Paradigms on breast cancer influence surgical treatment policies. Randomised trials that compared mastectomy with breast-conserving therapy (BCT) with adequate radiotherapy showed no difference in overall survival. However, after a long follow-up, BCT was associated with a higher local recurrence rate (up to four times higher). The EBCTCG meta-analysis of 2005 concluded that one breast cancer death can be avoided for four local recurrences avoided. A minority of breast cancer patients are younger than 40 years (6.5%). When confronted with the diagnosis of breast cancer, they potentially have a long lifespan. Therefore, it is crucial to avoid local recurrences. The following factors have a positive impact on local control: mastectomy (in stead of BCT), negative surgical margins and adjuvant treatment (radiotherapy and chemotherapy). In order to provide optimal local and systemic treatment for young patients, breast cancer requires a multidisciplinary approach and the patient has to be involved in the proper treatment decision. A predictive model is needed for doctors and patients to facilitate this process.