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Vascular involvement in the prognosis of primary cutaneous melanoma.

OBJECTIVE
To examine the role of vascular invasion as a prognostic factor in melanoma.


DESIGN
Retrospective survival analysis.


SETTING
Academic medical center.


PATIENTS
A total of 526 patients with primary cutaneous melanoma from the University of California, San Francisco, Melanoma Center database with 2 years of follow-up or documented relapse.


MAIN OUTCOME MEASURES
(1) Presence of vascular involvement defined as vascular invasion with tumor cells within blood or lymphatic vessels; or uncertain vascular invasion, with melanoma cells immediately adjacent to the endothelium. (2) Percentage with metastasis or death and relapse-free and overall survival.


RESULTS
The presence of either type of vascular involvement significantly increased the risk of relapse and death and reduced the survival associated with melanoma. The impact of vascular involvement on these outcomes was similar to that of ulceration. In a multivariate analysis, vascular involvement was the second most important factor (after tumor thickness) in the primary tumor in predicting survival.


CONCLUSIONS
Vascular involvement is an important independent predictor of metastasis and survival in melanoma. The phenomenon of uncertain vascular invasion describes an earlier step than definite vascular invasion in tumor progression.