Malignancies in Italian Patients with Systemic Sclerosis Positive for Anti-RNA Polymerase III Antibodies

OBJECTIVE: To evaluate the frequency of malignancies in Italian patients with systemic sclerosis (SSc) and anti-RNA polymerase III (RNAP III), antitopoisomerase I (topo I), or anticentromere antibodies (ACA); and to characterize the temporal relationship between the 2 diseases, in order to confirm data suggesting a close temporal relationship between the onset of SSc and malignancy in American patients with anti-RNAP III antibodies. METHODS: From a cohort of 466 consecutive SSc patients, 360 Italians with isolated positivity for anti-RNAP III (n = 16), anti-topo I (n = 101), or ACA (n = 243) were identified. Malignancy cases were divided according to their relationship with SSc onset into 3 categories: preceding, synchronous with, or metachronous to the onset of SSc (diagnosed more than 6 months before; 6 months before to 12 months after; and more than 12 months after onset of SSc, respectively). RESULTS: Malignancies were more frequent in the anti-RNAP III group (7/16 patients), than in the anti-topo I (11/101) and ACA groups (21/243) (p < 0.001). This difference was accounted for by the number of patients with cancer synchronous to the onset of SSc (3/16 in the anti-RNAP III group vs 0/101 in the anti-topo I and 1/243 in the ACA group; p < 0.001), whereas neither the number of malignancies preceding nor those metachronous to the onset of SSc was significantly different between the groups. CONCLUSION: In a cohort of Italian patients with SSc we observed a significant association between malignancies synchronous to SSc onset and positivity for anti-RNAP III antibodies, similar to that described in American patients with SSc.