Survival and predictors of breast cancer mortality in South Ethiopia: A retrospective cohort study

PLOS ONE RESEARCH ARTICLE Survival and predictors of breast cancer mortality in South Ethiopia: A retrospective cohort study Abel Shita1,2,3, Alemayehu Worku Yalew2, Edom Seife ID4, Tsion Afework2,3,5, Aragaw Tesfaw6, Zenawi Hagos Gufue ID7, Friedemann Rabe3,8, Lesley Taylor9, Eva Johanna Kantelhardt3,8,10, Sefonias Getachew ID2,3,5,8* a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 1 Mizan Aman College of Health Sciences, Department of Public Health, Addis Ababa, Southwest Ethiopia, 2 Department of Preventive Medicine, School of Public Health, Addis Ababa University, Addis Ababa, Ethiopia, 3 Global Health Working Group, Martin-Luther-University, Halle (Saale), Germany, 4 Department of Medicine, Oncology Center, Addis Ababa University, Addis Ababa, Ethiopia, 5 NCD Working Group School of Public Health Addis Ababa University, Addis Ababa, Ethiopia, 6 Department of Public Health, College of Health Science, Debre Tabor University, Debra Tabor, North West Ethiopia, 7 Department of Public Health, College of Medicine and Health Sciences, Adigrat University, Adigrat, Ethiopia, 8 Institute of Medical Epidemiology, Biometrics and Informatics, Martin Luther University, Halle, Germany, 9 City of Hope National Medical Center, Duarte, Los Angeles County, California, United States of America, 10 Department of Gynaecology, Martin Luther University, Halle, Germany * OPEN ACCESS Citation: Shita A, Yalew AW, Seife E, Afework T, Tesfaw A, Gufue ZH, et al. (2023) Survival and predictors of breast cancer mortality in South Ethiopia: A retrospective cohort study. PLoS ONE 18(3): e0282746. https://doi.org/10.1371/journal. pone.0282746 Editor: Mohammad-Reza Malekpour, NonCommunicable Diseases Research Center, Endocrinology and Metabolism Research Institute, Tehran University of Medical Sciences, ISLAMIC REPUBLIC OF IRAN Received: August 1, 2022 Accepted: February 22, 2023 Abstract Background Breast cancer is the most frequently diagnosed cancer and the leading cause of cancer death in over 100 countries. In March 2021, the World Health Organization called on the global community to decrease mortality by 2.5% per year. Despite the high burden of the disease, the survival status and the predictors for mortality are not yet fully determined in many countries in Sub-Saharan Africa, including Ethiopia. Here, we report the survival status and predictors of mortality among breast cancer patients in South Ethiopia as crucial baseline data to be used for the design and monitoring of interventions to improve early detection, diagnosis, and treatment capacity. Published: March 6, 2023 Peer Review History: PLOS recognizes the benefits of transparency in the peer review process; therefore, we enable the publication of all of the content of peer review and author responses alongside final, published articles. The editorial history of this article is available here: https://doi.org/10.1371/journal.pone.0282746 Copyright: © 2023 Shita et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Methods A hospital-based retrospective cohort study was conducted among 302 female breast cancer patients diagnosed from 2013 to 2018 by reviewing their medical records and telephone interviews. The median survival time was estimated using the Kaplan-Meier survival analysis method. A log-rank test was used to compare the observed differences in survival time among different groups. The Cox proportional hazards regression model was used to identify predictors of mortality. Results are presented using the crude and adjusted as hazard ratios along with their corresponding 95% confidence intervals. Sensitivity analysis was performed with the assumption that loss to follow-up patients might die 3 months after the last hospital visit. PLOS ONE | https://doi.org/10.1371/journal.pone.0282746 March 6, 2023 1 / 16 PLOS ONE Data Availability Statement: The data underlying the results presented in the study will be available from the primary or corresponding author upon reasonable request. The study was focused on two hospitals in South part of the country and it has the potential of identifying the anonymized information of patients which is not granted. Data are available also from the Ethics Committee of the School of public health Addis Ababa University () for researchers who meet the criteria for access to confidential data. Funding: The study was funded by the School of Public Health, Addis Ababa University, Ethiopia as part of a graduate studies program. The stipend for Sefonias Getachew as senior author was also supported by the Else-Kroener Foundation through Martin Luther University, Halle-Wittenberg, Germany, grant No. 2018_HA31SP. The funders had no role in study design, data collection, and analysis, decision to publish, or preparation of the manuscript. Competing interests: The authors have declared that no competing interests exist. Predictors of breast cancer mortality Results The study participants were followed for a total of 4,685.62 person-months. The median survival time was 50.81 months, which declined to 30.57 months in the worst-case analysis. About 83.4% of patients had advanced-stage disease at presentation. The overall survival probability of patients at two and three years was 73.2% and 63.0% respectively. Independent predictors of mortality were: patients residing in rural areas (adjusted hazard ratio = 2.71, 95% CI: 1.44, 5.09), travel time to a health facility �7 hours (adjusted hazard ratio = 3.42, 95% CI: 1.05, 11.10), those who presented within 7–23 months after the onset of symptoms (adjusted hazard ratio = 2.63, 95% CI: 1.22, 5.64), those who presented more than 23 months after the onset of symptoms (adjusted hazard ratio = 2.37, 95% CI: 1.00, 5.59), advanced stage at presentation (adjusted hazard ratio = 3.01, 95% CI: 1.05, 8.59), and patients who never received chemotherapy (adjusted hazard ratio = 6.69, 95% CI: 2.20, 20.30). Conclusion Beyond three years after diagnosis, patients from southern Ethiopia had a survival rate of less than 60% despite treatment at a tertiary health facility. It is imperative to improve the early detection, diagnosis, and treatment capacities for breast cancer patients to prevent premature death in these women. Background Breast cancer (BC) is currently the most common malignancy worldwide, with the majority of premature deaths occurring in Sub-Saharan Africa [1]. A recent prospective study across the region estimated that one-third of premature deaths in the region could be averted over the next decade with early diagnosis and improved access to treatment [2]. In contrast to lowincome countries, high-income countries have achieved a 40% decrease in breast cancer mortality since the 1980s in regions where 60% of cases were diagnosed at stage I or II and pu (...truncated)