Breast cancer stage at time of detection in women with systemic lupus erythematosus

Mounting evidence suggests an increased cancer risk in several autoimmune diseases, including systemic lupus erythematosus (SLE). However, greater scrutiny for cancer in subjects with chronic disease (compared to the general population) might explain this apparent association. If so, one would expect cancers in SLE to be diagnosed at earlier stages than in the general population. This might be particularly evident in cancers where screening is available, such as breast cancer. We linked the University of Pittsburgh lupus cohort with the Pennsylvania Cancer Registry to determine the frequency distribution for stage at diagnosis of invasive breast cancers in the SLE subjects. Data on staging of cancers occurring in the general population of Pennsylvania were obtained from The US Surveillance, Epidemiology, and End Results (SEER) Program of the National Cancer Institute. A lower percentage of women with SLE presented with localized breast cancer (nine of the 16, 56.2%) compared to the general population of women (63.5%). Although not definitive, this evidence suggests that cancers in SLE are not necessarily diagnosed at earlier stages than in the general population.