Objective To investigate whether the dosimetric effects of stereotactic body radiotherapy(SBRT)in hepatic carcinoma conform to the linear-quadratic(LQ)model.Methods Human hepatic carcinoma cell lines HepG2 and Hep3B cultured in vitro were selected and subjected to biological equivalent dose(BED)irradiation(6,8,10,12,14 Gy).The fractionation regimens included single-fraction irradiation(simulated SBRT)and 3-or 5-fraction irradiation(simulated IMRT).The surviving fraction after irradiation reflected the damage effects of different fractionation regimens;the effects of different fractionation regimens on cell proliferation were analyzed through survival curves;and cell scratch experiment after irradiation was used to observe the cell invasive and migration abilities after exposure to different fractionation regimens.Results Significant separation effect was observed in the in vitro validation of the LQ model in SBRT for hepatic carcinoma.For HepG2 cells and Hep3B cells,when BED<12 Gy(α/β=10 Gy),fractionation regimens did not show significant differences in terms of damage effects,proliferative ability,and invasive ability,indicating SBRT conformed to the LQ model;when BED≥12 Gy,single-fraction had more obvious damage effects as compared with multiple-fraction,indicating that the damage effect in SBRT was more significant than that in IMRT.Conclusion The LQ model applies to SBRT for hepatic carcinoma in a certain dose range,beyond which the damage effect is higher than the predicted results of the LQ model.

Objective To evaluate the therapeutic efficacies of neoadjuvant immunochemotherapy (NAIC )and neoadjuvant chemotherapy (NAC )for local advanced gastric adenocarcinoma and analyze the clinicopathological characteristics.Methods A retrospective cohort study was conducted on 243 patients with locally advanced gastric cancer admitted in Army Medical Center of PLA (Daping Hospital)and the First Affiliated Hospital of China Medical University from January 2017 to July 2023. After balancing the confounding factors by inclusion and exclusion criteria and propensity score matching (PSM),the tumor pathological regression (TRG)rate and safety of the 2 neoadjuvant treatment regimens were analyzed,and the clinical pathological characteristics were analyzed to find clinical pathological characteristics related to efficacy.Results After using PSM to balance the baseline characteristics of the 2 groups of patients,53 subjects in each group were included in the analysis.In terms of TRG,the pathological complete response (pCR)rate in the NAIC group (13 patients,25％)was significantly higher than that in the NAC group (2 patients,3.8％,P<0.05 ).Similar results were observed in terms of major pathological response (MPR),with 23 patients (43％)in the NAIC group achieving MPR,while 9 patients (17％)in the NAC group achieved MPR (P<0.05 ).In terms of safety,the incidence of treatment-related adverse events (TRAEs) of any grade in the NAIC group and the NAC group was comparable (96.2％ and 96.2％,respectively).In an exploratory subgroup analysis of tumor pathological regression,the patients with clinicopathological features such as age<65 years,male,stage Ⅲ～Ⅳ A of American Joint Committee on Cancer (AJCC)staging,histological type of adenocarcinoma,high-moderate differentiated,intestinal-type gastric cancer,stage T3～4 of clinical T-staging,and stage N2～3 of clinical N-staging were more likely to benefit from NAIC.Conclusion NAIC results in a higher rate of pathological regression and a comparable incidence of adverse events when compared with chemotherapy alone for patients with local advanced gastric adenocarcinoma.