Open Access Research article

Patterns and timing of sunlight exposure and risk of basal cell and squamous cell carcinomas of the skin – a case–control study

Michelle R Iannacone18*, Wei Wang2, Heather G Stockwell2, Kathleen O’Rourke2, Anna R Giuliano1, Vernon K Sondak3, Jane L Messina3456, Richard G Roetzheim7, Basil S Cherpelis56, Neil A Fenske456 and Dana E Rollison1

Author Affiliations

1 Department of Cancer Epidemiology, Moffitt Cancer Center, Tampa, FL, USA

2 Department of Epidemiology and Biostatistics, College of Public Health, University of South Florida, Tampa, FL, USA

3 Cutaneous Oncology Program, Moffitt Cancer Center, Tampa, FL, USA

4 Department of Pathology and Cell Biology, University of South Florida College of Medicine, Tampa, FL, USA

5 Department of Dermatology, University of South Florida College of Medicine, Tampa, FL, USA

6 Department of Cutaneous Surgery, University of South Florida College of Medicine, Tampa, FL, USA

7 Department of Family Medicine, University of South Florida College of Medicine, Tampa, FL, USA

8 Infections and Cancer Biology Group, International Agency for Research on Cancer, 150 cours Albert-Thomas, 69372, Lyon Cedex 08, France

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BMC Cancer 2012, 12:417  doi:10.1186/1471-2407-12-417

Published: 20 September 2012

Abstract

Background

Non-melanoma skin cancer (NMSC), comprised of basal (BCC) and squamous (SCC) cell carcinomas, is the most common cancer in Caucasians. Ultraviolet radiation (UVR) exposure is the most important environmental risk factor for NMSC. However, the precise relationship between UVR and the risk of NMSC is complex, and the relationship may differ by skin cancer type.

Methods

A case–control study was conducted among Florida residents to investigate measures of patterns (intermittent vs. continuous) and timing (childhood vs. adulthood) of sunlight exposure in BCC and SCC. Participants included 218 BCC and 169 SCC cases recruited from a university dermatology clinic and 316 controls with no history of skin or other cancers.

Results

A history of blistering sunburn (a measure of intermittent sunlight exposure) was associated with both BCC (OR = 1.96, 95% CI = 1.27-3.03) and SCC (OR = 2.02, 95% CI = 1.22-3.33). Additionally, having a job in the sun for ≥3 months for 10 years or longer (a measure of continuous sunlight exposure) was also associated with both BCC and SCC in our study population. With the exception of younger age at first blistering sunburn, measures of younger age at sunlight exposure tended to be associated with SCC, but not BCC risk.

Conclusions

Results from the current study suggest that sunlight exposure is associated with both BCC and SCC risk regardless of the pattern in which the exposure was received (i.e. intermittent vs. continuous). The data also suggest that sunlight exposure at a younger age may be more important for SCC but not BCC, however additional studies are needed to further characterize sunlight exposure-response relationships in different types of NMSC.

Keywords:
Case–control; Sunlight; Patterns; Basal cell carcinoma; Squamous cell carcinoma; Non-melanoma skin cancer