Prognostic value of pathological nodal burden after neoadjuvant chemotherapy in initially cN0-1 breast cancer patients: a dual-center, 10-year survival analysis.

Background: There is an interest in performing de-escalating axillary surgery after neoadjuvant chemotherapy (NAC). However, the significance of residual axillary node disease after NAC has not been well studied. Objectives: To investigate the pathological residual axillary lymph node tumor burden (ypN) of patients with initial clinical nodal stage cN0-1 breast cancer after NAC and determine its prognostic value. Design: Initial cN0-1 breast cancer patients who received NAC followed by axillary surgery at the First Hospital of Jilin University and the First Affiliated Hospital of Xi'an Jiaotong University between January 2011 and December 2019 were included. Methods: Survival outcomes were compared according to different clinical and pathological stage and nodal response to NAC. The main outcomes were disease-free survival (DFS) and overall survival (OS). Factors associated with survival were defined by Cox regression analysis. Results: A total of 911 patients were included, among whom 260 had cN0 and 651 had cN1 tumors. After NAC, 410 patients were ypN0, and another 501 were ypN+. The median follow-up time was 63 months. There was no significant difference in DFS or OS between the cN0 and cN1 groups in hormone receptor positive (HR+)/human epidermal growth factor receptor 2 positive (HER2+) and HR-/HER2- subtypes; instead, ypN status was significantly related to DFS and OS. In HR+/HER2- subtype, both cN and ypN stages did not show significant survival differences, but the ypN number and the nodal response to NAC showed significant prognostic value (p < 0.05). Among HR-/HER2+ patients, all cN status, ypN status, ypN number, and nodal response were significantly associated with survival (p < 0.05). Furthermore, tumor biology, axillary surgery, ypN status, pathological tumor size, and radiotherapy were independent prognostic factors for DFS and OS. Conclusion: The ypN status after NAC provide more prognostic information than the initial cN stage in cN0-1 patients, and the surgical axillary staging after NAC may have high clinical value.

Early evaluation of circulating tumor DNA as marker of therapeutic efficacy and prognosis in breast cancer patients during primary systemic therapy.

BACKGROUND: We assessed the potential role of serial circulating tumor DNA (ctDNA) as a biomarker to monitor treatment response to primary systemic therapy (PST) in breast cancer and evaluated the predictive value of ctDNA to further identify patients with residual disease. METHODS: We prospectively enrolled 208 plasma samples collected at three time points (before PST, after 2 cycles of treatment, before surgery) of 72 patients with stage Ⅱ-III breast cancer. Somatic mutations in plasma samples were identified using a customized 128-gene capture panel with next-generation sequencing. The correlation between early change in ctDNA levels and treatment response or long-term clinical outcomes was assessed. RESULTS: 37 of 72 (51.4%) patients harbored detectable ctDNA alterations at baseline. Patients with complete response showed a larger decrease in ctDNA levels during PST. The median relative change of variant allele fraction (VAF) was -97.4%, -46.7%, and +21.1% for patients who subsequently had a complete response (n = 11), partial response (n = 11), and no response (n = 15) (p = 0.0012), respectively. In addition, the relative change of VAF between the pretreatment and first on-treatment blood draw exhibited the optimal predictive value to tumor response after PST (area under the curve, AUC = 0.7448, p = 0.02). More importantly, early change of ctDNA levels during treatment have significant prognostic value for patients with BC, there was a significant correlation between early decrease of VAF and longer recurrence-free survival compared to those with an VAF increase (HR = 12.54; 95% CI, 2.084 to 75.42, p = 0.0063). CONCLUSION: Early changes of ctDNA are strongly correlated with therapeutic efficacy to PST and clinical outcomes in BC patients. The integration of preoperative ctDNA evaluation could help improving the perioperative management for BC patients receiving PST.

Effect of HER2-low-positive status on neoadjuvant chemotherapy and survival outcome of breast cancer: a 10-year dual-center retrospective study.

Various novel HER2-targeted antibody-conjugated drugs (ADCs) have shown satisfactory antitumor activity in HER2-low-positive breast cancer (BC). It is urgent to clarify whether HER2-low-positive tumors have unique biological behavior and should be considered a new molecular subtype. We screened eligible BC patients and collected relevant information at the First Hospital of Jilin University and the First Affiliated Hospital of Xi'an Jiaotong University from January 2010 to December 2020. A total of 1027 patients were included in our study cohort, and 66.0% (678/1027) had HER2-low-positive tumors. Compared to HER2-zero patients, HER2-low-positive patients tended to have more lymph node metastasis, a larger proportion of hormone receptor (HR)-positive tumors, and a lower proliferation rate (Ki-67). The pathologic complete response (pCR) rate of HER2-low-positive patients was lower than that of HER2-zero patients (19.3% vs 26.1%), especially in the HR-positive subgroup (12.00% vs 20.29%). However, multivariate logistic regression analysis showed that HER2 status was not an independent factor for predicting pCR. HER2-low-positive patients had a higher overall survival (OS) rate in the HR-positive subgroup. The Cox regression model analysis suggested that HER2-low-positive status did not statistically significantly affect the survival outcomes, regardless of disease-free survival (DFS) (P=0.308) or OS (P=0.066). In conclusion, HER2-low-positive tumors have unique clinical and pathological characteristics, with a lower pCR rate in the HR-positive subgroup and better survival in the HR-negative subgroup compared to HER2-zero tumors. However, the effect of HER2-low-positive status on pCR or survival outcomes was not statistically significant.

Effects of a lymphedema prevention program based on the theory of knowledge-attitude-practice on postoperative breast cancer patients: A randomized clinical trial.

BACKGROUND: Breast cancer-related lymphedema (BCRL) is one of the common postoperative complications that severely affects the functions of the arm and quality of life. Since lymphedema is difficult to treat and prone to recurrence, early prevention of lymphedema is crucial. METHODS: Patient diagnosed with breast cancer (N = 108) were randomized to the intervention (n = 52) or control group (n = 56). In the intervention group, patients were provided the lymphedema prevention program based on the theory of knowledge-attitude-practice during the perioperative period and the first three chemotherapy sessions (mainly includes health education, seminars, knowledge manuals, sports guidance, peer education, and WeChat group).The limb volume, handgrip strength, arm function, and quality of life were measured in all patients at the baseline, 9 weeks (T1), and 18 weeks (T2) after surgery. RESULTS: The incidence of lymphedema in the Intervention group was numerically lower than in the control group after implementing the lymphedema prevention program, but the difference was not statistically significant (T1: 1.9% vs. 3.8%, p = 1.000; T2: 3.6% vs. 7.1%, p = 0.744). However, compared with the control group, the intervention group showed there was less deterioration in handgrip strength (T1 [t = -2.512, p < 0.05] and T2 [t = -2.538, p < 0.05]), improved postoperative upper limb dysfunction (T1 [t = 3.087, p < 0.05] and T2 [t = 5.399, p < 0.05]) and less deterioration in quality of life (T1 [p < 0.05] and T2 [p < 0.05]). CONCLUSION: Although the investigated lymphedema prevention program improved arm function and quality of life, it did not reduce the incidence of lymphedema in postoperative breast cancer patients.

A common variant SNP rs1937810 in the MPP7 gene contributes to the susceptibility of breast cancer in the Chinese Han population.

BACKGROUND: Breast cancer (BC) is common cancer caused by environmental factors and genetic ones. Previous evidence has linked gene MAGUK P55 Scaffold Protein 7 (MPP7) to BC, despite that there has been no research evaluating the relationship between MPP7 genetic polymorphisms and BC susceptibility. We aimed to investigate the potential association of the MPP7 gene with the susceptibility to BC in Han Chinese individuals. METHODS: In total, 1390 patients with BC and 2480 controls were enrolled. For genotyping, 20 tag SNPs were chosen. The serum levels of protein MPP7 were measured in all subjects using an enzyme-linked immunosorbent assay. Genetic association analysis was performed in both genotypic and allelic modes, and the relationship between BC patients' clinical features and genotypes of relevant SNPs was examined. The functional implications of significant markers were also evaluated. RESULTS: After adjusting for Bonferroni correction, SNP rs1937810 was found to be significantly associated with the risk of BC (p = 1.19 × 10-4 ). The odds ratio of CC genotypes in BC patients was 49% higher than in controls (1.49 [1.23-1.81]). Serum MPP7 protein levels were significantly higher in BC patients than in controls (p < 0.001). The protein level of the CC genotype was the highest, and that of the CT and TT genotypes decreased in turn (both p < 0.001). CONCLUSIONS: Our results linked SNP rs1937810 to the susceptibility of BC and the clinical features of BC patients. This SNP is also proved to be significantly related to the serum level of protein MPP7 in both BC patients and controls.

Dynamic Simulator for Three-Phase Gravity Separators in Oil Production Facilities.

In this study, a dynamic simulator for three-phase gravity separators in oil production facilities is proposed. The mass conservation equation is established to calculate the pressure, water level, and oil level in the separator and the mass balance equation of the dispersed phase to calculate the oil-water separation efficiency. The proportional integral controllers are applied to control the water level, oil level, and pressure in the separator by setting the opening of the three outlet valves of oil, gas, and water. The model is verified using field data by means of the given valve opening and given proportional integral controller parameters, respectively. Subsequently, the verified simulator is applied to study the dynamic behavior of the separator filling process and the effect of pressure, oil level, and water level setpoint changes on the separator operating status. A detailed analysis of the changes in the liquid level, pressure, and opening of three outlet valves is presented. Then, the effects of operating conditions such as the inlet flow, water setpoint, and weir height on the separation efficiency are discussed. This simulator can be applied for the design of oil, gas, and water three-phase separation processes. In addition, through this simulator, the parameters that are difficult to be measured by instruments during the operation of the separator can be calculated, providing technical support for the construction of the digital twin of the separator.

Evolution of morphology and cohesive force of hydrate particles in the presence/absence of wax.

In the exploitation of deep-sea oil and gas resources, the multiphase production and transportation process is frequently plagued by pipeline blockage issues. Especially when hydrates and wax coexist simultaneously, the viscosity and plugging tendency of multiphase flow systems will synergistically increase. Understanding the evolution of morphology of hydrate particles and the agglomeration characteristics of hydrate particles in the presence or absence of wax crystals is crucial to flow assurance industry. With the assistance of a visualized reactor equipped with a three axis moving platform, microscopic images of cyclopentane hydrate during hydrate growth were obtained, and the cohesive force between hydrate particles was measured. It was found that during the hydrate growth on wax-free water droplets, the untransformed water inside the particles gradually wetted the surface of the particle. With the increase in temperature and contact time, the shell of hydrate particles changed from solid and rough to smooth and moist. The cohesive force measured in this work ranges from 3.14 ± 0.52 to 11.77 ± 0.68 mN m-1 with different contact times and temperature. When the contact time was 0 s and 10 s, the cohesive force between particles increased first and then stabilized with temperature. When the contact time was 20 s, the cohesive force was greater than the first two cases and showed an overall stable trend. An interesting phenomenon was also discerned: a large water bridge between particles formed during their separation process. For the wax-containing system, it required a longer time for water droplets to be converted into hydrate particles than that for wax-free systems. After wax participated in hydrate growth, hydrate particles showed the properties of elasticity and stickiness, which resulted in a larger liquid bridge between hydrate particles after their contact. It was suggested that wax crystal would alter the shell structure of hydrate particles, and change the surface properties of hydrate particles and the formation process of the liquid bridge, leading to significant and rapid increase in the cohesive force.

Polymorphism of MMP-3 gene and imbalance expression of MMP-3 / TIMP-1 in articular cartilage are associated with an endemic osteochondropathy, Kashin- Beck disease.

BACKGROUND: The etiology of Kashin-Beck disease (KBD), an endemic osteochondropathy, is largely unknown. Matrix metalloproteinase-3 (MMP-3) plays a central role in the initiation and progression of cartilage destruction, however, no study has reported on the relationship between KBD and MMP-3. The objective of this study was to explore the polymorphism of MMP-3 gene and expression of MMP-3 / TIMP-1(Tissue inhibitors of matrixmetalloproteinases-1) in the pathogenesis of KBD. METHODS: Single nucleotide polymorphism (SNP) genotyping was conducted in 274 KBD cases and 248 healthy controls for eight SNPs in MMP-3 using the Sequenom MassARRAY system. Additionally, the expression of MMP-3、TIMP-1 in different layers of the articular cartilage was analyzed by immunohistochemistry for 22 KBD patients, 15 osteoarthritis (OA) patients and 21 controls. RESULTS: The results showed that six SNPs (rs520540、rs591058、rs679620、rs602128、rs639752 and rs678815) in MMP-3 were associated with the increased risk of KBD, however, after Bonferroni correction, only the SNP rs679620 in the recessive model remained significant difference (OR = 2.31, 95%CI = 1.29-4.14, P = 0.0039), homozygous for "T" allele have a risk for KBD than "C" allele carriers. Moreover, the percentages of cells expressing MMP-3 in articular cartilage were significantly higher in the KBD and OA groups than in the controls (t = 5.37 and 4.19, P<0.01). While the KBD and OA groups had lower levels of TIMP-1 positive staining compared with the controls (t = 5.23and 5.06, P<0.01). And there was no significant different between KBD and OA for the levels of MMP-3 and TIMP-1 positive staining (t = 0.05and 0.28, P>0.05). CONCLUSIONS: MMP-3 is associated with the susceptibility of KBD, and the imbalance expression of MMPs / TIMPs leading to cartilage degradation may play an important role in cartilage degradation and osteoarthritis formation in OA and KBD.

Effect of the Ethylene Vinyl Acetate Copolymer on the Induction of Cyclopentane Hydrate in a Water-in-Waxy Oil Emulsion System.

In this paper, the effect of the ethylene vinyl acetate (EVA) copolymer, commonly used in improving rheological behavior of waxy oil, is introduced to investigate its effect on the formation of cyclopentane hydrate in a water-in-waxy oil emulsion system. The wax content studied shows a negative effect on the formation of hydrate by elongating its induction time. Besides, the EVA copolymer is found to elongate the induction time of cyclopentane hydrate through the cocrystallization effect with wax molecules adjacent to the oil-water interface.

Study on the decomposition mechanism and kinetic model of natural gas hydrate slurry in water-in-oil emulsion flowing systems.

Hydrate slurry decomposition in flow systems is a significant subject that involves flow assurance and development of marine natural gas hydrates. Firstly, the decomposition mechanism of hydrate slurry is studied in this work, and it is proposed that desorption of the gas from the surface of the decomposed hydrate particles might be the main reason for the coalescence of particles and water droplets during the hydrate slurry decomposition. Secondly, a hydrate slurry decomposition kinetic model comprehensively considering the influencing factors (i.e., the intrinsic kinetics, heat and mass transfer) is proposed in this work, based on the classic intrinsic kinetic model and the hydrate slurry dissociation experiments conducted in a flow loop system. The fugacity difference is used as the driving force for the hydrate decomposition, and the influence of particle coalescence, and heat and mass transfer is also considered. The effect of the heat and mass transfer is coupled with the apparent decomposition reaction rate constant. Meanwhile, the time-dependent interfacial parameters would significantly impact on the hydrate dissociation rate, which are considered to enhance the predictive precision of the decomposition kinetic model. Further, the integrated decomposition kinetics model proposed in this paper could well describe the trends of the amount of released gas and the dissociation rate of the experimental flow systems. Through combining the experimental results of the hydrate slurry decomposition, the decomposition parameters under actual flowing conditions were obtained.

Study of the Comprehensive Kinetic Model of Natural Gas Hydrate Formation in a Water-in-Oil Emulsion Flow System.

Hydrate growth is influenced by many factors, including thermodynamics, kinetics, mass and heat transfer, and so on. There is thus a practical significance in establishing a model that comprehensively considers these influencing factors for hydrate crystal growth in multiphase transportation pipelines. On this basis, this paper presents a more practical and comprehensive bidirectional growth model of hydrate shells for an actual pipeline system. Thermodynamic phase equilibrium theory and water molecule penetration theory are applied in this model to develop a method for calculating the concentration change of hydrate-forming guest molecules and the permeation rate of water molecules. The temperatures on both sides of the hydrate shell are predicted by the heat transfer model. Simultaneously, decreasing the mass transfer coefficient with continuous hydrate growth is used to describe the problem in which the mass transfer efficiency decreases with a thickened hydrate shell. Then, the hydrate growth kinetic parameters of the pipeline system are optimized according to hydrate growth experiments conducted in a high-pressure flow loop and the microscopic characteristics of the particles were provided using the PVM and FBRM probes. The improved hydrate growth model can improve the prediction accuracy of hydrate formation in slurry systems.

Study on methane hydrate formation in gas-water systems with a new compound promoter.

The effects of a new promoter on the growth kinetics of methane hydrates were investigated using a visualized constant-pressure autoclave. The experimental results show that when the 1#, 2# and 3# unit promoter was compounded at a ratio of 2 : 1 : 1, the induction time was shortened greatly from 30 h to 0.64 h compared to the no promoter situation. Meanwhile, there was a larger amount of hydrate formation, and final hydrate volume fraction was 83.652%. Then, the hydrate formation characteristics under different additive dosages (500 ppm, 1000 ppm, 2000 ppm, 5000 ppm) and different subcooling degrees (2.5 °C, 3.5 °C, 4.5 °C, 5.5 °C, 6.5 °C) were investigated. The new promoter at these 4 concentrations could effectively shorten the induction time. And the higher the concentration, the smaller the induction time (0.22 h at 5000 ppm). It was also found that gas consumption and hydrate production rate increased first and then decreased with increasing promoter dosage. Finally, the optimal dosage was determined to be 2000 ppm, at which the induction time was shortened to 0.52 h, and the final hydrate volume fraction was 85.74%. Under the dosage of 2000 ppm and the subcooling degree of 6.5 °C, the shortest induction time (0.29 h) and the maximum formation rate (20.950 ml h-1) were obtained among all the experimental conditions in this work. Moreover, the greater the subcooling degree, the faster the hydrate nucleation, and the shorter the induction time. However, if the subcooling degree was too high, a hydrate layer formed rapidly at the gas-liquid interface in the autoclave, which would hinder hydrate formation and lead to the reduction of hydrate volume fraction to 60.153%. Therefore, a reasonable selection of the proportioning of promoters, dosage of the promoter and formation temperature could significantly promote the formation of hydrates. The findings in this work are meaningful to hydrate associated applications and can provide useful references for the selection of hydrate promoters.

Experimental study of growth kinetics of CO2 hydrates and multiphase flow properties of slurries in high pressure flow systems.

The formation and accumulation of hydrates in high pressure oil and gas pipelines bring great risks to field development and deep-water transportation. In this paper, a high pressure flow loop equipped with visual window was used to study the growth process of hydrates in a pipe flow system and slurry flow characteristics. Deionized water, industrial white oil and CO2 were selected as the experiment medium. A series of experiments with different initial pressures (2.5-3 MPa), liquid loads (7-9 L), flow rates (25-35 kg min-1) and water cuts (60-100%) were designed and carried out. Specifically, hydrate formation and slurry flow characteristics in two different systems, pure water and oil-water emulsion system, were compared. Both of the systems experienced an induction stage, slurry flow stage and followed by a plugging stage. Although hydrate growth gradually ceased in the slurry flow stage, plugging still occurred due to the continuous agglomeration of hydrates. Visual observation showed that there were obvious stratification of the oil-water emulsion systems at the later time of slurry flow stage, which directly resulted in pipe blockage. The hydrate induction time of the flow systems gradually decreased with the increasing initial pressure, initial flow rate and water content. And the induction time tended to decrease first and then slowly increase with the increasing liquid loading. For emulsion systems, the apparent viscosity and friction coefficient of the hydrate slurry increased with the increasing water content, indicating that there were higher plugging risks compared to the pure water systems. Moreover, the results of sensitivity analysis showed that the water content was the main factor affecting the hydrate induction time, followed by the influence of liquid carrying capacity and flow rate, and the initial pressure had the least influence on the induction time. Conclusions obtained in this paper can provide some reference not only for the prevention and management of hydrates in pipelines, but also for the application of CO2 hydrate as a refrigerant.

Hydrate slurry flow property in W/O emulsion systems.

Hydrate risk management strategy has become a promising way of dealing with hydrates in subsea transportation pipelines in recent years. In this way, hydrates are allowed to form in the pipeline and are treated as a slurry flow with the help of anti-agglomerants. This work investigated the effect of hydrate formation on the flow friction factor in water in oil (W/O) emulsion systems. A series of hydrate formation and slurry flow experiments were conducted using a high pressure flow loop. Results show that the friction factor is in direct proportion to the volume fraction of hydrates formed, as it increases significantly after hydrate formation onset and then increases gradually with hydrate growing. A novel method is proposed in this work to amend the effective hydrate volume fraction and take into account the effect of hydrate agglomeration and water occlusion. In addition, it is found that the slurry flow velocity has a significant effect on the friction factor variation. As a larger flow velocity can lift the particles suspension height and cause the particles to be away from the pipe wall surface, so it gives a smaller friction factor by reducing the collisions between hydrate particles and the pipe wall surface. With the modified effective hydrate volume fraction and particle chord length distribution data, a model is proposed to estimate the hydrate caused friction factor in W/O emulsion systems, which shows a good prediction accuracy in 10% and 20% water cut conditions.

Study on the blockage mechanism of carbon dioxide hydrate slurry and its microscopic particle characteristics.

In order to better understand the process of carbon dioxide hydrate formation and blockage, a series of experiments were performed in a high pressure hydrate experimental loop which has been constructed. The impacts of varying flow rate, pressure, and restarting of the pump on the plugging have been studied in this paper. The particle chord length distribution in the process of hydrate formation and blockage was monitored in real time by using the advanced device, Focused Beam Reflectance Measurement (FBRM). The results showed that the time taken for hydrate blockage to occur would significantly decrease at higher pressure, which meant higher pressure promoted the occurrence of hydrate blockage. At the same time, the time needed for carbon dioxide hydrate blockage increased with the flow rate. That is, the time for hydrate blockage increased when the flow rate changed from 754 kg h-1 to 1657 kg h-1. And once the pipeline has been blocked, restarting the pump may make the problem more serious. In addition, particle agglomeration led to a significant change in the particle chord length distribution during the process of hydrate formation and blockage, and the hydrate particle coalescence was the key cause of the hydrate plugging.

Study on the growth rate of natural gas hydrate in water-in-oil emulsion system using a high-pressure flow loop.

Hydrate slurry transport technology in deep-water pipelines has become a focal point among worldwide researches, due to its high economic efficiency. However, as the key part of the hydrate slurry transport technology research, the mechanism and laws of natural gas hydrate growth dynamics are still unclear in the flow emulsion system. On this basis, we have conducted a series of growth kinetic experiments in a high-pressure loop, investigated systematically several influencing factors (i.e. the flow rate, water-cut, AA concentration and so on) of growth kinetics, obtained the quantitative relations between these factors and the gas consumption as well as the hydrate growth rate (gas consumption rate). It could be gained from analysis of these influencing factors, that the hydrate growth rate has an extreme value (maximum) during the formation process in a slurry system. The controlling factor of hydrate formation differed at the stages before and after this maximum value. The intrinsic kinetics controlled before the value while heat/mass transfer influenced after it. The time needed for the hydrate growth rate to reach the maximum point was generally within 0.5 h after the hydrate mass formation.

Standard versus extralevator abdominoperineal excision and oncologic outcomes for patients with distal rectal cancer: A meta-analysis.

BACKGROUND: The role of extralevator abdominoperineal excision (ELAPE) for distal rectal cancer remains controversial, and the procedure is not widely accepted or practiced. METHODS: An electronic search of Medline, EMBASE, Web of Science, and similar databases for articles in English was performed from the inception of the study until October 31, 2017. Two reviewers extracted information and independently assessed the quality of included studies by the methodological index for nonrandomized studies, then data were analyzed with Review Manager 5.3 software and Stata version 12.0 software. RESULTS: Our meta-analysis included 17 studies with 3479 patients, of whom 1915 (55.0%) underwent ELAPE and 1564 (44.0%) underwent abdominoperineal excision (APE). Compared with patients undergoing APE, patients undergoing ELAPE had a significant reduced risk of no more than 3 years local recurrence (LR) (risk ratio [RR] = 0.27, 95% confidence interval [CI] = 0.08-0.94), 3-year mortality (odds ratio [OR] = 0.45, 95% CI = 0.20-0.97), intraoperative bowel perforation (IBP) involvement (RR = 0.48, 95% CI = 0.31-0.74), and circumferential resection margin (CRM) positivity (RR = 0.66, 95% CI = 0.43-1.00) at the threshold level. CONCLUSIONS: The application of ELAPE is more effective in reducing the chance of 3 years LR, mortality, IBP involvement and CRM positivity than conventional APE, and worthy of being widely applied in surgical treatment of the distal rectal cancer.

Superiority of Minimally Invasive Oesophagectomy in Reducing In-Hospital Mortality of Patients with Resectable Oesophageal Cancer: A Meta-Analysis.

BACKGROUND: Compared with open oesophagectomy (OE), minimally invasive oesophagectomy (MIO) proves to have benefits in reducing the risk of pulmonary complications for patients with resectable oesophageal cancer. However, it is unknown whether MIO has superiority in reducing the occurrence of in-hospital mortality (IHM). OBJECTIVE: The objective of this meta-analysis was to explore the effect of MIO vs. OE on the occurrence of in-hospital mortality (IHM). DATA SOURCES: Sources such as Medline (through December 31, 2014), Embase (through December 31, 2014), Wiley Online Library (through December 31, 2014), and the Cochrane Library (through December 31, 2014) were searched. STUDY SELECTION: Data of randomized and non-randomized clinical trials related to MIO versus OE were included. INTERVENTIONS: Eligible studies were those that reported patients who underwent MIO procedure. The control group included patients undergoing conventional OE. STUDY APPRAISAL AND SYNTHESIS METHODS: Fixed or random -effects models were used to calculate summary odds ratios (ORs) or relative risks (RRs) for quantification of associations. Heterogeneity among studies was evaluated by using Cochran's Q and I2 statistics. RESULTS: A total of 48 studies involving 14,311 cases of resectable oesophageal cancer were included in the meta-analysis. Compared to patients undergoing OE, patients undergoing MIO had statistically reduced occurrence of IHM (OR=0.69, 95%CI =0.55 -0.86). Patients undergoing MIO also had significantly reduced incidence of pulmonary complications (PCs) (RR=0.73, 95%CI = 0.63-0.86), pulmonary embolism (PE) (OR=0.71, 95%CI= 0.51-0.99) and arrhythmia (OR=0.79, 95%CI = 0.68-0.92). Non-significant reductions were observed among the included studies in the occurrence of anastomotic leak (AL) (OR=0.93, 95%CI =0.78-1.11), or Gastric Tip Necrosis (GTN) (OR=0.89, 95%CI =0.54-1.49). LIMITATION: Most of the included studies were non-randomized case-control studies, with a diversity of study designs, demographics of participants and surgical intervention. CONCLUSIONS: Minimally invasive oesophagectomy (MIO) has superiority over open oesophagectomy (OE) in terms of the occurrence of in-hospital mortality (IHM) and should be the first-choice surgical procedure in esophageal surgery.