Early onset breast cancer: Differences in environmental and reproductive factors, tumor phenotype and BRCA1/BRCA2 genotype between the north and south of the Mediterranean Sea.

e12016Background: Early onset breast cancer ( ≤ 40 years, EOBC) have a particular aggressive phenotype with a high rate of triple negative (TN) tumors and a worse prognosis. It has also been reported that EOBC occurring in North African countries have a more aggressive phenotype and outcome than in occidental countries. This report compares the environmental and reproductive factors, the tumor phenotype and the BRCA1/BRCA2 genotype in EOBC between France and North Africa. Methods: 455 women with invasive EOBC were included from 01/2014 to 06/2015 from 7 participating centers in 5 countries (Algeria, Egypt, France, Morocco, Tunisia). Life factors, tumor phenotype, familial history of BC, BRCA1 and BRCA2 genotype were compared between North Africa (n = 185) and France (n = 270). Results: A younger age at menarche, a higher number of childbearing, a longer duration of breastfeeding, a higher body mass index are found in North African women as compared to French women (p < 0.001). Use of oral contraceptives a...