Rural and urban disparities in the evolution of sentinel lymph node utilization in breast cancer.

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71 Background: Sentinel lymph node biopsy (SLNB) has become the preferred method for axillary nodal staging. We examined SLNB utilization in urban versus rural settings as this procedure was adopted. We hypothesized that SLNB rates in urban centers quickly increased prior to 2000, while the technology shift and acceptance of SLNB was slower in rural centers. Methods: The SEER registry was used to identify patients with invasive ductal or lobular breast cancer from 1998-2008. Exclusion criteria included evidence of distant metastatic disease, T4 tumors, no curative-intent operation performed, or incomplete staging data. Residential setting was divided into three groups based on population density: rural, intermediate population, and urban. Results: The overall rate of SLNB increased with time (9.5% in 1998 to 72.7% in 2008). The adoption of SLNB was slower in rural settings than in urban populations (p<0.001). By 2003, only urban areas were utilizing SLNB in over 50% of cases. When stratified by population density, there was a significant difference in SLNB rates according to type of surgery performed (lumpectomy vs mastectomy) as well as by T-stage, with lower T-stage positively correlating with the likelihood of SLNB usage in all categories. Overall, there was a two-year lag in the adoption of between the increases in SLNB utilization rates in these groups. Conclusions: Since 1998, the use of SLNB for breast cancer has slowly increased throughout the United States. Though widely accepted as the preferred staging method, the overall rate of SLNB remained near 50% and was lower in rural locations in 2004. By 2008, the SLNB rate for T1-T2 had increased to over 50% in all population categories. There was an overall 2-year lag in adoption of SLNB in less populated areas. While this may represent a more conservative approach as noted by the higher utilization in small tumors, the difference may be attributable to a shortage of experienced surgeons, lack of training, or lack of technological support at smaller institutions. The provision of continued training in emerging technologies for rural surgeons, such as SLNB, should remain a priority in continuing surgical education.