Assessing rural-urban disparities in the use of sentinel lymph node biopsy for melanoma

Background: We hypothesized that patients in urban areas with intermediate thickness cutaneous melanoma would have higher rates of sentinel lymph node biopsy (SLNB) relative to their rural-dwelling counterparts. Methods: The Surveillance, Epidemiology, and End Results database was queried for patients who underwent surgery for intermediate thickness cutaneous melanoma from 2004-2008. Patients were categorized as coming from urban or rural counties based on a nine-point scale. We used multivariate logistic regression models to predict use of SLNB. Covariates examined included sex, race/ethnicity, age, T stage, tumor histology, tumor location, and ulceration. The likelihood of undergoing SLNB was reported as OR with 95% CI. Results: Of 8441 patients, 8382 (99.3%) had complete information regarding use of SLNB. On multivariate analysis, patients from rural counties had a decreased likelihood of receiving a SLNB (OR 0.87, CI 0.78-0.97; P = 0.014). Additional factors associated with a decreased likelihood of receiving a SLNB included increasing age, Asian/Hispanic/Unknown race, and head and neck or overlapping primary tumor site. Conclusions: Patients in rural areas are less likely to receive a SLNB for intermediate thickness cutaneous melanoma than their urban-dwelling counterparts.