Background Psoriatic Arthritis (PsA) is a chronic, autoimmune, systemic inflammatory joint disease affecting 10%>35% of patients with psoriasis and 0.3%>1% of the general population. Rheumatic diseases have been associated with an increased prevalence of malignancy (1,2); the risk of developing malignancy significantly increases with disease severity and progression or possibly the treatment with immunosuppressive medications. There is a paucity of data on the prevalence of pre-cancerous and cancerous lesions in patients with PsA and their association with disease severity and treatment.
Objectives The aim of this analysis was to compare the prevalence of different types of malignancy in patients with Early and Established PsA, defined as <2 years and ≥2 years from diagnosis, respectively.
Methods Patients were recruited prospectively from a rheumatology clinic specializing in treating patients with PsA. Disease severity was assessed using CRP, ESR, DAS28, PASQ, and the PASI scores. The association of the treatment modalities with the prevalence of cancers was also analyzed.
Results A total of 84 patients with Early PsA and 112 patients with Established PsA were included in this analysis with mean (SD) duration of PsA of 1.0 (0.8) and 5.6 (9.2) years, respectively (P<0.001). Mean age (48.0 vs. 49.7 years in Early vs. Established PsA; P=0.274) and gender distribution (52.4% vs. 48.2% females, respectively; P=0.665) were comparable in the two cohorts. However, patients in the Established cohort were significantly younger at the onset of Psoriasis (38.7 vs. 34.1 years, respectively; P=0.030) and at the onset of Psoriatic Arthritis (47.9 vs. 44.3 years, respectively; P=0.037).
Among the 196 patients included in the analysis, 19 (9.7%) had a malignancy, of whom 14 (12.5% of patients) belonged to the Established cohort and 5 (6.0% of patients) belonged to the Early cohort (odds ratio - OR (95% CI) in Established vs. Early PsA =1.70 (0.79, 3.66); P=0.148). Three patients had two malignancies. The most frequently observed cancers were cervical (OR (95%CI) =6.4 (0.8, 52.1) in Established vs. Early PsA; P=0.083), bowel and lung (OR (95%CI) =0.24 (0.03, 2.38) in Established vs. Early PsA; P=0.225) cancer, occurring in 9 (4.6%), 4 (2.0%), and 4 (2.0%) of the patients, respectively. Backward selection multivariate logistic regression adjusting for the age of diagnosis of PSO showed that the incidence of malignancy was significantly different between the two cohorts (OR (95%CI) =3.3 (1.06, 10.0) in Established vs. Early PsA; P=0.039). Baseline age, DAS28, PASI, or duration of PsA symptoms, as well as age of diagnosis of PsA were not significantly associated with cancer incidence and were, therefore, not maintained in the model. Finally, no treatment type was significantly associated with an increased rate of malignancy.
Conclusions Overall, an increased prevalence rate of malignancies was observed in patients with Established vs. Early PsA. Given the cross-sectional nature of the study, no causal inference can be made. Further studies are required to determine the significance of this finding.
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Disclosure of Interest None Declared