Objective:To investigate the drug resistance factors in postoperative gemci-tabine chemotherapy after radical resection of pancreatic cancer.Methods:The retrospective case-control study was constructed. The clinicopathological data of 255 patients with pancreatic cancer who were firstly admitted to the Department of Hepatobiliary Surgery of the First Affiliated Hospital of Xi ′an Jiaotong University from January 2018 to June 2021 were collected. There were 140 males and 115 females, aged (59±10)years. All patients underwent radical resection of pancreatic cancer and received postoperative gemcitabine-based adjuvant chemotherapy. Observation indicators: (1) follow-up; (2) postoperative chemotherapy; (3) drug resistance and changing of regimen; (4) factors influencing postoperative chemotherapy resistance. Measurement data with normal distribution were represented as Mean± SD, and comparison between groups was conducted using the independent sample t test. Measurement data with skewed distribution were represented as M( Q1, Q3), and compari-son between groups was conducted using the Mann-Whitney U test. Count data were described as absolute numbers, and comparison between groups was conducted using the Pearson chi-square test. Univariate analysis was conducted using the corresponding statistical methods based on data type. Multivariate analysis was conducted using the Logistic regression model with forward method. Kaplan-Meier method was used to draw survival curve, and Log-Rank test was used for survival analysis. Results:(1) Follow-up. All 255 patients were followed up for 18.6(16.7,21.4)months. The median survival time of 255 patients was 18.2[95% confidence interval ( CI) as 15.8-20.6]months. (2) Postoperative chemotherapy. Of the 255 patients, there were 5 cases receiving postoperative chemotherapy as gemcitabine monotherapy, 167 cases receiving postoperative chemotherapy as the AG combination (gemcitabine plus albumin-bound paclitaxel), 74 cases receiving postoperative chemotherapy as the GS combination (gemcitabine plus S-1) and 9 cases receiving postoperative chemotherapy as the GP combination (gemcitabine plus platinum). (3) Drug resistance and changing of regimen. Of the 255 patients, 81 cases completed the course of postoperative chemotherapy and evaluation. Of the 81 patients, there were 18 cases with no recurrence or metastasis of tumor, 10 cases with tumor local recurrence, 40 cases with tumor lymph node metastasis or distant metas-tasis, 3 cases with tumor local recurrence combined with distant metastasis, 10 cases with elevation of CA19-9. Of the 81 patients, 18 cases responded to chemotherapy, 63 cases underwent resistant to chemotherapy, including 11 cases with primary resistance and 52 cases with acquired resistance. The 63 patients with chemotherapy resistance underwent changing of regimen. (4) Factors influencing postoperative chemotherapy resistance. Results of multivariate analysis showed that chemotherapy cycle<6 is an independent risk factor for postoperative chemotherapy resistance in patients ( hazard ratio=17.18, 95% CI as 2.07-142.28, P<0.05). Conclusion:Adjuvant chemotherapy cycle <6 is an independent risk factor for postoperative chemotherapy resistance for gemcitabine based chemo-therapy in pancreatic cancer patients receiving radical resection.

Objective To construct and validate an effective prognostic nomogram for the patients with incidental gallbladder cancer(IGBC).Methods The clinical data of 161 patients with IGBC requiring radical surgery admitted to the First Affiliated Hospital of Xi'an Jiaotong University from May 2011 to October 2022 was analyzed retrospectively.COX proportional risk regression model was used to screen for influencing factors on overall survival(OS)of IGBC.Nomogram was constructed based on independent influencing factors that affected the prognosis of IGBC patients.The concordance index(C-index)and calibration curve were used to validate the performance of the model.Receiver operating characteristic(ROC)curve analysis and decision curve analysis(DCA)were used to validate the predictive accuracy and net benefit of the plotted column chart.Results Univariate COX regression analysis suggested that age,T stage,N stage,M stage,preoperative carcinoembryonic antigen(CEA),preoperative carbohydrate antigenl9-9(CA19-9),preoperative red blood cell volume distribution on width coefficient of variation(RDW-CV),treatment method,and recurrence and metastasis were risk factors which affected the long-term survival of IGBC patients after radical surgery.Multivariate COX regression analysis suggested that T stage,N stage,preoperative CA19-9,preoperative RDW-CV,preoperative AST,treatment methods,and recurrence and metastasis were independent risk factors which affected the prognosis of IGBC patients.The C-index of the constructed prognostic model was 0.872.The calibration plot demonstrated good performance of the Nomogram.ROC curve analysis showed an area under the curve of 0.869,confirming a high sensitivity and specificity.A high net benefit was proven by DCA.Conclusions The constructed Nomogram.can accurately and intuitively predict the survival probability of IGBC patients after radical surgery.

Pancreatic cancer has a very poor prognosis.Early diagnosis and treatment are especially critical for improving its prognosis.Nanotechnology has been widely used in the diagnosis and treatment of pancreatic cancer.Relying on the unique physicochemical properties of nanoparticles and their rich surface modifications,effective enrichment of tumor sites can be achieved.Magnetic iron oxide nanoparticles(MIONPs)is one of the commonly used nanomaterials in the diagnosis and treatment of pancreatic cancer,and has good biocompatibility.Through special surface modification,it can be used in targeted diagnosis and treatment of pancreatic cancer.MIONPs can be used as a contrast agent for MRI,and by modifying the surface,they also can be used in targeted imaging of pancreatic cancer.And they can also be modified as a drug delivery system to achieve targeted delivery of drugs and improve therapeutic effects.However,the application of MIONPs in pancreatic cancer diagnosis and treatment still faces some challenges,such as nanotoxicity and cost issues.With the development of technology,MIONPs are expected to play an important role in the personalized diagnosis and treatment of pancreatic cancer.