Clinicopathological prognostic characteristics and long‑term outcomes of patients with breast cancer and collagen disorder in comparison to those without collagen disorder.

Collagen disorders are chronic autoimmune diseases with a complex clinical course; however, the risk of breast cancer in patients with collagen disorders remains unclear. The present study aimed to investigate long-term outcomes in women with breast cancer and collagen disorders. A total of 25 patients with breast cancer and collagen disorders who were treated between January 2004 and December 2011 were included. The clinicopathological factors, treatment, recurrence-free survival (RFS) and overall survival (OS) were reviewed. The mean age was 56.4±12.6 years, and 14, eight and three patients had cancer of clinical stages I, II and III, respectively. Regarding comorbid collagen disorders, 11 patients had rheumatoid arthritis, four had systemic lupus erythematosus, four had polymyositis/dermatomyositis, two had mixed connective tissue disease, two had Sjogren's syndrome, one had scleroderma and one had adult-onset Still's disease. The expression statuses of hormone receptors (HR) and human epidermal growth factor receptor 2 (HER2) were HR(+), HER2(+) and HR(-)HER2(-) in 20 (80.0%), four (16.0%) and four (16.0%) patients, respectively. A total of 22 (84.0%) patients received steroids or immunosuppressive drugs for collagen disorders. The collagen disorder group had a higher mean Ki-67 labeling index than the control group (41.1 vs. 20.8%; P=0.007). After median observation periods of 103 and 114 months, the RFS and OS rates were lower in the collagen group than in the control group (64.5 and 80.7% vs. 85.3 and 94.3%, respectively; P<0.01). Patients with breast cancer and collagen disorders had relatively high Ki-67 expression, and relatively low RFS and OS rates. Thorough follow-up is necessary for patients with breast cancer who also have collagen disorders and high Ki-67 values.