Risk of incident cancer in psoriasis patients treated with biologics. Meta-analysis of nested case-control studies in Psonet registries. Description of study and preliminary results

Background: Immunosuppressive drugs are known to increase the risk of cancer, and this is one of the main long-term concerns for psoriasis therapy, specially biologics.Cancer is a rare outcome and existing registries are underpowered to detect an increase in risk. In trasnplanted patients latency from exposure to cancer is several years.
Aim: To describe the existence of a dose-response effect in the association between cumulative exposure to biologics and risk of incident cancer in psoriasis patients.
Methods: Meta-analysis of nested case-control studies in the participating cohorts. In each registry, patients with previous cancer were excluded from the study. Cases of cancer were reviewed locally and externally by two clinicians to exclude in-situ and benign tumours. Each case of cancer was matched with four controls on year of birth, gender and area. Data on matched sets was censored at the date of cancer diagnosis in the case, and cumulative lifetime exposure to systemic psoriasis therapy was calculated. Conditional logistic regression models
were calculated for overall exposure to biologics, a second one with overall exposure to biologics and classic immunosuppressive drugs and a fully adjusted model with other possible confounders: modified Charlson index (as a measure of comorbidities and contact with the health system, calculated using the available variables), smoking, exposure to phototherapy and duration of psoriasis. Sensitivity analysis were done including squamous cell carcinoma and both SCC and BCC. Results of these models form each cohort were merged using meta-analysis.
Results: These are partial results of the ongoing study. Up to now, we have limited results from Spain and Italy. We merged results from 186 cancer cases and 576 controls, extracted from 24296 person years of follow-up in all registries. Odds ratios of 1 year exposure to biologics were: raw 1.07 (95%CI: 0.94-1.21), adjusted for use of other systemic therapy 1.05 (95%CI:0.91-1.21), and fully adjusted 1.10 (95%CI:0.94-1.29).
Conclusion: Although results are still preliminary, it seems that patients with psoriasis treated with biologics do not have an increased risk of develop cancer