapy and 12 (18%) patients received local resection. The median dose of radiotherapy was 54 Gy (range: 45-64 Gy) and the main concurrent chemotherapy regimen was capecitabine combined with cisplatin ( n=34, 52%). The completion rate of radiotherapy during concurrent chemoradiotherapy was 100%, and the chemotherapy completion rate was 88%. During the therapy, 5 patients (8%) were interrupted but completed concurrent chemoradiotherapy in full dose, and 8 patients (12%) reduced the dose of concurrent chemotherapy due to the toxicities. During the chemoradiotherapy, 15 cases (23%) experienced grade 3-4 leukopenia, and 17 cases (26%) experienced grade 3-4 radiation dermatitis. No treatment-related death occurred during the treatment. The median follow-up time was 50.4 months (range: 4.4-142.2 months), local recurrence occurred in 7 cases (11%), distant metastasis occurred in 3 cases (5%), and the 5-year DFS, LRFFS and OS rates were 78.8%, 86.5% and 85.1%, respectively. Cox univariate analysis indicated that T stage was significantly associated with DFS ( P=0.006), and tended to be associated with OS ( P=0.054). Conclusions:Intensity-modulated radiotherapy combined with concurrent chemotherapy is an effective treatment for anal squamous cell carcinoma, with tolerable acute toxicities. T stage is an influencing factor of DFS in anal squamous cell carcinoma patients.

The kidneys are one of the main excretory organs for drugs and when drugs are not excreted effectively, they can accumulate in the kidneys or in the interstitial tubules, leading to drug-induced kidney injury. The tubulointerstitium accounts for 80% of the volume of the kidney and is the primary site of response to various types of renal injury. This article focuses on drug-induced acute interstitial nephritis, highlighting its clinical symptoms, listing common induction drugs, analysing pathological features, and explaining its pathogenesis from the perspective of immune response, with the aim of providing a basic and clinical evidence for subsequent studies.

Objective:To investigate the clinical efficacy and prognostic influencing factors of radical surgery for duodenal gastrointestinal stromal tumor (GIST).Methods:The retrospective cohort study was conducted. The clinicopathological data of 741 duodenal GIST patients who under-went radical surgery in 17 medical centers, including 121 cases in Renji Hospital Affiliated to Shanghai Jiaotong University School of Medicine, 121 cases in Chinese PLA General Hospital, 116 cases in Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 77 cases in Fudan University Shanghai Cancer Center, 77 cases in West China Hospital, Sichuan University, 31 cases in Guangdong Provincial People′s Hospital, 24 cases in Fujian Cancer Hospital, 22 cases in Fujian Medical University Union Hospital, 25 cases in Shengjing Hospital of China Medical University, 19 cases in Xiangya Hospital, Central South University, 23 cases in Zhejiang Cancer Hospital, 17 cases in Liaoning Cancer Hospital＆Institute, 17 cases in the First Affiliated Hospital of Xiamen University, 15 cases in Sun Yat-sen University Cancer Center, 14 cases in the First Affiliated Hospital of Nanjing Medical University, 14 cases in Zhongshan Hospital Affiliated to Xiamen University and 8 cases in General Hospital of Chinese People′s Liberation Army Air Force, from January 2010 to April 2020 were collected. There were 346 males and 395 females, aged 55(range, 17?86)years. Observation indicators: (1) neoadjuvant treatment; (2) surgical and postoperative situations; (3) follow-up; (4) stratified analysis. Follow-up was conducted using outpatient examination or telephone interview. Patients were followed up once every 3?6 months during neoadjuvant therapy and once every 6?12 months after radical surgery to detect tumor recurrence and survival of patient up to April 2022. Measurement data with normal distribution were represented as Mean± SD. Measurement data with skewed distribution were represented as M(range), and comparison between groups was conducted using the Mann-Whitney U test. Count data were described as absolute numbers or percentages, and comparison between groups was conducted using chi-square test or Fisher exact probability. The Kaplan-Meier method was used to draw survival curves and calculate survival rates. Log-rank test was used for survival analysis. The COX regression model was used for univariate and multivariate analyses. Propensity score matching was done by the 1∶1 nearest neighbor matching method, and the matching tolerance was 0.02. Results:(1) Neoadjuvant therapy. Of the 741 patients, 34 cases received neoadjuvant therapy for 8(range, 3?44)months. Cases assessed as partial response, stable disease and progressive disease before the radical surgery of the 34 cases were 21, 9, 4, respectively. The tumor diameter of the 34 patients before the neoadjuvant therapy and before the radical surgery were 8.0(range, 3.0?26.0)cm and 5.3(range, 3.0?18.0)cm, with the regression rate as 31.9%(range, ?166.7% to 58.3%). (2) Surgical and postoperative situations. Of the 741 patients, 34 cases underwent radical surgery after receiving neoadjuvant therapy, and 707 cases underwent radical surgery directly. All the 741 patients underwent radical surgery successfully, in which 633, 102 and 6 cases received open surgery, laparoscopic surgery and endoscopic treatment, respectively. Of the 633 cases receiving open surgery and the 102 cases receiving laparoscopic surgery, cases with surgical resection range as pancreatoduodenectomy (PD) was 238, and cases with surgical resection range as duodenal limited resection, including duodenal wedge resection, distal gastrectomy, segmental duodenal resection, local resection of duodenal tumor or segmental duodenum combined with subtotal gastrectomy, was 497, 226, 55, 204, 12. Of the 741 patients, 131 cases had post-operative complications including 113 cases with grade Ⅰ?Ⅱ complications and 18 cases with ≥ grade Ⅲ complications of the Clavien-Dindo classification. The duration of postoperative hospital stay of the 741 patients was 13(range, 4?120)days. Of the 707 patients receiving direct radical surgery, 371 cases were evaluated as extremely low risk, low risk, medium risk of the modified National Institutes of Health (NIH) risk classification after surgery, and 336 cases were evaluated as high risk in which 205 cases receive postoperative adjuvant imatinib therapy with the treatment time as 24(range, 6?110)months. (3) Follow-up. All the 741 patients were followed up for 58(range, 7?150)months. During the follow-up, 110 patients had tumor recurrence and metastasis. The 1-, 3-, 5-year overall survival rates and 1-, 3-, 5-year disease-free survival rates of the 741 patients were 100.0%, 98.6%, 94.5% and 98.4%, 90.9%, 84.9%, respectively. The 1-, 3-, 5-year overall survival rates and 1-, 3-, 5-year disease-free survival rates of the 707 patients receiving direct radical surgery were 100.0%, 98.5%, 94.3% and 98.4%, 91.1%, 85.4%, respectively. (4) Stratified analysis. ① Analysis of prognostic factors in patients undergoing radical surgery directly. Results of univariate analysis showed that primary tumor location, tumor diameter, mitotic count, modified NIH risk classification and tumor gene information were related factors affecting the overall survival of 707 patients with primary duodenal GIST who underwent direct radical surgery ( hazard ratio=0.43, 0.18, 0.22, 0.06, 0.29, 95% confidence intervals as 0.20?0.93, 0.09?0.35, 0.10?0.50, 0.03?0.12, 0.09?0.95, P<0.05). The primary tumor location, tumor diameter, mitotic count, modified NIH risk classification were related factors affecting the disease-free survival of 707 patients with primary duodenal GIST who underwent direct radical surgery ( hazard ratio=0.65, 0.25, 0.25, 0.10, 95% confidence intervals as 0.41?1.03, 0.17?0.37, 0.15?0.42, 0.07?0.15, P<0.05). Results of multivariate analysis showed that primary tumor located at the horizontal segment of duodenum, mitotic count >5/50 high power field, tumor gene KIT exon 9 mutation were independent risk factors affecting the overall survival of 365 patients with primary duodenal GIST after removing 342 patients without tumor gene information who underwent direct radical surgery ( hazard ratio=2.85, 2.73, 3.13, 95% confidence intervals as 1.12?7.20, 1.07?6.94, 1.23?7.93, P<0.05). Tumor diameter >5 cm and mitotic count >5/50 high power field were independent risk factors affecting the disease-free survival of 707 patients with primary duodenal GIST who underwent direct radical surgery ( hazard ratio=3.19, 2.98, 95% confidence intervals as 2.05?4.97, 1.99?4.45, P<0.05). ② Effect of postoperative adjuvant therapy on prognosis of high-risk patients of modified NIH risk classification. Of the 336 patients evaluated as high risk of the modified NIH risk classification, the 5-year overall survival rate and 5-year disease-free survival rate were 94.6% and 77.3% in the 205 cases with postoperative adjuvant therapy, versus 83.2% and 64.4% in the 131 cases without postoperative adjuvant therapy, showing significant differences between them ( χ2=8.39, 4.44, P<0.05). Of the 205 patients evaluated as high risk of the modified NIH risk classification who received postoperative adjuvant therapy, there were 106 cases receiving postoperative adjuvant therapy <36 months, with the 5-year overall survival rate and 5-year disease-free survival rate were 87.1% and 58.7%, and there were 99 cases receiving post-operative adjuvant therapy ≥36 months, with the 5-year overall survival rate and 5-year disease-free survival rate were 100.0% and 91.5%. There were significant differences in the 5-year overall survival rate and 5-year disease-free survival rate between the 106 patients and the 99 patients ( χ2=13.92, 29.61, P<0.05). ③ Comparison of clinical efficacy of patients with different surgical methods. Before propensity score matching, cases with primary tumor located at bulb, descending, horizontal, ascending segment of duodenum, cases with tumor diameter ≤5 cm and >5 cm were 95, 307, 147, 34, 331, 252, in the 583 patients receiving open surgery with complete clinical data, versus 15, 46, 17, 5, 67, 16 in the 83 patients receiving laparoscopic surgery with complete clinical data, showing no significant difference in the primary tumor location ( χ2=0.94, P>0.05), and a significant difference in the tumor diameter ( χ2=17.33, P<0.05) between them. After propensity score matching, the above indicator were 16, 39, 20, 8, 67, 16 in the 83 patients receiving open surgery, versus 15, 46, 17, 5, 67, 16 in the 83 patients receiving laparoscopic surgery, showing no significant difference between them ( χ2=1.54, 0.00, P>0.05). Cases with postoperative complications, cases with grade Ⅰ?Ⅱ complica-tions and ≥grade Ⅲ complications of the Clavien-Dindo classification, duration of postoperative hospital stay, the 5-year overall survival rate and 5-year disease-free survival rate were 17, 12, 5, 11(range, 5?120)days, 92.0%, 100.0% in the 83 patients receiving open surgery, versus 9, 7, 2, 11(range, 5?41)days, 91.6%, 97.3% in the 83 patients receiving laparoscopic surgery, showing no signi-ficant difference in postoperative complications, duration of postoperative hospital stay, the 5-year overall survival rate and 5-year disease-free survival rate ( χ2=2.91, Z=3 365.50, χ2=3.02, 1.49, P>0.05) between them. There was no significant difference in complications of the Clavien-Dindo classification between them ( P>0.05). ④ Comparison of clinical efficacy of patients with primary tumor located at the descending segment of duodenum who underwent surgery with different surgical resection scopes. Before propensity score matching, cases with tumor diameter ≤5 cm and >5 cm, cases with tumor located at opposite side of mesangium and mesangium were 71, 85, 28, 128 in the 156 patients with primary tumor located at the descending segment of duodenum who underwent PD with complete clinical data, versus 92, 41, 120, 13 in the 133 patients with primary tumor located at the descending segment of duodenum who underwent duodenal limited resection with complete clinical data, showing significant differences between them ( χ2=16.34, 150.10, P<0.05). After propensity score matching, the above indicator were 28, 13, 16, 25 in the 41 patients with primary tumor located at the descending segment of duodenum who underwent PD with complete clinical data, versus 28, 13, 16, 25 in the 41 patients with primary tumor located at the descending segment of duodenum who underwent duodenal limited resection with complete clinical data, showing no significant difference between them ( χ2=0.00, 0.00, P>0.05). Cases with postopera-tive complications, cases with grade Ⅰ?Ⅱ complications and ≥grade Ⅲ compli-cations of the Clavien-Dindo classification, duration of postoperative hospital stay, the 5-year overall survival rate and 5-year disease-free survival rate were 13, 11, 2, 15(range, 9?62)days, 94.2%, 64.3% in the 41 patients with primary tumor located at the descending segment of duodenum who underwent PD with complete clinical data, versus 9, 8, 0, 15(range, 7?40)days, 100.0%, 78.8% in the 41 patients with primary tumor located at the descending segment of duodenum who underwent duodenal limited resection with complete clinical data, showing no significant difference in post-operative complica-tions, the 5-year overall survival rate and 5-year disease-free survival rate ( χ2=0.99, 0.34, 1.86, P>0.05) between them. There was no significant difference in complications of the Clavien-Dindo classification ( P>0.05) and there was a significant difference in duration of postopera-tive hospital stay ( Z=614.50, P<0.05) between them. Conclusions:The clinical efficacy of radical surgery for duodenal GIST are ideal. Primary tumor located at the horizontal segment of duodenum, mitotic count >5/50 high power field, tumor gene KIT exon 9 mutation are independent risk factors affec-ting the overall survival of patients undergoing direct radical surgery and tumor diameter >5 cm and mitotic count >5/50 high power field are independent risk factors affecting the disease-free survival of patients. There is no significant difference in the short-term efficacy and long-term prognosis between patients undergoing open surgery and laparoscopic surgery. For patients with primary tumor located at the descending segment of duodenum, the duration of postoperative hospital stay is longer in patients undergoing PD compared with patients undergoing duodenal limited resection. For patients evaluated as high risk of the modified NIH risk classification, posto-perative adjuvant therapy and treatment time ≥36 months are conducive to improving the prognosis of patients.

Objective:To investigate the workflow, efficacy and safety of MR-Linac in liver malignancies.Methods:Clinical data of 15 patients with hepatocellular carcinomas (HCC) or liver metastases treated with MR-Linac between November 2019 and July 2021 were retrospectively analyzed. The workflow of MR-Linac was investigated and image identification rate was analyzed. Patients were followed up for response and toxicity assessment.Results:Fifteen patients (6 HCC, 8 liver metastases from colorectal cancer, 1 liver metastasis from breast cancer) were enrolled. A total of 21 lesions were treated, consisting of 10 patients with single lesion, 4 patients with double lesions and 1 patient with triple lesions. The median tumor size was 2.4 cm (0.8-9.8 cm). The identification rate for gross tumor volume (GTV) in MR-Linac was 13/15. Although GTV of two patients were unclearly displayed in MR-Linac images, the presence of adjacent blood vessel and bile duct assisted the precise registration. All the patients were treated with stereotactic body radiation therapy (SBRT). For HCC, the median fraction dose for GTV or planning gross tumor volume (PGTV) was 6 Gy (5-10 Gy) and the median number of fractions was 9(5-10). The median total dose was 52 Gy (50-54 Gy) and the median equivalent dose in 2 Gy fraction (EQD 2Gy) at α/ β= 10 was 72 Gy (62.5-83.3 Gy). For liver metastases, the median fraction dose for GTV or PGTV was 5 Gy (5-10 Gy) and the median number of fractions was 10(5-10). The median total dose was 50 Gy (40-50 Gy) and the median EQD 2Gy at α/ β=5 was 71.4 Gy (71.4-107.1 Gy). At 1 month after SBRT, the in-field objective response rate (ORR) was 8/13 and the disease control rate was 13/13. At 3-6 months after SBRT, the in-filed ORR was increased to 6/6. During the median follow-up of 4.0 months (0.3-11.6), 4-month local progression-free survival, progression-free survival and overall survival were 15/15, 11/15 and 15/15, respectively. Toxicities were mild and no grade 3 or higher toxicities were observed. Conclusions:MR-Linac provides a platform with high identification rates of liver lesions. Besides, the presence of adjacent blood vessel and bile duct also assists the precise registration. It is especially suitable for liver malignancies with promising local control and well tolerance.

Objective:To describe a prospective study of pre-operative tumor-bed boost performed at the 1.5 T MR-Linac in combination with adjuvant whole breast irradiation, and a first case, with an accentuation on clinical feasibility and safety.Methods:A phase II, single arm study recruiting early stage patients follows a paradigm that first boosts the tumor bed and then undergoes breast conservative surgery in 2 weeks, and last irradiates the whole breast in 6 weeks. The primary endpoint is ≥ grade 2 acute breast toxicity. A 43 years old patient affected by a breast carcinoma, not special type of the right-sided lateral quadrant, staged cT 2N 0M 0, was planned and treated. The dose, 8 Gy for one time, was calculated by Monaco on CT simulation images. Both the air electron stream effect (ESE) and the electron return effect (ERE) at the presence of 1.5 T magnetic field were evaluated. During the pre-treatment evaluation, we carried out adaptation-to-position adjustment. Results:The normal organ dosimetry is within toleration. The Dmax to the skin, the chin and the right upper arm was 8.44 Gy, 28.5 cGy and 17.8 cGy, respectively. There was no increased toxicity from ERE and ESE, and the treatment was well tolerated without > grade 1 acute toxicity. The patient received breast conservative surgery on day 7 without delayed wound healing.Conclusions:This is the first case successfully treated within a clinical trial by pre-operative tumor-bed boost under 1.5 T MR-Linac in our institution. More participants are needed to validate and optimize the paradigm.

Objective:To investigate the dosimetric characteristics, acute toxicity and short-term efficacy of postmastectomy hypofractionated internal mammary (IM) chain irradiation with electrons in patients with high-risk breast cancer.Methods:A total of 155 patients with breast cancer who underwent modified mastectomy between November 2018 and January 2020 were selected. Among them, 137(88.4%) patients were classified as stage Ⅲ and 18(11.6%) as stage Ⅱ. All patients received standard chemotherapy, endocrine therapy and anti-Her2 targeted therapy. CTV im was divided into three subregions: CTV im1, CTV im2 and CTV im3, which represented the first, second and third intercostal IM, respectively. The planning target volume of subraclavicular region (PTV sc) was delineated. CTV cw and CTV im were irradiated with 6-15 MeV electron at 43.5 Gy in 15 fractions over 3 weeks. Moreover, PTV sc was irradiated with 6 MV X-ray at 43.5 Gy in 15 fractions over 3 weeks using two-dimensional radiotherapy (2DRT) or three-dimensional radiotherapy (3DRT). The dosimetric characteristics of CTV im, PTV sc, lung, heart, left anterior descending coronary artery (LAD) and right coronary artery (RA) were evaluated, and the acute toxicity and short-term efficacy were analyzed. Results:The mean dose (D mean) of CTV im was (43.3±2.6) Gy, D 95% was (30.5±8.3) Gy, V 90% was (85.0±10.5)% and V 80% was (91.0±7.4)%, respectively. The corresponding parameters of CTV im1 were significantly lower than those of CTV im2 and CTV im3(all P<0.001). Body mass index exerted no significant effect on IM dose ( P>0.05). Compared with 2DRT, 3DRT for SC significantly increased theD mean of CTV im[(43.4±2.6) Gy vs.(41.4±2.3) Gy, P=0.021], and the hot spot within PTV sc[V 110%: (26.7±17.5) cm 3vs.(12.5±8.4) cm 3, P=0.018; V 120%: (6.1±5.3) cm 3vs.(2.0±2.6) cm 3, P=0.023]. TheD mean of the ipsilateral lung was (9.8±1.9) Gy, and V 20Gy was (19.7±4.7)%. TheD mean of heart was (3.3±1.7) Gy in the whole group, (4.7±1.4) Gy for the left-sided breast cancer and (2.6±1.2) Gy for the right-sided breast cancer, respectively. TheD mean of LAD for the left-sided breast cancer was (13.9±4.9) Gy. TheD mean of RA for the right-sided breast cancer was (7.5±3.7) Gy. The incidence rates of ≥ grade 2 acute radiation dermatitis, esophagitis and pneumonitis were 19.3%, 4.5% and 2.6%, respectively. With a median follow-up time of 20.5 months (range: 9.9-41.8 months), 2 cases of chest wall recurrence, 2 regional lymph node recurrence, 6 distant metastases and 1 death were reported. Conclusions:When hypofractionated internal mammary chain is irradiated by electrons after mastectomy, the doses to the lung, heart and coronary artery are low, and the acute toxicities are mild. However, the dose to CTV im1 is inadequate. Although short-term efficacy is high, long-term follow-up is warranted.

Objective:To compare magnetic resonance imaging (MRI)-based and computed tomography (CT)-based target volume delineation and dose coverage in partial breast irradiation (PBI) for patients with breast cancer, aiming to explore the application value of MRI localization in PBI after breast-conserving surgery.Methods:Twenty-nine patients with early breast cancer underwent simulating CT and MRI scans in a supine position. The cavity visualization score (CVS) of tumor bed (TB) was evaluated. The TB, clinical target volume (CTV), planning target volume (PTV) were delineated on CT and MRI images, and then statistically compared. Conformity indices (CI) between CT- and MRI-defined target volumes were calculated. PBI treatment plan of 40 Gy in 10 fractions was designed based on PTV-CT, and the dose coverage for PTV-MRI was evaluated.Results:The CVS on CT and MRI images was 2.97±1.40 vs. 3.10±1.40( P=0.408). The volumes of TB, CTV, PTV on MRI were significantly larger than those on CT, (24.48±16.60) cm 3vs. (38.00±19.77) cm 3, (126.76±56.81) cm 3vs. (168.42±70.54) cm 3, (216.63±81.99) cm 3vs. (279.24±101.55) cm 3, respectively, whereas the increasing percentage of CTV and PTV were significantly smaller than those of TB. The CI between CT-based and MRI-based TB, CTV, PTV were 0.43±0.13, 0.66±0.11, 0.70±0.09( P<0.001), respectively. The median percentage of PTV-MRI receiving 40 Gy dose was 81.9%(62.3% to 92.4%), significantly lower than 95.6%(95.0%~97.5%) of PTV-CT. Conclusions:The CVS between CT and MRI is not significantly different, but the MRI-based TB, CTV, PTV are significantly larger than CT-based values. The PTV-MRI is of underdose if PBI treatment plan is designed for PTV-CT. As a supplement of CT scan, MRI can enhance the accuracy of TB delineation after breast-onserving surgery.