Special issues related to the adjuvant therapy in very young women.

A small minority of breast cancer patients consists of young women (<40 years: <6%). Thus, they may not be properly represented in clinical trials. They present with unfavorable tumor characteristics, but young age is an independent negative prognosticator: age is a surrogate for biological mechanisms determining an aggressive cancer phenotype. In premenopausal patients with estrogen receptor-positive (ER+) tumors, adjuvant ovarian function suppression (OSF) was as effective as chemotherapy in ten randomized clinical trials. Chemotherapy reduces the risks of recurrence and death irrespective of endocrine responsiveness of the tumor; however, in patients with ER+ tumors this might result in chemotherapy-induced menopause. Accordingly, OFS did not prolong survival in addition to chemotherapy in meta-analyses and recent clinical trials except in subgroups of particularly young women. Adjuvant tamoxifen is efficient in premenopausal patients with ER+ tumors irrespective of age and the use of chemotherapy. Clinical trials addressing the role of OFS are underway, and future trials should be planned so that the population of young women can be properly analyzed.