(ChemotherapyAdvisor) – Patients with autoimmune (AI) diseases face elevated risks of kidney, bladder and prostate cancer; in addition, overall survival (OS) among these cancer patients might be worse than among cancer patients without a history of autoimmune disease, according to a study published in The Journal of Urology.

“The overall risks of urological cancers were increased after AI diseases,” reported lead author Xiangdong Liu, MD, of the Center for Primary Health Care Research at Lund University, in Mamö, Sweden, and coauthors.  Cancer-specific survival rates were “reassuring that AI diseases may not influence (cancer) prognosis,” Dr. Liu and coauthors reported. But overall survival was decreased for all three cancers for patients with prior AI diagnoses, possibly implying “survival disadvantage due to comorbidity.”

The authors analyzed urological cancer risks among patients with any of 33 different autoimmune diseases, using data from the Swedish National Hospital Discharge Register and Swedish Cancer Registry. In all, data for 402,462 patients diagnosed with autoimmune diseases were included in the study.

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Associations between AI and subsequent urological cancers were complex. Elevated risks (calculated as standardized incidence ratios [SIRs]) for urological cancers in general were noted among patients diagnosed with 26 AIs; the overall association between AIs and subsequent urological cancer, however, was modest, representing a 9% increase (SIR 1.09; 95% CI: 1.06-1.13).

However, elevated hazard ratios (HRs) for cancer-specific survival were found for four autoimmune diseases, and increased HRs for OS were associated with prior diagnosis of 18 of the 33 studied autoimmune diseases. Multiple sclerosis was the only autoimmune disease for which overall urological cancer risk was lower (SIR 0.73; 95% CI: 0.58-0.90) than among controls. However, cancer-specific risks were higher for some autoimmune disorders, the authors noted.

Autoimmune polyarteritis nodosa was associated with elevated risks (SIRs) for kidney cancer (SIR 2.85; 95% CI: 1.22-5.64) and prostate cancer (SIR 1.70; 95% CI: 1.18-2.36). Polymyositis/dermatomyositis diagnoses were associated with elevated risks of kidney cancer (SIR 2.68; 95% CI: 1.33-4.80) and bladder cancer (SIR 2.45; 95% CI: 1.45-3.89), the authors noted. Both disorders are idiopathic inflammatory autoimmune diseases. Cancer risks were also significantly increased following Wegener granulomatosis (SIR 1.40; 95% CI: 1.23-1.59) and pernicious anemia (SIR 1.31; 95% CI: 1.13-1.50), they reported.

The overall risk of bladder cancer following an autoimmune disease diagnosis was SIR 1.21 (95% CI: 1.15-1.27). Other specific autoimmune diseases that increased bladder cancer risk included lupus, rheumatoid arthritis and Graves disease.

Patients diagnosed with prostate cancer after any autoimmune disease had better cancer-specific survival than controls (HR 0.88; 95% CI: 0.83-0.94) but worse OS (HR 1.14; 95% CI: 1.09-1.18), the authors reported.