Revisiting the link between oropharyngeal dysphagia and cancer in autoimmune myositis: a descriptive study

Objectives: To explore the link between moderate to severe oropharyngeal dysphagia and cancer in autoimmune myositis (AIM) other than inclusion body myositis (IBM). Methods: The medical records of patients with AIM seen in rheumatology in two university hospitals from January 2000 to December 2022 were retrospectively reviewed. Using an updated AIM subclassification, patients were classified by expert opinion as pure dermatomyositis (DM), immune-mediated necrotizing myopathy (IMNM), scleromyositis, lupomyositis, anti-MDA-5 syndrome, antisynthetase syndrome (ASyS) or polymyositis syndrome. Objective oropharyngeal dysphagia at myositis diagnosis was defined by an abnormal videofluoroscopic swallowing study and/or the need for percutaneous gastrojejunostomy. The presence of cancer within 3 years of myositis diagnosis was recorded. Results: Pure DM accounted for 50% (n = 20/40) of the cases of objective oropharyngeal dysphagia, while anti-MDA-5 syndrome and ASyS together represented 8% (n = 3/40). Cancers occurred predominantly in pure DM (n = 27/33), and rarely in scleromyositis (n = 1/53), anti-MDA-5 syndrome and ASyS (n = 0/62). Among patients 50 years of age or older with pure DM (n = 50), cancer was present in 40% (n = 4/10) of patients with no muscle weakness, 45% (n = 10/22) in those with proximal weakness alone, 44% (n = 4/9) in those with moderate dysphagia and 100% of those with severe dysphagia (n = 9/9) (p = 0.02 by two-sided Fisher’s exact test). Conclusion: Recognizing scleromyositis, anti-MDA-5 and ASyS as distinct from pure DM improves risk stratification for cancer screening. In patients ≥ 50 years with pure DM, severe oropharyngeal dysphagia is strongly associated with cancer, suggesting a paraneoplastic myopathy with an ineffective anticancer immune response.