- Objective. To determine whether the frequency of cancer is increased among patients with systemic sclerosis (SSc). Methods. A retrospective chart review of 248 patients who were followed up prospectively was conducted. Results. Cancers developed in 18 patients (7.3%) during 2,001 patient-years at risk. The most frequent types were cancers of the lung (7 patients) and breast (5 patients). Older age at diagnosis of SSc was a significant risk factor for cancer. Lung cancer was associated with the presence of pulmonary fibrosis. The age-standardized incidence rate for all cancers (7.9/1,000) was 2.1 times the overall rate in the Ontario population (P > 0.0001). Conclusion. The frequency of cancer is increased in patients with SSc.