Another Way to Avoid Skin Cancer

Summarized by Robert W. Griffith, MD
April 23, 2002 (Reviewed: April 5, 2004)

Introduction

Sunlight (the ultraviolet-B, or UV-B rays) plays an important role in causing all three types of skin cancer - melanoma, basal cell carcinoma (BCC), and squamous cell carcinoma (SCC). Unfortunately, the possession of a dark, tanned skin is appealing to many young US adults, so that artificial tanning devices have gained widespread popularity. The increased risk of BCC and SCC in people using tanning lamps has been reported recently in the Journal of the National Cancer Institute.

What was done

This was a population-based, case-control study. People with newly diagnosed BCC and SCC in the general population of New Hampshire, USA, were identified with the help of dermatologists and path labs. All the people with SCC and a random sample of those with BCC were selected for interview. (There were more BCC cases, so only a sample was selected.) People's names, matched by age and gender, were taken from driving license lists and Medicare rolls, to supply a 'case-control' group.

The response to requests for interviews was fairly good -- 78% in the case-subjects, and 66% in the control subjects. Interviews were conducted with 603 BCC cases, 293 SCC cases, and 540 controls. Information was collected about each person's sun sensitivity (tendency to sunburn) sun exposure (e.g. time spent outdoors, history of sunbathing, number of painful sunburns), previous radiation treatment, and smoking history. Participants were then asked if they ever used a sunlamp or a tanning bed, or went to a tanning salon. If they had, they were asked to give their age at first and last use.

The findings

Analyses of the interview results showed that users of any tanning device were 2.5 times more likely to develop squamous cell skin cancer, and 1.5 times more likely to develop basal cell skin cancer. These results were statistically significant, i.e. they were highly unlikely to have emerged by chance. Making allowances for a history of sunburns, sunbathing, or sun exposure didn't alter the results. The effects were the same in men and women.

People who use tanning devices before age 20, or 20 or more years before being diagnosed, are even more likely than others to develop skin cancer. However, this difference wasn't statistically significant i.e. it could be a chance effect. There weren't enough participants to be able to find out the risk for different amounts of exposure to tanning devices.

Conclusions

If there were any doubts about the dangers of the suns rays, this study should dispel them. For people with fair skins, a change in attitude towards the prevailing cult of 'a healthy tan' is absolutely necessary. Alarmingly, a 1994 study reported that more than 50% of high-school girls had used a commercial tanning bed at least 4 times in the previous year. Although this was 8 years ago, it's unlikely that the problem has shrunk. It may be time for 'regulatory action'; at the very least, some sort of 'informed consent'.

Source

• Use of tanning devices and risk of basal cell and squamous cell skin cancers. MR. Karagas, VA. Stannard, LA. Mott,  et al., J Natl Cancer Inst , 2002, vol. 94, pp. 224--226

Related Links
How to Avoid Skin Cancer
Recognizing Skin Cancer
Online Atlas of Dermatology

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