Head/neck skin cancer tied to chronic sun exposure

NEW YORK, July 22 (Reuters) People with melanomas in the head and neck area have experienced a greater total amount of sun exposure than those who develop the deadly skin cancers in their trunk area, Australian researchers report.

The findings lend support to the theory that melanomas on different parts of the body arise through different mechanisms, the researchers note in the Journal of Clinical Oncology.

Dr. David C. Whiteman of the Queensland Institute of Medical Research and colleagues tested their theory that people with melanomas of the head and neck would have been exposed to a greater cumulative amount of sun than people with melanomas on the trunk.

They compared 154 patients with melanoma of the trunk, 76 with head and neck melanomas, and 76 with lentigo maligna or lentigo maligna melanoma (LMM), the slowest-growing form of the disease. LMM patients acted as a reference group to which the other two groups were compared.

Head and neck melanoma patients were more than twice as likely as trunk melanoma patients to have had high levels of sun exposure, and were more than three times as likely to be exposed to sun on the job. However, they were half as likely to have high levels of recreational sun exposure.

''Melanomas of the head and neck are associated with chronic patterns of sun exposure, whereas trunk melanomas are associated with intermittent patterns of sun exposure, supporting the hypothesis that melanomas may arise through divergent causal pathways,'' Whiteman and his colleagues conclude.

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