Objective:To explore the patterns of failure after postoperative intensity-modulated radiotherapy for gastric cancer.Methods:Clinical data of patients diagnosed with gastric cancer or gastroesophageal junction carcinoma with pathological stages T 3-4N 0 or T xN 1-3 admitted to Cancer Hospital of Chinese Academy of Medical Sciences from May 2009 to December 2018 were retrospectively analyzed. All patients received postoperative radiotherapy. During the follow-up, tumor recurrence was confirmed by imaging or endoscopic or pathological data, etc. According to the location of tumor recurrence, recurrence patterns were divided into local, regional and distant recurrence. Differences in recurrence patterns among different groups were compared using t-test and Chi-square test. Patient survival was assessed through Kaplan-Meier method. Results:A total of 76 patients were enrolled, with a median age of 49 years old (27-67 years old), 34 cases (45%) were classified as T 3 stage, 40 cases (53%) of T 4 stage, and 75 cases (99%) of N 1-3 stage, respectively. Seventy-three patients (92%) were classified as stage Ⅲ, and 38 patients (50%) underwent D2 dissection. The median follow-up time was 32.8 months (7.1-138.5 months). The median time of recurrence was 17.6 months (2.9-113.6 months). The median survival time after recurrence was 8.19 months (0.6-91.9 months). There were 13 cases (17%) of local recurrence, 6 cases (8%) of regional recurrence, and 72 cases (95%) of distant metastasis in patients. Peritoneal metastasis (33 cases, 43%) and distant lymph node metastasis (12 cases, 16%) were the main patterns of distant recurrence. Conclusions:By intensity-modulated radiotherapy technology, adjuvant radiotherapy yields favorable local and regional control for gastric cancer. Distant metastasis is still the main pattern of recurrence.

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.

Objective To evaluate the predictive value of T2-fluid attenuated inversion recovery (FLAIR)signal suppression rate for the short arm of chromosome 1 and long arm of chromosome 19 (1p/19q)molecular features in lower-grade gliomas (LGG),and to construct and verify the predictive model based on magnetic resonance imaging (MRI)tumor features and T2-FLAIR signal suppression rate.Methods Clincal and imaging data of the patients with pathologically confirmed supratentorial LGG (WHO grade 2～3)in our medical center from 2017 to 2021 were collected and retrospectively analyzed.According to the results of postoperative molecular pathology,they were divided into 1 p/19q-codeleted (1 p/19q-Codel)and 1 p/19q-noncodeleted (1 p/19q-Noncodel)groups.MRI tumor features were blindly assessed by 2 neuroradiologists.Five circular regions of interest were respectively delineated in the tumor area and the normal-appearing white matter in contralateral semioval center using the hot-spot method in order to calculate the T2-FLAIR signal suppression rate.The differences of clinical features,MRI tumor features and T2-FLAIR signal suppression rate were analyzed between the 2 groups.Univariate and multivariate logistic regression analyses were used to screen independent predictors and constructa predictive model and nomogram.Receiver operating characteristic (ROC)curve,calibration curve and Hosmer-Lemeshow test were applied to assess the model performance,and the model was internally validated by bootstrap method.Results A total of 146 supratentorial LGG patients were enrolled,including 68 being assigned into the 1 p/19q-Codel group and 78 into the 1 p/19q-Noncodel group.The T2-FLAIR signal suppression rate was 0.43 (0.28,0.62)in the 1 p/19q-Noncodel group,which was significantly higher than that in the 1 p/19q-Codel group[0.29 (0.24,0.35),P<0.001].Multivariate logistic regression analysis showed that T2-FLAIR signal suppression rate>0.374 (P<0.001),cortex infiltration (P=0.001) and calcification (P=0.004) were independent predictors for 1 p/19q status.The AUC value of T2-FLAIR signal suppression rate>0.374 in predicting 1 p/19q-Noncodel was 0.720,the sensitivity was 60.26％ and the specificity was 83.82％.DeLong test indicated that T2-FLAIR signal suppression rate>0.374 was more effective than T2-FLAIR mismatch sign in predicting 1 p/19q molecular features (P<0.001).ROC curve analysis suggested that the predictive model established by T2-FLAIR signal suppression rate>0.374 combined with cortex infiltration and calcification had good performance,with an AUC value of 0.808,and the AUC value verified internally by bootstrap method was 0.807.At the same time,the calibration and goodness of fit of the model were good.Conclusion T2-FLAIR signal suppression rate can be used as a quantitative imaging marker to predict 1 p/19q-Noncodel LGG.The predictive model with T2-FLAIR signal suppression rate>0.374 combined with cortex infiltration and calcification can effectively predict 1 p/19q molecular features.

Abstract Allergic diseases can occur in all systems of the body, covering the whole life cycle, from children to adults and to old age, can be lifelong onset and even fatal in severe cases. Children account for the largest proportion of the victims of allergic disease, Children s allergies start from scratch, ranging from mild to severe, from less to more, from single to multiple systems and systemic performance, so the prevention and treatment of allergic diseases in children is of great importance, which can not only prevent high risk allergic conditions from developing into allergic diseases, but also further block the process of allergy. At present, there is no consensus on the management system of allergic children in kindergartens and primary schools. The "Consensus on Allergy Management and Prevention in Kindergartens and Primary Schools", which includes the organizational structure, system construction and management of allergic children, provides evidence informed recommendations for the long term comprehensive management of allergic children in kindergartens and primary schools, and provides a basis for the establishment of the prevention system for allergic children.

Objective:To investigate the value of preoperative prediction of Ki-67 expression status in breast cancer based on multi-phase enhanced MRI combined with clinical imaging characteristics prediction model.Methods:This study was retrospective. A total of 213 breast cancer patients who underwent surgical treatment at Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College between June 2016 and May 2017 were enrolled. All patients were female, aged 24-78 (51±10) years, and underwent routine breast MRI within 2 weeks prior to surgery. According to the different Ki-67 expression of postoperative pathological results, patients were divided into high expression group (Ki-67≥20%, 153 cases) and low expression group (Ki-67<20%, 60 cases). The radiomic features of breast cancer lesions were extracted from phase 2 (CE-2) and phase 7 (CE-7) images of dynamic contrast enhanced (DCE)-MRI, and all cases were divided into training and test sets according to the ratio of 7∶3. The radiomic features were first selected using ANOVA and Wilcoxon signed-rank test, followed by the least absolute shrinkage and selection operator method regression model. The same method of parameters selection was applied to clinical information and conventional imaging features [including gland classification, degree of background parenchymal enhancement, multifocal/multicentric, lesion location, lesion morphology, lesion long diameter, lesion short diameter, T 2WI signal characteristics, diffusion-weighted imaging (DWI) signal characteristics, apparent diffusion coefficient (ADC) values, time-signal intensity curve type, and axillary lymph nodes larger than 1 cm in short axis]. Support vector machine (SVM) was then used to construct prediction models for Ki-67 high and low expression states. The predictive performance of the models were evaluated using receiver operating characteristic (ROC) curves and area under cueve(AUC). Results:Totally 1 029 radiomic features were extracted from CE-2 and CE-7 images, respectively, and 9 and 7 best features were obtained after selection, respectively. And combining the two sets of features for a total of 16 features constituted the CE-2+CE-7 image best features. Five valuable parameters including lesion location, lesion short diameter, DWI signal characteristics, ADC values, and axillary lymph nodes larger than 1 cm in short axis, were selected from all clinical image features. The SVM prediction models obtained from the radiomic features of CE-2 and CE-7 images had a high AUC in predicting Ki-67 expression status (>0.70) in both the training set and the test set. The models were constructed by combining the CE-2, CE-7, and CE-2+CE-7 radiomic features with clinical imaging features, respectively, and the corresponding model performance in predicting Ki-67 expression status was improved compared with the models obtained by using the CE-2, CE-7, and CE-2+CE-7 radiomic features alone. The SVM prediction model obtained from CE-2+CE-7 radiomic features combined with clinical imaging features had the best prediction performance, with AUC of 0.895, accuracy of 84.6%, sensitivity of 87.9%, and specificity of 76.2% for predicting Ki-67 expression status in the training set and AUC of 0.822, accuracy of 70.3%, sensitivity of 76.1%, and specificity of 55.6% in test sets.Conclusion:The SVM prediction model based on DCE-MRI radiomic features can effectively predict Ki-67 expression status, and the combination of radiomic features and clinical imaging features can further improve the model prediction performance.

Objective:To explore the impacts of comprehensive geriatric assessment (CGA) on setup errors during the radiotherapy of elderly patients with rectal cancer.Methods:A total of 45 patients over 70 years of age and receiving radiotherapy were enrolled in the study. A comprehensive geriatric assessment was conducted before the radiotherapy. The enrolled patients had a median age of 77 years, including 28 male and 17 female cases. Meanwhile, 31 patients were determined to be in a good CGA status and 14 were determined to be in a poor CGA status, and 35 patients received radiotherapy in the prone position and 10 in the supine position. Cone beam CT (CBCT) was used for setup correction during radiotherapy. CBCT was performed daily in the first week and once a week from the second week. By fusing and aligning the CBCT images with simulation CT images according to the lumbar vertebra, setup errors in the left-right ( x axis), cranio-caudal ( y axis), and anterior-posterior ( z axis) directions were obtained. A total of 338 CBCT images were obtained. A generalized linear model was used to evaluate the effects of multiple factors on the setup errors. Results:During the radiotherapy, setup errors of all patients were (0.24±0.19) cm in the left-right direction, (0.33±0.25) cm in the cranio-caudal direction, and (0.19±0.15) cm in the anterior-posterior direction. The setup error in the cranio-caudal direction was more than that in the left-right direction and that in the anterior-posterior direction ( Z=-4.86, -7.72, P< 0.001). The setup error in the left-right direction was greater than that in the anterior-posterior direction ( Z=-2.79, P=0.005). The mean setup errors of the good and poor status groups in the left-right direction were (0.21 ± 0.17) and (0.30 ± 0.22) cm, respectively ( Z=2.16, P=0.031). There was no statistically significant difference in the setup errors between cranio-caudal direction and anterior-posterior direction ( P>0.05). The setup errors in the anterior-posterior direction were (0.17 ± 0.13) and (0.27 ± 0.19) cm, respectively for the prone and supine positions during the radiotherapy ( Z=2.85, P=0.004). There was no statistically significant difference in the setup errors between the left-right direction and the cranio-caudal direction ( P>0.05). Conclusion:The status of CGA elderly patients with rectal cancer affects the setup error in the left-right direction. It may be necessary to clinically adjust the PTV margin.

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 compare the outcomes of watch&wait (W&W) strategy in patients with locally advanced rectal cancer who achieved complete clinical response (cCR) after neoadjuvant therapy, with those who obtained pathological complete response (pCR) after total mesorectal excision (TME).Methods:This is a retrospective cohort analysis study. Patients histologically proven with locally advanced rectal adenocarcinoma (stage Ⅱ-Ⅲ) who had received neoadjuvant chemotherapy were eligible between January 2014 and December 2019. In whom we included patients who had cCR offered management with W&W strategy after completing neoadjuvant therapy and follow-up ≥1 year (W&W group), and patients who did not have cCR but pCR after TME (pCR group). The primary endpoints were 3-year and 5-year overall survival (OS), colostomy-free survival (CFS), disease-free survival (DFS), non-local regrowth disease-free survival (NR-DFS), and organ preservation rate. Kaplan-Meier analysis was used for survival analysis and log-rank test was performed. For comparative analysis, we also derived one-to-one paired cohorts of W&W versus pCR using propensity-score matching (PSM).Results:A total of 118 patients were enrolled, 49 of whom had cCR and managed by W&W, 69 had pCR, with a median follow-up period of 49.5 months (12.1-79.9 months). No difference was observed in the 3-year OS (97.1% vs. 96.7%) and 5-year OS (93.8% vs. 90.9%, P=0.696) between the W&W and pCR groups. Patients managed by W&W had significantly better 3-year and 5-year CFS (89.1% vs. 43.5%, P<0.001), better 3-year DFS (83.6% vs. 97.0%) and 5-year DFS (83.6% vs. 91.2%, P=0.047) compared with those achieving pCR. The 3-year NR-DFS (95.9% vs. 97.0%) and 5-year NR-DFS (92.8% vs. 97.0%, P=0.407) did not significantly differ between the W&W and pCR groups. Local regeneration occurred in six cases, and 87.7% of patients had successful rectum preservation in the W&W group. In the PSM analysis (34 patients in each group), absolutely better CFS (90.1% vs. 26.5%, P<0.001) was noted in the W&W group. A median interval of 17.5 weeks was observed for achieving cCR, while only 23.9% of patients achieved cCR within 5 to 12 weeks from radiation completion. Patients with short-course sequential chemoradiotherapy achieved cCR significantly later when compared with those with long-course concurrent chemoradiotherapy (19.0 vs. 9.8 weeks, P<0.001). Conclusions:The oncological outcomes of W&W strategy in patients with locally advanced rectal cancer are safe and effective, significantly improving the quality of life. Longer interval for cCR evaluation may improve rectal organ preservation rate.

Objective:To investigate the efficacy and prognosis of hypofractionated intensity-modulated radiation therapy combined with hormonal therapy in the treatment of pelvic lymph node metastatic prostate cancer.Methods:Clinical data of 42 IV A prostate cancer patients who received hypofractionated intensity-modulated radiation therapy combined with hormonal therapy in Cancer Hospital of Chinese Academy of Medical Sciences between 2006 and 2018 were retrospectively analyzed. The total irradiation doses to the prostate and seminal vesicles were 67.5 Gy/25f, 2.7 Gy/f. The prophylactic irradiation doses to the pelvic lymph nodes were 45-50 Gy with a daily fraction dose of 1.8-2.0 Gy. Thirty-three patients with residual lymph nodes were boosted to 60.0-67.5 Gy for the residual area, 2.4-2.7 Gy/f. Androgen deprivation therapy included surgical castration or luteinizing hormone-releasing hormone agonists combined with antiandrogens. Survival rate was calculated using Kaplan- Meier method. The differences between two groups were analyzed by log-rank test. Prognostic factors were identified by univariate and multivariate analyses. Results:The median follow-up was 65.5 months (range, 5 to 150 months). The 5-year and 10-year failure-free survival (FFS) rates in the whole group were 67% and 45%, respectively. No clinical recurrence was observed in the irradiation field. The 5-year and 10-year prostate cancer-specific survival/overall survival (PCSS/OS) rates were 85% and 60%, respectively. Gleason score (≥8 and<8) and duration of hormonal therapy impacted the FFS (both P<0.05). The duration of hormonal therapy was an independent prognostic factor for PCSS/OS ( P=0.003). Conclusions:Hypofractionated intensity-modulated radiotherapy combined with hormonal therapy yields optimistic clinical efficacy in the treatment of pelvic lymph node metastatic prostate cancer. Gleason score (≥8 and <8) and duration of hormonal therapy are critical prognostic factors.