Utilization of Patient-Specific Characteristics and Competing Risks to Tailor the Duration of Surveillance Imaging After Surgery for Renal Cell Carcinoma

The appropriate duration of follow-up after surgical resection of renal cell carcinoma (RCC) remains incompletely defined. To better inform on this time line, we investigate when an individual's risk of RCC recurrence becomes less significant than their risk of non-RCC death. We identified 1672 patients who underwent surgery for M0 RCC between 1999 and 2018. Patients were stratified by pathologic stage, histology, age, and Eastern Cooperative Oncology Group (ECOG) performance status. Cumulative incidence functions were estimated for RCC recurrence and non-RCC death using Fine and Gray models. Follow-up durations were estimated as the time point at which the cumulative incidence of non-RCC death exceeded that of RCC recurrence. At a median follow-up of 2.1 years (IQR 0.6-5.1 years), a total of 272 recurrences (16.3%) and 234 non-RCC deaths (14.0%) occurred. The fitted model showed significant associations of stage with RCC recurrence and of age and ECOG with non-RCC death. For 50-year-old patients with pT1aN0-x clear cell and ECOG 0, the incidence of non-RCC death exceeded that of recurrence after 4.4 years. However, if such patients had an ECOG status of 1 or 2 to 4, the incidence of non-RCC death exceeded that of recurrence at 30 days, suggesting that routine oncologic surveillance may not be necessary. Alternatively, regardless of ECOG status, the incidence of non-RCC death failed to exceed that of recurrence for >13.9 years in all patients age 50 with > pT3aN0-x clear cell thereby suggesting longer surveillance than currently recommended. Modeling competing risks of RCC recurrence and non-RCC death provide patient-specific estimates when follow-up may be reasonably discontinued.