The burden of malignant neoplasms (cancer) in Ethiopia, 2000–16: analysis of Evidences from Global Burden of Disease Study 2016 and Global health estimates 2016

Background: Cancer figures among the leading causes of morbidity and mortality worldwide. More than 60% of world total new annual cancer cases occur in Africa, Asia, and Central and South America. In Ethiopia, cancer accounts for about 5.8% of total national mortality. The increasing burden of common non communicable diseases such as cancer leads to epidemiological shift of disease burden to non-infectious diseases. However, lesser emphasis is given to cancer. Although, measuring the burden is important to design prevention strategy, a comprehensive estimate is lacking in Ethiopia. Hence, we aimed to systematically measure the burden of cancer in Ethiopia. Methods: The research used data from Global burden of disease study (GBD 2016) and Global health Estimate 2016; that originally collected the information through vital registration, verbal autopsy, surveys, reports, published scientific articles and modeling. Results: In 2016, cancer caused an estimated 50913.5 (95% CI: 36092.1–73018.8) deaths among all age and both gender groups with a crude death rate of 49.7/100,000 and ASDR of 93.5/100,000 population. It contributed for 18.5% of NCD related death and 7.3% of total death, 16.9% of NCR related ASDR and 9% of total ASDR, and 12.7% of national NCD related DALYs and 4.3% of the national total DALYs. The number of death and DALYs from cancer has been increased by 47.4% and 45.1% respectively. Whereas CDR and ASDR from cancer has been declined by 4.2% and 9.7% respectively. The top five causes of cancer related mortality was from Other malignant neoplasms, breast cancer, cervix uteri cancer, colon and rectum cancers, and leukemia whereas lymphomas along with the aforementioned cancers contribute for the highest cancer DALYs. Conclusion and recommendation : the burden of malignant neoplasms (cancer) is remarkably increasing throughout the periods between 2000 and 2016. It carries the higher burden of age standardized death rate (ASDR) from NCD. Specifically, other malignant neoplasms, Breast cancer, cervix uteri cancer, colon and rectum cancers, leukemia and lymphomas caused the


Introduction
Cancer is a disease in which abnormal cells grow and reproduce uncontrollably and invade nearby tissues by spreading to other parts of the body through blood streams and lymphatic systems hindering the activities of the normal cells (1-3). Cancer incidence has increased in most countries worldwide, owing to a growing and aging population and to an expansion of key risk factors, such as smoking, obesity, and unhealthy diet (4,5).
Cancer figure among the leading causes of morbidity and mortality worldwide, with approximately 18.1 million cases, 0.5 million new cases and 9.6 million cancer related deaths in 2018 (6). One in 5 men and one in 6 women worldwide develop cancer during their lifetime, and one in 8 men and one in 11 women die from the disease. Worldwide, the total number of people who are alive within 5 years of a cancer diagnosis, called the 5-year prevalence, is estimated to be 43.8 million (7). The 5 most common sites of cancer diagnosed for both sexes in 2018 were lung (11.6%), breast (11.5%), colorectal (10.2%), prostate (7.1%), and stomach (5%) (6).
More than 60% of world total new annual cancer cases occur in Africa, Asia, and Central and South America. These regions account for 70% of the world cancer deaths (6). Furthermore, the number of new cases is expected to rise to 29.5 million by the years 2040 (8). This is an alarming prospect, especially for Low-income countries (LICs), where the weak health systems are severely resource constrained and already overwhelmed by the large burden of communicable diseases (1, 7).
Cancer is increasingly recognized as a critical public health problem in Africa. While communicable dis eases continue to burden African populations, it is becoming clear that non communicable diseases also require the attention of those whose goal is to ensure the health of Africans (2, 6,9). Today, 60% more Africans die from cancer than succumb to malaria and the number of cancer deaths is rising at an alarming rate (9).
According to GLOBOCAN forecasts, the number of estimated cancer deaths in 2015 approximately 635,400. Africa's cancer burden is projected to reach an alarming 1.4 million new cases and 1 million deaths by 2030, simply due to the aging and growth of the population and also adoption of behav iors and lifestyles associated with economic development, such as smoking, unhealthy diet, and physical inactivity (8,9). Similarly, mortality due to cancer is increasing in Africa, cancer mortality was estimated to be 542,000 with a diagnosis of 715,000 new cancer cases as of 2008 (10).
In Ethiopia, cancer accounts for about 5.8% of total national mortality. Although population-based data do not exist in the country except for Addis Ababa, it is estimated that the annual incidence of cancer is around 60,960 cases and the annual mortality is over 44,000. For people under the age of 75 years, the risk of being diagnosed with cancer is 11·3% and the risk of dying from the disease is 9·4% (11). The most prevalent cancers in Ethiopia among the adult population are breast cancer (22.2%), cancer of the cervix (9.3%) and colorectum (7%). About two-thirds of reported annual cancer deaths occur among women (12). However, most prevalent cancer in Ethiopia among children is leukemia, lymphoma, retinoblastoma, wilms' tumour (nephroblastoma), bone and soft tissue sarcomas (13).
Even though the epidemic of non-communicable disease is expected to increase, its burden is not clearly known in the country. Therefore, this study aimed to measure the burden of cancer in Ethiopia  premature death and time lived in states of less than optimal health, loosely referred to as "disability".

Statistical analysis and interpretation
This study analyzed the burden of malignant neoplasms (cancer) in Ethiopia from the general measurement of disease burden and from the burden of group II (NCD) diseases. The GBD study and GHE approaches to estimate all-cause mortality and cause-specific mortality rates by age, sex, and year has been described elsewhere (14). Causes of death by age, sex, and year for all causes were measured mainly using cause of death ensemble modeling (CODEm); that models different statistics and estimates outcomes based on the performance of fitted models (16). DALY was measured by summing years of life lost (YLL) due to premature mortality and years lived with disability (YLD), a measure of non-fatal health loss, in a single metric. YLL were estimated using standard GBD methods whereby each death is multiplied by the normative standard life expectancy at each age. YLD were estimated using sequelae prevalence and disability weights derived from population-based surveys.
For most sequelae, the GBD 2016 study used a Bayesian meta-regression method, DisMod-MR 2.1, designed to address key limitations in descriptive epidemiological data, including missing data, inconsistency, and large methodological variation between data sources (14). 13.4/100,000, 9.9/100,000 and 6.7/100,000 population respectively by the year 2016.

Results
Although, ASDR from testicular cancer, stomach cancer, oesophagus cancer and cervical cancer has been declined between 29-43%, the death from ovary cancer, brain and nervous system cancers, kidney cancer and pancreas cancer was increased by 12-27.5% between 2000 and 2016. While the overall cancer related mortality (ASDR) was declined by 9.7% during the specified period of time (

Discussion
The burden of cancer in terms of mortality and disability adjusted life years was measured among all ages and genders for Ethiopia between 2000 and 2016 by using aggregates of data from the global health estimates. The number of death from cancer has been increased by 47.4% between 2000 and 2016. However, crude death rate and age standardized death rates were declined by 4.2% and 9.7% respectively with in the specified periods. The change in the overall cancer mortality may highlight the increasing incidence of cancer and contribution of factors leading to increased density of cancer and other non-communicable diseases such as: ageing, nutritional transition, environmental change and population growth (5, 9-13).
The contribution of cancer for the total mortality and mortality specific to non-communicable diseases was increased tremendously. In 2016 cancer has been contributed for 18.5% of deaths from noncommunicable diseases and 7.3% of the total death reported in Ethiopia. It indicates a tremendous increment from the 2014s report, where cancer has been contributed for 6% of the total death reported in Ethiopia. Studies witnessed that the role of non-communicable diseases as general and cancer could significantly increases in the epidemiology of disease burden particularly in Africa, where the burden of NCD is increasing by 27% surpassing the global average of 17% (5,11,(15)(16)(17).
Unless effective measure is taken the burden of cancer in Ethiopia as well as Africa could exceed all combined communicable diseases as the most common causes of death in the near futures (2, 5).
This implies that NCDs like cancer represent a leading threat to health, economies and overall human development in the country. This is because in lower income countries, the increase in the relative burden from NCDs and the decrease in communicable disease burden are occurring more rapidly than in high-income countries. Particularly the burden of cardiovascular diseases and cancer is rapidly increasing (16)(17)(18)(19). A research conducted in India also witnessed this finding, which the number of new cases and deaths due to cancer doubled in 26 years (15).
Although, epidemiological shift observed in most developing countries has the major role in the burden of cancer (15)(16)(17)(18) interventions designed to address non-communicable diseases particularly cancer were poorly implemented in developing countries. Until recently the Ethiopian government has not been designed a preventive strategy to overcome the burden of cancer and non-communicable diseases at large. Also global interventions that were designed yet in the millennium and sustainable development goals were targeted on infectious diseases, maternal and child health and nutritional problems and less emphasis was given for cancer and other NCDs (5,(14)(15)(16)(17)(18)(19) DALYs due to all specific types of cancer has been increased substantially except for stomach cancer.
DALYs from ovary cancer was doubled while DALYs from Prostate cancer, Brain and nervous system cancers, Pancreas cancer, Liver cancer, Kidney cancer, Trachea, bronchus, lung cancers, Lymphomas, multiple myeloma, Mouth and oropharynx cancers and other malignant neoplasms has been increased by 55-94% with in the same period. This may be as a result of increased burden of smoking and alcohol consumption; the major risk factors related to most cancers cases (5,(14)(15)(16)(17)(18) along with other predisposing factors and absence of good medical facilities.
This research is based on secondary data analysis and the primary data was based on model estimations, therefore, the potential biases related to this and the issue of validity is there. Moreover, the forecasted values from the trend may change through time due to change in intervention programs; this intern affects the reliability of the estimate. Hence all interpretations should consider these limitations.   CDR=Crude death rate, ASDR=Age-standardized death rate, NCD=Non-communicable disease Therefore, the existing disease prevention strategies should incorporate NCD prevention strategies with a particular emphasis for cancer screening, prevention and care.