Tanning Beds Revisited

Abstract & Commentary

By William B. Ershler, MD

Synopsis: The practice of tanning by artificial means, such as by sunlamps or sunbeds, continues to be popular, particularly in young people despite the acknowledged risk for increased skin cancer. Most data in this regard have been derived from case-control analyses. In the current report from the Nurses Health Study II examining 20-year follow-up of 73,494 nurses, an increased incidence of basal cell, squamous cell, and melanoma was observed in those who reported tanning bed use either during high school/college years or from age 25-35 years.

Source: Zhang M, et al. Use of tanning beds and incidence of skin cancer. J Clin Oncol 2012;30:1588-1593.

Artificial exposure to ultraviolet light, such as in a tanning salon, has been associated with increased skin cancers. A meta-analysis of 19 studies revealed that ever-use of sunbeds was associated with 15% increased risk of melanoma compared with never having used a sunbed.1 This analysis revealed a similar increase in squamous cell carcinoma (SCC), but the risk was found to be insignificant for basal cell carcinoma (BCC). Most prior studies have used case-control methodology with only limited data derived from prospective cohorts. The current research was designed to evaluate skin cancer risk in the context of prior tanning bed use by capitalizing on the rich data available in the Nurses Health Study II (NHSII).

The investigators report on 73,494 female nurses who responded by questionnaire every 2 years over a 20-year span (from 1989 to 2009). Embedded in the questionnaires were questions regarding the frequency of use of tanning beds during high school/college years and at ages 25-35 years. Also extracted from the questionnaire were the development of skin cancer (BCC, SCC, or melanoma). The investigators used Cox proportional hazards models and carefully adjusted for host risk factors, ultraviolet index of residence, and sun exposure behaviors at a young age.

During follow-up, 5,506 nurses were diagnosed with BCC, 403 with SCC, and 349 with melanoma. The multivariable-adjusted hazard ratio (HR) of skin cancer for an incremental increase in use of tanning beds of four times per year during both periods was 1.15 (P < 0.001) for BCC, 1.15 (P < 0.03) for SCC, and 1.11 (P < 0.13) for melanoma. Compared with tanning bed use at ages 25 to 35 years, there was a significantly higher risk of BCC for use during high school/college (multivariable-adjusted HR for use more than six times per year compared with no use was 1.73 during high school/college vs. 1.28 at ages 25-35 years; P for heterogeneity < 0.001).

Commentary

There has been concern that the common use of such tanning beds among adolescents and young adults, estimated to be 20-40% in these age groups in the United States,2,3 will result in the increased occurrence of skin cancers later in life. The current data provide strong evidence that this is the case, as it demonstrates a dose-response relationship between tanning bed use and the risk of skin cancers, especially BCC, and the association is stronger for patients with a younger age at exposure.

Clinical Oncology Alert (COA) readers will recall commentary on an article published last year4 and reported in the August 2011 COA issue in which an Australian group demonstrated a clear association of adolescent sunbed use and increased risk of early-onset melanoma. Furthermore, there was an apparent dose effect as the risk increased the earlier one started and was most apparent in those with greatest use. In the current prospective observational study, a similar conclusion is drawn, although the greatest risk was for the development of BCC, but was also evident for melanoma and SCC.

There is increasing pressure coming from public and private health agencies, such as the National Institutes of Health and the American Cancer Society, for increased restrictions on indoor tanning, particularly as it is marketed for adolescents and young adults. Inasmuch as BCC is the most common form of cancer in the United States and it is clearly associated with substantial quality of life and economic issues, prevention strategies should be paramount. The Zhang report should be high on the reading list of those who concern themselves with public health policy.

References

1. The association of use of sunbeds with cutaneous malignant melanoma and other skin cancers: A systematic review. Int J Cancer 2007;120:1116-1122.

2. Geller AC, et al. Use of sunscreen, sunburning rates, and tanning bed use among more than 10 000 US children and adolescents. Pediatrics 2002;109:1009-1014.

3. Lazovich D, et al. Prevalence of indoor tanning use in Minnesota, 2002. Arch Dermatol 2005;141:523-524.

4. Cust AE, et al. Sunbed use during adolescence and early adulthood is associated with increased risk of early-onset melanoma. Int J Cancer 2011;128:2425-2435.