The Carcinogenic Risk of Psoriasis and Its Treatments
Date Issued
2009
Date
2009
Author(s)
Lee, Meng-Sui
Abstract
Backgroundsoriasis is a kind of chronic diseases which cannot be cured at present. Patients may need lifelong treatment. Moreover, patients in serious conditions may require long-term use of systemic drugs or phototherapy to ease the condition. everal studies have shown that psoriasis patients who do not receive systemic treatment have slightly higher risks of getting cancer than the general population. Although psoriasis is not confirmed to lead to cancer, it is worthwhile to discuss the issue more deeply concerning whether using systemic treatment proved or suspected to be carcinogenic increases the risks of getting cancer for psoriasis patients.tudy Purposehe study was aimed at discovering the Indirect Standardized Incidence Ratio (SIR) of nonmelanoma skin cancer (NMSC), lymphoma and melanoma happening on patients with various disease severity of psoriasis. The study would also explore the relevance between different treatment types and the occurrence of NMSC by means of Time-dependent Cox regression mode. aterial and Methodhe cohort of psoriasis was defined based on the administrative claims data of a randomly sampled cohort (n = 1,000,000) of National Health Insurance beneficiaries in Taiwan with the diagnostic column of ICD-9 code being 696, 696.0 or 696.1. Cases of NMSC, melanoma or lymphoma were defined when patients were diagnosed with the above diseases after getting into the cohort and treated with compatible treatment. Psoriasis patients were then divided into two groups: severe or mild in accordance with the experience of receiving systemic treatment. We calculate SIR of cancer for each study group.fter adjusting the age, gender, Charlson comorbidity index and arsenic-exposure, Time-dependent Cox regression model was then applied to analyze variables of treatments such as PUVA therapy, UVB therapy, Methotrexate, Cyclosporin, Retinoids, Azathioprine and Tar to discover how the timing of different events and the accumulated times of treatment as well as the amount of doses affected NMSC. The study also conducted sensitivity analysis of the timing of the accumulated doses of Retinoids.esultshere were 7061 patients defined as the generation of psoriasis, among which 870 were severe psoriasis patients and 6191 mild were ones. fter adjusting age and gender, the SIR of NMSC was 4.29 (95% CI 2.90-6.35) while the SIR of mild psoriasis was 3.72 (95% CI 2.34-5.90) and 7.08 (95% CI 3.38-14.85) of the SIR of severe psoriasis. The SIR of melanoma was 3.75 (95% CI 0.94-14.99) while the SIR of mild psoriasis was 2.26 (95% CI 0.32-16.04) and 11.01 (95% CI 1.55-78.16) of the SIR of severe psoriasis. The SIR of lymphoma was 2.30 (95% CI 1.15-4.60) while the SIR of mild psoriasis was 1.75(95% CI 0.73-4.20) and 4.85 (95% CI 1.56-15.04) of the SIR of severe psoriasis.here were 6737 patients newly diagnosed with psoriasis, among which 22 cases were diagnosed with NMSC in the Time-dependent Cox regression model of discovering the effects of variables of treatments on the occurrence of NMSC. In addition to age and arsenic-exposure, the more the accumulated doses of Azathioprine were, the higher risks of the occurrence of NMSC would be. There was no statistical significance of how the accumulated times and doses of the other treatment affected the occurrence of NMSC.iscussionild psoriasis patients had higher risks of getting NMSC than the reference group which implied psoriasis itself was carcinogenic. The occurrence rate of NMSC, melanoma and lymphoma was slightly higher for severe psoriasis patients, which was possibly related to the severity of psoriasis or its treatments.tudies concerning the risks of getting NMSC with Azathioprine were mainly about patients with rheumatoid arthritis, organs transplantation or inflammatory bowel disease. There were still no large scale researches regarding NMSC caused by psoriasis treated with Azathioprine. UVA therapy was significantly carcinogenic in getting NMSC in the West literatures while its risks were comparatively lower in Asian studies. The risk of getting NMSC with PUVA therapy in our study is not significant. In addition to the difference of races and skin types, the accumulated times of treatment tend to being low may be also a critical factor. As for the treatment of NMSC with Methotrexate and Cyclosporin, the risks of getting cancer were not significant, which may be the result of insufficient tracing time.onclusionhe risks of getting NMSC, melanoma and lymphoma for severe psoriasis patients were higher than the reference group. The risks of getting NMSC for mild psoriasis patients were higher than the reference group. Therefore, psoriasis itself was carcinogenic of getting NMSC. The study had proved that the occurrence of NMSC was related to psoriasis patients’ using Azathioprine. Consequently, psoriasis patients should use the drugs cautiously and avoid being exposed to the ultra light.
Subjects
psoriasis
treatment of psoriasis
carcinogenic
Indirect Standardized Incidence Ratio
National Health Insurance Research Database
SDGs
Type
thesis
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