A study on the prognostic factors of breast cancer survival time using bayesian cox model

Abstract Background: Breast cancer is one of the common diseases among women with various factors involved in it. The purpose of this study was to investigate the effect of tumor markers, estrogen receptor (ER), human epidermal growth factor receptor 2 (Her2), and Ki67 antigen, and other factors affecting the survival time of patients with breast cancer in Yazd City, Iran, using Bayesian multiple Cox regression analysis. Methods: This was a population-based study of 538 women with breast cancer registered in the clinical database of the Ramezanzade Radiotherapy Center from the April 2005 until March 2012. Comprehensive data on prognostic factors, comorbidity and treatment together with complete follow-up for survival were used to evaluate improvements in mortality. Data was analyzed using R 3.4.2 software. P-value of less than 0.050 was considered as the significance level. Findings: The mean age of patients with breast cancer and the mean survival time were 48.03 ± 11.16 years and 97.64 ± 4.23 months, respectively. Based on Kaplan-Meier method, the 1, 3, 5 and 8-year cumulative survivals in patients with breast cancer were 0.976, 0.898, 0.823, and 0.737, respectively. Bayesian Cox regression analysis showed that surgery [Hazard ratio (HR): 1.631, 95% Prediction interval (PI): 1.102-2.422)], ki67 (HR: 3.260, 95%PI: 1.6308-6.372), stage (HR: 5.620, 95%PI: 4.079-7.731), lymph node (HR: 1.765, 95%PI: 1.127-2.790), and estrogen receptor (HR: 2.033, 95%PI; 2.023-3.354) were significantly related to survival time. Conclusion: According to Bayesian multiple cox regression, stage, Ki67, lymph node, estrogen receptor, and surgery variables have a positive effect on death hazard. By combining Bayesian and semi-parametric methods in survival analysis, in order to use prior information and relaxation of parametric assumption, the model gain more flexibility and robustness against misspecification of the probability model; this gives more valuable results. © 2018, Isfahan University of Medical Sciences(IUMS). All rights reserved. Author keywords Breast cancerEstrogen receptorKi-67 antigenRegression analysisSurvival analysi

Assessment of AFT and Cox Models in Analysis of Factors Influencing the survival of Women with Breast Cancer in Yazd city

BACKGROUND AND OBJECTIVE: Breast cancer is one of the most common cancers in women. The statistical methods in the survival analysis of these patients are accelerated time models and Cox model. The purpose of this study is to evaluate two models in determining the effective factors in the survival of breast cancer. METHODS: The study was an analytical and cohort study of survival analysis. The 538 of the patients referred to Ramezanzade Radiotherapy Center who had breast cancer and recorded survival status as a census from the April 2005 until March 2012 in Yazd. and survived by phone call. The Kaplan-Meier estimate was used to describe the survival of the patients. The research variables included clinical and demographic factors. The choice of final variables in the model was done by the methods of diminishing the dimension and all possible Cox regressions by the acaian criterion. Then, the best accelerated time model was considered Getting different distributions was also determined by the Akayake criteria. FINDINGS: The most effective Cox model among all Cox models was variables including Age, Her2 and Ki67 variables (AIC = 30270). The generalized gamma model was the most optimal accelerated time model (AIC 463.966). Her2 was significant in both accelerated and cox models(p0.05). CONCLUSION: In both accelerated time- Generalized Gamma- models and Cox Models, the Her2 variable was identified as a risk factor for breast cancer and There is a positive impact on the risk of death and reduced survival

Doctor can I buy a new kidney? I've heard it isn't forbidden: what is the role of the nephrologist when dealing with a patient who wants to buy a kidney?

Organ trafficking is officially banned in several countries and by the main Nephrology Societies. However, this practice is widespread and is allowed or tolerated in many countries, hence, in the absence of a universal law, the caregiver may be asked for advice, placing him/her in a difficult balance between legal aspects, moral principles and ethical judgments. In spite of the Istanbul declaration, which is a widely shared position statement against organ trafficking, the controversy on mercenary organ donation is still open and some experts argue against taking a negative stance. In the absence of clear evidence showing the clinical disadvantages of mercenary transplantation compared to chronic dialysis, self-determination of the patient (and, with several caveats, of the donor) may conflict with other ethical principles, first of all non-maleficence. The present paper was drawn up with the participation of the students, as part of the ethics course at our medical school. It discusses the situation in which the physician acts as a counselor for the patient in the way of a sort of “reverse” informed consent, in which the patient asks advice regarding a complex personal decision, and includes a peculiar application of the four principles (beneficence, non-maleficence, justice and autonomy) to the donor and recipient parties

The impacts of fracturing fluid viscosity and injection rate on the near wellbore hydraulic fracture propagation in cased perforated wellbores

Copyright 2015 ARMA, American Rock Mechanics Association.In this study, hydraulic fracturing tests were conducted on 150 mm synthetic cubic samples. The borehole drilled in the center of the sample was cased and perforations were created in the samples. A true tri-axial stress cell was used to simulate real far field stress conditions. In addition, dimensional analyses were performed to correspond the results of lab experiments to field-scale operations. Three different fracturing fluids with viscosities ranging from 20 to 600 Pa.s were used to investigate the effects of varying fracturing fluid viscosities and fluid injection rates on fracturing mechanism. The results indicated that by increasing the fracturing fluid viscosity and fluid injection rates, the fracturing energy rises, and consequently the fracturing pressures will increase. However, as the fracturing energy is transferred to the sample at a faster rate, the fracturing power increases, and accordingly the fracture initiation angle rises; this would lead to more curved fracture planes. It was evident that fractures would reorient perpendicular to the minimum principal stress direction despite the angle of initiation. Furthermore, it was observed that the presence of casing in the wellbore would influence the stress distribution around the casing in such a way that the fracture propagation tends to deviate from the wellbore vicinity

An Investigation of Hydraulic Fracturing Initiation and Near-Wellbore Propagation from Perforated Boreholes in Tight Formations

In this study, hydraulic fracturing tests were conducted on 10 and 15 cm synthetically manufactured cubic tight mortar samples. The use of cube samples allowed application of three independent stresses to mimic real far field stress conditions. A true triaxial stress cell was used for this purpose. The lab test parameters were scaled to simulate the operations at field scale. The hole and perforations were made into the sample after casting and curing were completed. Various scenarios of vertical and horizontal wells and in situ stress regimes were modeled. These factors are believed to play a significant role in fracture initiation and near-wellbore propagation behavior; however, they are not independent parameters, hence should be analyzed simultaneously. In addition to experimental studies, analytical solutions were developed to simulate the mechanism of fracture initiation in perforated boreholes in tight formations. Good agreements were observed between the experimental and analytical results. The results of this study showed that a lower initiation pressure is observed when the minimum stress component is perpendicular to the axis of the perforations. It was also seen that, even when the cement sheath behind the casing fails, the orientation of the perforations may affect the initiation of the induced fracture noticeably. Furthermore, it was found that stress anisotropy influences the fracturing mechanism in a perforated borehole, and affects the geometry of the initiated near-wellbore fracture

Figure 6 from: Li Q, Hu H, Triapitsyn S, Yi L, Lu J (2018) Anagrus dmitrievi sp. n. (Hymenoptera, Mymaridae), an egg parasitoid of Zyginidia eremita (Hemiptera, Cicadellidae), a pest of maize in Xinjiang, China. ZooKeys 736: 43-57. https://doi.org/10.3897/zookeys.736.20883

A new Palaearctic species of Anagrus Haliday (Hymenoptera, Mymaridae), A. (Anagrus) dmitrievi Triapitsyn & Hu, sp. n., is described, diagnosed, and illustrated from Xinjiang Uyghur Autonomous Region of China. It was reared from parasitized eggs of the leafhopper Zyginidia (Zyginidia) eremita Zachvatkin (Hemiptera, Cicadellidae) on leaves of maize. A key to the 21 named species of Anagrus known from China is provided. Zyginidia eremita is an important economic pest in Xinjiang, occurring in approximately 90% of maize fields. The phenology and life cycle of Z. eremita is summarized. Parasitism of its eggs by A. dmitrievi in maize fields was 12–75 % (average about 38 %), thus making it a rather effective natural enemy