Prospective Study of Skin Cancer Development and Changes in Naevi in Psoriasis Patients Receiving Biologic Therapy

Patients with moderate to severe psoriasis require systemic immunosuppressive treatments which increase the risk of developing melanomas and non-melanoma skin cancers (NMSCs). Biologic therapy has been increasingly used for the last decade for these patients for its higher efficacy and less side effects. To study the effects of these immune-modulators on the development of skin cancers, 45 psoriasis patients receiving biologic therapy (Etanercept, Infliximab, Adalimumab, and Ustekinumab) and 43 healthy control subjects were prospectively followed up in one year, with dermoscopic comparison pictures of all their pigmented naevi and suspected skin cancers. This was performed using Solarscan, as well as total body photographs. Both groups had comparable mean age, sex ratio, history of past sun exposure, past history of skin cancers, and number of total naevi. No subject had developed melanomas during the study period in either group. There were comparable numbers of dysplastic naevi (DNs) in both groups (4 biologic patients developed 6 DNs collectively, and 4 control subjects developed 4 DNs). To increase the power of the study, looking at the major dermoscopic changes such as enlargement, regression, colour changes, and structural changes within each photographed naevi there was no significant difference between the groups. There were 2 biologic patients who developed 3 NMSCs (2 basal cell carcinomas (BCCs) and 1 keratoacanthoma), and 3 control patients who developed 3 NMSCs (2 BCCs and 1 keratoacanthoma). This study showed that our patients receiving biologic therapy for treatment of moderate to severe psoriasis did not have increased rate of development of DNs and NMSCs compared to our control group. It is recommendable to continue regular skin examinations for patients on biologic therapy to monitor the effects of long-term immunosuppression, and in particular look out for dysplastic naevi that may be undergoing changes with the use of dermoscopic tools