Dermatomyositis and cancer are significantly associated

A French multicentre retrospective study of 73 patients with cancer-associated dermatomyositis, followed for an average of 3.92 years, involving experts from the Institute of Myology, showed that :

  • 82.2% had classic dermatomyositis, 8.2% had amyopathic dermatomyositis and 9.6% had hypomyopathic dermatomyositis;
  • 76.7% had been diagnosed with cancer in the year preceding or following the onset of dermatomyositis;
  • 20.6% had been diagnosed with cancer an average of 13.1 months before the onset of dermatomyositis, with a worsening or relapse of the cancer at the time of diagnosis of dermatomyositis for 11 of them;
  • 21.9% had a diagnosis of dermatomyositis on average 12 months before cancer, with an aggravation or relapse of dermatomyositis at the time of diagnosis of cancer for 7 of them;
  • 57.5% had a concomitant diagnosis of cancer and dermatomyositis (including 81% with asymptomatic cancer);
  • 54.8% had experienced remission of their cancer, with clinical remission of their dermatomyositis complete in 70% of cases.

The risk of mortality was associated with having an active cancer, being male or older, but not with having active dermatomyositis. Oral corticosteroids appear to have a protective effect.

This study reinforces the need for a systematic search for cancer in cases of dermatomyositis.

 

Prognostic factors for patients with cancer-associated dermatomyositis: a retrospective, multicenter cohort study of 73 patients. Teboul A, Allenbach Y, Tubach F et al. Rheumatology (Oxford). 2024 Nov 26:keae629.