The outcome of very young patients with early breast cancer is worser compared to older patients with a similar clinical presentation. The triple negative, luminal B, HER2+ subtypes are more frequent in this population. Adequate local treatment (breast-conserving surgery or total mastectomy) must be discussed with the patient. The role of radiotherapy is very important in these patients with high risk of local recurrence. The progress in adjuvant treatment of very young patients requires studies of tailored treatments.