Sun advice: lots of hot air

All the things we’re told about melanoma, or skin cancer, prevention seem to be just plain wrong. Sunscreen blocks may in fact increase the risk, while advice on keeping out of the sun seems to be too simplistic.

The proof of this lies in the statistics coming back from various study groups. It seems there’s a melanoma epidemic going on; in New South Wales, Australia, for example, cases have doubled in the past two years, while other surveys have shown a rise of up to 43 per cent a year.

And all of this is happening at a time when public awareness of melanoma, and its supposed prevention, couldn’t be higher.

Scientists fear that melanoma has entered the political arena, and the complexities surrounding this condition are not being translated to the public. The medical profession still knows very little about melanoma, but what it does know does not sit well with the general advice handed out. For example, scientists know that people who are constantly out in the sun are less likely to develop melanoma than those who go out in it only intermittently, and there seems to be an important interaction between skin type and the disease.

One problem is that scientists don’t know which part of the sun’s spectrum is responsible for bringing on the disease, or the role and importance of ultraviolet radiation in tumour growth.
Without this knowledge, sunscreens are useless and, worse, may in fact be responsible for bringing on the cancer in some cases.

One researcher who has studied the latest epidemic in New South Wales is suggesting that there could be two types of melanoma: one which is responsible for the thin lesions which can be easily removed, and a second form which generates thicker lesions, and which may be preexisting. In other words, it was there irrespective of sun exposure. If his supposition is accurate, it would only mean that melanoma follows the pattern of other, better-understood, cancers where most skin cancer cells prove to be harmless, and may even regress (BMJ, January 20, 1996).