Association of cancer and anti-synthetase syndrome: a retrospective multicentre study.

Abstract

Objectives: We aimed to assess the incidence of cancer associated myositis among patients with anti-synthetase syndrome, identify factors associated with cancer associated myositis, and its impact on prognosis.

Methods: We conducted a retrospective multicentre study, including adult patients with anti-synthetase syndrome. Factors associated with cancer were assessed using a multivariable logistic regression model. Unsupervised analysis was used to identify a cluster of patients associated with cancer. Cox proportional hazard ratio model was used to assess impact of cancer associated myositis on mortality.

Results: Among the 122 patients included, 14 (11.4%) met cancer associated myositis criteria. Standardised incidence ratio was 5.4 (5.14 to 5.65, p < 0.0001). Patients with cancer associated myositis were older, had more often a history of cancer, had lower creatine kinase (CK) level and less muscular weakness. They had a significantly worse overall survival compared to those without (log-rank test χ² = 16.2, p < 0.0001)). Age and history of cancer were independently associated with cancer associated myositis. Patients with cancer associated myositis segregated within a cluster characterized by an older age, a milder muscular involvement, and less Jo-1 antibodies. Finally, cancer associated myositis was an independent predictor of death.

Conclusion: Cancer associated myositis is not rare in anti-synthetase syndrome with higher incidence compared to general population. Due to its higher mortality, cancer should be carefully screened, especially in older patients with history of cancer.