Systematic review and meta-analysis of esophageal cancer in Africa:Epidemiology, risk factors, management and outcomes

BACKGROUND Esophageal cancer(EC) is associated with a poor prognosis, particularly so in Africa where an alarmingly high mortality to incidence ratio prevails for this disease.AIM To provide further understanding of EC in the context of the unique cultural and genetic diversity, and socio-economic challenges faced on the African continent.METHODS We performed a systematic review of studies from Africa to obtain data on epidemiology, risk factors, management and outcomes of EC. A non-systematic review was used to obtain incidence data from the International Agency for Research on Cancer, and the Cancer in Sub-Saharan reports. We searched EMBASE, PubMed, Web of Science, and Cochrane Central from inception to March 2019 and reviewed the list of articles retrieved. Random effects metaanalyses were used to assess heterogeneity between studies and to obtain odds ratio(OR) of the associations between EC and risk factors; and incidence rate ratios for EC between sexes with their respective 95% confidence intervals(CI).RESULTS The incidence of EC is higher in males than females, except in North Africa where it is similar for both sexes. The highest age-standardized rate is from Malawi(30.3 and 19.4 cases/year/100000 population for males and females, respectively)followed by Kenya(28.7 cases/year/100000 population for both sexes). The incidence of EC rises sharply after the age of 40 years and reaches a peak at 75 years old. Meta-analysis shows a strong association with tobacco(OR 3.15,95%CI: 2.83-3.50). There was significant heterogeneity between studies on alcohol consumption(OR 2.28, 95%CI: 1.94-2.65) and on low socioeconomic status(OR139, 95%CI: 1.25-1.54) as risk factors, but these could also contribute to increasing the incidence of EC. The best treatment outcomes were with esophagectomy with survival rates of 76.6% at 3 years, and chemo-radiotherapy with an overall combined survival time of 267.50 d.CONCLUSION Africa has high incidence and mortality rates of EC, with preventable and nonmodifiable risk factors. Men in this setting are at increased risk due to their higher prevalence of tobacco and alcohol consumption. Management requires a multidisciplinary approach, and survival is significantly improved in the setting of esophagectomy and chemoradiation therapy.