Atopy improves survival and decreases risk of brain metastasis in cutaneous melanoma.

Abstract

Background: Development of new melanoma therapies has increased survival, and more patients are living to develop brain metastasis (BrM). Identifying those at increased risk of BrM is of significant public health importance, and our objective was to assess the relationship between atopy and survival or reduced BrM cumulative incidence (CI) in melanoma.

Methods: This retrospective study was conducted in individuals (≥65 years) in linked Surveillance, Epidemiology and End Results and Medicare data. History of atopy diagnosed prior to melanoma was ascertained using ICD-9/ICD-10 codes. Associations between atopy, CI of BrM and overall survival were assessed using cox proportional hazards models to estimate hazard ratios (HR) and p-values.

Results: A total of 23,508 cutaneous melanoma cases were identified. Overall, 6.1% developed BrM, and 38% had history of atopy. Atopy was associated with a 18% decrease in death (p<0.001). Among those without metastasis at diagnosis, atopy decreased BrM CI by 16% (p=0.006). Among those with metastasis at diagnosis (any site), only those who received checkpoint inhibitors had a suggestive but non-significant survival with atopy.

Conclusions: Atopy confers improved survival and decreased BrM CI. History of atopy in the elderly may identify those with more robust immune function that may be more responsive to treatment.

Impact: Elderly individuals with prior diagnosis of atopy had significantly improved survival and decreased incidence of BrM as compared to individuals without atopy. This suggests that history of atopy may identify a subgroup within melanoma with improved response to treatment and a more robust immune system.