Background: Cutaneous metastatic disease is uncommon and the outcome after cutaneous metastasis has rarely been thoroughly studied. The objective of this work was to study the survival after diagnosis of cutaneous metastasis in a large series of patients and to evaluate survival according to the type of cancer.
Patients and methods: This retrospective study was conducted out in the Laboratoire d'Histo-pathologie Cutanée of Strasbourg. Between 1950 to 1996, 228 patients with cutaneous metastasis were diagnosed on the basis of typical histopathology, confirmed by two dermatopathologists. We excluded lymphoma or leukaemia with secondary skin involvement. Medical and demographic data were collected from hospital data, and the "Registre du Cancer du Bas-Rhin". The type of neoplasm, the time of diagnosis of primary cancer and the time of death (or survival at 12/31/1996) was established in 200 patients, 99 men and 101 women with a mean age 62.4 +/- 13 years. We found 64 cases of breast carcinoma, 36 cases of lung carcinoma, 31 cases of melanoma and 69 cases of other cancers. Long term actuarial survival after cutaneous metastasis was calculated using by the Kaplan-Meier method.
Results: The median survival after cutaneous metastasis was 6.5 months (mean 22.8 +/- 43.8 months). The mortality rate was 13 p. 100 at 1 month, 48 p. 100 at 6 months and 64.5 p. 100 at 12 months. Median survival was calculated according to the primary neoplasm: breast carcinoma: 13.8 months, melanoma: 13.5 months, lung carcinoma: 2.9 months (36 cases). The outcome of patients with cutaneous metastasis of lung carcinoma was worse than those with melanoma (p < 10(-4)) and breast cancer (p < 10(-4)). Survival after cutaneous metastasis of other cancers could not be compared because of the small size of the subgroups: median survival after cutaneous metastasis of non cutaneous squamous cell carcinoma of the head and neck: 8.8 months (5 cases), cutaneous squamous cell carcinoma: 6.5 months (12 cases), carcinoma of oesophagus: 4.7 months (2 cases), colo-rectal cancer: 4.4 months (9 cases), pancreatic cancer: 3.3 months (2 cases), stomach cancer: 1.2 months (7 cases) and liver and gall bladder carcinoma: < 1 month (3 cases). Survival beyond 10 years was observed in 9 patients: 3 melanoma, 2 breast cancers, 2 prostatic carcinomas, 1 larynx carcinoma and 1 cutaneous squamous cell carcinoma.
Conclusion: This is the first study in which the survival after the occurrence of skin metastasis was systematically analysed in a large series of patients. It shows that half of patients with cutaneous metastasis die within the first 6 months after the diagnosis. Those cases due to lung carcinoma have the poorest prognosis.