| Abstract: | ![]()
Polymyositis and dermatomyositis (PM/DM) have been associated with cancer, although the long-term risks are poorly understood. To evaluate the risk of cancer by time periods subsequent to PM/DM diagnosis, a cohort of 539 patients hospitalized with PM/DM in Denmark between 1977 and 1989 was identified from the Danish Central Hospital Discharge Register. Cancer incidence among cohort members was ascertained by linkage to the Danish Cancer Registry using a unique personal-identification number. The overall cancer risk was elevated significantly among patients with DM (standardized incidence ratio [SIR]=3.8, 95 percent confidence interval [CI]=2.6–5.4) and to a lesser extent PM (SIR=1.7, CI=1.1–2.4). Significant excesses were observed for cancers of lung, ovary, and lymphatic and hematopoietic system. However, the excess cancer incidence declined steadily with increasing years since initial diagnosis of PM/DM. The cancer risk was increased about sixfold (SIR=5.9, CI=3.8–8.7) during the first year, but was lower during the second year (SIR=2.5, CI=1.1–4.8), with no significant excesses in subsequent years of follow-up. These findings confirm that PM/DM may occur as a paraneoplastic syndrome that calls for steps aimed at early cancer detection and treatment. Among long-term survivors of PM/DM, however, there is little evidence to warrant extensive preventive and screening measures beyond those recommended for the general population.Drs Chow, McLaughlin, and Fraumeni, and Ms Gridley are with the Epidemiology and Biostatistics Program, Division of Cancer Etiology, National Cancer Institute, Bethesda, MD, USA. Dr McLaughlin is currently with the International Epidemiology Institute, Rockville, MD. Ms Mellemkjær and Dr Olsen are with the Division for Cancer Epidemiology, Danish Cancer Society, Copenhagen, Denmark. Address correspondence to Dr Chow, National Cancer Institute 6130 Executive Blvd, EPN/415, Rockville, MD 20852, USA. |
