5 and 3 mm. It is obvious that the prognosis is better with less thickness. Patients with tumours less than 0.76 mm thickness have then a likelihood of recurrence of less than 1% in 10 year [10]. We did not find a trend towards lesser Breslow thickness in our study, nor a lower Clark index after the screening campaign. So no trend towards a better prognosis of melanoma could be identified by our information and screening campaign. Here also, insufficient statistical power may be a problem for the initial analysis, but regrouping to three periods of three or for years did not change the picture. Because melanomas are rare tumours and physicians had to register a limited number of cases each, it was expected that they would be motivated to do so.

We elaborated a user friendly registration map and introduced the melanoma registration project in the LOK, where physicians come together per discipline to discuss professional matters. It proved extremely difficult, however, to motivate the dermatologists to register. This part of the initial planning was therefore abandoned. On the contrary the technique of extracting the melanomas from the LIKAR-register, a working cancer register in the province, followed by enriching the data for each melanoma by interrogating the pathologists on the case was a much better approach. It is important to collect the right and relevant data on each melanoma. So our registration form had to be complete, appealing and not too large or difficult to fill in. We therefore did not ask for the number of mitoses in the tissue sample, an item we probably will include in the dataset in the future.

Our study was intended to be a first step to an ongoing tumour-specific register for melanomas that would enable us to follow the evolution of the melanomas in our province. Not only the incidence, but also the characteristics of the tumours can change. Those changes could be a result of changing sun-exposure habits or a change in screening efforts. A specific in-depth registration of characteristics of melanomas is the only possibility to give us that information. This study identified a small scale effect of the intervention on the melanoma incidence in males, but not in females and without any effect on the distribution of the tumour stages. This intervention was targeted at the population as a whole.

It has been suggested that effectiveness of skin cancer screening Batimastat may be higher if targeted at high-risk persons only. We therefore consider targeting our actions in the future at people who are at increased risk, either by their personal skin characteristics or by occupation. This especially includes people frequently working in open air. Selection of such high risk people can easily be done by occupational medicine and by general practitioners.