LOCAL INFILTRATIVE GROWTH-BEHAVIOR OF SQUAMOUS-CELL CARCINOMAS OF THE SKIN AND GUIDELINES FOR TREATMENT

The infiltrative growth behaviour of squamous cell of the skin carcinomas is characterized by subclinical outgrowths, very frequently extending horizontally and sometimes over long distances. They are presented in the form of a negative exponential function. These outgrowths have an irregular pattern. It is much more extensive in the case of tumours with a clinical diameter of more than 20 nm. All types of "blind" therapy such as cryopexy, irradiation, laser, and surgery monitored in only two dimensions involve an inevitable risk of recurrences, which can be calculated statistically from the results available. Routine histographical surgery of skin carcinomas in the form of continuous, 3-dimensional histology can dramatically reduce the risk of local relapse, especially in the case of small and medium-sized carcinomas. The test group presented here (411 carcinomas) was treated with histographic surgery using the paraffin section method; during the follow-up period (maximum: 7 years, minimum: 3 years) the danger of recurrence was 2.2% for all carcinomas but only 0.6% for those up to 20 mm in diameter (n = 340). Carcinomas with a diameter of more than 20 mm (n = 71) involved a much higher risk of recurrence with 9.8%. This is probably because of local micrometastases, which require more generous local excision with a safety margin of about 10 mm.