ABSTRACT
Breast cancer is the leading cause of death among solid tumors in women, and the incidence is still increasing in the Western world, especially among younger women. In the Netherlands, there are close to 10,000 new cases every year in a population of 15 million people. At present, the disease will affect 12% of all women, and approximately 40% of patients will die from metastatic disease. Gain in survival can be expected from early detection and the use of adjuvant therapy. Mammographic screening strategies result in earlier diagnosis of breast cancer, and a 2530% decrease in breast cancer mortality in woman over the age of 50 years.1 However, mammographic screening is more likely to detect slower growing and better differentiated tumors (which inherently have a better prognosis) rather than rapidly growing aggressive tumors which often present as interval cancers.2,3 Adjuvant chemo-and hormonal therapy have been shown to improve survival in breast cancer patients, but do have sideeffects, and therefore selection of those patients who will gain the most benefit is critical. In addition to traditional prognostic factors (see Chapter 2) and predictive factors (such as steroid receptors (Chapter 9) and human epidermal growth factor receptor 2 (HER2)/neu (Chapter 13), other factors are required. There is a panoply of prognostic factors for breast cancer. Many of them are directly (e.g. cell cycle regulators4) or indirectly (e.g.
