Cancer rates differ between African- and U.S.-born black Americans, a new study finds.
“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 study co-author Dr. Ahmedin Jemal, an American Cancer Society epidemiologist.
“Our study shows that approach masks important potential differences that may be key to guiding cancer prevention programs for African-born black immigrants,” Jemal added.
The researchers analyzed 2000-2012 U.S. data to compare rates of the top 15 cancers in African-born blacks to U.S.-born blacks.
Blacks born in sub-Sahara Africa had much higher rates of infection-related cancers (liver, stomach and Kaposi sarcoma) than U.S.-born blacks. They also had higher rates of blood cancers (leukemia and non-Hodgkin lymphoma), prostate cancer and thyroid cancers (in females only).
For example, the rate of Kaposi sarcoma was 12 times higher in African-born black women than U.S.-born black women, the researchers found. Kaposi sarcoma is a cancer that causes lesions in soft tissues.
However, the lung cancer rate for African-born black men was 30 times lower than for U.S.-born blacks. African-born men also had lower colon cancer rates.
The researchers also found that cancer rates varied by region of birth in Africa. For example, higher rates of liver cancer among males and of thyroid cancer in females were confined to those born in eastern Africa, while the higher rate of prostate cancer among men was limited to those born in western Africa.
Trends in cancer incidence rates: Incidence rates for all cancers combined increased from the mid-1970s to the early 1990s in blacks; rates were higher and increased faster in males than in females. Since the early 1990s, rates have generally decreased in males, but remained stable in females. During the most recent time period (2003-2012), overall cancer incidence rates decreased faster in black males (2.0% per year) compared to white males (1.2%).4 The declines in overall cancer incidence largely involved cancers of the lung and prostate. Overall cancer incidence rates were stable among both black and white females during 2003-2012.4
The study was published online April 13 in the journal Cancer.
Environmental, cultural, social and genetic factors may explain the differences in cancer rates between African- and U.S.-born blacks. Learning more about such influences could lead to targeted cancer prevention programs, Jemal and his colleagues said in a journal news release.
Blacks from sub-Sahara Africa are among the fastest-growing populations in the United States. They accounted for a large proportion of the estimated 2.1 million black African immigrants in the United States in 2015, according to notes with the study.