The standard treatment for locally advanced rectal cancer is neoadjuvant chemoradiotherapy(nCRT) followed by surgery. The therapeutic efficacy of patients after nCRT differs greatly. Effective use of nCRT can accurately predict the efficacy and help patients avoid damage caused by excessive treatment. This article describes the main methods of current nCRT and newly proposed concepts, such as totally neoadjuvant therapy, summarzies its impact on the efficacy of locally advanced rectal cancer, introduces the potential predictive biomarkers of efficacy evaluation for nCRT and the latest advances in clinical, histological and molecular predictors, and discusses the potential value of efficacy prediction in nCRT .

Objective:To compare the efficacy and safety of placing self-expanding metallic stent (SEMS) and emergency surgery in treatment of patients with obstructive colon cancer.Methods:A retrospective cohort study was conducted. The clinical data of 111 colon cancer patients with obstruction admitted to Shanxi Province Cancer Hospital from January 2017 to April 2020 were retrospectively analyzed, and all patients were divided into the emergency group (44 cases receiving emergency radical surgery) and the stenting group (67 cases receiving elective radical surgery after intra-intestinally placing SEMS). General data, operation-related indexes and postoperative recurrence and metastasis of both groups were compared. The Kaplan-Meier method was used for survival analysis, and Cox proportional risk model was used to analyze the factors influencing the prognosis.Results:Among 111 patients, 69 cases were male and 42 cases were female; the age was (61±13) years. There were not statistically significant differences in the general data between the emergency group and the stenting group (all P > 0.05). The proportion of patients receiving laparoscopic surgery in the stenting group was higher than that in the emergency group [32.84% (22/67) vs. 6.82% (3/44), P = 0.001]; the proportion of patients with the detected number of lymph nodes ≥12 in the stenting group was higher than that in the emergency group [94.03% (63/67) vs.79.55% (35/44), P = 0.020]; the proportion of patients with stoma prevention in the emergency group was higher than that in the stenting group [36.36% (16/44) vs. 17.91% (12/67), χ2 = 4.80, P = 0.029], and the duration of postoperative hospitalization in the emergency group was longer than that in the stenting group [14.0 (10 d, 17 d) vs. 11 d (10 d, 14 d), Z = -2.004, P = 0.045]. There were no statistically significant differences in postoperative pathological TNM staging, vascular infiltration, nerve invasion, local recurrence and distant metastasis between the 2 groups (all P > 0.05). The difference in 3-year disease-free survival rate was statistically significant between the emergency group and the stenting group (52.3% vs. 64.2%, χ2 = 2.2, P = 0.142), and difference in 3-year overall survival rate was statistically significant between the emergency group and the stenting group (56.8% vs. 73.1%, χ2 = 3.02, P = 0.087). The multivariate Cox regression analysis showed that tumor location, TNM staging, and vascular infiltration were independent influencing factors for 3-year disease-free survival of patients with obstructive colon cancer (all P < 0.05); age, tumor location, TNM staging, and vascular infiltration were independent influencing factors for 3-year overall survival of patients with obstructive colon cancer (all P < 0.05). Conclusions:Compared with emergency surgery, placement of SEMS bridging surgery for obstructive colon cancer is safe and reliable, and tumor location, TNM staging, and vascular infiltration are closely related to prognosis.

Objective The purpose of this study was to explore a suitable method to model no-reflow phenomenon following ischemic stroke and to evaluate perfusion decrease from multiple perspectives.Methods Laser scatter contrast imaging and two-photon live imaging were used to compare transient middle cerebral artery occlusion in C57BL/6 and BALB/c mice and perfusion alterations in BALB/c mice with 1 or 1.5 h of ischemia.Several imaging techniques including laser scatter contrast imaging,low and higher magnification images of perfused brain slices and two-photon microscopy to monitor erythrocyte flow rate and flux were used to assess in vivo dynamics as well as whole brain sections and microvasculature for decreased cerebral perfusion after transient middle cerebral artery occlusion.Infarct size and behavioral deficits were assessed with microtubule-associated protein 2 staining and behavioral scoring.Results In C57BL/6 mice,most capillaries in the middle cerebral artery region remained flowing during ischemia,whereas most capillaries were blocked in BALB/c mice.In addition,cortical perfusion at 24 h of recanalization was significantly reduced to 76.1%of baseline following 1.5 h of ischemia in BALB/c mice(P=0.046 compared with the sham group),whereas for it was reduced to 79.9%following 1h of ischemia which was not significantly different from the sham group(P=0.299).Transient middle cerebral artery occlusion in BALB/c mice for 1.5 h resulted in a reduction in whole-brain perfusion to 75.1%(P＜0.001 compared with the sham group),and erythrocyte flow rate assessed by two-photon live-imaging of erythrocyte flow on the cortical surface of the middle cerebral artery basin was reduced to 50.3%of baseline levels at 24 h of recanalization(P=0.010 compared with the sham group),and erythrocyte flux decreased to 38.9%of baseline levels(P= 0.010 compared with the sham group);high-magnification imaging of sections assessed an approximately 76%reduction in the length of capillaries with perfusion(P=0.0001 compared with the sham group),and a reduction in the fraction of the total volume occupied by perfused capillaries by an approximately 76%reduction(P＜0.001 compared with the sham-operated group).Microtubule-associated protein 2 staining suggested that transient middle cerebral artery occlusion for 1.5 h in BALB/c mice resulted in infarcts that accounted for approximately 36%of the total cerebral area and behavioral scores elevated to 9,suggesting behavioral deficits.Conclusion Transient ischemia in BALB/c mice for 1.5 h resulted in a significant decrease in cerebral perfusion as well as capillary no-reflow and thus can model the no-reflow phenomenon following ischemic stroke.The combination of laser scatter contrast imaging,low magnification and higher magnification images of perfused brain slices,and two-photon microscopy live imaging allows for a multifaceted assessment of perfusion changes.