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 investigate the clinical characteristics, treatment and prognosis of newly-treated patients with primary central nervous system lymphoma (PCNSL).Methods:Clinical data of 117 newly-treated PCNSL patients who were admitted to the First Hospital of Jilin University, the Fifth Medical Center of Chinese PLA General Hospital, Harbin Medical University Cancer Hospital, and Cancer Hospital of Chinese Academy of Medical Sciences & Peking Union Medical College from August 2009 to February 2018 were retrospectively analyzed. The patients' age, sex, Eastern Cooperative Oncology Group (ECOG) physical status (PS) score, pathological type, involvement of deep brain tissue, number of lesions, cerebrospinal fluid protein concentration, International Extranodal Lymphoma Study Group (IELSG) score, Memorial Sloan Kettering Cancer Center (MSKCC) score, treatment strategy, and response after the first-line therapy were analyzed using univariate and multivariate Cox proportional hazards models to identify the independent influencing factors for progression-free survival (PFS) and overall survival (OS) of PCNSL patients. Kaplan-Meier method was used for survival analysis.Results:In 117 newly-treated PCNSL patients, 59 cases (50.4%) presented with increased intracranial pressure or focal neurological symptoms at diagnosis; there were 65 cases (55.6%) with single lesions and 52 cases (44.4%) with multiple lesions; 1 patient (0.9%) had lymphoma of T-cell origin, and 116 cases (99.1%) had diffuse large B-cell lymphoma (DLBCL). Among 95 evaluable patients, 41 patients (43.2%) achieved complete remission (CR), 20 patients (21.1%) achieved partial remission (PR), 16 patients (16.8%) achieved stable disease (SD), and 18 patients (18.9%) had progressive disease (PD). In 117 patients with median follow-up of 66.0 months (95% CI 57.9-74.1 months), the median PFS and OS were 17.4 months (95% CI 11.5-23.3 months) and 45.6 months (95% CI 20.1-71.1 months), respectively. The 2-, 3- and 5-year PFS rates were 41.2%, 28.6% and 19.3%, and OS rates were 63.7%, 52.4% and 46.3%, respectively. Univariate Cox regression analysis showed that baseline high-risk MSKCC score group was an adverse prognostic factor for PFS ( P = 0.037), and the first-line chemotherapy with ≥4 cycles of high-dose methotrexate (HDMTX), HDMTX in combination with rituximab, ≥4 cycles of rituximab in combination with HDMTX, and achieving CR or ≥PR after the first-line treatment reduced the risk of disease progression and prolonged the PFS time (all P <0.01); age >60 years old, ECOG-PS score of 2-4 points, elevated cerebrospinal fluid protein concentration, high-risk IELSG score, and high-risk MSKCC score were adverse prognostic factors for OS, and ≥4 cycles of HDMTX and achieving CR or ≥PR after the first-line treatment were favorable factors for OS. Multivariate Cox regression analysis verified that rituximab in combination with HDMTX (yes vs. no: HR = 0.349, 95% CI 0.133-0.912, P = 0.032) and achieving ≥PR after the first-line chemotherapy (yes vs. no: HR = 0.028, 95% CI 0.004-0.195, P < 0.001) were independent favorable factors for PFS; age >60 years old (>60 years old vs. ≤60 years old: HR = 10.878, 95% CI 1.807-65.488, P = 0.009) was independent unfavorable factor for OS, while ≥4 cycles of HDMTX treatment (≥4 cycles vs. <4 cycles: HR = 0.225, 95% CI 0.053-0.947, P = 0.042) was independent favorable factor for OS. Conclusions:The older the PCNSL patients at initial treatment, the worse the prognosis. Intensive and continuous treatment for achieving deeper remission may be the key for improving the outcome of PCNSL patients.

Objective:To evaluate the value of chemoradiotherapy and surgery in cervical esophageal cancer (CEC).Methods:Data of 459 patients with CEC from 2004 to 2017 were collected and retrospectively analyzed from the surveillance, epidemiology, and end results (SEER) database of National Cancer Institute (US). All patients were divided into the chemoradiotherapy group ( n=379) and surgery group ( n=80) according to the treatment methods. Survival analysis was performed by Kaplan-Meier method and survival curve was drawn. Multivariate survival analysis was conducted by Cox proportional hazards regression model. The death rate of different causes between two groups was calculated by cumulative incidence function (CIF). The differences of death rate between two groups were evaluated by Fine-Gray competing risk model. By analyzing the clinical characteristics and survival of CEC patients, the overall survival (OS) was compared between the surgery and chemoradiotherapy groups. Results:The 2- and 5-year survival rates in the chemoradiotherapy group were 43.1% and 22.4%, while those of the surgical group were 46.8% and 26.0%, respectively. No significant difference was observed in the OS between the chemoradiotherapy and surgery groups ( P=0.750). Cox multivariate analysis showed that treatment (surgery group vs. chemoradiotherapy group) was not an independent prognostic factor for OS. Based on the results of competing risk analysis, the risk of esophageal cancer-specific death in the chemoradiotherapy group was higher than that in the surgery group, and the difference was statistically significant between two groups ( P<0.001). The risk of other cause-specific death in the chemoradiotherapy group was lower than that in the surgery group ( P<0.001). The proportion of patients who died of oral, oropharyngeal, hypopharyngeal and laryngeal diseases in the surgery group was significantly higher than that in the chemoradiotherapy group(all P<0.001). Conclusions:No significant difference is observed in the OS of CEC patients treated with chemoradiotherapy or surgery. In the surgery group, the risk of esophageal cancer-specific death is lower, whereas the risk of other cause-specific death is higher compared with those in the chemoradiotherapy group.

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 summarize the experience of radiation oncology residency training programs in western coutries, and provide evidence to improve the present Phase-I Radiation Oncology Residency Training Programs in China.Methods:An electronic questionnaire-based survey was conducted among residents and staffs in 6 top cancer centers in China and 5 centers from Europe and North America to collect their feedback regarding the description and comparison of different programs.Results:A total of 70 responses and 4 papers explaining relevant training programs from 26 residents and 23 teachers in Chinese hopsitals and 20 residents and 1 teacher from Europe and North America were received. The Radiation Oncology Residency Training Programs in China were designed into 2 phases, and the results in the current study were involved with the first phase. Program designs were similar in the following aspects: goal, clinical practice-based training, rotation curriculum, interim and final assessment. However, the total timeframe in the investigated Chinese Phase-I programs was shorter than that in western hospitals (2 to 3 years vs. 4 to 5 years). Chinese programs covered major common diseases, whereas rotation design was performed based on each individual disease in western programs. In Chinese programs, the working hours were mainly 40-60 h every week. Although the working hours were commensurate with local workforce regulations, the residents from MSK program had an outstanding longer working time of 60-80 h every week and treated more patients compared with other programs. Conclusions:The investigated Phase-I Radiation Oncology Residency Training Programs in 6 top cancer centers in China share common features in goals, training modes and assessments with western programs. However, our programs have shorter timeframe and less detailed requirements in individual disease than the western programs.

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.