Epidemiology of cancers in Zambia: A significant variation in cancer incidence and prevalence across the nation

Abstract

Background Cancer is one of the leading causes of death worldwide. More than two-thirds of deaths due to cancers occur in low- and middle- income countries where Zambia belongs. This study, therefore, sought to assess the epidemiology of various types of cancers in Zambia. Methods We conducted a retrospective observational study using the Zambia National Cancer Registry (ZNCR) population based data from 2007 to 2014. Zambia Central Statistics Office (CSO) demographic data were used to determine catchment area denominator used to calculate prevalence and incidence rates of cancers. Age-adjusted rates and case fatality rates were estimated using standard methods. We used a Poisson Approximation for calculating 95% confidence intervals (CI). Results The seven most cancer prevalent districts in Zambia were Luangwa, Kabwe, Lusaka, Monze, Mongu, Katete and Chipata. Cervical cancer, prostate cancer, breast cancer and Kaposi’s sarcoma were the four most prevalent cancers as well as major causes of cancer related deaths in Zambia. Age adjusted rates and 95% CI for these cancers were: Cervix uteri (186.3; CI = 181.77 - 190.83), prostate (60.03; CI = 57.03 - 63.03), breast (38.08; CI = 36.0 - 40.16) and Kaposi’s sarcoma (26.18; CI = 25.14 - 27.22). CFR were: Leukaemia (38.1%); pancreatic cancer (36.3%); lung cancer (33.3%); and brain, nervous system (30.2%). The cancer population was associated with HIV with p- value of 0.000 and a Pearson correlation coefficient of 0.818. Conclusions The widespread distribution of cancers with high prevalence observed in the southern zone may have been perpetrated by lifestyle and sexual culture (traditional male circumcision known to prevent STIs is practiced in the northern belt) as well as geography. Intensifying cancer screening and early detection countrywide as well as changing the lifestyle and sexual culture would greatly help in the reduction of cancer cases in Zambia.