Some research has shown that patients with certain autoimmune diseases have a lower risk of breast cancer, whereas others have demonstrated increased risk. But there is a paucity of research regarding outcomes in patients with both autoimmune disease and breast cancer. At the 2022 American Society of Clinical Oncology (ASCO) Annual Meeting, a group of researchers presented data regarding characteristics and outcomes in this population.
The researchers conducted a retrospective analysis of 137,324 patients with breast cancer included in SEER-Medicare data from 2007 to 2014. They evaluated whether the presence of autoimmune disease affected overall survival (OS) or cancer-specific survival (CSS), controlling for other characteristics such as age, race, and chronic kidney disease.
Overall, 26.69% of patients had documented autoimmune disease, mostly rheumatoid arthritis (23.35%), psoriasis (2.41%), and systemic lupus erythematosus (1.12%).
Patients with stage IV breast cancer and autoimmune disease had significantly better OS and CSS. Notably, patients with an autoimmune disease had a median OS of 36 months compared to 30 months in patients with no documented history of autoimmune disease. This remained true even after the researchers controlled for age, race, and kidney disease. However, patients with autoimmune disease and stage I-III breast cancer had lower OS compared to patients without autoimmune disease.
“These results suggest that that anti-tumor immunity plays an important role in late-stage breast cancer and could be potentially exploited to improve the effectiveness of immunotherapy,” wrote the authors, led by Demitrios Dedousis, of University Hospitals, Case Medical Center, and Cleveland VA Hospital in Ohio.