Burden of Cancers Attributable to Infectious Agents in Nigeria: 2012–2014

Abstract

IntroductionInfections by certain viruses, bacteria, and parasites have been identified as risk factors for some cancers. In Nigeria, like many other developing countries, infections remain a leading cause of morbidity and mortality. While there are data on the incidence of different cancers in Nigeria, there has been no study of cancers attributable to infections. This study was carried out to determine the burden of cancers attributable to infections using data from two population-based cancer registries (PBCRs) in Nigeria.MethodsWe obtained data on cancers associated with EBV, human papillomavirus (HPV), hepatitis B and C, HIV, HHV8, Helicobacter pylori, and Schistosoma spp. from the databases of Abuja and Enugu cancer registries in Nigeria. We used population-attributable fraction for infections-associated cancers in developing countries that are based on prevalence data and relative risk estimates from previous studies.ResultsThe PBCRs reported 4,336 incident cancer cases [age standardized incidence rate (ASR) 113.9 per 100,000] from 2012 to 2014, of which 1,627 (37.5%) were in males and 2,709 (62.5%) were in females. Some 1,030 (23.8%) of these cancers were associated with infections (ASR 44.4 per 100,000), while 951 (22.0%) were attributable to infections (ASR 41.6 per 100,000). Cancers of the cervix (n = 392, ASR 28.3 per 100,000) and liver (n = 145, ASR 3.4 per 100,000); and non-Hodgkin’s lymphoma (n = 110, ASR 2.5 per 100,000) were the commonest infections-associated cancers overall. The commonest infectious agents associated with cancers in this population were HPV, EBV, hepatitis B and C, HIV, and HHV8.ConclusionOur results suggest that 23.8% of incident cancer cases in this population were associated with infections, while 22.0% were attributable to infections. The infections attributable cancers are potentially preventable with strategies, such as vaccination, risk factor modification, or anti-infective treatment.

Global burden of cancer attributable to infections in 2018: a worldwide incidence analysis

“…The estimates in our study are limited by scarcity of local data, especially in low-income countries. To allow for meaningful comparisons, precise estimates can and should be made by individual countries using all available sources of data, 31,32 and we hope that our approach for calculating attributable fractions can serve as a useful and standardised model. Periodical assessments of repre sentative case-series of cancer in sentinel sites with high-quality cancer registries could assist with long-term monitoring of trends in the burden of infection-related cancers.…”

The Pattern of Cancer Cases in the Rest of Cross River State Not Covered by the Calabar Cancer Registry between 2004 and 2013

“…In adult females, breast, cervix, skin and soft tissue are dominant and differ from males in that hepatobiliary cancers are not in the first ten and ovary, uterine and cancer from the rest of the genitalia feature in the first ten. The cancers of affluence (Breast, prostate) seems to have marginally overtaken infection [36] /povertyrelated cancers (cervix and hepatobiliary cancers) in our environment. This is the pattern reported in many African and Caribbean studies [5,27,37,38].…”

Challenges of Human Papillomavirus Infection and Associated Diseases in Low-Resource Countries

“…24 In Nigeria, penile invasive squamous cell carcinoma makes up less than 1% of malignancies among men and occurs at a median age of 60 years or older. 25 Worldwide, 40% of penile cancers are attributable to HPV infection. 26 The prevalence of penile HPV infection in reports worldwide ranges from 29% to 82% and varies by country, population studied, and area of genitalia sampled.…”

“…27 Although precancerous lesions of the penis (ie, penile intraepithelial neoplasia) are rare, HPV DNA positivity is observed in 60% to 100% of these lesions. 25 HPV types 16 and 18 are the most common genotypes detected in squamous cell carcinoma of the penis. 28 Penile HPV infection is dependent on high-risk sexual behavior including lifetime number of sexual partners, number of recent sexual partners, age at first intercourse, as well as sexual frequency.…”