Incidence of cancer among patients with systemic sclerosis in Korea: results from a single centre.

ABSTRACT

OBJECTIVE: The aim of this study was to determine whether the incidence of cancer has increased among patients with systemic sclerosis (SSc) in Korea. METHODS: The study subjects consisted of 112 patients who had been consecutively evaluated for at least 6 months between 1990 and 2007. We retrospectively reviewed their medical records, investigated the incidence rate of cancer and compared it with that of the Korea National Cancer Centre database. RESULTS: Nine out of 112 patients developed cancer (four males and five females). The average age at diagnosis of cancer was 56.4 years and the mean disease duration was 8.9 years. The standardized incidence ratio (SIR) for SSc patients was 4.2 [95% confidence interval (CI) 2.3-6.1], 3.7 for women (95% CI 1.2-6.2) and 6.4 for men (95% CI 1.6-11.2). Lung cancer was the most common cancer (n = 4), followed by oesophagus (n = 1), stomach (n = 1), liver (n = 1), pancreas (n = 1), and squamous cell carcinoma of unknown origin (n = 1). All patients who developed lung cancer were female and non-small cell carcinoma in origin. The SIR of lung cancer in female patients was 23.0 (95% CI 6.0-40.0). Two out of four lung cancer patients had concomitant interstitial lung disease (ILD); all were non-smokers. Treatment agents, autoantibodies, smoking, and lung involvement were not significantly different between SSc patients with or without cancer. CONCLUSION: The SIR of cancer was significantly higher in SSc patients, and especially in those who were male, than in the general population. Lung cancer was the most common cancer. Active surveillance for the detection of cancer should be performed in all SSc patients.