[Histological and clinical prognostic factors in squamous cell carcinoma of the skin. A contribution to the multicenter carcinoma study of the association of surgical and oncological dermatology].

The guidelines of the International Union against Cancer are generally used to assess malignancy of squamous cell carcinoma of the skin. Beside TNM-staging, histological grading is performed. This system has been extended by a selection of histological parameters which were studied with respect to prognosis, based on a review of 184 patients with squamous cell carcinoma. An increased malignancy was found in carcinomas with the following features: clinical diameter greater than 2 cm, low degree of keratinization, high degree of cellular polymorphism, high mitotic index and high tumor thickness index (metastases only from tumor thickness 2.4 mm and subcutaneous infiltration), desmoplasia and ulceration. Consideration of histological tumor parameters improved prognosis assessment. Multivariate analyses with large case series are necessary to determine ranks of the prognostic factors. Therefore, the data analysis of all centers that contribute to the carcinoma registry will make a precise definition of high- and low-risk carcinomas possible and can thus influence therapy and follow-up procedures.