Fig. 1: Risk stratification and frequency of screening for IIM-related cancer.
The recommendations apply only to adult patients diagnosed with idiopathic inflammatory myopathy (IIM) within the 3-year period after IIM symptom onset. Individual patients with adult-onset IIM can be risk-stratified according to IIM subtype, myositis-specific antibody (MSA) and myositis-associated autoantibody (MAA) profile and clinical features, resulting in assignment to categories of ‘high’, ‘moderate’ or ‘standard’ risk of IIM-associated cancer. Screening modalities and frequency are recommended according to the assigned risk category. ‘Basic’ and ‘enhanced’ screening panels are outlined in the figure. Additional screening with 18F-fluoro-deoxy-glucose PET–CT (18F-FDG PET–CT) should be considered for patients with adult-onset IIM who are considered at a ‘high risk of IIM-related cancer’ where underlying cancer has not been detected by investigations at the time of IIM diagnosis or as a single screening investigation for patients with anti-TIF1γ antibody-positive dermatomyositis with disease onset at age >40 years and with ≥1 additional ‘high risk’ clinical feature. Clinicians should consider carrying out upper and lower gastrointestinal endoscopy for patients with adult-onset IIM at ‘a high risk of IIM-related cancer’, where underlying cancer has not been detected by investigations at the time of IIM diagnosis, and nasoendoscopy at the time of diagnosis of adult-onset IIM in geographical regions where the risk of nasopharyngeal carcinoma is increased. Screening for IIM-associated cancer is not routinely required for patients with juvenile-onset IIM or verified inclusion body myositis. ASSD, anti-synthetase syndrome; CADM, clinically amyopathic dermatomyositis; HMGCR, 3-hydroxy 3-methylutaryl coenzyme A reductase; IBM, inclusion body myositis; IMNM, immune-mediated necrotizing myopathy; MDA5, melanoma differentiation-associated gene 5; NXP2, nuclear matrix protein 2; RNP, ribonucleoprotein; SAE1, small ubiquitin-like modifier-1 activating enzyme; SRP, signal recognition particle; TIF1γ, transcription intermediary factor 1γ. aAnti-PM-Scl, anti-Ku, anti-RNP, anti-SSA/Ro, anti-SSB/La antibodies. bIf not already part of country/region-specific age- and sex-appropriate cancer screening programmes. Adapted with permission from41.
