The cancer risk according to three subtypes of ANCA-associated vasculitis: A propensity score-matched analysis of a nationwide study

It remains unknown whether cancer risk differs among the three subtypes of anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV) and what the cancer risk factors are. We conducted a nationwide study in Korea to evaluate the risk of cancer in patients with AAV and to identify the risk factors for cancer.We analyzed the Health Insurance Review and Assessment database of Korea and identified 1982 patients diagnosed with AAV between January 1, 2007 and December 31, 2017. The patients and controls with no history of AAV or cancer were matched 1:4 by propensity scores. The study outcome measure was incidence of cancer during 11 years of follow-up.Patients with granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), and eosinophilic granulomatosis with polyangiitis (EGPA) numbered 684, 606, and 692, respectively. The overall incidence of cancer was higher among patients with AAV than in controls (HR 1.32, 95% CI 1.08-1.61). The risk of hematological malignancy, lung cancer, and bladder cancer in the GPA group, lung cancer in the MPA group, and hematological malignancy in the EGPA group were significantly higher than in controls (HR 7.39, 3.20, 4.20, 2.86, and 4.65, respectively). Age, male sex, GPA subtype, and cyclophosphamide use were significantly associated with cancer risk in patients with AAV.Overall cancer incidence was increased in patients with AAV. Cancer risk was higher in patients with GPA than in those with MPA or EGPA. The use of cyclophosphamide was associated with an increased risk of cancer, while rituximab was not.