Histological and clinical prognostic factors in squamous cell carcinoma ofthe skin. A contribution to the multicenter carcinoma study of the Association of Operative 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-st aging, histological grading is performed. This system has been extended by a selection of histological parameters which were studied with respect to p rognosis, based on a review of 184 patients with squamous cell carcinoma. A n increased malignancy was found in carcinomas with the following features: clinical diameter greater than 2 cm,low degree of keratinization, high deg ree of cellular polymorphism, high mitotic index and high tumor thickness i ndex (metastases only from tumor thickness 2,4 mm and subcutaneous infiltra tion), desmoplasia and ulceration. Consideration of histological tumor para meters improved prognosis assessment. Multivariate analyses with large case series are necessary to determine ranks of the prognostic factors. Therefo re, the data analysis of all centers that contribute to the carcinoma regis try will make a precise difinition of high- and low-risk carcinomas possibl e and can thus influence therapy and follow-up procedures.