Breast cancer in very young women: Clinicopathological study of 149 patients ≤25 years old

BACKGROUND: Breast cancer in young women has different clinical and pathologic features and a more aggressive biological behavior when compared to breast cancers in older women. However, information is limited to the group of very young women (≤25 years). OBJECTIVES: The aim of the present study was to investigate the pathological characteristics of breast cancer in 149 Brazilian women who were ≤25 years old at the time of breast cancer diagnosis. MATERIALS AND METHODS: Tumor samples diagnosed between 2003 and 2009 were analyzed from the archives of the Bacchi Laboratory. RESULTS: In our series of 149 Brazilian women ≤25 years, 8.7% presented with in situ disease only. Of 136 invasive carcinomas, 91.9% were of the ductal type and 45.6% were of histological grade III. Overall, estrogen receptor (ER) was positive in 59.6% cases, and HER2 overexpression was detected in 32.8%. We also found a low prevalence of Luminal A cases and a high prevalence of Triple Negative cases. Statistical analysis showed that HER2 and basal-like groups had a lower overall survival expectation. Follow-up data showed high frequencies of regional lymph node metastasis, distant metastasis, and tumor-related deaths. CONCLUSION: The present study represents the largest series of breast cancer arising in women ≤25 years and establishes the main clinical, pathological, immunohistochemical and follow-up features of this population.