Background: Antineutrophil cytoplasmic antibody-associated vasculitis (AAV) is a group of systemic necrotizing small vessel vasculitides. Microscopic polyangiitis (MPA) and granulomatosis with polyangiitis (GPA) are two most common types of AAV affecting mainly middle-aged and elderly people. Previous data indicated an increased occurrence of cancer in AAV patients [1], which has been mainly attributed to exposure to cyclophosphamide [2].

Objectives: The purpose of this paper was to analyze cancer incidence in unselected patients with GPA and MPA treated in one academic center since 1988 with follow-up until 2020.

Methods: With case record review, the baseline characteristics, outcomes and malignancy development in a cohort of 251 patients were assessed. Patients were followed up from time of diagnosis to their death or most recent hospital or outpatient’s assessment.

Results: Twenty-eight of 251 patients with AAV (65 % cANCA, 26% pANCA, 9.0 % ANCA-negative) developed a total of 32 malignancies during a mean follow-up of 8.6 years. Patients characteristic is presented in table 1 . Mean time since AAV onset to cancer diagnosis was 5.86±6.78 years. Of these malignancies, 2 melanoma, 6 were non-melanoma skin cancers, 4 gastrointestinal tract cancer (2 colon, 1 stomach, 1 liver), 3 bladder cancer, 2 breast cancer, 2 uterine cancer, 1 ovarian cancer, 2 prostate cancer, 1 testis cancer, 2 lung cancer, 6 haematological malignancies (1 lymphoma, 1 chronic myeloid leukemia, 4 monoclonal gammopathy of unknown significance), additionally 1 benign salivary gland tumor was found. Four of the 16 patients with renal transplants developed a total of 6 malignancies. There were no differences in the incidence of cancer by gender, age, severity and activity of the disease, ANCA status, smoking status, number of relapses and treatment. There was no association between cancer and cumulative dose of cyclophosphamide.

Conclusion: In the AAV group, 11% of patients developed different type of cancer. The most common was non-melanoma skin cancer. The risk of developing malignancy increased with follow-up time. We found no association of tumor development and cumulative cyclophosphamide dose.

REFERENCES:

[1]Rahmattulla et al. Incidence of malignancies in patients with antineutrophil cytoplasmic antibody-associated vasculitis diagnosed between 1991 and 2013. Arthritis Rheum. 2015;67(12):3270–3278.

[2]Faurschou M et al. Prolonged risk of specific malignancies following cyclophosphamide therapy among patients with granulomatosis with polyangiitis. Rheumatology (Oxford) 2015; 54:1345–1350.

Disclosure of Interests: None declared