In this analysis, Shah and colleagues examined a cohort of 1044 patients with scleroderma to identify factors that were associated with the presence of cancer and with a short cancer/scleroderma interval (±2 years) to provide insight on temporality. Among these participants, 168 (16.1%) had a diagnosis of cancer; the most prevalent types were breast (29.8%), skin including nonmelanoma (24.4%), lymphoma (7.7%), and lung (7.1%). Other cancers occurring in < 5% of participants were prostate, thyroid, colon, endometrial, and ovarian cancer.
In multivariable logistic regression, the clinical characteristics significantly associated with a diagnosis of cancer were age in years at onset of scleroderma (odds ratio [OR], 1.04; 95% confidence interval [CI], 1.02-1.05) and white race (OR, 2.71; 95% CI, 1.22-6.04). Autoantibody status, gender, smoking status, and cutaneous subtype of disease were not significantly associated with a diagnosis of cancer. In multivariable logistic regression evaluating predictors of a short cancer/scleroderma interval, anti-RNA polymerase III positivity (OR, 5.08; 95% CI, 1.60-16.1) and age in years at scleroderma onset (OR, 1.04; 95% CI, 1.00-1.08) were statistically significant.
Anticentromere positivity, anti-topoisomerase I positivity, white race, gender, smoking status, and cutaneous subtype of disease were not significantly associated with a short cancer/scleroderma interval. Furthermore, when the cancer/scleroderma interval was evaluated as a continuous variable, older age at scleroderma onset was significantly correlated with a shorter cancer/scleroderma interval, especially in participants who were positive for anti-topoisomerase I.
The authors concluded that increased age at scleroderma onset was strongly associated with cancer risk. In addition, anti-RNA polymerase III status was an independent predictor of a short cancer/scleroderma interval at any age, but particularly in patients with older age at scleroderma onset.
There is a growing awareness of the relationship between scleroderma and cancer, and these results provide clinicians with some insight as to which patients with scleroderma may be at higher risk for cancer. Although informative, these findings raise many questions, including what specific age at onset of scleroderma should trigger a vigorous evaluation for cancer, what particular autoantibodies should be assessed to understand cancer risk, and whether there is a type of scleroderma in which we don’t need to be concerned about cancer. To help address these questions, future research is needed, but it will certainly be useful to see the findings from this study replicated.
In addition, given the wide range of cancers seen in these patients, we will need further guidance as to what specific cancer evaluations to perform. In particular, will age-appropriate cancer screening be enough, or will special evaluations be needed? Despite the rarity of scleroderma, cancer risk is an important area of future research, along with the other critical issues, such as disease involvement of the skin, lungs, and gastrointestinal tract.