| Part ?A prospective phase I study of hypofractionated neoadjuvant radiotherapy for locally advanced gastric cancerPurpose:This study sought to assess the maximum tolerated dose(MTD)and dose-limited toxicity(DLT)of hypo-fractionated chemoradiotherapy for local advanced gastric cancer.Method:Patients with cT3-4 and/or lymph node-positive locally advanced gastric cancer or Siewert II/III esophagogastric junction adenocarcinoma were enrolled.Preoperative chemoradiation was followed by 3 cycles of oxaliplatin+S-1 neoadjuvant chemotherapy with an interval duration of 3-4 weeks.D2 resection was performed 2-4 weeks after neoadjuvant therapy.Three cycles of adjuvant chemotherapy were planned after surgery.Intensitymodulated radiotherapy(IMRT)was used.The radiotherapy dose level was defined using three levels,namely,40.0 Gy/2.5 Gy,41.6 Gy/2.6 Gy,43.2 Gy/2.7 Gy delivered concurrently with S-1 at 80 mg/m2.Results:From May 2016 to Dec 2016,nine patients with a median age of 63 years were enrolled in this study.The most common grade ?-? adverse events were leukopenia(88.9%),nausea(88.9%),vomiting(77.8%)and weight loss(66.7%).Grade III adverse events consisted of vomiting and weight loss.Conclusion:The MTD of hypo-fractionated radiotherapy for locally advanced gastric cancer was 40.0 Gy/2.5 Gy,and the DLTs were vomiting and weight loss.Part ?Preoperative versus postoperative chemo-radiotherapy for locally advanced gastric cancer:a propensity score-matched analysisPurpose:To compare long-term oncologic outcomes in locally advanced gastric cancer patients after preoperative chemo-radiotherapy(pre-CRT)and postoperative chemo-radiotherapy(post-CRT).Methods:From January 2009 to April 2019,222 patients from 2 centers with stage T3/4 and/or N positive gastric cancer who received pre-CRT and post-CRT were included.After propensity score matching(PSM),comparisons of local regional control(LC),distant metastasis-free survival(DMFS),disease-free survival(DFS)and overall survival(OS)were performed using Kaplan-Meier analysis and log-rank test between pre-and post-CRT groups.Results:The median follow-up period for survivors was 30 months.120 matched cases were generated for analysis.Three-year LC,DMFS,DFS and OS for pre-vs.post-CRT groups were 93.8%vs.97.2%(p=0.244),78.7%vs.65.7%(p=0.017),74.9%vs.65.3%(p=0.042)and 74.4%vs.61.2%(p=0.055),respectively.Pre-CRT were significantly associated with DFS in uni-and multi-variate analysis.Conclusion:Preoperative CRT showed advantages of long-term outcome compared with postoperative CRT.Part ?Effectiveness of oesophageal gastric junction tumour motion with and without a pneumatic abdominal compression beltPurpose:To investigate the effect of a pneumatic abdominal compression belt(PACB)on suppressing the movement of primary lesions in the oesophageal gastric junction(EGJ).Methods:Ten patients with EGJ adenocarcinoma were treated with preoperative concurrent chemoradiotherapy.Titanium clips A and B were placed on the upper and lower edges of the gross tumour with a gastroscope,respectively.Forty sets of images of the two titanium clips located in the EGJ were obtained by 4DCT in 10 patients in the supine position with and without a PACB.Of the 10 patients,5 were treated with a PACB,and the other 5 were not.All patients received CBCT for the first 5 fractions and the 7th,12th,17th and 22nd fractions before treatment,and 90 sets of images were obtained for analysis.Paired t-tests and independent t-tests were used to test for differences.Results:With and without a PACB,in the cranio-caudal(CC)direction,the internal motion of clip A was 0.0±0.1 cm and 0.1±0.1 cm(P=0.001),respectively.With and without PACB,in the left-right(LR),anterior-posterior(AP)and cranio-caudal(CC)directions,the internal motion of clip B was(0.1±0.1),(0.1±0.1),and(0.1±0.1)cm and(0.2±0.1),(0.2±0.1),and(0.5±0.3)cm(P=0.000,0.000 and 0.000),respectively.The inter-fraction motion of clip B in the LR,AP and CC directions was(0.2±0.2),(0.2±0.2),and(0.2±0.2)cm and(0.7±0.8),(0.7±0.7),and(0.5±0.4)cm(P=0.002,0.002 and 0.005)with or without a PACB,respectively.The movement of clip B in LR,AP or CC directions were significantly greater than that of clip A,which might be more benefit from PACB.To ensure that 90%of the tumour volume receives 95%of the prescription dose,0.9,0.9 and 0.9 cm ITV margins in the LR,AP and CC directions are suggested for EGJ lesions with PACB to better cover the tumour intra-and inter-fraction movements.Conclusion:A pneumatic abdominal compression belt can reduce the intra-and inter-fraction movements of EGJ tumours during preoperative radiotherapy. |
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