Indoor tanning and the MC1R genotype: risk prediction for basal cell carcinoma risk in young people.

A M Molinaro,Erikka Loftfield,A E Bale,Brenda Cartmel,D J Leffell,S T Mayne,L M Ferrucci,David J Leffell,Susan T Mayne,Allen E Bale,Leah M Ferrucci,Annette M Molinaro

doi:10.1093/aje/kwu356

Abstract

Basal cell carcinoma (BCC) incidence is increasing, particularly in young people, and can be associated with significant morbidity and treatment costs. To identify young individuals at risk of BCC, we assessed existing melanoma or overall skin cancer risk prediction models and built a novel risk prediction model, with a focus on indoor tanning and the melanocortin 1 receptor gene, MC1R. We evaluated logistic regression models among 759 non-Hispanic whites from a case-control study of patients seen between 2006 and 2010 in New Haven, Connecticut. In our data, the adjusted area under the receiver operating characteristic curve (AUC) for a model by Han et al. (Int J Cancer. 2006;119(8):1976-1984) with 7 MC1R variants was 0.72 (95% confidence interval (CI): 0.66, 0.78), while that by Smith et al. (J Clin Oncol. 2012;30(15 suppl):8574) with MC1R and indoor tanning had an AUC of 0.69 (95% CI: 0.63, 0.75). Our base model had greater predictive ability than existing models and was significantly improved when we added ever-indoor tanning, burns from indoor tanning, and MC1R (AUC = 0.77, 95% CI: 0.74, 0.81). Our early-onset BCC risk prediction model incorporating MC1R and indoor tanning extends the work of other skin cancer risk prediction models, emphasizes the value of both genotype and indoor tanning in skin cancer risk prediction in young people, and should be validated with an independent cohort.

Highlights

Basal cell carcinoma (BCC), which accounts for 70%–80% of Nonmelanoma skin cancers (NMSCs) [2, 3], has increased dramatically in recent decades, notably among young women [1, 4,5,6]
The melanocortin 1 receptor gene, MC1R, has been consistently associated with high-risk skin cancer phenotypes, including red hair and fair skin; common variants of MC1R are recognized as contributing to the risk of melanoma [9, 11, 17, 18] and NMSC [9, 19, 20] independent of phenotype
Given the increase in indoor tanning in young populations and the high incidence of BCC, we were interested in evaluating whether MC1R and indoor tanning added to the predictive ability of BCC risk models, as seen in some melanoma risk models

Summary

Introduction

There are few BCC risk prediction models [8, 9], yet several exist for melanoma [8,9,10,11,12,13,14,15,16] that typically evaluate demographic, phenotypic, and clinical factors. Indoor tanning has recently emerged as an important risk factor for both melanoma [21, 22] and NMSC [23] and seems relevant for skin cancer in younger populations [24,25,26]. Given the increase in indoor tanning in young populations and the high incidence of BCC, we were interested in evaluating whether MC1R and indoor tanning added to the predictive ability of BCC risk models, as seen in some melanoma risk models.

Methods

Results

Conclusion