Anti-synthetase syndrome linked to cancer-related myositis

Patients with anti-synthetase syndrome show a higher incidence of cancer-related myositis than the general population, suggests a study.

“Due to its higher mortality, cancer should be carefully screened, especially in older patients with history of cancer,” said the authors, who assessed the incidence of cancer-associated myositis among those with anti-synthetase syndrome, identified factors related to cancer-associated myositis, and examined its impact on prognosis.

This retrospective multicentre study included 122 adult patients with anti-synthetase syndrome and assessed factors associated with cancer using a multivariable logistic regression model. They also performed an unsupervised analysis to identify a cluster of patients associated with cancer and used a Cox model to assess the impact of cancer-associated myositis on mortality.

Of the 122 patients included, 14 (11.4 percent) met the criteria for cancer-related myositis, with a standardized incidence ratio of 5.4 (p<0.000). Those with myositis tended to be older, more often had a history of cancer, and had lower creatine kinase level and less muscular weakness.

Cancer-associated myositis contributed to a significantly worse overall survival (log-rank test χ² = 16.2; p<0.0001) and was independently associated with age and history of cancer.

“Patients with cancer-associated myositis segregated within a cluster characterized by an older age, a milder muscular involvement, and less Jo-1 antibodies,” the authors said. “Finally, cancer-associated myositis was an independent predictor of death.”