The study consists of three parts. Part 1 is a prospective non-randomized feasibility study in patients with breast cancer after primary surgery during chemotherapy or endocrine therapy comparing blood count, lymphocytes, quality of life and local and general side effects between the groups Part 2 is a prospective randomized feasibility study with a waiting list for three months comparing changes in quality of life, depression, diurnal cortisol profile and expression of zeta-chains in T- and NK-cells after three months of treatment or waiting in patients of two different strata (early breast cancer UICC I/II and metastatic breast cancer) Part 3 consists of two follow-up periods of 12 months respective. Patients may choose to continue, quit or restart mistletoe treatment upon their own decision, endpoints from part 2 are evaluated every 6 months.
