Increased incidence of carcinoma of the tongue in patients with systemic sclerosis.

OBJECTIVE: To describe the incidence of carcinoma of the tongue in a large cohort of patients with systemic sclerosis (SSc).

METHODS: In total, 769 patients with SSc were prospectively followed over 16 years for the development of cancer. Patients with a diagnosis of carcinoma of the tongue were identified to determine the incidence of this cancer in SSc. The results were compared to the incidence of tongue cancer in the SEER cancer registries.

RESULTS: A total of 3775 patient-years of followup of 769 patients with SSc (392 diffuse cutaneous, 377 limited cutaneous) prospectively evaluated for the occurrence of cancer disclosed 9 patients who were diagnosed with oral cavity and pharyngeal carcinomas. Six of these patients had squamous cell carcinoma of the tongue. One of these had both pharyngeal and tongue squamous cell carcinomas within a 4-year period, and another had 3 separate squamous cell carcinomas of the tongue. The standardized incidence ratio of squamous cell carcinoma of the tongue observed in this cohort of patients with SSc was 25-fold higher than that expected in an age adjusted population from the SEER cancer registries. All patients with SSc identified within this cohort with oral cavity carcinomas had the diffuse subset of the disease.

CONCLUSION: There is a highly significant increase in the incidence of squamous cell carcinoma of the tongue in patients with SSc. A remarkable observation was that all patients within this cohort who developed oral cancer had the diffuse subset of SSc. This suggests a relationship between the etiology or pathogenesis of the diffuse form of SSc and development of squamous cell carcinoma of the tongue in this group of patients.