Sentinel Lymph Node Biopsy in Patients with Thick Primary Cutaneous Melanoma: Patterns of Use and Underuse Utilizing a Population-Based Model

Background. Sentinel lymph node biopsy (SLNB) for thick cutaneous melanoma is supported by national guidelines. We report on factors associated with the use and underuse of SLNB for thick primary cutaneous melanoma. Methods. The Surveillance, Epidemiology, and End Results database was queried for patients who underwent surgery for thick primary cutaneous melanoma from 2004 to 2008. We used multivariate logistic regression models to predict use of SLNB. Results. Among 1,981 patients, 833 (41.8%) did not undergo SLNB. Patients with primary melanomas of the arm (OR 2.07, CI 1.56–2.75; ), leg (OR 2.40, CI 1.70–3.40; ), and trunk (OR 1.82, CI 1.38–2.40; ) had an increased likelihood of receiving a SLNB, as did those with desmoplastic histology (OR 1.47, CI 1.11–1.96; ). A decreased likelihood of receiving SLNB was noted for advancing age ≥ 60 years (age 60 to 69: OR 0.58, CI 0.33–0.99, ; age 70 to 79: OR 0.32, CI 0.19–0.54, ; age 80 or more: OR 0.10, CI 0.06–0.16, ) and unknown race/ethnicity (OR 0.21, CI 0.07–0.62; ). Conclusions. In particular, elderly patients are less likely to receive SLNB. Further research is needed to assess whether use of SLNB in this population is detrimental or beneficial. 1. Introduction Lymphatic mapping and sentinel lymph node biopsy (SLNB) was developed by Morton et al. as an alternative to elective lymph node dissection for patients with intermediate thickness melanoma [1]. However, information from institutional studies and post hoc analyses from randomized clinical trials indicate that SLNB provides accurate and important prognostic information, even among patients with thick melanoma [2–11]. Current guidelines from the National Comprehensive Cancer Network (NCCN) advocate the SLNB for all melanomas >1？mm in thickness [12]. Such guidelines have been in place since 1998 [13]. The use of SLNB for thick cutaneous melanomas has nevertheless remained controversial due to the nihilistic belief that thick melanomas are associated with an unacceptably high likelihood of distant metastatic disease [14]. Given that only half of all patients with thick primary melanomas will be alive 10 years after their diagnosis, [2] some physicians believe that such patients are unlikely to benefit from SLNB because their outcome will be dictated by their occult metastasis and not the presence or absence of sentinel lymph node metastasis. To date, little data have been acquired regarding use of SLNB for thick melanomas, and the factors that may contribute to its use are largely unknown. Our goals were to assess the prevalence of SLNB use for thick