Prognostic factors of survival time after hematopoietic stem cell transplant in acute lymphoblastic leukemia patients: Cox proportional hazard versus accelerated failure time modelsReport as inadecuate




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Journal of Experimental and Clinical Cancer Research

, 27:74

First Online: 23 November 2008Received: 30 August 2008Accepted: 23 November 2008

Abstract

BackgroundThe aim of this study is to evaluate the prognostic factors of overall survival OS after haematopoietic stem cell transplant HSCT in acute lymphoblastic leukaemia ALL patients using accelerated failure time AFT, Cox proportional hazard PH, and Cox time-varying coefficient models.

Methods206 patients were enrolled after HSCH in Shariati Hospital between 1993 and 2007. There was evidence of marked departures from the proportional hazards assumption with two prognostic factors, relapse and chronic graft-versus-host disease cGVHD P < .001. Performance among AFT and Cox-s models was assessed using explained variation and goodness of fit methods. Discrimination among the exponential, Weibull, generalized gamma GG, log-logistic, and lognormal distributions was done using maximum likelihood and Akaike information criteria.

ResultsThe 5-year OS was 52% 95%CI: 47.3–56.7. Peak mortality hazard occurred at months 6–7 after HSCT followed by a decreasing trend. In univariate analysis, the data was better fitted by GG distribution than by other distributions. Univariate analysis using GG distribution showed a positive association between OS with acute graft-versus-host disease aGVHD P = .021, no relapse P < .001, cGVHD P < .001, neutrophil recovery P < .001 and platelet recovery P < .001. Based on Cox PH models; however cGVHD and relapse were the predictive factors of OS P < .001. Multivariate analysis indicated that, OS is related to relapse P < .001 and platelet recovery P = .037, where predictive power of Weibull AFT models was superior to Cox PH model and Cox with time-varying coefficient R = 0.46 for AFT, R = .21 for Cox PH and R = .34 for Cox time-varying coefficient. Cox-Snell residual shows Weibull AFT fitted to data better than other distributions in multivariate analysis.

ConclusionWe concluded that AFT distributions can be a useful tool for recognizing prognostic factors of OS in acute lymphoblastic leukemia patients.

Electronic supplementary materialThe online version of this article doi:10.1186-1756-9966-27-74 contains supplementary material, which is available to authorized users.

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Author: Kourosh Sayehmiri - Mohammad R Eshraghian - Kazem Mohammad - Kamran Alimoghaddam - Abbas Rahimi Foroushani - Hojjat Zeraat

Source: https://link.springer.com/







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