Patterns of surveillance imaging after nephrectomy in the Medicare population.

Abstract

To characterize patterns of imaging surveillance after nephrectomy in a population-based cohort of older patients with kidney cancer. Using the Surveillance, Epidemiology and End Results (SEER)-Medicare database, we identified patients aged ≥ 66 years who underwent partial or radical nephrectomy for localized kidney cancer diagnosed between 2000 and 2009. Primary outcomes were chest imaging (X-ray or computed tomography [CT]) and abdominal imaging (CT, MRI or ultrasonography) in Medicare claims from 4 to 36 months after surgery. We estimated the frequency of imaging in three time periods (postoperative months 4-12, 13-24, 25-36), stratified by tumour stage. Repeated-measures logistic regression was used to identify the patient and disease characteristics associated with imaging. Rates of chest imaging were 65-80%, with chest X-ray surpassing CT in each time period. Rates of abdominal imaging were 58-76%, and cross-sectional imaging was more common than ultrasonography in each time period. Use of cross-sectional chest and abdominal imaging increased over time, while the use of chest X-ray decreased (P < 0.01). Ultrasonography use remained stable for patients with T1 and T2 disease, but the rate of use decreased in patients with T3 disease (P < 0.05). Rates of chest and abdominal imaging increased with tumour stage (P < 0.001). Patterns of imaging suggest possible overuse in patients at low risk of recurrence and underuse in those at greater risk. New surveillance imaging guidelines may reduce unwarranted variability and promote risk-based, cost-effective management after nephrectomy.