Abstract 844: Immune-related diseases and risk of skin cancer
Authors: Lin Erica M. , Lim Rachel , Li Tricia , Weinstock Martin , Qureshi Abrar , Cho Eunyoung 
Published: July 2021

Abstract
Introduction: The immune system plays an important role in skin cancer development, as evidenced by elevated rates in organ transplant recipients. However, there are limited studies on the association between immune-related diseases and skin cancer. This study prospectively evaluates the relationship between immune-related diseases and risks of melanoma, squamous cell carcinoma (SCC), and basal cell carcinoma (BCC) using two cohorts of women and men: the Nurses' Health Study (NHS) and the Health Professionals Follow-up Study (HPFS).
Methods: In the NHS and HPFS, participants completed biennial questionnaires that gathered information on lifestyle factors and medical history. In our study, the NHS data is comprised of 83,824 participants over a 26-year period (1986-2012), representing 1,738,926 person years. The HPFS data includes 48,277 participants over a 26-year period (1986-2012), representing 874,315 person years. Cox proportional hazard models were applied to estimate the associations between immune-related diseases (ulcerative colitis/Crohn's disease, multiple sclerosis, psoriasis, rheumatoid arthritis, systemic lupus erythematosus, hypothyroidism, hyperthyroidism, and vitiligo) and skin cancer risk, both individually and as one composite variable. Multivariate models were adjusted for age and other skin cancer risk factors (body mass index, smoking status, alcohol consumption, hair color, number of blistering sunburns, nevi count, sunburn reaction, family history of melanoma and cumulative UV exposure level). Due to the small number and lower skin cancer risk in the nonwhite population, the analysis was limited to white participants. Exclusion criteria were participants who had melanoma, SCC, BCC, or other cancers at baseline.
Results: During the follow-up period, 558 melanoma, 1,696 SCC, and 17,145 BCC incident cases were documented in the NHS and 589 melanoma, 1,388 SCC, and 9,962 BCC cases in the HPFS. When assessing individual diseases, there was a significantly increased risk for SCC and BCC among male participants with ulcerative colitis/Crohn's disease; relative risks (RR) were 1.69 (1.06, 2.67) and 1.38 (1.15, 1.66) respectively. Male participants with multiple sclerosis were also at a significantly increased risk of BCC; RR was 1.78 (1.17, 2.72) In female participants, participants with hypothyroidism and hyperthyroidism were at significantly decreased risk for BCC; RR were 0.88 (0.78, 0.99) and 0.81 (0.68, 0.96) respectively. There were no significant associations between diagnosis of skin cancer and immune-related diseases when evaluating them as one composite variable.
Conclusions: Risk of skin malignancy in patients with immune-related diseases is disease dependent. There is an increased risk of SCC/BCC and BCC in male patients with ulcerative colitis/Crohn's disease and multiple sclerosis, respectively.
Citation Format: Erica M. Lin, Rachel Lim, Tricia Li, Martin Weinstock, Abrar Qureshi, Eunyoung Cho. Immune-related diseases and risk of skin cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 844.