title: The incidence and associations of malignancy in a large cohort of patients with biopsy-determined idiopathic inflammatory myositis.
abstract: The South Australian (SA) myositis database has registered all patients with biopsy-proven inflammatory myositis in SA from 1980 to 2009. We determined the incidence and associations of malignancy in myositis by linking this database with the SA cancer registry. Standardized incidence ratios (SIR) for malignancy were determined using the total SA population over the same time period, stratified by age and gender. The SIR for cancer in the myositis population (n = 373) was 1.39, p = 0.047. There was a trend towards an increased SIR in dermatomyositis but no increased risk of malignancy in polymyositis or inclusion body myositis. Malignancies of the lung and prostate were the commonest and 28 % of malignancies occurred within one year of IIM diagnosis. The odds of developing cancer were significantly raised in the presence of a shawl sign, male gender, and in patients with overlap syndrome or rheumatoid arthritis whilst myalgia was a significant protective factor. HLA-A28 allele was overrepresented in patients with malignancy (11 vs 2 %, p = 0.006). Patients in SA with myositis are at modestly increased risk for malignancy. We report clinical and genetic risk factors allowing the identification of patients at greatest risk for malignancy.
authors: Department of Rheumatology, Royal Adelaide Hospital, North Terrace, Adelaide, SA 5000, Australia. Vidya.limaye@health.sa.gov.au
authors: Vidya
authors: V
authors: Limaye
authors: Colin
authors: C
authors: Luke
authors: Graeme
authors: G
authors: Tucker
authors: Catherine
authors: C
authors: Hill
authors: Susan
authors: S
authors: Lester
authors: Peter
authors: P
authors: Blumbergs
authors: Peter
authors: P
authors: Roberts-Thomson
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D015897:Comorbidity; D016208:Databases, Factual; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009220:Myositis / Q000453:epidemiology* / Q000235:genetics; D009369:Neoplasms / Q000453:epidemiology* / Q000235:genetics; D012042:Registries; D012306:Risk; D012737:Sex Factors; D013021:South Australia / Q000453:epidemiology