Non-metastatic kidney cancer patients after primary surgery (n = 2433) from 2007 to 2011 were identified in SEER-Medicare. Surveillance intensity was measured as the number of unique inpatient and outpatient claims made for kidney cancer starting 60 days after primary surgery. Multivariable linear regressions assessed relationships between patient factors and surveillance intensity (log-transformed). Parameters were reported using risk ratios (RRs).
Patients diagnosed in contemporary years experienced 10% more surveillance visits/12 months (RR 1.10 for every 1-year increase, 95% CI 1.07-1.13, p < 0.001). Compared to pT1 stage, patients with pT2-4 disease experienced 108% more surveillance visits/12 months (RR 2.08, 95% CI 1.90-2.27, p < 0.001). Both older age and living in a metro/urban area, as compared to a big metropolitan location, were associated with significantly fewer follow-up visits (10-year increase in age: RR 0.89, 95% CI 0.83-0.95, p < 0.001; metro/urban: RR 0.86, 95% CI 0.79-0.93, p < 0.001). Surgery type (radical, partial or ablation), gender, race and Charlson comorbidity score were not significantly associated with surveillance intensity.
Similar to guidelines, surveillance intensity in practice was associated with stage, but not with surgery type. Other factors such as diagnosis year, care location and patient age were associated with the amount of surveillance administered by the clinician. These additional influences are augmenting the heterogeneous delivery of kidney cancer surveillance care.