title: Polymyositis and dermatomyositis associated with malignancy: a 30-year retrospective study.
abstract: BACKGROUND
  Polymyositis and dermatomyositis in association with malignancy are paraneoplastic syndromes, but the incidence, treatment and factors that predict associated cancer and its prognosis all remain unclear.
  
  
  METHODS
  During the 30-year period 1969-99, we treated 64 patients who had polymyositis (including two with cancer) and 28 patients who had dermatomyositis (including 10 with cancer). We compared the clinical findings of the patients who had cancer with the findings of those who did not have cancer.
  
  
  RESULTS
  The risk of cancer is significantly higher in dermatomyositis and somewhat higher in polymyositis. An increased cancer risk was found in male patients with dermatomyositis who were older than 50 years. Cancer was diagnosed within 4 years before or after the diagnosis of polymyositis or dermatomyositis, and usually within 1 year. An operation was not possible in many of the patients with cancer because of the advanced stage of the disease.
  
  
  CONCLUSIONS
  Our findings suggest that early discovery of malignancy is critical in cases of polymyositis and dermatomyositis.
authors.affiliation: Fourth Department of Internal Medicine, Toho University, School of Medicine, Tokyo, Japan. waka@oha.toho-u.ac.jp
authors.forename: Nobuo
authors.initials: N
authors.lastname: Wakata
authors.forename: Teruyuki
authors.initials: T
authors.lastname: Kurihara
authors.forename: Eizo
authors.initials: E
authors.lastname: Saito
authors.forename: Masao
authors.initials: M
authors.lastname: Kinoshita
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000704:Analysis of Variance; D001706:Biopsy; D002423:Cause of Death; D003882:Dermatomyositis / Q000150:complications / Q000453:epidemiology* / Q000628:therapy; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000150:complications / Q000453:epidemiology* / Q000628:therapy; D017285:Polymyositis / Q000150:complications / Q000453:epidemiology* / Q000628:therapy; D012189:Retrospective Studies; D018570:Risk Assessment; D012737:Sex Factors; D016019:Survival Analysis; D013997:Time Factors