A Quantitative Examination of Lymph Drainage from Perilesion Skin in Human Melanoma

Abstract

An increase in lymph flow from melanomas to draining lymph nodes has been reported in animal studies. It has been postulated that this contributes to metastatic potential of cancers. Data from animal studies are not easily extrapolated to humans; animal studies use immunosuppressed animals modified to overexpress lymphangiogenic growth factors, injected with human tumor cell lines, or manipulated to develop aggressive tumors. Human studies are required to investigate lymph flow in humans with cancers such as melanoma. The present study aims to quantify the removal rate constant k (a measure of local lymph flow per unit volume of distribution of the radiotracer) from the vicinity of melanomas, benign nevi, and normal skin in humans in vivo using quantitative lymphoscintigraphy (QL). 16 patients with pigmented lesions underwent QL to quantify k near the lesion (k(perilesion)) and in contralateral matched normal skin (k(control)). The lesions were then excised and, based on histological outcome, the patients were divided into two groups: benign nevus (n=9) and melanoma (n=7). There was no difference between k(perilesion) and k(control) in either the benign naevus (p=0.29, paired t test) or the melanoma group (p=0.93). k(perilesion) in melanomas (0.233±0.123% min(-1)) was not increased relative to k(perilesion) in benign nevi (0.376±0.231% min(-1), p=0.16, unpaired t test). We found no evidence for increased lymphatic drainage in melanoma relative to benign nevi or normal matched skin in humans.