Based on the TAS, about 15 million people were transported as slaves from Africa, not counting those who died en-route to the Americas, Caribbean and Europe 7. The TAS comprised the following three journeys: (1) Outward passage from Europe to Africa carrying manufactured goods; (2) Middle passage from Africa to the Americas/Caribbean carrying African captives and other commodities; and (3) Homeward passage carrying sugar, tobacco, rum, rice, cotton and other goods back to Europe. These slave routes included diverse countries. The European countries involved in the TAS were Portugal, France, Netherlands, Spain, Denmark, Norway and United Kingdom. Slaves were primarily imported from the African countries – Benin, Nigeria, Ghana, Gambia, Senegal, Mozambique, and Angola. The middle passage took the slaves from Africa to the American and Caribbean countries – Barbados, Cuba, Haiti, Dominican Republic, Netherlands Antilles, Trinidad and Tobago, Jamaica, Brazil, and the US. Most of the slaves ended up in South America or the Caribbean with about 500,000 transported to North America. Unfortunately, most of the slaves in the Caribbean, Central America and South America died while the slave population in North America had higher life expectancy 7.

In this manuscript, we explored the burden of prostate cancer among the TAS population targeting Black men of West African Ancestry to answer the question:Does the prostate cancer disparities seen in Black men around the world follow the path of the TAS?

The lack of population-based cancer registries in developing countries, especially African countries, leaves only hospital-based prostate cancer morbidity and mortality data. Thus, most of the articles identified in our review presented only hospital-based data. There was no published study on prostate cancer morbidity and mortality in Benin, Gambia, and Senegal. Although there was no published study reporting prostate cancer morbidity and mortality in Senegal, Gueye et al. 12 found the clinical characteristics of prostate cancer among the Senegalese (median PSA of 37.0 ng/mL) to be different from American Blacks (median PSA of 6.3 ng/mL) and Whites (median PSA of 6.1 ng/mL); p < 0.001. Senegalese men had worse median (and mean) PSA level and worse tumor stage. As noted by the authors, these differences can possibly be explained by the considerable differences in early detection between US men and Senegalese men.

Reports on prostate cancer patterns in Ghanaian men were found in only two published studies. The first study was a review of the genitourinary cancers seen at the Accra Korle-Bu Teaching Hospital, Klufio 13. The authors found prostate cancer to comprise about 64% (349 cases) of all genitourinary cancers from 1980 to 1990. In a more recent study, Wiredu and Armah 14 conducted a 10-year review (1991–2000) of all cancer mortality patterns at the same institution based on autopsy and death certification data, and found prostate cancer to be the second leading cause of cancer deaths (286 cases). None of the studies presented the actual incidence, prevalence or mortality from prostate cancer.

Contrary to the WHO IARC global ranking, several published studies indicate higher incidence of prostate cancer in Nigerian men. A total of 17 original papers, which met our review criteria, were found to document prostate cancer patterns in Nigeria. Odedina, Ogunbiyi and Ukoli previously reviewed all the 17 articles in 2006 8. The first published paper reviewed by Odedina, Ogunbiyi and Ukoli 8 was as early as 1981 and the latest study in 2005. The studies were conducted in different regions of Nigeria, including the North, Southeast, West, and in rural South. The authors concluded that the body of evidence from the 17 studies indicates high prostate cancer risk among Nigerian men and a prostate cancer burden similar to that of Black men in the US. Table 1 provides a summary of the prostate cancer incidence and prevalence rates reported in the review article.

There were no published articles that met our review criteria for the countries Barbados, Cuban, Dominican Republic, Haiti, and Netherlands Antilles. Three published studies met the criteria for prostate cancer patterns in Brazil. The earliest study, in 1991, reviewed the Cancer Registry data of São Paulo between 1969 and1974 15 and found Mulatto and Black men to be disproportionately affected by prostate cancer compared to White men. The authors concluded that the prostate cancer disparities seen among Mulattos and Blacks in Brazil were similar to the experiences of Blacks in the US. In another study of Blacks, Mulattos and Whites, Barros et al. 16 explored the prevalence of prostate cancer from 1999 to 2001 at the Federal University of Bahia's hospital. Based on a sample of 162 patients who had prostate biopsy, the authors found no statistically significant differences among the three ethnic groups on mean PSA level (22.0 ng/dl for White, 18.1 ng/dl for Mulatto, and 19.3 ng/dl for Black; p value of 0.65) and prostate adenocarcinoma prevalence (53.3% for White, 53.3% for Mulatto, and 64.9% for Black; p value of 0.36). The final study in Brazil targeted a population with a high number of Bantu African ancestors in São Paulo. Screening 473 volunteers between the age of 40 and 79, Paschoalin et al. 17 found the prevalence of prostate cancer to be greater among Blacks and Mulattos compared to Whites. The proportion of biopsy-confirmed prostate cancer among 121 patients were 8.5% Black men, 6.7% for Mulatto men, and 0.6% for White men (p = 0.006).

The classic study by Glover et al. 10 in 1998 provided a significant update on prostate cancer in Jamaica. Prior to this study, African American men were cited as having the highest rate for prostate cancer in the world. Glover et al. 10 conducted a 5-year retrospective review of over 1,000 prostate cancer cases between 1989 and 1994 in Kingston, Jamaica. The authors reported a mean-age adjusted incidence rate of 304 per 100,000 based on 1,121 prostate cancer cases retrieved from the Jamaican Cancer Registry, government pathology laboratory, hospital and clinic records, and physician office records. The authors concluded that the prostate cancer incidence in Kingston was significantly higher than that of the US Blacks. Glover et al. 10 confirmed the results from an earlier study by Brooks and Wolf 18, who found prostate cancer to be the most prevalent cancer among Jamaican men in Kingston and St. Andrew based on a review of all cancer cases from 1958 to 1987. More recently, Hanchard et al. 19 in 2001 reported prostate cancer as the leading site for incidence of cancer in males based on the 1941 malignant neoplasms recorded in Kingston and St. Andrew among males. The authors reported 619 cases of prostate cancer and age-standardized incidence rate of 56.4. In 2002, Blake et al. 20 also reported that prostate cancer continued to be the leading cancer mortality site among Jamaican men.

The three published studies found to be relevant for Trinidad and Tobago were by Bunker et al. 212223. In 2004, Bunker at al 21 reported a population-based prostate cancer study, screening on about half the population of Tobago men. Over 2,500 men between the age of 40 and 79 years were screened using serum prostate-specific antigen (PSA) and digital rectal examination (DRE). The authors found biopsy-confirmed prostate cancer prevalence in this population to be about 11% (277 out of 2,583 men). These results confirmed the findings of an earlier report on the same population by Bunker et al. 22 based on the screening of 2,484 men between the age of 40 and 79 in Tobago. In another report, Bunker et al. 23 compared the Tobago population of West African descent to the men of Asian-Indian descent in Trinidad, targeting men between 50 and 64. The prostate cancer prevalence based on population-based screening was found to be significantly higher for the Afro-Tobagonian men (8.3%) compared to the Asian-Indian men (2.3%). This difference was also observed on all age categories: 50–54; 55–59; and 60–64.

The populations of Black men in the United Kingdom (UK) provide a very interesting population to study because they are mostly Afro-Caribbean and West African men. Thereby, they uniquely reflect a microcosm of the West African and Caribbean populations described above. Ethnic variations in prostate cancer have just recently been studied in the UK, with the landmark study of The Prostate Cancer in Ethnic Subgroups (PROCESS) group 2425. Chinegwundoh et al 24 published an earlier study in 2006. The researchers conducted a population-based audit of new prostate cancer diagnosis between January 1, 1999 and December 31, 2000 for the following regions: the London Boroughs of Tower Hamlets; Hackney; Newham; and the City of London. The total population in these regions was over 600,000 with an ethnic classification of White (British, Irish, "other" White), Black (Black Caribbean, Black African, Other Black, White and Black African mixed, White and Black Caribbean mixed), and Asian (Indian, Pakistani, Bangladeshi, other Asian, White & Asian mixed). The confirmed prostate cancer cases included 248 European men, 91 African-Caribbean men, and 20 South Asian men. These ethnic groups were compared on age-adjusted incidence rates for prostate cancer. The author's findings are summarized in Figures 1 and 2. African-Caribbean men had the highest age-specific incidence rates compared to European and Asian men. Interestingly, the relative risk for prostate cancer for the African-Caribbean men was three times that of European men. As noted by the authors, this risk is more than the risk documented for African American men in the US. A reason that has been suggested for the larger relative difference between African-Caribbean and European men is a lower prostate cancer rate for White men in the UK 25.

In a follow-up study published this year, the PROCESS study group 25 conducted a retrospective population-based audit of prostate cancer incidences in North Bristol, South West London, South East London, and North East London from 1997 to 2001. Within this 5-year period, 2 140 prostate cancer cases were reported with: 61.4% White, 20% Black Caribbean, 4.8% Black African, 0.5% Black unclassified, 6% other ethnic groups, and 7% un-coded ethnicity. A summary of the findings are provided in Figures 3, 4, 5, 6. The authors confirmed their previous findings in the Chinegwundoh et al.'s study 24. An interesting component of the current study is the comparison of the Black Caribbean group to the Black African group, with no statistically significant difference on age-adjusted prostate cancer rates between both groups.