Clinical epidemiology and the impact of co-morbidity on survival
Breast cancer will increasingly affect the lives of older women, especially in developed countries. In the last three decades, women of all age groups have experienced the benefits of a lowering mortality rate though earlier diagnosis and effective treatment. These benefits have been counteracted by the rising incidence, resulting from higher levels of exposure to risk factors and possibly also from the increased detection of occult, non lethal invasive breast cancers. At the same time, demographics are characterized by a large increase in the elderly population, which will become even more pronounced during the next decades. The most remarkable increase in the absolute number of newly diagnosed breast cancer patients and long-term survivors (at risk for recurrent disease or second breast cancers) will thus exhibit among the higher age groups, the prevalence doubling from 3.5% in 2000 to 7% in 2015 in the Netherlands (Poll-Franse et al. 2004). Being confronted with these rising numbers of patients or anticipating them, many doctors and clinical researchers have taken a special interest in the study of breast cancer in older women (Bouchardy et al. 2007), as is reflected by the increasing number of papers with a special focus on this group.