Cancer mortality trends among middle-aged men and women in Nigeria: data from the WHO cancer mortality database

Introduction

Globally, cancer has become a major source of morbidity and mortality [1]. In 2008, there were approximately 12.7 million cases and 7.6 million cancer-related deaths [2] with 56% of the newly reported cases occurring in developing countries. It is projected that 70% of all new cases by 2030 will be found in developing countries [3]. Developing or low income countries have recently been the regions with predominantly the highest cancer prevalence in the world, and the highest rates of undiagnosed and untreated cancer-related diseases [4, 5].
Most of the increase in cancer incidence is primarily due to population growth and life expectancy [6]. The peculiarity of cancer disease in Nigeria has several facets. For instance, it is estimated that 100,000 new cases of cancer occur every year [2]. In 2008, Nigeria represented 15% of the 681,000 new cases of cancer that occurred in Africa [1]. Since three decades, public awareness and sensitization by non-Governmental and Governmental organizations through collaboration have been the major evidence to combat the disease in developing countries [7, 8]. Also, diagnosis of cancer was characterized by late clinical presentation in an advanced stage of the disease, when only chemotherapy and palliative care could be given. The majority of these patients with cancer present with stage III or IV disease, which is associated with lower survival rates and higher mortality rates [9, 10].
Despite the initiation of a program of National System of Cancer Registries in 2009 by the Nigerian Federal Ministry of Health (FMOH) and the Institute of Human Virology Nigeria (IHVN), there is dearth of data and sparse literature on the trends and peculiarity of cancer in Nigeria. Lower income countries use a hospital-based cancer registry and the WHO database as the fundamental source of information on cancer.
The aim of this article is to compare and contrast the trends of cancer mortality among males and females in Nigeria, and to establish the uniqueness of this disease in the Nigerian population

Material and methods

Data on both cancer information and mortality rates utilized for this study are based on the 2014 WHO mortality database, Health statistics and information systems [11].

Statistical analysis

The analysis was conducted using SPSS Statistics v. 17. The mortality rates were presented as “standardized mortality rate per 100,000 populations”.

Results

Figures 1 and 2 present the cancer mortality time trends among middle-aged men and women in Nigeria from 2000 to 2012. The mortality of liver cancer among men was significantly higher than among women. Prostate cancer in men (70/100,000) was significantly more frequent than breast cancer (30/100,000) in women.
Among women, frequency of cervix uteri cancer decreased progressively from the year 2000 to 2012. The observed mortality rate of lymphomas was similar in both sexes. The percentage mortality of different types of cancers is represented in Figures 3 and 4. Prostate (32%) and breast cancers (34%) caused the most deaths in men and women respectively. The mortality from lung cancer was significantly higher in men (25%) than in women (10%). Figures 5 and 6 also present the cancer incidence among men and women respectively. The most common types of cancer in men were prostate and liver cancer. For women, the most common cancers were breast and cervix uteri cancer.

Discussion

Several decades ago, nearing the beginning of the 21st century, Nigeria was one of the leading countries for cancer mortality in Africa [1]. During this period it had the highest cancer incidence in Africa, which was more predominant among men [1, 2]. However, the breakthrough came years after. In the years 2000–2012, Nigeria had a progressive, significant decline in cancer mortality among both men and women. Prevalence of cancer in Nigeria was consistently higher in women than in men. This could be attributed to the higher risk factors among women than men. For instance, the current cancer risk factor from tobacco smoking and total alcohol per capita consumption is higher in women than men [12]. Our study reveals that the commonest cancers in Nigeria from 2000 to 2012 were prostate among males and breast cancer among women. We also observed a slight decline in cancer mortality during this period.
While Nigeria can celebrate the success of declining prevalence of cancer, it must not be forgotten that the diminished peculiarity of the Nigerian cancer health and policy system. Though there is a national cancer registry, there is a lack of effective cancer plans, monitoring and surveillance [13]. There is also a lack of operational policy, strategy or action to reduce the burden of tobacco use [14], and complete absence of bans on advertising, promoting and sponsorship which increases risk of cancer [15]. Cancer screening and early detection of cancer are not generally available at the public primary health care level [16, 17]. Cancer treatments such as radiotherapy and chemotherapy are not generally available in the public health system [18]. Palliative care such as community/home care for people with advanced stage cancer is also not generally available [19].
In conclusion, we made two observations and questions from the study. The first is that cancer mortality has declined slightly over the last two decades; and what important factors promote these developments in Nigeria? The second is that cancer mortality is significantly higher among men than women; and what are the next steps towards further eradication of cancer and cancer-related diseases in developing countries such as Nigeria?

Conflict of interest

The authors declare no conflict of interest.

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