B. C. Chapman1, A. Paniccia1, J. Merkow1, J. J. Kwak2, P. Koo2, B. Bagrosky2, N. Pearlman1, C. Gajdos1, M. McCarter1, N. Kounalakis1 1University Of Colorado School Of Medicine,Department Of Surgery,Aurora, CO, USA 2University Of Colorado School Of Medicine,Department Of Radiology,Aurora, CO, USA
Introduction: Sentinel node positivity is the single most important prognostic factor in predicting survival in cutaneous
melanoma. Traditionally, sentinel lymph nodes (SLN) are identified preoperatively using 2-D planar lymphoscintigraphy;
however, a new technique utilizing SPECT/CT may improve nodal detection rate in head and neck melanoma. The
purpose of this study is to compare lymph node yield and nodal positivity rates utilizing SPECT/CT versus conventional
lymphoscintigraphy.
Methods: Retrospective review of a prospectively maintained database of patients undergoing SLN biopsy for cutaneous
melanoma of the head and neck between February 1998 and June 2015. Patient demographics, melanoma pathologic
features, number of SLN, and nodal positivity rates were compared in patients utilizing SPECT/CT versus conventional
lymphoscintigraphy. A multivariable logistic regression analysis was utilized to identify factors associated with the
identification of a positive sentinel lymph node.
Results: Two hundred seventy-eight patients underwent SLN biopsy: 201 underwent traditional lymphoscintigraphy and
77 patients underwent SPECT/CT. There was no difference in gender (75% vs. 75% males; p=0.95), however the
SPECT/CT group trended towards being older (57 vs. 53 years, p=0.05). The depth of primary lesion was similar in the
two groups (2.1 vs. 2.1 mm; p=0.76) and incomplete data in the lymphoscitigraphy group limited the analysis on
ulceration and mitotic rate. The total number of SLN identified was greater in the SPECT/CT group (2.7 vs. 2.4;
p=0.0292) and a positive SLN was identified more frequently in the SPECT/CT group (n=16, 20.8% vs. n=24, 8.6%;
p=0.060). Age , gender, location of primary lesion, presence of ulceration, total number of lymph node harvested, and
intraoperative technique utilized to identify SLN (radiocolloid with or without blue dye injection), were not associated with
SLN positivity; however, depth of primary lesion (OR 1.40; p=0.002) and use of SPECT/CT (OR 2.75; p=0.023) were
significantly associated with a positive SLN. The multivariable logistic regression model c-statistic was 0.72, indicating a
moderate predictive value.
Conclusion: Patients with head and neck melanoma who undergo SPECT/CT have higher SLN yields. After controlling
for common factors associated with the presence of positive SLN, the use of SPECT/CT has 3-fold higher likelyhood of
identifying a positive SLN compared to traditional lymphoscintigraphy. Long-term follow-up is needed to further define the
impact of SPECT/CT on recurrence and survival.