Background: We compared the histology and patterns of occurrence of breast cancers in Nigeria (n = 297) and Finland (n = 285).
Patients and methods: The histology of invasive ductal carcinoma (IDC) was re-evaluated using similar criteria. The clinical data were extracted from medical records.
Results: The mean age at presentation was 42.7 (12.2) years in Nigeria vs. 58.7 (12.5) years in Finland. In both populations there was an association between reproductive factors and the occurrence of breast cancer. In Nigeria, 53.2% of cases belonged to stages 3 and 4 (vs. 6.7% in Finland). In Finland there were higher frequencies of lobular, tubular and mucinous types than in Nigeria. The Nigerian material had more medullary type (2.7% vs. 0.7% in Finland), extensive necrosis, nuclear atypia and pleomorphism, with coexisting pleomorphic ductal carcinoma in situ. At 2 years after treatment, the survival figures for Nigeria and Finland were 72.8% and 96.4%, respectively.
Conclusion: The histology of Nigerian and Finnish cancers clearly differ. Nigerian cancers appear more advanced with higher grade. The atypical in situ component is clearly more common in Nigeria. Part of the differences can be explained by diagnostic and treatment delays associated with misguided socio-cultural beliefs, poor health care access and impaired immunity.