Preoperative neutrophil-to-lymphocyte ratio predicts symptomatic anastomotic leakage in elderly colon cancer patients: Multicenter propensity score-matched analysis

BACKGROUND The neutrophil-to-lymphocyte ratio(NLR),a composite inflammatory biomarker,is associated with the prognosis in patients with colorectal tumors.However,whether the NLR can be used as a predictor of symptomatic postoperative ana-stomotic leakage(AL)in elderly patients with colon cancer is unclear.AIM To assess the role of the NLR in predicting the occurrence of symptomatic AL after surgery in elderly patients with colon cancer.METHODS Data from elderly colon cancer patients who underwent elective radical colectomy with anastomosis at three centers between 2018 and 2022 were retrospectively analyzed.Receiver operating characteristic curve analysis was performed to determine the best predictive cutoff value for the NLR.Twenty-two covariates were matched using a 1:1 propensity score matching method,and univariate and multivariate logistic regression analyses were used to determine risk factors for the development of postoperative AL.RESULTS Of the 577 patients included,36(6.2%)had symptomatic AL.The optimal cutoff value of the NLR for predicting AL was 2.66.After propensity score matching,the incidence of AL was significantly greater in the≥2.66 NLR subgroup than in the<2.66 NLR subgroup(11.5%vs 2.5%;P=0.012).Univariate logistic regression analysis revealed statistically significant correlations between blood transfusion intraoperatively and within 2 d postoper-atively,preoperative albumin concentration,preoperative prognostic nutritional index,and preoperative NLR and AL occurrence(P<0.05);multivariate logistic regression analysis revealed that an NLR≥2.66[odds ratio(OR)=5.51;95%confidence interval(CI):1.50-20.26;P=0.010]and blood transfusion intraoperatively and within 2 d postoperatively(OR=2.52;95%CI:0.88-7.25;P=0.049)were risk factors for the occurrence of symptomatic AL.CONCLUSION A preoperative NLR≥2.66 and blood transfusion intraoperatively and within 2 d postoperatively are associated with a higher incidence of postoperative symptomatic AL in elderly patients with colon cancer.The preoperative NLR has predictive value for postoperative symptomatic AL after elective surgery in elderly patients with colon cancer.

Robotic versus laparoscopic distal pancreatectomy for pancreatic ductal adenocarcinoma: A propensity score-matched analysis

Background: Minimally invasive surgery is becoming increasingly popular in the field of pancreatic surgery. However, there are few studies of robotic distal pancreatectomy(RDP) for pancreatic ductal adenocarcinoma(PDAC). This study aimed to investigate the efficacy and feasibility of RDP for PDAC. Methods: Patients who underwent RDP or laparoscopic distal pancreatectomy(LDP) for PDAC between January 2015 and September 2020 were reviewed. Propensity score matching analyses were performed. Results: Of the 335 patients included in the study, 24 underwent RDP and 311 underwent LDP. A total of 21 RDP patients were matched 1:1 with LDP patients. RDP was associated with longer operative time(209.7 vs. 163.2 min;P = 0.003), lower open conversion rate(0% vs. 4.8%;P < 0.001), higher cost(15 722 vs. 12 699 dollars;P = 0.003), and a higher rate of achievement of an R0 resection margin(90.5% vs. 61.9%;P = 0.042). However, postoperative pancreatic fistula grade B or C showed no significant intergroup difference(9.5% vs. 9.5%). The median disease-free survival(34.5 vs. 17.3 months;P = 0.588) and overall survival(37.7 vs. 21.9 months;P = 0.171) were comparable between the groups. Conclusions: RDP is associated with longer operative time, a higher cost of surgery, and a higher likelihood of achieving R0 margins than LDP.

Laparoscopic liver resection for hepatocellular carcinoma complicated with significant portal hypertension:A propensity score-matched survival analysis

Background: Significant portal hypertension(SPH) is a relative contraindication for patients with resectable hepatocellular carcinoma(HCC). However, increasing evidence indicates that liver resection is feasible for HCC patients with SPH. Methods: HCC patients with cirrhosis who underwent laparoscopic liver resection(LLR) in two centers from January 2013 to April 2018 were included. Surgical and survival outcomes were analyzed to explore potential prognostic factors. Propensity score matching(PSM) analysis was performed to minimize bias. Results: A total of 165 patients were divided into two groups based on the presence(SPH, n = 76) or absence(non-SPH, n = 89) of SPH. Patients in the SPH group had longer operative time, more blood loss, and more advanced TNM stage than patients in the non-SPH group( P < 0.05). However, there were no significant differences in the postoperative 90-day mortality rate( n = 0), overall postoperative complications(47.4% vs. 41.6%, P = 0.455), Clavien-Dindo classification( P = 0.347), conversion to open surgery(9.2% vs. 6.7%, P = 0.557), or length of hospitalization(16 vs. 15 days, P = 0.203) between the SPH and non-SPH groups before PSM. Similar results were obtained after PSM. The 1-, 3-, and 5-year overall survival(OS) and recurrence-free survival rates in the SPH group were not significantly different from those in the non-SPH group both before and after PSM(log-rank P > 0.05). After PSM, alpha-fetoprotein(AFP) ≥ 400 μg/L [hazard ratio(HR) = 4.71, 95% confidence interval(CI): 2.69-8.25], ascites(HR = 2.18, 95% CI: 1.30-3.66), American Society of Anesthesiologists(ASA) classification(Ⅲ vs. Ⅱ)(HR = 2.13, 95% CI: 1.11-4.07) and tumor diameter > 5 cm(HR = 3.91, 95% CI: 2.02-7.56) independently predicted worse OS. Conclusions: LLR for patients with HCC complicated with SPH appears feasible at the price of increasing operative time and blood loss. AFP, ascites, ASA classification and tumor diameter may predict the prognosis of HCC complicated with SPH after LLR.

Down-staging depth score to predict outcomes in locally advanced rectal cancer achieving ypl stage after neoadjuvant chemo-radiotherapy versus de novo stage pl cohort:A propensity score-matched analysis

Objective：Prognosis of patients with locally advanced rectal cancer（LARC）but achieving yp T1–2N0 stage after neoadjuvant concurrent chemo-radiotherapy（CRT）has been shown to be favorable.This study aims to determine whether the long-term outcome of yp T1–2N0 cases can be comparable to that of p T1–2N0 cohort that received definitive surgery for early disease.Method：From January 2008 to December 2013,449 consecutive patients with rectal cancer were treated and their outcome maintained in a database.Patients with LARC underwent total mesorectal excision（TME）surgery at4–8 weeks after completion of CRT,and those achieving stage yp I were identified as a group.As a comparison,stage p I group pertains to patients whose initially limited disease was not upstaged after TME surgery alone.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 yp I and p I groups.Down-staging depth score（DDS）,a novel method of evaluating CRT response,was used for subset analysis.Results：Of the 449 patients,168 matched cases were generated for analysis.Five-year LC,DMFS,DFS and OS for stage p I vs.yp I groups were 96.7%vs.96.4%（P=0.796）,92.7%vs.73.6%（P=0.025）,91.2%vs.73.6%（P=0.080）and 93.1%vs.72.3%（P=0.040）,respectively.In the DDS-favorable subset of the yp I group,LC,DMFS,DFS and OS resulted in no significant differences in comparison with the p I group（P=0.384,0.368,0.277 and0.458,respectively）.Conclusions：LC was comparable in both groups;however,distant metastasis developed more frequently in down-staged LARC than de novo early stage cases,reflecting the need to improve the efficacy of systemic treatment despite excellent pathologic response.DDS can be an indicator to identify a subset of the yp I group whose longterm oncologic outcomes are as good as those of stage p I cohort.

First-line pemetrexed-platinum doublet chemotherapy with or without bevacizumab in non-squamous non-small cell lung cancer: A real-world propensity score-matched study in China

Objective: To evaluate the efficacy and safety profile of first-line bevacizumab(Bev)-containing pemetrexedplatinum chemotherapy in a real-world Chinese cohort with advanced non-squamous non-small cell lung cancer(NS-NSCLC).Methods: A total of 415 eligible patients with NS-NSCLC who received first-line pemetrexed-platinum chemotherapy at National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College between February 2010 and September 2017 were reviewed retrospectively: 309 Bev(-) and 106 Bev(+) cases. Bev was administered at 7.5 mg/kg every 3 weeks in the Bev(+) group. To reduce the risk of a selection bias, a propensity score-matching(PSM) was conducted and 105 pairs of Bev(-) and Bev(+) cases were identified.Results: The median duration of follow-up was 15.8 months. The median progression-free survival(PFS) was prolonged significantly in the Bev(+) group than in the Bev(-) group in overall(9.8 vs. 7.8 months, P=0.006) and PSM pairs(9.8 vs. 6.6 months, P<0.001). Moreover, patients receiving maintenance therapy with pemetrexed plus Bev had longer PFS than those interrupted after induction chemotherapy, or those receiving mono-maintenance with pemetrexed(12.3 vs. 4.8 vs. 8.6 months;P<0.001). Multivariate analyses revealed Bev to be one of the favorable prognostic factors for PFS, along with the predictor of maintenance therapy.Conclusions: First-line induction and maintenance therapy with Bev(7.5 mg/kg every 3 weeks) combined with pemetrexed-platinum chemotherapy was efficacious and superior to non-Bev chemotherapy in Chinese patients with advanced NS-NSCLC.

Stratified Analysis of Survival Benefit for ABO-incompatible Deceased-donor Liver Transplantation:Multicenter Propensity Score-matched Study

Background and Aims:Liver transplantation(LT)using ABO-incompatible(ABOi)grafts can extend the donor pool to a certain extent and hence reduce the waiting time for transplantation.However,concerns of the impending prognosis associated with this option,especially for patients with liver failure and higher model for end-stage liver disease(MELD)scores,who tend to be more fragile during the waiting period before LT.Methods:Recipients undergoing LT for acute-onchronic liver failure or acute liver failure were retrospectively enrolled at four institutions.Overall survival was compared and a Cox regression analysis was performed.Propensity score matching was performed for further comparison.Patients were stratified by MELD score and cold ischemia time(CIT)to determine the subgroups with survival benefits.Results:Two hundred ten recipients who underwent ABOi LT and 1,829 who underwent ABO compatible(ABOc)LT were enrolled.The 5-year overall survival rate was significantly inferior in the ABOi group compared with the ABOc group after matching(50.6%vs.75.7%,p<0.05).For patients with MELD scores≤30,using ABOi grafts achieved a comparable overall survival rate as using ABOc grafts(p>0.05).Comparison of the survival rates revealed no statistically significant difference for patients with MELD scores≥40(p>0.05).For patients with MELD scores of 31-39,the overall survival rate was significantly inferior in the ABOi group compared with the ABOc group(p<0.001);however,the rate was increased when the liver graft CIT was<8 h.Conclusions:For recipients with MELD scores≤30,ABOi LT had a prognosis comparable to that of ABOc LT and can be regarded as a feasible option.For recipients with MELD scores≥40,ABOi should be adopted with caution in emergency cases.For recipients with MELD scores of 31-39,the ABOi LT prognosis was worse.However,those patients benefited from receiving ABOi grafts with a CIT of<8 h.

Comparison of the survival outcomes between primary and secondary muscle-invasive bladder cancer: a propensity score-matched study

Background:Studies have classified muscle-invasive bladder cancer(MIBC)into primary(initially muscle-invasive,PMIBC)and secondary subtypes(initially non-muscle-invasive but progresses,SMIBC),for which controversial survival outcomes were demonstrated.This study aimed to compare the survival outcomes between PMIBC and SMIBC patients in China.Methods:Patients diagnosed with PMIBC or SMIBC at West China Hospital from January 2009 to June 2019 were retrospectively included.Kruskal-Wallis and Fisher tests were employed to compare clinicopathological characteristics.Kaplan-Meier curves and Cox competing proportional risk model were used to compare survival outcomes.Propensity score matching(PSM)was employed to reduce the bias and subgroup analysis was used to confirm the outcomes.Results:A total of 405 MIBC patients were enrolled,including 286 PMIBC and 119 SMIBC,with a mean follow-up of 27.54 and 53.30 months,respectively.The SMIBC group had a higher proportion of older patients(17.65%[21/119]vs.9.09%[26/286]),chronic disease(32.77%[39/119]vs.22.38%[64/286]),and neoadjuvant chemotherapy(19.33%[23/119]vs.8.04%[23/286]).Before matching,SMIBC had a lower risk of overall mortality(OM)(hazard ratios[HR]0.60,95%confidence interval[CI]0.41-0.85,P=0.005)and cancer-specific mortality(CSM)(HR 0.64,95%CI 0.44-0.94,P=0.022)after the initial diagnosis.However,higher risks of OM(HR 1.47,95%CI 1.02-2.10,P=0.038)and CSM(HR 1.58,95%CI 1.09-2.29,P=0.016)were observed for SMIBC once it became muscle-invasive.After PSM,the baseline characteristics of 146 patients(73 for each group)were well matched,and SMIBC was confirmed to have an increased CSM risk(HR 1.83,95%CI 1.09-3.06,P=0.021)than PMIBC after muscle invasion.Conclusions:Compared with PMIBC,SMIBC had worse survival outcomes once it became muscle-invasive.Specific attention should be paid to non-muscle-invasive bladder cancer with a high progression risk.

Utilization of Transthoracic Echocardiography Is Associated with a Decreased 6-month Readmission Rate in Hospitalized Heart Failure:A Propensity Score-matched Analysis

Objective::Repeated hospitalization due to congestion is a characteristic of the whole course of heart failure.Echocardiography can be used to assess cardiac function and volume status.However,whether echocardiography can reduce the rehospitalization rate remains unclear.This study aimed to evaluate the impact of transthoracic echocardiography(TTE)use on readmission rates in hospitalized patients with heart failure.Methods::The study was based on the Zigong heart failure database,which contained information on 2,008 adult patients with heart failure admitted to the Zigong Fourth People’s Hospital(Sichuan Province,China)from December 2016 to June 2019.Patients were divided into 2 groups according to the usage of TTE on the day of hospital admission(TTE group(1,371 patients)and no TTE group(637 patients),respectively).The primary outcome was the 6-month readmission rate.The statistical approaches used included multivariate Cox regression,propensity score analysis,and an inverse probability weighting model to ensure the robustness of the findings.Results::A significant reduction in 6-month readmission rate was observed among the TTE group compared with the no TTE group(hazard ratio=0.60,95%confidence interval(CI)=0.52-0.69,P<0.001).The frequencies of intravenous nitrates,diuretics,and inotropes during hospitalization were significantly higher in the TTE group compared with those in the no TTE group(10.9%vs.8.3%,88.5%vs.86.2%,and 66.9%vs.65.6%,respectively,all P<0.001).The proportion of patients returning to the emergency department within 6 months was significantly lower in the TTE group compared with the no TTE group(35.6%vs.50.3%,P<0.001).Conclusions::Utilization of TEE on admission day was associated with a reduced 6-month readmission rate in hospitalized patients with heart failure.

Bleeding risk comparing targeted low-dose heparin with bivalirudin in patients undergoing percutaneous coronary intervention results from a propensity score-matched analysis of the evaluation of drug-eluting stents and ischemic events (EVENT) registry

Background Prior randomized trials have shown reduced bleeding with bivalirudin compared with unfractionated heparin （UFH） in patients undergoing percutaneous coronary intervention （PCI）. However, it is not known if this benefit is also present when UFH doses are more tightly controlled （as measured by activated clotting time, ACT）.

Heparin-binding protein as a predictor of mortality in patients with diabetes mellitus and community-acquired pneumonia in intensive care unit:a propensity score matched study

BACKGROUND:Patients with diabetes mellitus(DM)are vulnerable to community-acquired pneumonia(CAP),which have a high mortality rate.We aimed to investigate the value of heparin-binding protein(HBP)as a prognostic marker of mortality in patients with DM and CAP.METHODS:This retrospective study included CAP patients who were tested for HBP at intensive care unit(ICU)admission from January 2019 to April 2020.Patients were allocated to the DM or non-DM group and paired with propensity score matching.Baseline characteristics and clinical outcomes up to 90 days were evaluated.The primary outcome was the 10-day mortality.Receiver operating characteristic(ROC)curves,Kaplan-Meier analysis,and Cox regression were used for statistical analysis.RESULTS:Among 152 enrolled patients,60 pairs were successfully matched.There was no significant difference in 10-day mortality,while more patients in the DM group died within 28 d(P=0.024)and 90 d(P=0.008).In the DM group,HBP levels at ICU admission were higher in 10-day non-survivors than in 10-day survivors(median 182.21[IQR:55.43-300]ng/ml vs.median 66.40[IQR:34.13-107.85]ng/mL,P=0.019),and HBP levels could predict the 10-day mortality with an area under the ROC curve of 0.747.The cut-off value,sensitivity,and specificity were 160.6 ng/mL,66.7%,and 90.2%,respectively.Multivariate Cox regression analysis indicated that HBP was an independent prognostic factor for 10-day(HR 7.196,95%CI:1.596-32.455,P=0.01),28-day(HR 4.381,95%CI:1.449-13.245,P=0.009),and 90-day mortality(HR 4.581,95%CI:1.637-12.819,P=0.004)in patients with DM.CONCLUSION:Plasma HBP at ICU admission was associated with the 10-day,28-day,and 90-day mortality,and might be a prognostic factor in patients with DM and CAP.

Robotic vs laparoscopic abdominoperineal resection for rectal cancer:A propensity score matching cohort study and metaanalysis

BACKGROUND Robotic surgery(RS)is gaining popularity;however,evidence for abdominoperineal resection(APR)of rectal cancer(RC)is scarce.AIM To compare the efficacy of RS and laparoscopic surgery(LS)in APR for RC.METHODS We retrospectively identified patients with RC who underwent APR by RS or LS from April 2016 to June 2022.Data regarding short-term surgical outcomes were compared between the two groups.To reduce the effect of potential confounding factors,propensity score matching was used,with a 1:1 ratio between the RS and LS groups.A meta-analysis of seven trials was performed to compare the efficacy of robotic and laparoscopic APR for RC surgery.RESULTS Of 133 patients,after propensity score matching,there were 42 patients in each group.The postoperative complication rate was significantly lower in the RS group(17/42,40.5%)than in the LS group(27/42,64.3%)(P=0.029).There wasno significant difference in operative time(P=0.564),intraoperative transfusion(P=0.314),reoperation rate(P=0.314),lymph nodes harvested(P=0.309),or circumferential resection margin(CRM)positive rate(P=0.314)between the two groups.The meta-analysis showed patients in the RS group had fewer positive CRMs(P=0.04),lesser estimated blood loss(P<0.00001),shorter postoperative hospital stays(P=0.02),and fewer postoperative complications(P=0.002)than patients in the LS group.CONCLUSION Our study shows that RS is a safe and effective approach for APR in RC and offers better short-term outcomes than LS.

Clinical effect of laparoscopic radical resection of colorectal cancer based on propensity score matching

BACKGROUND The incidence of colorectal cancer(CRC)is increasing annually.Laparoscopic radical resection of CRC is a minimally invasive procedure preferred in clinical practice.AIM To investigate the clinical effect of laparoscopic radical resection of CRC on the basis of propensity score matching(PSM).METHODS The clinical data of 100 patients who received inpatient treatment for CRC at Changde Hospital,Xiangya School of Medicine,Central South University(The First People’s Hospital of Changde City)were analyzed retrospectively.The control group included patients who underwent open surgery(n=43),and those who underwent laparoscopic surgery formed the observation group(n=57).The baseline information of both groups was equipoised using 1×1 PSM.Differences in the perioperative parameters,inflammatory response,immune function,degree of pain,and physical status between the groups were analyzed.RESULTS Thirty patients from both groups were successfully matched.After PSM,baseline data showed no statistically significant differences between the groups:(1)Periop-erative parameters:The observation group had a longer surgery time,less intra-operative blood loss,earlier first ambulation and first anal exhaust times,and shorter gastric tube indwelling time than the control group;(2)Inflammatory response:24 h after surgery,the levels of interleukin-6(IL-6),C-reactive protein(CRP),and tumor necrosis factor-α(TNF-α)between groups were higher than preoperatively.IL-6,CRP,and TNF-αlevels in the observation group were lower than in the control group;(3)Immune function:At 24 h after surgery,counts of CD4-positive T-lymphocytes(CD4+)and CD4+/CD8-positive T-lymphocytes(CD8+)in both groups were lower than those before surgery,whereas CD8+was higher than that before surgery.At 24 h after surgery,both CD4+counts and CD4+/CD8+in the observation group were higher than those in the control group,whereas CD8+counts were lower;(4)Degree of pain:The visual analog scale scores in the observation group were lower than those in the control group at 24 and 72 h after surgery;and(5)Physical status:One month after surgery,the Karnofsky performance score in the observation group was higher than that in the control group.CONCLUSION Laparoscopic radical resection of CRC has significant benefits,such as reducing postoperative pain and postoperative inflammatory response,avoiding excessive immune inhibition,and contributing to postoperative recovery.

Can propensity score matching replace randomized controlled trials?

Randomized controlled trials(RCTs)have long been recognized as the gold standard for establishing causal relationships in clinical research.Despite that,various limitations of RCTs prevent its widespread implementation,ranging from the ethicality of withholding potentially-lifesaving treatment from a group to relatively poor external validity due to stringent inclusion criteria,amongst others.However,with the introduction of propensity score matching(PSM)as a retrospective statistical tool,new frontiers in establishing causation in clinical research were opened up.PSM predicts treatment effects using observational data from existing sources such as registries or electronic health records,to create a matched sample of participants who received or did not receive the intervention based on their propensity scores,which takes into account characteristics such as age,gender and comorbidities.Given its retrospective nature and its use of observational data from existing sources,PSM circumvents the aforementioned ethical issues faced by RCTs.Majority of RCTs exclude elderly,pregnant women and young children;thus,evidence of therapy efficacy is rarely proven by robust clinical research for this population.On the other hand,by matching study patient characteristics to that of the population of interest,including the elderly,pregnant women and young children,PSM allows for generalization of results to the wider population and hence greatly increases the external validity.Instead of replacing RCTs with PSM,the synergistic integration of PSM into RCTs stands to provide better research outcomes with both methods complementing each other.For example,in an RCT investigating the impact of mannitol on outcomes among participants of the Intensive Blood Pressure Reduction in Acute Cerebral Hemorrhage Trial,the baseline characteristics of comorbidities and current medications between treatment and control arms were significantly different despite the randomization protocol.Therefore,PSM was incorporated in its analysis to create samples from the treatment and control arms that were matched in terms of these baseline characteristics,thus providing a fairer comparison for the impact of mannitol.This literature review reports the applications,advantages,and considerations of using PSM with RCTs,illustrating its utility in refining randomization,improving external validity,and accounting for non-compliance to protocol.Future research should consider integrating the use of PSM in RCTs to better generalize outcomes to target populations for clinical practice and thereby benefit a wider range of patients,while maintaining the robustness of randomization offered by RCTs.

Effect of induction chemotherapy with cisplatin, fluorouracil, with or without taxane on locoregionally advanced nasopharyngeal carcinoma: a retrospective, propensity score-matched analysis

Background:Available data in the literature comparing different induction chemotherapy(IC)regimens on locoregionally advanced nasopharyngeal carcinoma(NPC)are scarce.The purpose of the present study was to evaluate the outcomes of locoregionally advanced NPC patients who were treated with taxane,cisplatin and 5-fluorouracil(TPF)or cisplatin and 5-fluorouracil(PF)as IC followed by concurrent chemoradiotherapy(CCRT).Methods:In total,1879 patients with locoregionally advanced NPC treated with IC and CCRT from a prospectively maintained database were included in the present observational study.We compared overall survival(OS),disease-specific survival(DSS),distant metastasis-free survival(DMFS),and locoregional relapse-free survival,using the pro-pensity score method.Results:In total,1256 patients received TPF or PF as IC backbone.The TPF group showed significantly better OS(hazard ratio[HR],0.660;95%confidence interval[CI]0.442-0.986;P=0.042),DSS(HR,0.624;95%CI 0.411-0.947;P=0.027)and DMFS(HR,0.589;95%CI 0.406-0.855;P=0.005)compared with the PF group in multivariable analy-ses.Propensity score matching identified 294 patients in each cohort and confirmed that TPF was associated with significantly improved 5-year OS(88.1%vs.80.7%;P=0.042),DSS(88.5%vs.80.7%;P=0.021)and DMFS(87.9%vs.78.6%;P=0.012)rates compared with the PF group.There were no significant differences in locoregional relapse-free survival before or after matching.Conclusions:In our study,IC with the TPF regimen combined with CCRT showed improved long-term survival for the patients with locoregionally advanced NPC compared with the PF regimen.However,a prospective randomized clinical trial to validate these findings is necessary.

Comparison of breast-conserving surgery and mastectomy in early breast cancer using observational data revisited:a propensity score-matched analysis

Recent observational studies showed that breast-conserving surgery(BCS) resulted in superior survival compared to mastectomy in breast cancer patients. This study compared the clinical outcomes of BCS and mastectomy using propensity score(PS)matching analysis, which had advantages over conventional methods in reducing bias. Nonmetastatic breast cancer patients who underwent BCS and mastectomy were matched 1:1 based on their PS. We used the Kaplan-Meier method and Cox-regression model to estimate the treatment effects. A total of 2,866 patients with a median follow-up time of 67 months were included in the original study population. Although the mastectomy cohort(N=1,219) had more advanced disease compared to the BCS cohort(N=1,647), LRFS was similar between the two groups(93.8% vs. 92.4%, P>0.05). BCS(vs. mastectomy) was associated with improved DFS(73.8% vs. 58.7%, P<0.01) and CSS(91% vs. 78.2%, P<0.01) in the original population. In the PS-matched population(N=1,668), clinicopathological features were equally distributed between the two cohorts. BCS(vs. mastectomy) was not associated with improved DFS(70.7% vs. 66.9%, P>0.05) or CSS(87.5% vs. 84.9%, P>0.05). We found that PS methods reduce bias when estimating treatment effects using observational data. BCS and mastectomy show equivalent outcomes in nonmetastatic breast cancer patients.

Comparison of diagnostic efficacy between transrectal and transperineal prostate biopsy:a propensity score-matched study

This study compared the diagnostic efficacy of transrectal ultrasound(TRUS)-guided prostate biopsy(TRBx)and transperineal prostate biopsy(TPBx)in patients with suspected prostate cancer(PCa).We enrolled 2962 men who underwent transrectal(n=1216)or transperineal(n=1746)systematic 12-core prostate biopsy.Clinical data including age,prostate-specific antigen(PSA)level,and prostate volume(PV)were recorded.To minimize confounding,we performed propensity score-matching analysis?We measured and compared PCa detection rates between TRBx and TPBx,which were stratified by clinical characteristics and Gleason scores.The effects of clinical characteristics on PCa detection rate were assessed by logistic regression.For all patients,TPBx detected a higher proportion of clinically significant PCa(P<0.001).Logistic regression analyses illustrated that PV had a smaller impact on PCa detection rate of TPBx compared with TRBx.Propensity score-matching analysis showed that the detection rates in TRBx were higher than those in TPBx for patients aged≥80 years(80.4%vs 56.5%,P=0.004)and with PSA level 20.1-100.0 ng ml^-1(80.8%vs 69.1%,P=0.040).In conclusion,TPBx was associated with a higher detection rate of clinically significant PCa than TRBx was;however,because of the high detection rate at certain ages and PSA levels,biopsy approaches should be optimized according to patents'clinical characteristics.

Impact of neoadjuvant chemoradiotherapy on the local recurrence and distant metastasis pattern of locally advanced rectal cancer: a propensity score-matched analysis

Background:Previous studies have demonstrated different predominant sites of distant metastasis between patients with and without neoadjuvant chemoradiotherapy(NCRT).This study aimed to explore whether NCRT could influence the metastasis pattern of rectal cancer through a propensity score-matched analysis.Methods:In total,1296 patients with NCRT or post-operative chemoradiotherapy(PCRT)were enrolled in this study between January 2008 and December 2015.Propensity score matching was used to correct for differences in baseline characteristics between the two groups.After propensity score matching,the metastasis pattern,including metastasis sites and timing,was compared and analyzed.Results:After propensity score matching,there were 408 patients in the PCRT group and 245 patients in the NCRT group.NCRT significantly reduced local recurrence(4.1%vs.10.3%,P=0.004),but not distant metastases(28.2%vs.27.9%,P=0.924)compared with PCRT.In both the NCRT and PCRT groups,the most common metastasis site was the lung,followed by the liver.The NCRT group developed local recurrence and distant metastases later than the PCRT group(median time:29.2[18.8,52.0]months vs.18.7[13.3,30.0]months,Z=–2.342,P=0.019;and 21.2[12.2,33.8]vs.16.4[9.3,27.9]months,Z=–1.765,P=0.035,respectively).The distant metastases occurred mainly in the 2nd year after surgery in both the PCRT group(39/114,34.2%)and NCRT group(21/69,30.4%).However,20.3%(14/69)of the distant metastases appeared in the 3rd year in the NCRT group,while this number was only 13.2%(15/114)in the PCRT group.Conclusions:The predominant site of distant metastases was the lung,followed by the liver,for both the NCRT group and PCRT group.NCRT did not influence the predominant site of distant metastases,but the NCRT group developed local recurrence and distant metastases later than the PCRT group.The follow-up strategy for patients with NCRT should be adjusted and a longer intensive follow-up is needed.

Concurrent chemoradiotherapy with weekly docetaxel versus cisplatin in the treatment of locoregionally advanced nasopharyngeal carcinoma:a propensity score-matched analysis

Background:Promising efficacy and manageable toxicity of docetaxel-based concurrent chemoradiotherapy(CCRT)were reported in head and neck cancer.In addition,the effect of CCRT in combination with cisplatin and/or 5-fluorouracil on both locoregionally advanced and metastatic/recurrent nasopharyngeal carcinoma(NPC)was verified.However,CCRT with docetaxel for locoregionally advanced NPC are not well studied.This study aimed to compare effectiveness and toxicities of CCRT with weekly docetaxel versus tri-weekly cisplatin for locoregionally advanced NPC.Methods:Clinical data of patients with locoregionally advanced NPC newly diagnosed between January 2010 and December 2014 receiving CCRT with either weekly docetaxel(15 mg/m2)or tri-weekly cisplatin(80-100 mg/m2)were reviewed.Propensity score matching at a 1:1 ratio was performed to balance baseline characteristics.Adverse events and survival were compared between the two groups.Results:A total of 962 patients were included as the whole cohort,and 448 patients were matched and were regarded as the matched cohort.The median follow-up duration was 48 months for the whole cohort.The 3-year nodal recurrence-free survival rate was significantly increased for patients treated with docetaxel in both the whole(hazard ratio[HR]=0.37,95%confidence interval[CI]0.19-0.72,P=0.030)and matched cohorts(HR=0.33,95%CI 0.14-0.79,P=0.023).However,no significant differences were observed in overall survival,local recurrence-free survival,and distant metastasis-free survival between the two groups in both cohorts.Significantly higher rates of grade 3 radiodermatitis(6.7%vs.1.8%,P=0.001),mucositis(74.5%vs.37.9%,P<0.001),and leucopenia(2.2%vs.11.6%,P<0.001)were observed in the docetaxel group,but any grade of renal injury(1.8%vs.15.1%,P<0.001),vomiting(18.8%vs.88.3%,P<0.001),and ALT elevation(19.2%vs.31.3%,P=0.027)were more common in the cisplatin group.Conclusions:CCRT with weekly low-dose docetaxel is an effective and tolerable therapeutic regimen for locally advanced NPC.It provides a survival benefit mainly by improving the control of regional lymph node metastases,especially for patients with low pretreatment EBV DNA levels.

Robotic-assisted versus open total pancreatectomy: a propensity score-matched study

Background:Total pancreatectomy(TP)is a complex surgical procedure with significant postoperative morbidity.Despite the narrowed range of indications for TP,the introduction of neoadjuvant chemotherapy and the increasing complexity of surgical resections performed in high-volume centers has increased the number of annually performed TPs,especially regarding malignant disease.The introduction of robotic-assisted pancreatic surgery has provided a novel and minimally invasive approach for TP,yet the feasibility of this technique is still unknown.This study assessed the safety and efficacy of robotic-assisted total pancreatectomy(RTP)compared to conventional open total pancreatectomy(OTP).Methods:All patients who underwent TP between March 2015 and July 2019 in a high-volume institution for pancreatic surgery were included in this retrospective study.Clinical data and perioperative outcomes were derived from the prospectively maintained institutional database.A 1:1 propensity score matching(PSM)method was utilized to compare the RTP and OTP cohorts to minimize bias.Results:A standardized surgical protocol was utilized for RTP following a learning curve of RPD and RDP.The median operative time for patients who underwent RTP was significantly decreased compared to those who underwent OTP[300(IQR,250-360)vs.360 min(IQR,300-525),P=0.031].Additionally,en bloc resection and spleen-preserving rates were also higher in the RTP cohort.Major 30-day morbidity(Clavien-Dindo>IIIa)and 90-day mortality were similar between the two cohorts.After a median follow-up time of 15(IQR,8-24)months,both the RTP and OTP cohorts had a comparable quality of life regarding exocrine and endocrine insufficiency.Conclusions:RTP appears to be safe and feasible when utilized in high-volume centers for the indicated management of benign and highly selected malignant pancreatic disease.However,further prospective randomized studies are needed to assess the feasibility of this approach.

Performance of Bayesian Propensity Score Adjustment for Estimating Causal Effects in Small Clinical Trials

Propensity score (PS) adjustment can control confounding effects and reduce bias when estimating treatment effects in non-randomized trials or observational studies. PS methods are becoming increasingly used to estimate causal effects, including when the sample size is small compared to the number of confounders. With numerous confounders, quasi-complete separation can easily occur in logistic regression used for estimating the PS, but this has not been addressed. We focused on a Bayesian PS method to address the limitations of quasi-complete separation faced by small trials. Bayesian methods are useful because they estimate the PS and causal effects simultaneously while considering the uncertainty of the PS by modelling it as a latent variable. In this study, we conducted simulations to evaluate the performance of Bayesian simultaneous PS estimation by considering the specification of prior distributions for model comparison. We propose a method to improve predictive performance with discrete outcomes in small trials. We found that the specification of prior distributions assigned to logistic regression coefficients was more important in the second step than in the first step, even when there was a quasi-complete separation in the first step. Assigning Cauchy (0, 2.5) to coefficients improved the predictive performance for estimating causal effects and improving the balancing properties of the confounder.