No difference in the prevalence of benign breast changes between women from Ghana and Norway: an autopsy study

Breast carcinoma develops gradually through multiple steps, some of which are recognizable as benign or premalignant histological changes. The age-standardized breast-cancer incidence rate is three times higher in Norway than in Ghana. A similar difference in the prevalence of benign and premalignant breast changes in the general populations would be expected if the difference in incidence rates were mainly due to cancer initiation factors, but not if it were caused by later stage promotion and progression factors. Breast tissue was taken by a standardized protocol from the autopsies of 44 Ghanaian and 26 Norwegian women between 15 and 60 years of age. Blind-labelled hematoxylin and eosin stained sections were examined independently by each of the three authors and the occurrence of histological changes in each section was recorded. The study revealed no significant difference between Norwegian and Ghanaian women in the prevalence of either proliferative or non-proliferative breast changes. The recorded incidence of breast cancer in Ghana may be under-estimated because of lower access to health services, lower patient awareness, and absence of population screening for breast cancer. Otherwise, the results support the conclusion that the lower incidence of breast cancer in Ghana than in Norway is mainly due to late-stage promotion and progression rather than initiation factors.