Histo-Phenotypic Aspects of Breast Cancer in Women under 40 Years Old, in Yaoundé

Introduction: Breast cancer is the most common cancer in women worldwide, with an increasing incidence. Although it is rare and no much studied in young women, it represents 7% of cases worldwide and often appears more aggressive with a poor prognosis compared to its counterpart in older women. The main objective of our study was to describe the histological and phenotypic aspects of breast cancer in women of age under 40. Methodology: We conducted a descriptive and analytical cross-sectional study, with retrospective collection of data over a period of 05 years. All women diagnosed with breast cancer were included and divided into 2 study groups: under 40 years old and over 40 years old. Data were analyzed using SPSS version 23.0 software, compared using the Chi square or Fisher exact test. A p value < 0.05 was indicative of significance. Results: We retained 196 files, either 89 for those under 40 and 107 for those over 40. Young patients with breast cancer had a higher stage, grade and tumor size. Lymph node involvement was more observed in women under 40 years (69.6% vs 53.2%). Older women were more likely to be hormone receptor positive (54.2% vs 38.2%); p = 0.018. HER-2 overexpression was higher in women younger than 40 years (39.32% vs 25.23%); p = 0.080 with a high Ki67 proliferation index (30.3% versus 2.8%); p < 0.001. Triple-negative and Her-2 tumors were much more frequent in young women (48.3% vs. 36.4%; p = 0.063) and (17.97%