Retrospective Study
Copyright ©The Author(s) 2022. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Hepatol. Sep 27, 2022; 14(9): 1767-1777
Published online Sep 27, 2022. doi: 10.4254/wjh.v14.i9.1767
Decrease in liver cancer incidence rates in Bamako, Mali over 28 years of population-based cancer registration (1987-2015)
Amina Amadou, Dominique Sighoko, Bourama Coulibaly, Cheick Traoré, Bakarou Kamaté, Brahima S Mallé, Maëlle de Seze, Francine N Kemayou Yoghoum, Sandrine Biyogo Bi Eyang, Denis Bourgeois, Maria Paula Curado, Siné Bayo, Emmanuelle Gormally, Pierre Hainaut
Amina Amadou, Institute for Advanced Biosciences, Grenoble 38700, France
Amina Amadou, Department of Prevention Cancer Environment, Centre Léon Bérard, Lyon 69008, France
Dominique Sighoko, Department of Medicine, University of Chicago, Chicago, IL 60611, United States
Bourama Coulibaly, Cheick Traoré, Bakarou Kamaté, Brahima S Mallé, Francine N Kemayou Yoghoum, Sandrine Biyogo Bi Eyang, Siné Bayo, Department of Pathological Anatomy and Cytology, University Hospital of Point G, Bamako BP333, Mali
Maëlle de Seze, Université Paris 1 Panthéon-Sorbonne, Paris 75005, France
Denis Bourgeois, Health, Systemic, Process, UR 4129 Research Unit, Université Claude Bernard Lyon 1, Villeurbanne 69100, France
Maria Paula Curado, Epidemiology and Statistics Nucleus, ACCamargo Cancer Center, Sao Paulo 01508-010, Brazil
Emmanuelle Gormally, Sciences and Humanities Confluence Research Center, Université Catholique de Lyon, Lyon 69288, France
Pierre Hainaut, Institut pour l’Avancée des Biosciences, Grenoble 38700, France
Author contributions: Amadou A, Sighoko D, Hainaut P, and Gormally E designed the study, analyzed the data, and wrote the manuscript; Coulibaly B, Traoré C, Kamaté B, Mallé BS, Kemayou Yoghoum FN, Biyogo Bi Eyang S, and Bayo S contributed to the collection of the data; de Seze M, Bourgeois D, and Curado MP analyzed the data; and all authors have read and approved the manuscript.
Institutional review board statement: On behalf of the ministry of health, the regional cancer registry for Bamako district was used to support cancer surveillance activities. It is an official authoritative source of information on cancer incidence and survival in Mali. Relevant policies, regulations, and laws are strictly implemented to guide the handling of information in cancer registries. These procedures protect the confidentiality and privacy of both cancer patients and healthcare professionals. After declassifying the patient information, with no identifiers for cancer patients, the regional cancer registry provides access to the data for researchers in the form of databases.
Informed consent statement: The informed consent was waived.
Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article.
Data sharing statement: Data from the cancer registry of Bamako, Mali are available on demand from the cancer registry.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See:
Corresponding author: Emmanuelle Gormally, DPhil, Professor, Sciences and Humanities Confluence Research Center, Université Catholique de Lyon, 10 place des Archives, Lyon 69288, France.
Received: July 21, 2021
Peer-review started: July 21, 2021
First decision: November 16, 2021
Revised: December 20, 2021
Accepted: September 13, 2022
Article in press: September 13, 2022
Published online: September 27, 2022

Primary liver cancer is common in West Africa due to endemic risk factors. However, epidemiological studies of the global burden and trends of liver cancer are limited. We report changes in trends of the incidence of liver cancer over a period of 28 years using the population-based cancer registry of Bamako, Mali.


To assess the trends and patterns of liver cancer by gender and age groups by analyzing the cancer registration data accumulated over 28 years (1987-2015) of activity of the population-based registry of the Bamako district.


Data obtained since the inception of the registry in 1987 through 2015 were stratified into three periods (1987-1996, 1997-2006, and 2007-2015). Age-standardized rates were estimated by direct standardization using the world population. Incidence rate ratios and the corresponding 95% confidence intervals (CI) were estimated using the early period as the reference (1987-1996). Joinpoint regression models were used to assess the annual percentage change and highlight trends over the entire period (from 1987 to 2015).


Among males, the age-standardized incidence rates significantly decreased from 19.41 (1987-1996) to 13.12 (1997-2006) to 8.15 (2007-2015) per 105 person-years. The incidence rate ratio over 28 years was 0.42 (95%CI: 0.34-0.50), and the annual percentage change was -4.59 [95%CI: (-6.4)-(-2.7)]. Among females, rates dropped continuously from 7.02 (1987-1996) to 2.57 (2007-2015) per 105 person-years, with an incidence rate ratio of 0.37 (95%CI: 0.28-0.45) and an annual percentage change of -5.63 [95%CI: (-8.9)-(-2.3)].


The population-based registration showed that the incidence of primary liver cancer has steadily decreased in the Bamako district over 28 years. This trend does not appear to result from biases or changes in registration practices. This is the first report of such a decrease in an area of high incidence of liver cancer in Africa. This decrease may be explained by the changes and diversity of diet that could reduce exposure to aflatoxins through dietary contamination in this population.

Keywords: Hepatocellular carcinoma, Hepatitis B infection, Aflatoxin, West Africa, Cancer registration, Annual percentage change

Core Tip: Epidemiology of liver cancer is limited in West Africa. This study investigated incidence trends of liver cancer over 28 years of the population-based cancer registry in Bamako, Mali. Findings showed a significant decrease in liver incidence rates in both males and females. This is the first study reporting a decrease in the incidence rates of liver cancer in an urban population in West Africa. Evidence points to a reduction of exposure to aflatoxin caused by lifestyle and dietary changes. The magnitude of this effect suggests that reduction of aflatoxin exposure may achieve major protective effects in West Africa.