Seasonality of presentation of cutaneous melanoma, squamous cell cancer and basal cell cancer in the Oxford Region.

The seasonality of presentation of 1019 skin melanomas in Oxford Region 1952-1975, and of 1,523 squamous cell and 4,865 basal cell skin cancers in the region 1967-1975, were analysed using data from the Oxford Cancer Registry. For males and for females, for each of the histologies there was a peak of presentations during July to September. In further subdivisions of the data by age and by skin site, a summer or autumn peak was generally present except where numbers of cases were small. Amplitude of seasonality did not show consistent differences by histology, sex, or skin site, but for both melanoma and squamous cell cancer amplitude was greater for persons aged under 55 years than for older persons. There was no substantial seasonality for presentations of cancers of all non-skin sites in the region. The seasonality of presentation of skin cancers appeared not to be mainly an artefact of the cancer registration process or of organisational aspects of medical care attendance, and only a small proportion of it could be explained as an artefact of the longer term increase in registrations of these cancers. The visibility of skin cancers might have lead to seasonal variation in rapidity of presentation to medical care, for instance for social reasons, or the results might reflect a short induction period effect of exposure to a seasonal insult, perhaps sun radiation, on the aetiology, growth or symptoms of skin cancers; for melanoma there is previous evidence suggesting a short induction period aetiological effect of sun radiation.