Squamous cell carcinoma of the skin of the trunk and limbs: the incidence of metastases and their outcome.

The incidence and outcome of metastatic squamous cell carcinoma of the skin is poorly documented. This study, undertaken in a population accessible to long-term follow-up, documents the metastatic aspects of squamous cell carcinoma of the skin of the trunk and limbs. In a review of 695 cases, metastases occurred in 34 cases, with a metastatic rate of 4.9%, an overall mortality of 3.4%, and a 70.6% mortality in the metastatic group. Forty-six per cent of overall mortality was associated with inoperable or recurrent regional disease without evidence of distant metastases. The risk factor associated with the development of metastatic disease were; delayed presentation; large neglected lesions; misdiagnosis; and multiple treatments to the primary lesions. In this series no correlation was found between the histological degree of differentiation of the primary tumour and the development of metastases. The mean latent period between treatment of the primary and the diagnosis of metastases was 11 months. Histopathological review of the regional lymph nodes in the operable group showed that adverse pathology such as multiple nodes, extracapsular spread, vascular and perineural invasion, were associated with regional recurrence and short survival. Twenty-one patients with operable metastases had a mean survival of 53.8 months. This was compared with 13 patients with inoperable disease, in whom the mean survival was 12.2 months (P less than 0.05).