Malignancy is increased in ANCA-associated vasculitis

OBJECTIVE: In the light of previous reports of an association between malignancy and renal vasculitis, we aimed to investigate the association of malignancy in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis, either Wegener's granulomatosis (WG) or microscopic polyangiitis (MPA), and compare it with the general population and disease control groups comprising patients with systemic lupus erythematosus (SLE) or Henoch-Schonlein purpura (HSP). METHODS: A retrospective review of 200 consecutive patients with WG or MPA was performed. Malignancies preceding or concurrent with vasculitis were recorded and the incidence of malignancy was compared with those in a population of 129 patients with HSP, 333 patients with SLE and a normal population in the West Midlands of the UK. RESULTS: Twenty patients had a diagnosis of malignancy, 14 had MPA and six had WG. Patients with ANCA-associated vasculitis had an increased risk of malignancy compared with HSP patients, of whom six patients had malignancy (relative risk 0.85, confidence interval 0.69-1.05; P = 0.034), or SLE patients, of whom five patients had malignancy (relative risk 0.31, 95% confidence interval 0.14-0.7; P<0.0001). The rate of malignancy compared with an age-matched control group was increased in patients with ANCA-associated vasculitis and HSP (ANCA-associated vasculitis, relative risk 6.02, 95% confidence interval 3.72-9.74; HSP, relative risk 5.25, 95% confidence interval 2.4-11.5). The presence of ANCA was not predictive of malignancy. CONCLUSION: In conclusion, patients with ANCA-associated vasculitis have an increased risk of preceding or concurrent malignancy.