Pathological features and survival outcomes of very young patients with early breast cancer: how much is "very young"?

We collected information on 497 consecutive breast cancer patients aged less than 35 years operated at the European Institute of Oncology. The main aim of the study is to compare biological and clinical features dividing the population by age: <25 years, 25-29 and 30-34 years old. Pattern of recurrence and survival were also analyzed. Patients aged <25 years had 81.8% poorly differentiated tumors compared with 66.7% and 56.5% in the 25-29 and 30-34 groups, respectively; no other significant difference were found in the distribution of clinical and immunohistochemical features The distribution of Luminal A and B, Triple Negative and HER2 subtypes (immunohistochemically defined) was not statistically different among the three age groups. No difference was found in the incidence of loco-regional relapses, distant metastases, disease-free survival (p = 0.79) and overall survival (p = 0.99) between the three age groups. This latter findings was confirmed using age as a continuous variable assuming a linear association between age and the outcomes considered, too. In conclusion, our data indicate that the group of patients with breast cancer below 35 years is essentially a homogenous group when classical clinical and immunohistochemical features were considered.