Background:
A variety of methods have been used to identify the SLN in cutaneous melanoma. [99mTc] Tilmanocept, a multivalent mannose-containing radiopharmaceutical designed for SLN detection, is unique in its ability to more precisely determine whether a single SLN or multiple independent SLNs exist based on its biologic intelligent design. The objective of this study is to determine the number of sentinel lymph nodes in melanoma patients using Tilamocept to guide sentinel lymph node (SLN) detection.
Methods:
Multi-center retrospective review of patients with cutaneous melanoma undergoing SLN biopsy using Tilmanocept between January 2008 - August 2014 was conducted. Data analyses included descriptive statistics, t-tests, Fisher’s exact tests and Chi-square tests.
Results:
Of the 573 patients in the cohort, mean age was 60.3 +/- 16.6 years and 62.5% were male. Primary tumor sites included: 33.2% trunk, 27.3% head/neck, 18.5% lower extremity and 20.7% upper extremity. A median of 3 (range 1-28) SLNs were identified and resected by following the rule of 10%. Overall, 83.4% of patients had >1 SLN identified by Tilmanocept. Patients with >1 SLN were more likely to have a positive node (p=0.008), younger (p =0.001), had a higher pathologic AJCC tumor stage (p=0.018) and higher Clark level (p=0.031). Additionally, >1 SLN was associated with tumor location (p<0.001). In a multivariate model, age, tumor location and Breslow depth were significantly associated with >1 SLN. In addition, positive SLN status was significantly associated with younger age, greater Breslow depth, mitosis rate and AJCC tumor stage, and presence of ulceration, microsatellite lesions, lymphatic and vascular invasion.
Conclusions:
Tilmanocept detects multiple independent SLNs in the majority of melanoma patients.