en Supportive and Palliative Care Case Report and Series <p style="margin: 0in 0in 10pt; text-align: justify;"><font color="#000000"><b><span font-size:="" mso-ascii-theme-font:="" mso-bidi-theme-font:="" mso-hansi-theme-font:="" new="" style="line-height: 115%; font-family: " times="">Introduction: </span></b></font>There is a lack of information on the extent of dependency between&nbsp;chronic diseases and the survival rate of breast cancer. Until date, none of the models&nbsp;proposed has determined the impact of chronic diseases on breast cancer survival. This&nbsp;study, therefore, aimed to investigate the impacts of chronic diseases such as diabetes,&nbsp;blood pressure, and endocrine disorders on the survival of breast cancer patients through&nbsp;a comprehensive research.<br> <b style="color: rgb(0, 0, 0);"><span font-size:="" mso-ascii-theme-font:="" mso-bidi-theme-font:="" mso-hansi-theme-font:="" new="" style="line-height: 115%; font-family: " times="">Methods: </span></b>All (n = 1822) breast cancer patients treated in the three hospitals of Tehran&nbsp;from 2007 through mid&ndash;2016 were included in this study. A comprehensive study was&nbsp;conducted by focusing on the chronic disease data of the studied patients. The parametric and semi-parametric approaches, as well as non-parametric Kaplan-Meier analysis,&nbsp;were performed. This research proposes two models for analyzing breast cancer survival. A comparative analysis of the models was performed based on the Akaike criterion.<br> <b style="color: rgb(0, 0, 0);"><span font-size:="" mso-ascii-theme-font:="" mso-bidi-theme-font:="" mso-hansi-theme-font:="" new="" style="line-height: 115%; font-family: " times="">Results: </span></b>Chronic diseases have been found to affect the survival of breast cancer patients. This research considered 436 individuals, among the patients with chronic diseases including hypertension, diabetes, hypo- and hyperthyroidism, and heart problems&nbsp;at the frequencies of 12.38%, 11.69%, 8.71%, and 8.02%, respectively. This study indicated that the 5-year survival of breast cancer patients with chronic diseases was 72%&nbsp;and that it was 82% for other breast cancer patients. The statistical analysis and the two&nbsp;proposed models revealed that chronic diseases significantly affect the survival of the&nbsp;<br> study patients.<br> <b style="color: rgb(0, 0, 0);"><span font-size:="" mso-ascii-theme-font:="" mso-bidi-theme-font:="" mso-hansi-theme-font:="" new="" style="line-height: 115%; font-family: " times="">Conclusions: </span></b>This comprehensive research evidence a significant difference in the survival rate of breast cancer patients with and without chronic diseases. The statistical&nbsp;analysis of the data indicated that chronic diseases can significantly affect the survival&nbsp;probability in breast cancer. Heart problems and the combination of chronic diseases&nbsp;have a major influence on the survival rate of breast cancer patients as compared to&nbsp;other cases.</p> <p style="margin: 0in 0in 10pt; text-align: justify;"></p> Breast Cancer, Chronic Diseases, Survival Analysis 26 32 http://mcijournal.com/browse.php?a_code=A-10-153-1&slc_lang=en&sid=1 Karim Atashgar atashgar@iust.ac.ir 10031947532846001518 10031947532846001518 Yes Department of Industrial Engineering, Malek Ashtar University of Technology, Tehran, Iran Ayeh Sheikhaliyan ayeh.sheikhaliyan@gmail.com 10031947532846001519 10031947532846001519 No Department of Industrial Engineering, Malek Ashtar University of Technology, Tehran, Iran Mina Tajvidi tajvidi@med.mui.ac.ir 10031947532846001520 10031947532846001520 No Department of Radiotherapy, Isfahan University of Medical Science, Tehran, Seyed Hadi Molana drshmolana@yahoo.com 10031947532846001521 10031947532846001521 No Iran University of Medical Sciences, Tehran, Iran Leyla Jalaeiyan l.jalaeian@gmail.com 10031947532846001522 10031947532846001522 No Department of Industrial Engineering, Malek Ashtar University of Technology, Tehran, Iran