Background/Purpose: Anti-synthetase syndrome (ASyS) is a rare, heterogeneous inflammatory myopathy characterized by presence of anti-aminoacyl transfer RNA synthetase autoantibodies with multisystem disease manifestations including myositis, inflammatory arthritis, and “mechanic’s hands” rash.1 Other forms of idiopathic inflammatory myopathy, mainly dermatomyositis, are associated with increased risk of malignancy.2 Although ASyS has been presumed to have low associated malignancy risk, reports of malignancy have been presented.3 The goal of this study was to describe the incidence and types of malignancy in a cohort of ASyS patients.

Methods: A retrospective observational study was conducted by reviewing medical records of adults diagnosed with ASyS across 3 sites at the same institution. Charts were reviewed to identify whether malignancy of any type was diagnosed around the time of ASyS diagnosis defined as up to 5 years before or after. Demographic, clinical, radiologic, and immunologic data, including ILD patterns and myositis-specific antibodies, were collected and descriptive statistics were performed. Incidence rates per person-years are calculated for three intervals: 5 years before, 5 years after, and 5 years before and after ASyS diagnosis.

Results: A total of 236 patients diagnosed with ASyS were identified with 40 (17%) receiving a diagnosis of malignancy within 5 years of ASyS diagnosis. Of these, 18 (45%) and 22 (55%) occurred before and after ASyS diagnosis, respectively. Demographics, disease characteristics, potential malignancy risk factors, and trialed therapies of the identified cohort with concurrent malignancy are outlined in Table 1. The incidence of malignancy was 1.8 per 100 person-years, slightly higher post-ASyS diagnosis (2.03/100 person-years) than pre-ASyS diagnosis (1.57/100 person-years) (Table 2). The most common category of malignancy was solid tumors (47.5%) followed by skin cancer (42.5%). The most common individual cancer type was squamous cell carcinoma (20%), followed by basal cell carcinoma (12.5%), of the skin. Identified malignancies and their frequencies are shown in Table 3.

Conclusion: Malignancy was seen in 17% of ASyS within a period of 5 years prior to and 5 years after diagnosis of their rheumatic disease with incidence 1.8 cases per 100 person-years. Comparison to rates in the general population and further elucidation of disease and treatment characteristics associated with risk of malignancy is warranted. Mahler M, Miller FW, Fritzler MJ. Idiopathic inflammatory myopathies and the anti-synthetase syndrome: a comprehensive review. Autoimmun Rev. 2014;13(4-5):367-371.Olazagasti JM, Baez PJ, Wetter DA, Ernste FC. Cancer risk in dermatomyositis: a meta-analysis of cohort studies. Am J Clin Dermatol. 2015; 16:89-98. Rozelle A, Trieu S, Chung L. Malignancy in the setting of the anti-synthetase syndrome. J Clin Rheumatol. 2008;14(5):285-288.

Characteristics of patients diagnosed with malignancy within 5 years of anti-synthetase syndrome diagnosis

Incidence rates of malignancy in anti-synthetase syndrome (5 years before diagnosis, 5 years after diagnosis, and 5 years before and after diagnosis)

Malignancy categories and types in the cohort of patients with anti-synthetase syndrome diagnosed with malignancy within 5 years of anti-synthetase diagnosis

« Back to ACR Convergence 2025

ACR Meeting Abstracts - https://acrabstracts.org/abstract/exploring-malignancy-in-anti-synthetase-syndrome-a-multisite-retrospective-study/