Age-related lymphatic dysfunction in melanoma patients

Age-related outcomes have become increasingly common in evaluating patients with melanoma. For instance, as age increases, sentinel node (SN) nonidentification increases and SN positivity decreases. Furthermore, advanced age is a risk factor for in-transit disease. We hypothesized that increasing age is accompanied by alterations in lymphatic function, possibly explaining these findings.

Our center's melanoma database was queried to identify patients who underwent successful sentinel node biopsy after lymphoscintigraphy. Records of those treated between 2000 and 2005 were reviewed for age, sex, drainage basin, intraoperative radioactivity, and SN pathology.

The 858 patients had a mean age of 55 years; 59% were men. Mean radioactivity in the hottest SN was 5232 counts per second; 179 patients (21%) had SN metastases. SN count rates were significantly and inversely related to age (P < .001 by Pearson correlation, analysis of variance, and chi(2) test). Mean counts per second were 6105, 5883, and 2720 for axillary, inguinal, and cervical basins, respectively (P < .01), and count rates in these basins were consistently lower with increasing age (neck and axilla, P < .001; groin, P = .060; Pearson correlation). Multivariate analysis confirmed an independent inverse association between age and count rates (P < .001), overall and within each primary tumor site.

Lymphatic function, as assessed by radiocolloid transit to and uptake within the SN, declines with age. Altered lymphatic function in older patients may modify metastatic patterns; knowledge of this may help clarify findings of reduced nodal positivity and increased in-transit disease in this population.