Differences found in cancer occurrence within African and US born blacks

American Cancer SocietyApr 14 2017

The cancer profile of African-born blacks differs from that of United States-born blacks and varies by region of birth, according to a new study. The study, appearing in CANCER, suggests differences in environmental, cultural, social, and genetic factors, and points to an opportunity to study the risk factors associated with the cancer burden in African-born blacks to help create targeted interventions.

Sub-Saharan African-born blacks are one of the fastest-growing populations in the United States, comprising a substantial proportion of the estimated 2.1 million black African immigrants in the United States in 2015. However, there is a lack of data regarding the cancer burden in this group.

To learn more, researchers from the American Cancer Society, the Ohio State University, and Covance Laboratories reviewed incidence data covering 2000-2012 from the Surveillance, Epidemiology, and End Results (SEER 17) program to compare the frequency of the top 15 cancers in African-born blacks with that of U.S.-born blacks by sex and region of birth.

Because the investigators did not have data on the number of sub-Saharan African born immigrants living in SEER areas, they were not able to estimate the incidence of cancers by place of birth, and instead examined the proportion of individual cancers among overall cancers in this group.

They found that compared to United States-born non-Hispanic blacks, sub-Saharan African-born blacks had significantly higher proportion of infection-related cancers (liver, stomach, and Kaposi sarcoma), blood cancers (leukemia and non-Hodgkin lymphoma), prostate cancer, and thyroid cancers (in females only). For example, the proportion of Kaposi sarcoma was 12 times higher in African-born black women than US-born black women.

In contrast, African-born black men had lower incidence for smoking-related and colorectal cancers. For example, the proportion of lung cancer was 30% lower in African-born black men compared to blacks born in the U.S.

Furthermore, cancer occurrence in African-born blacks versus U.S.-born blacks varied by region of birth. For example, the higher incidence for liver cancer noted among male African-born blacks and for thyroid cancer in African-born females were confined to Eastern African-born blacks, whereas the higher incidence for prostate cancer was confined to Western African-born blacks.

"Typically, cancer occurrence among blacks in the United States is presented as one homogenous group, with no breakdown by country or region of birth," said Ahemdin Jemal, D.V.M., Ph.D., American Cancer Society epidemiologist and co-author of the study. "Our study shows that approach masks important potential differences that may be key to guiding cancer prevention programs for African-born black immigrants."

Article: Cancer Incidence Profile in Sub-Saharan African-Born Blacks in the United States: Similarities and Differences With US-Born Non-Hispanic Blacks; Jemal et al. CANCER; Published Online: April 13, 2017 DOI: 10.1002/cncr.30701.