Clinical and immunological features of patients with cancer-associated systemic sclerosis: An observational study

Clinical and immunological features of patients with cancer-associated systemic sclerosis: an observational study.

Several studies have reported an increased incidence of cancer in patients with systemic sclerosis (SSc). The presence of RNA polymerase III antibodies (anti-RNA Pol 3) associates with an increased risk of cancer, but other risk factors need yet to be identified. We aimed to assess clinical and immunological predictive factors of cancer-associated SSc to guide clinicians when setting up selective cancer screening.

We conducted a monocentric, retrospective, observational study of SSc patients with and without associated malignancy. Clinical, laboratory and imaging data were collected, as well as SSc treatment. Subgroup analyses were performed according to the type of cancer and the time of diagnosis.

Of 464 SSc patients, 74 (16%) had cancer, with breast (n=26) and lung cancer (n=13) being the most frequent. Diagnosis of cancer was made less than 3 years before or after SSc diagnosis for 23 patients (31%). In a multivariate analysis, anti-RNA Pol 3 and anti-SSA antibodies were significantly associated with an increased overall risk of cancer with an odds ratio (OR) of 4.12 (95% CI [1.6-10.7]; P<0.01) and 2.43 (95% CI [1.1-5.4]; P<0.05), respectively. Age at diagnosis of SSc and delay from the SSc diagnosis were also independent risk factors of cancer. Interstitial lung disease and anti-topoisomerase antibodies were associated with an increased risk of lung cancer and cancer occuring more than three years after SSc diagnosis.

In addition to anti-RNA Pol 3 antibodies, anti-SSA antibodies associated with an increased risk of cancer in SSc patients. Interstitial lung disease was a risk factor specifically for lung cancer and cancers diagnosed more than 3 years after SSc diagnosis. For these patients, a systematic and regular cancer screening should be considered.