Prevalence of comorbidity at breast cancer diagnosis increases with age and is likely to influence the likelihood of receiving treatment according to guidelines. The aim of this study was to examine the effect of breast cancer treatment on mortality, taking age at diagnosis and comorbidity into account.
Land, L. H., Dalton, S. O., Jensen, M-B., & Ewertz, M. (2012). Influence of comorbidity on the effect of adjuvant treatment and age in patients with early-stage breast cancer. B J C, 107(11), 1901-7. https://doi.org/10.1038/bjc.2012.472