POS0838 INCIDENCE OF CANCER IS SIGNIFICANTLY INCREASED IN EOSINOPHILIC GRANULOMATOSIS WITH POLYANGIITIS PATIENTS: RESULTS FROM A MULTICENTRE STUDY.

Abstract

BackgroundNo large assessment of the general cancer occurrence in eosinophilic granulomatosis with polyangiitis (EGPA) has been reported.ObjectivesThe aim is to investigate the incidence of malignancies in EGPA patients and to examine the effect of immunosuppressive therapy on malignancy risk in these patients.MethodsThe occurrence of cancers was assessed in a cohort of 303 incident EGPA patients (54.8% female, 44% MPO-ANCA positive, 53 [41-61] years old at diagnosis), diagnosed between 1987 and 2019. Demographic, clinical and laboratory data, and the use of immunosuppressive drugs were assessed. Through linkage with Regional Italian Cancer Registries, information about any malignancy occurring before and after EGPA diagnosis was collected. For each patient, the person-years (PY) of follow-up was calculated till the first event: cancer occurrence, last follow-up or death. The PY was stratified by sex, age (in 5-year groups) and calendar-decades (2000-2009 and 2010-2019). Standardized incidence ratios (SIR) between observed and expected numbers (retrieved from the AIRTUM-AIOM database) of cancers were calculated with exact Poisson regression analysis and used as a measure of risk difference.ResultsThirty patients developed a total of 42 malignancies during a median follow-up of 4.4 [2.1-8.5] years. After excluding patients with a diagnosis of cancer before EGPA onset, 20 first malignancies were observed in 1276 PY observation period. The SIR (95% Poisson CI) malignancy risk was 1.99 (1.22-3.08; p=0.007) for all cancers at all sites, and 1.86 (0.98-2.75; p= 0.025) for all cancers excluding non-melanoma skin cancers. Incidence rates were significantly higher in ANCA positive patients (SIR 2.43 [1.30-4.16]; p=0.007) when compared to ANCA negative, and in those treated with cyclophosphamide (SIR 2.42 [1.11-4.60]; p=0.030) when compared to other immunosuppressive agents. Median latency from EGPA onset and first cancer diagnosis was 5 (2-11) years, with 63.3% of patients developing cancer within 1 and 5 years. Malignancy-free survival at 2, 5, and 10 years of follow-up was 96%, 91%, and 70%, respectively. Of these malignancies, 30% were skin cancers, 25% prostate cancers and 20% breast cancers. Comparing patients who developed malignancies with those who did not, any significant difference was noted regarding sex, ANCA status, age at diagnosis, clinical manifestations, BVAS, FFS, environmental exposure, smoking habit and cancer familiarity. Type of treatment and cumulative doses of cyclophosphamide were not associated with higher incidence of cancers.ConclusionEGPA patients have a two-fold risk of overall malignancy than the general population. This cancer excess might be driven by a combination of already known treatment-associated factors and other unknown disease-associated factors, which should be further investigatedReferencesNAFigure 1.Disclosure of InterestsNone declared