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

Background: Sentinel lymph node biopsy (SLNB) has become the preferred method for axillary nodal staging. The authors examined SLNB utilization in urban versus rural settings as this procedure was adopted and hypothesized that SLNB rates among urban populations increased faster, while the technology shift and acceptance of SLNB were slower at rural centers.

Methods: The Surveillance, Epidemiology and End Results database was used to identify patients with invasive node-negative ductal or lobular breast cancer diagnosed from 1998 to 2008. Exclusion criteria were distant metastatic disease, T4 tumors, or incomplete data. Residential setting was divided into groups on the basis of population density.

Results: The overall rate of SLNB increased with time (from 10% in 1998 to 73% in 2008). The adoption of SLNB was slower in rural settings than among urban populations (P < .001). By 2003, only urban areas were using SLNB in >50% of cases. Overall, there was a 2-year lag between the increases in SLNB utilization rates in these groups. There was a significant difference in SLNB rates according to tumor size.

Conclusion: The overall rate of SLNB remained near 50% and was lower in rural locations in 2004. By 2008, the SLNB rate for T1 and T2 tumors had increased to >50% in all population categories. SLNB utilization was lower in all population categories as tumor size increased. There was an overall 2-year lag in the adoption of SLNB in less populated areas. Although this may represent a more conservative approach, the difference may be attributable to a shortage of experienced surgeons, lack of training, or lack of technological support at smaller institutions.