• Title/Summary/Keyword: parametric competing-risks

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Survival of Colorectal Cancer in the Presence of Competing-Risks - Modeling by Weibull Distribution

  • Baghestani, Ahmad Reza;Daneshvar, Tahoura;Pourhoseingholi, Mohamad Amin;Asadzadeh, Hamid
    • Asian Pacific Journal of Cancer Prevention
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    • v.17 no.3
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    • pp.1193-1196
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    • 2016
  • Background: Colorectal cancer (CRC) is the commonest malignancy in the lower gastrointestinal tract in both men and women. It is the third leading cause of cancer-dependent death in the world. In Iran the incidence of colorectal cancer has increased during the last 25 years. Materials and Methods: In this article we analyzed the survival of 447 colorectal patients of Taleghani hospital in Tehran using parametric competing-risks models. The cancers of these patients were diagnosed during 1985 - 2012 and followed up to 2013. The purpose was to assess the association between survival of patients with colorectal cancer in the presence of competing-risks and prognostic factors using parametric models. The analysis was carried out using R software version 3.0.2. Results: The prognostic variables included in the model were age at diagnosis, tumour site, body mass index and sex. The effect of age at diagnosis and body mass index on survival time was statistically significant. The median survival for Iranian patients with colorectal cancer is about 20 years. Conclusions: Survival function based on Weibull model compared with Kaplan-Meier survival function is smooth. Iranian data suggest a younger age distribution compared to Western reports for CRC.

Survival of Colorectal Cancer Patients in the Presence of Competing-Risk

  • Baghestani, Ahmad Reza;Daneshvar, Tahoura;Pourhoseingholi, Mohamad Amin;Asadzade, Hamid
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.15
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    • pp.6253-6255
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    • 2014
  • Background: Colorectal cancer (CRC) is considered to be a main cause of malignancy-related death in the world, being commonly diagnosed in both men and women. It is the third leading cause of cancer dependent death in the world and there are one million new cases diagnosed per year. In Iran the incidence of colorectal cancer has increased during the last 25 years and it is the fifth cause of cancer in men and the third in women. Materials and Methods: In this article we analyzed the survival of 475 colorectal patients of Taleghani hospital in Tehran with the semi-parametric competing-risks model. Results: There were 55% male cases and at the time of the diagnosis most of the patients were between 48 and 67years old. The probability of a patient death from colorectal cancer with survival of more than 25 years was about 0.4. Body mass index, height, tumour site and gender had no influence. Conclusions: According to these data and by using semi-parametric competing-risks method, we found out that only age at diagnosis has a significant effect on these patient survival time.