The prognosis for older post-menopausal breast cancer patients is worse than for younger post-menopausal patients. This applies to the relatively healthy patients taking part in randomized clinical studies, but is also the case for older breast cancer patients in the general population. The worse prognosis may be explained by inadequate treatment, and possibly also by age-specific tumour and patient characteristics. As older patients are rarely included in randomized trials, it is still insufficiently clear what constitutes adequate treatment for them. It is therefore important to include more elderly patients in clinical studies into the effectiveness of breast cancer therapy. An important aim is to allow correct assessment of which patients will die with, and which patients will die from breast cancer, so that treatment can be adjusted accordingly.