Influence of age and cancer history on prevalence of autoimmunity in patients with metastatic melanoma: A large retrospective study.

Abstract

e22016 Background: While immune checkpoint inhibitors (ICIs) have improved the survival rates of metastatic melanoma in recent years, immune-related adverse events (irAEs) remain a major toxicity. Studies have established that pre-existing autoimmunity increases the risk of severe irAEs following ICI therapy (1). Melanoma is common cancer in older patients, and older age is believed to be a risk factor of autoimmunity. However, there is controversy concerning the influence of age increasing the risk of irAEs between clinical trials, which exclude patients with confirmed or suspected autoimmunity, and less-selective but lower-power case reports (2). In order to understand potential irAE risk following ICI treatment, we measured the prevalence of pre-existing autoimmune disease by age and cancer type. Methods: We studied 293,938 patients aged 18-106 years old who were treated at the University of Connecticut Health Center between 2000 and 2018 using GE Centricity’s IDX database. Patients were organized into four study groups based on International Classifications of Diseases codes (ICD-9 and ICD-10), specifically primary melanoma and three comparisons groups: non-cutaneous neoplasms alone, melanoma with non-cutaneous neoplasms, and patients without cancer history. A list of 340 ICD codes corresponding to 105 autoimmune conditions were queried. Results: Non-cutaneous cancer, in the absence or presence of melanoma, was associated with a higher prevalence of autoimmunity (27.0%, 29.4%, respectively) compared to the rates in patients with melanoma alone and those without cancer history (11.1%, 8.7%, respectively, p < 0.05). In patients with both melanoma and non-cutaneous cancers, those with metastases had an 11.7% increase in autoimmune prevalence compared to patients without metastases (p < 0.0001), the largest metastasis-associated increase observed across all cancer groups. Lastly, a logistic regression demonstrated that age is weakly correlated with autoimmunity (r = 0.01, p < 0.0001). Conclusions: The findings suggest that a history of metastasis, non-cutaneous cancer, and advanced age are associated with a higher prevalence of pre-existing autoimmunity in melanoma patients. As ICIs are indicated for metastatic melanoma, our findings warrant future studies and careful risk assessment of autoimmunity in senior patients.