Stem-like markers in the circulating tumor cells assessment in ovarian cancer.

2021 ◽  
Vol 39 (15_suppl) ◽  
pp. e17542-e17542
Author(s):  
Snezhanna Gening ◽  
Tatyana Abakumova ◽  
Inna Antoneeva ◽  
Tatyana Gening
Keyword(s):  
Ovarian Cancer ◽  
Tumor Cells ◽  
Circulating Tumor Cells ◽  
Proportional Hazards ◽  
Proportional Hazards Model ◽  
Cox Regression ◽  
Cox Proportional Hazards ◽  
Cox Proportional Hazards Model ◽  
Ca 125 ◽  
Blood Samples

e17542 Background: Circulating tumor cells (CTCs) are a potential source of dissemination and relapse in ovarian cancer (OC). Stem cell properties can provide a survival advantage for CTCs. The clinical significance of stem-like CTCs in OC remains to be studied. We aimed to assess the quantities of the stem, epithelial, mesenchymal CTCs and their relationships with the clinical parameters in the OC. Methods: Peripheral blood samples (7.5 ml) were obtained from patients with primary epithelial OC before treatment. CTCs were isolated by flow cytometry (Cytoflex S (Beckman Coulter, USA)) using antibodies to CD45 (BioLegend, USA); CD44 (BioLegend, USA), CD133 (Miltenyi biotec, Germany), ALDH (Stemcell, Canada) to detect the stem markers; EpCAM (BioLegend, USA), cytokeratins 8, 18 (Abcam plc., UK), vimentin (BioLegend, USA) for epithelial and mesenchymal markers. Blood samples from patients with benign ovarian tumors served as a control. Informed voluntary consent was obtained from all the women. Statistical processing included Mann-Whitney U-test, linear regression, Cox proportional hazards model for progression-free survival (PFS) (Statistica 13.0 (TIBCO, USA)). Results: The study included 30 patients, median age 64 (34-76) years. 15 patients had a FIGO stage IV, 12 - stage III, 1 – stage II and 1 – stage I. The content of CTCs populations is presented in the table. The CTCs counts did not differ depending on age, platelet count, and stage 3 or 4. The amount of CD45-CK+Vim- was higher in the presence of ascites (p = 0.035). We found a regression relationship between the serum CA-125 and the number of CD45-CD44+CD133+ (R2= 0.220, p = 0.016); the leukocyte count in blood and CD45-CD44+ALDHhigh (R2= 0.234, p = 0.017); the number of CD45-Vim+ and CD45-CD44+CD133+ALDH+ (R2= 0.305, p = 0.014); CD45-CK-Vim+ and CD45-EpCAM+CK+ (R2= 0.717, p < 0.001). The Cox regression model for PFS included the number of CD45-CD44+CD133+ALDH+ (HR 1.51 95% CI 1.01-2.24 p = 0.043) and the cytoreductive surgery performance (HR 0.09 95% CI 0.01-0.89 p = 0.039) during the first line of treatment. Conclusions: Various populations of circulating tumor cells coexist in ovarian cancer patients. The use of a combination of stem markers in the CTCs detection can increase their prognostic value in OC. This work was supported by the RFBR grant No. 19-315-90011.[Table: see text]

Predictive factors of cytoreductive surgery in epithelial ovarian cancer in a Mexican women cohort.

2019 ◽  
Vol 37 (15_suppl) ◽  
pp. e17099-e17099
Author(s):  
Flavia Morales Vasquez ◽  
Ricardo Raziel Peña Gonzalez ◽  
Horacio Noé López Basave
Keyword(s):  
Ovarian Cancer ◽  
Cytoreductive Surgery ◽  
Proportional Hazards ◽  
Proportional Hazards Model ◽  
Cox Proportional Hazards ◽  
Cox Proportional Hazards Model ◽  
Ca 125 ◽  
Mexican Women ◽  
Hazards Model ◽  
Optimal Debulking

e17099 Background: Cytoreductive surgery is the most important prognostic factor in ovarian cancer. To identify in a timely manner the patients who are not candidates for optimal debulking, does not delay and optimize the treatment. Objetive: Identify the presurgical factors that characterize patients in whom optimal cytoreduction is not possible. Methods: Observational study in a retrospective cohort (n = 255) that compared pre-surgical factors between patients with optimal debulking (n = 65) and suboptimal (n = 190). Non-parametric tests were used, a Cox proportional hazards model was constructed and survival curves were drawn by method of Kaplan y Meier. Results: 255 patients were included. 75% achieved optimal debulking. 9 out of 10 evaluated tomography criteria showed association (p < 0.001) with suboptimal cytoreduction. The best cut-off value of Ca-125 to predict suboptimal surgery was 774 IU / mL. Only clinical ascites showed association with the result of the surgery (p < 0.001). There was no difference in complications between both groups (p = 0.267). The rate of optimal debulking has improved over time (p = 0.049). The turn of the surgeries has no impact on the overall survival of the patients (p = 0.792). Conclusions: Objective parameters (tomography and laboratory) should be used to select patients who are not candidates for surgery. The Clinical evaluation without objective parameters is not enough

Serum IGFBP4 levels in combination with miliary disease: A candidate predictor of ovarian cancer progression-free survival.

2012 ◽  
Vol 30 (15_suppl) ◽  
pp. 5079-5079
Author(s):  
Samantha Cohen
Keyword(s):  
Ovarian Cancer ◽  
Cancer Progression ◽  
Proportional Hazards ◽  
Proportional Hazards Model ◽  
Residual Disease ◽  
Statistical Significance ◽  
Serum Levels ◽  
Cox Proportional Hazards ◽  
Cox Proportional Hazards Model ◽  
Separate Analysis

5079 Background: Insulin-like growth factor binding protein, IGFBP4, was shown to be highly expressed across all stages of epithelial ovarian cancer (EOC) and serum levels are elevated in EOC. Moreover, IGFBP4 levels are ~3x greater in women with malignant pelvic masses. We investigated whether ascites volume and the presence of miliary disease in combination with serum levels of IGFBP4 are independent predictors of survival. Methods: A prospective and retrospective analysis was performed. Patients were enrolled at the time of cytoreductive surgery. Ascites volume was either absent, <500 cc (low), or >= 500 cc (high), and the presence of miliary disease was recorded. The IGFBP4 cutoff was 1064.5 ug/ml based upon previous results. The Kaplan-Meier product limit method was used to estimate PFS probabilities. The Cox proportional hazards model was used to estimate hazard ratios (HR) and corresponding 95% CI. Results: 57 cases were included in the analysis of ascites volume and miliary disease. Cytoreductive outcomes were complete gross resection (44.8%), optimal (<=1cm residual disease; 44.8%), and suboptimal ( >1cm residual disease; 10.3%). Histologic subtypes: papillary serous (n=35; 61.4%), mucinous (n=15; 26.3%), endometrioid (n=4; 7.0%), and clear cell (n=3; 5.3%). Stage distribution was 21.1% I/II, and 78.9% III/IV. PFS was unaffected by ascites volume (p=0.341) or miliary disease. Among this cohort, 29 had IGFBP4 levels available for a separate analysis. Patients with high IGFBP4 and miliary disease were 5.5 times as likely to recur compared with patients with miliary disease and low IGFBP4 (HR=5.55 [0.77, 39.82]), and the statistical significance was borderline (p<0.088). No statistically significant differences were detected between rates of recurrence among patients with high and low IGFBP4 values in combination with ascites volume. Conclusions: These exploratory studies suggest that patients with high IGFBP4 serum levels and miliary disease were > 5 times as likely to recur compared to women with miliary disease and low IGFBP4 levels. Future studies examining these variables using a larger population and examining the biologic basis of this relationship are planned.

Nuclear size of circulating tumor cells in advanced prostate cancer to reveal a potential biomarker for clinical outcomes and androgen receptor indifference.

2021 ◽  
Vol 39 (6_suppl) ◽  
pp. 167-167
Author(s):  
Jasmine Jiemei Wang ◽  
Karen Angelica Cavassani ◽  
Pai-Chi Teng ◽  
Jie-Fu Chen ◽  
Yu Jen Jan ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Androgen Receptor ◽  
Tumor Cells ◽  
Circulating Tumor Cells ◽  
Cell Lines ◽  
Proportional Hazards Model ◽  
Cox Proportional Hazards ◽  
Cox Proportional Hazards Model ◽  
Nuclear Size ◽  
Potential Biomarker

167 Background: Circulating tumor cells (CTCs) have arisen as contemporary noninvasive prognostic biomarkers for prostate cancer (PCa). Previously, a subgroup of PCa CTCs, with particularly small nuclei ( < 8.5 μm), were found to be correlated with the presence of visceral metastases. This subgroup was named very-small-nuclear CTCs (vsnCTCs). We hypothesized vsnCTCs as a putative biomarker of a lethal subtype associated with androgen receptor (AR) indifference and nuclear shape instability in metastatic castration resistant PCa (mCRPC). Methods: CTCs in blood from 76 patients with mCRPC were analyzed using NanoVelcro CTC assay for CTC nuclear size measurement and CTC RNA profiling of AR-indifferent pathways. Overall survival (OS) and progression free survival (PFS) of androgen receptor signaling inhibitor (ARSI), taxanes and other therapy were correlated with CTC nuclear size using Kaplan-Meier analysis and Cox proportional hazards model. Emerin fluorescence intensity and localization from patients with and without vsnCTC were compared. RNA profiles of CTCs were scored using Prostate Cancer Subtype (PCS) classification system. The CTC-PCS scores from patients with and without vsnCTC were compared using Mann-Whitney test. To investigate the underlying biology of vsnCTC phenotype, the nuclear size, the nuclear sizes of ARSI-resistant and lineage plasticity PCa cell lines were measured and correlated with the expression levels of RNA related to ARSI-indifferent pathways and nuclear envelope protein Emerin. Results: Patients with vsnCTC (i.e., vsnCTC+) had significantly shortened OS and PFS compared with patients without vsnCTC (i.e., vsnCTC-). The median OS was 34 (vsnCTC+, n = 49) vs. 149 (vsnCTC-, n = 27) weeks (HR = 2.6 with 95% CI 1.5 to 4.5, p < 0.001). The median PFS was 12 (vsnCTC+, n = 32) vs. 26 (vsnCTC-, n = 18) weeks (HR = 2.2 with 95% CI 1.3 to 4.0, p = 0.004). CTC nuclear sizes were significantly smaller in patients with prior ARSI therapy. CTC-RNA analysis revealed that vsnCTC+ patients had a significant higher CTC-PCS1 Z score(n = 19) compared with vsnCTC- patients(n = 26)(p = 0.01). In the cell line models, nuclear sizes were significantly smaller in cell lines with ARSI-resistance(p = 0.002) and lineage plasticity (p = 0.006). Emerin expression is significantly lower in vsnCTC+ patients(p = 0.009) and ARSI-resistant cell lines(p = 0.03). Conclusions: This study casts light on the importance of the vsnCTC in patients with mCRPC, as vsnCTC+ patients represented a group at risk for faster clinical progression who are at the highest risk for mortality. This has potential importance in optimizing therapeutic choices. We posit that the vsnCTC represents a new hallmark of an aggressive subtype of mCRPC and is related to the cellular mechanism of AR-indifference and Emerin dysregulation, which promotes lethal progression of metastatic PCa.

Cause-Specific Survival for Women Diagnosed With Cancer During Pregnancy or Lactation: A Registry-Based Cohort Study

2009 ◽  
Vol 27 (1) ◽  
pp. 45-51 ◽  
Author(s):  
Hanne Stensheim ◽  
Bjørn Møller ◽  
Tini van Dijk ◽  
Sophie D. Fosså
Keyword(s):  
Ovarian Cancer ◽  
Cohort Study ◽  
Proportional Hazards ◽  
Proportional Hazards Model ◽  
Population Based ◽  
Cox Proportional Hazards ◽  
Cox Proportional Hazards Model ◽  
Birth Registry ◽  
Increased Risk ◽  
Cause Specific Survival

Purpose To assess if cancers diagnosed during pregnancy or lactation are associated with increased risk of cause-specific death. Patients and Methods In this population-based cohort study using data from the Cancer Registry and the Medical Birth Registry of Norway, 42,511 women, age 16 to 49 years and diagnosed with cancer from 1967 to 2002, were eligible. They were grouped as not pregnant (reference), pregnant, or lactating at diagnosis. Cause-specific survival for all sites combined, and for the most frequent malignancies, was investigated using a Cox proportional hazards model. An additional analysis with time-dependent covariates was performed for comparison of women with and without a postcancer pregnancy. The multivariate analyses were adjusted for age at diagnosis, extent of disease, and diagnostic periods. Results For all sites combined, no intergroup differences in cause-specific death were seen, with hazard ratio (HR) of 1.03 (95% CI, 0.86 to 1.22) and HR 1.02 (95% CI, 0.86 to 1.22) for the pregnant and lactating groups, respectively. Patients with breast (HR, 1.95; 95% CI, 1.36 to 2.78) and ovarian cancer (HR, 2.23; 95% CI, 1.05 to 4.73) diagnosed during lactation had an increased risk of cause-specific death. Diagnosis of malignant melanoma during pregnancy slightly increased this risk. For all sites combined, the risk of cause-specific death was significantly decreased for women who had postcancer pregnancies. Conclusion In general, the diagnosis of most cancer types during pregnancy or lactation does not increase the risk of cause-specific death. Breast and ovarian cancer diagnosed during lactation represents an exception. We confirmed the “healthy mother effect” for women with a postcancer pregnancy.

scholarly journals NCOG-33. HEMATOLOGIC PREDICTORS OF OUTCOMES IN GLIOBLASTOMA TREATED WITH SURGERY AND CHEMORADIATION

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii136-ii136
Author(s):  
Nicholas Damico ◽  
Theresa Elder ◽  
Michael Kharouta ◽  
Anthony Sloan ◽  
Amber Kerstetter-Fogle ◽  
...  
Keyword(s):  
Proportional Hazards ◽  
Proportional Hazards Model ◽  
Cox Regression ◽  
Cox Proportional Hazards ◽  
Cox Proportional Hazards Model ◽  
Continuous Variables ◽  
Surgical Biopsy ◽  
Platelet Counts ◽  
Cell Counts ◽  
Time Point

Abstract BACKGROUND There are conflicting reports regarding the prognostic value of platelet and other blood counts in glioblastoma. However, few series have looked at all hematologic parameters simultaneously. METHODS We performed a retrospective chart review of patients diagnosed with supratentorial glioblastoma from 2014-2019 who started conventional chemoradiation following initial surgical biopsy and/or resection. Hematologic parameters were collected at baseline, in the preoperative and postoperative periods and at the initiation and completion of chemoradiation. This included platelet counts, hemoglobin levels, white blood cell counts (WBC), neutrophil and lymphocyte counts with neutrophil:lymphocyte (NLR) and platelet:lymphocyte ratios (PLR) calculated at each time point. Cox regression was performed to assess the association between each hematologic parameter and both overall survival (OS) and progression free survival (PFS). A multivariate Cox proportional hazards model adjusted for all hematologic parameters, age, sex, race and KPS was generated for each time point. All hematologic parameters were modeled as continuous variables. RESULTS A total of 58 patients met inclusion criteria. 18 were female and 40 male. The median age was 59.5 (range 43-82). Median follow up for all patients was 15.3 months. A total of 52 patients completed radiation therapy and 18 completed 6 cycles of adjuvant chemotherapy. Hemoglobin and neutrophil counts at the conclusion of chemoradiation were associated with OS and PFS on univariate and multivariate analyses. The HR for OS were 0.74 (95% CI 0.5807-0.9313) and 1.28 (1.143-1.441) respectively. The HR for PFS were 0.70 (0.5531-0.8881) and 1.16 (1.05-1.271) respectively. Postoperative lymphocyte and platelet counts at initiation of chemoradiation were both associated with OS with unadjusted HR of 3.2 (1.037-9.960) and HR of 0.99 (0.9898-0.9999) respectively, which remained significant on multivariate analysis. However, neither were associated with PFS. CONCLUSION Several hematologic parameters are associated with glioblastoma outcomes in these initial analyses. Further analyses with additional patients are ongoing.

scholarly journals 508. Title Favipiravir for the Treatment of Coronavirus Disease 2019; A Propensity Score Matched Cohort Study

2021 ◽  
Vol 8 (Supplement_1) ◽  
pp. S356-S356
Author(s):  
Rand A Alattar ◽  
Shiema A Ahmed ◽  
Tasneem Abdallah ◽  
Rashid Kazman ◽  
Aseelah N Qadmour ◽  
...  
Keyword(s):  
Clinical Improvement ◽  
Propensity Scores ◽  
Proportional Hazards ◽  
Proportional Hazards Model ◽  
Cox Regression ◽  
Supplemental Oxygen ◽  
Cox Proportional Hazards ◽  
Cox Proportional Hazards Model ◽  
Ordinal Scale ◽  
All Cause Mortality

Abstract Background We investigated clinical outcomes of favipiravir in patients with COVID-19 pneumonia. Methods Patients who between 23 May 2020 and 18 July 2020 received ≥24 hours of favipiravir were assigned to the favipiravir group, while those who did not formed the non-favipiravir group. The primary outcome was 28-day clinical improvement, defined as two-category improvement from baseline on an 8-point ordinal scale. Propensity scores (PS) for favipiravir therapy were used for 1:1 matching. Cox regression was used to examine associations with the primary endpoint. Results The unmatched cohort included 1,493 patients, of which 51.7% were in the favipiravir group, and 48.3% were not receiving supplemental oxygen at baseline (table 1). Favipiravir was started within a median of 5 days from symptoms onset. Significant baseline differences between the two unmatched groups existed, but not between the PSmatched groups (N = 774) (table 1). After PS-matching, there were no significant differences between the two groups in the proportion with 28-day clinical improvement (93.3% versus 92.8%, P 0.780), or 28-day all-cause mortality (2.1% versus 3.1%, P 0.360) (Table 2). Favipiravir was associated with more viral clearance by day 28 (79.8% versus 64.1%, P &lt; 0.001) (table 2). In the adjusted Cox proportional hazards model, favipiravir therapy was not associated 28-day clinical improvement (adjusted hazard ratio 0.978, 95% confidence interval 0.862 –1.109, P 0.726) (Table 3). Conclusion Favipiravir therapy for COVID-19 pneumonia is well tolerated but is not associated with an increased likelihood of clinical improvement or reduced all-cause mortality by 28 days. Disclosures All Authors: No reported disclosures

scholarly journals Clinicopathological Characteristics and Prognostic Prediction in Pseudomyxoma Peritonei Originating From Mucinous Ovarian Cancer

2021 ◽  
Vol 11 ◽  
Author(s):  
Fengxian Fu ◽  
Xulan Ma ◽  
Yiyan Lu ◽  
Hongbin Xu ◽  
Ruiqing Ma
Keyword(s):  
Ovarian Cancer ◽  
Pseudomyxoma Peritonei ◽  
Proportional Hazards ◽  
Proportional Hazards Model ◽  
Survival Rates ◽  
Clinicopathological Characteristics ◽  
Cox Proportional Hazards ◽  
Cox Proportional Hazards Model ◽  
Rank Test ◽  
Hazards Model

ObjectiveTo describe the clinicopathological characteristics of mucinous ovarian cancer (MOC)-derived pseudomyxoma peritonei (PMP) and identify prognostic factors for survival.MethodsMedical records from patients with MOC-derived PMP who attended the Aerospace Center Hospital, Beijing, China between January 2009, and December 2019 were retrospectively reviewed. Survival analysis was performed with the Kaplan-Meier method, the log-rank test, and a Cox proportional hazards model.ResultsCytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) for PMP originating from MOC were performed on 22 patients, who had a median age of 52 years at the time of surgery. At the last follow-up in June 2020, 9 (41%) patients were still alive. Median OS was 12 months (range, 1 to 102 months), and the 2-, 3-, and 5-year survival rates were 23, 9, and 5%, respectively.ConclusionHistopathologic subtype and PCI may be applied as predictors of prognosis in patients with MOC-derived PMP. Patients with high-grade disease could benefit from completeness of cytoreduction (CCR) 0/1.

Genetic and nongenetic factors for contralateral progression of unilateral moyamoya disease: the first report from the SUPRA Japan Study Group

2021 ◽  
pp. 1-10
Author(s):  
Yohei Mineharu ◽  
Yasushi Takagi ◽  
Akio Koizumi ◽  
Takaaki Morimoto ◽  
Takeshi Funaki ◽  
...  
Keyword(s):  
Risk Factors ◽  
Moyamoya Disease ◽  
Proportional Hazards ◽  
Proportional Hazards Model ◽  
Cox Regression ◽  
Cox Proportional Hazards ◽  
Cox Proportional Hazards Model ◽  
Multicenter Cohort Study ◽  
Cox Regression Analysis ◽  
Unilateral Moyamoya Disease

OBJECTIVE Although many studies have analyzed risk factors for contralateral progression in unilateral moyamoya disease, they have not been fully elucidated. The aim of this study was to examine whether genetic factors as well as nongenetic factors are involved in the contralateral progression. METHODS The authors performed a multicenter cohort study in which 93 cases with unilateral moyamoya disease were retrospectively reviewed. The demographic features, RNF213 R4810K mutation, lifestyle factors such as smoking and drinking, past medical history, and angiographic findings were analyzed. A Cox proportional hazards model was used to find risk factors for contralateral progression. RESULTS Contralateral progression was observed in 24.7% of cases during a mean follow-up period of 72.2 months. Clinical characteristics were not significantly different between 63 patients with the R4810K mutation and those without it. Cox regression analysis showed that the R4810K mutation (hazard ratio [HR] 4.64, p = 0.044), childhood onset (HR 7.21, p < 0.001), male sex (HR 2.85, p = 0.023), and daily alcohol drinking (HR 4.25, p = 0.034) were independent risk factors for contralateral progression. CONCLUSIONS These results indicate that both genetic and nongenetic factors are associated with contralateral progression of unilateral moyamoya disease. The findings would serve to help us better understand the pathophysiology of moyamoya disease and to manage patients more appropriately.

Abstract 15644: Proinflammatory Diet Independently Predicts Shorter Event-free Survival in Patients With Heart Failure

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Junghee Kang ◽  
Debra K Moser ◽  
Martha J Biddle ◽  
Terry A Lennie
Keyword(s):  
Heart Failure ◽  
Proportional Hazards ◽  
Proportional Hazards Model ◽  
Cox Regression ◽  
Enzyme Inhibitor ◽  
Cox Proportional Hazards ◽  
Cox Proportional Hazards Model ◽  
Event Free Survival ◽  
Free Survival ◽  
Phone Calls

Introduction: Inflammation is a common biological process accompanying chronic conditions, such as heart failure (HF) that can be moderated by diet. The association between foods thought to promote inflammation and event-free survival in patients with HF has not been investigated. Hypothesis: The inflammatory potential of individuals’ diets, measured using the dietary inflammatory index (DII), will be associated with event-free survival in patients with HF. Methods: The DII scores were calculated from 4-day food diaries recorded at baseline by 213 patients with HF (age 61±12years, 35% female, 43% NYHA III/IV). Patients were followed for a median of 365 days by monthly phone calls, medical record review, and death records to determine time to all cause-hospitalization or death. The DII scores were dichotomized using median value for the Cox regression model. Hierarchical multivariate Cox proportional hazards model was used to determine whether DII scores predicted event-free survival after controlling for age, gender, body mass index, prescribed angiotensin-converting-enzyme inhibitor, beta-blocker, cholesterol lowering agent, antiinflammatory agent, N-terminal pro B-type natriuretic peptide, comorbidity, depressive symptoms, and the New York Heart Association functional classification. Results: The DII scores independently predicted event-free survival in the model constant ( p = 0.012). Higher DII scores were associated with more than double the risk of an event compared to lower DII scores (HR: 2.28, 95% Confidence Interval =1.21-4.36). Conclusions: Greater intake of foods considered to promote inflammation was associated with shorter event-free survival in patients with HF. These results provide further evidence of the importance of diet to HF outcomes.

scholarly journals Simulation Extrapolation Method for Cox Regression Model with a Mixture of Berkson and Classical Errors in the Covariates using Calibration Data

2019 ◽  
Vol 15 (2) ◽  
Author(s):  
Jean de Dieu Tapsoba ◽  
Edward C. Chao ◽  
Ching-Yun Wang
Keyword(s):  
Proportional Hazards ◽  
Proportional Hazards Model ◽  
Cox Regression ◽  
Cox Proportional Hazards ◽  
Cox Proportional Hazards Model ◽  
Classical Type ◽  
Calibration Data ◽  
Finite Sample ◽  
Cox Regression Analysis ◽  
Simulation Extrapolation

Abstract Many biomedical or epidemiological studies often aim to assess the association between the time to an event of interest and some covariates under the Cox proportional hazards model. However, a problem is that the covariate data routinely involve measurement error, which may be of classical type, Berkson type or a combination of both types. The issue of Cox regression with error-prone covariates has been well-discussed in the statistical literature, which has focused mainly on classical error so far. This paper considers Cox regression analysis when some covariates are possibly contaminated with a mixture of Berkson and classical errors. We propose a simulation extrapolation-based method to address this problem when two replicates of the mismeasured covariates are available along with calibration data for some subjects in a subsample only. The proposed method places no assumption on the mixture percentage. Its finite-sample performance is assessed through a simulation study. It is applied to the analysis of data from an AIDS clinical trial study.

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