Risk of cancer in patients with dermatomyositis or polymyositis, and follow-up implications: a Scottish population-based cohort study

We conducted a national, retrospective population-based cohort study of 705 patients hospitalized with a first diagnosis of dermatomyositis (DM) or po lymyositis (PM) during 1982-1996 based on linkage of hospital discharge, ca ncer registration, and death records in Scotland. Risks of cancer were asse ssed by calculating standardized incidence ratios (SIR). A first malignancy was diagnosed concurrently or subsequently in 50 patients with DM (SIR 7.7 , 95% CI 5.7-10.1), and 40 patients with PM (2.1, 1.5-2.9). Significantly e levated risks were observed for lung, cervix uteri, and ovarian cancer in p atients with DM, and for Hodgkin's disease in patients with PM. The excess risk of cancer was highest around the time of diagnosis, and for patients w ith DM remained high for at least 2 years. Risks were elevated for both sex es but only significantly so for females. and were highest in patients aged 45-74 years at the time of diagnosis for DM and 15-44 for PM. (C) 2001 Can cer Research Campaign http://www.bjcancer.com.