Oncologic Surveillance After Radical Nephroureterectomy in Upper Tract Urothelial Carcinoma Patients: A Novel Risk-Based Approach
INTRODUCTION
Current guidelines lack evidence of specific time points when the risk of non-cancer related death exceeds cancer related death, and therefore the appropriate surveillance duration for upper tract urothelial carcinoma (UTUC) patients after radical nephroureterectomy (RNU) remains unknown. Herein, we developed a novel approach for post RNU surveillance applying Weibull model estimates which dynamically illustrates oncologic surveillance that balances the risk of UTUC related death and the risk of non-UTUC death.
METHODS
We identified 431 non-metastatic UTUC patients who underwent RNU from 1980 to 2015. Patients were stratified by pathologic stage (pTa-1N0M0, pT2N0M0, pT3/4N0M0, and pTanyN+M0) and chronological age (age ≤60, 61-70, 71-80, and age >80). Under a statistician&[prime]s direction, the risks of UTUC death and non-UTUC death were estimated by using parametric models for time-to failure with Weibull distributions. Surveillance duration was estimated at the time point when the risk of non-UTUC deaths exceeded the risk of UTUC death.
RESULTS
At a median follow-up of 9.0 years (range, 1.4 to 13.5 years), a total of 149 (34.5%) patients died with UTUC progression. The Weibull model indicated the risk hazard rate of UTUC death stratified by pathological T stage and patients with pTanyN+ had a seven times higher risk of cancer related death than those with pTa-1N0M0 (Figure). However, the hazard rates of UTUC death in all stages decreased over time as the survival period increased from the time of RNU surgery. In contrast, the hazard rate of non-UTUC death stratified by age indicated that patients >80 years old had a three times higher risk of non-UTUC death as compared to those ≤60 years old, and the risk hazard for non-UTUC death increased in all age groups over time. By the interaction between Weibull model estimates for the risk of death stratified by stage and chronological age, vastly different surveillance durations were observed. Specifically, the risk of non-UTUC death exceeded the risk of UTUC death at 1.5 years in pT3/4N0M0 patients >80 years old, while the risk of non-UTUC death in those ≤60 years old never failed to exceed the risk of UTUC death for more than 10 years.
CONCLUSION
We present a novel methodology which simulated the patient&[prime]s course of death with UTUC and the natural interplay with the patient&[prime]s age status. This novel strategy may provide a better balance between the derived benefit from UTUC surveillance and medical resource allocation.
Funding: none