Prediction of Competing Mortality for Decision-making Between Surgery or Observation in Elderly Patients With T1 Kidney Cancer

Objective To predict the risk of cancer-specific mortality (CSM) or other-cause mortality (OCM) for T1 kidney cancer patients, aiming at identifying those who would benefit from surgery over observation. Patients and Methods Overall, 11,192 T1 kidney cancer patients treated with surgery or observation in the Surveillance, Epidemiology, and End Results-Medicare database were assessed. A competing risk regression (CRR) model was fitted to predict CSM and OCM after surgery or observation. Covariates consisted of age, gender, race, Charlson comorbidity index (CCI), history of acute kidney injury or chronic kidney disease, tumor size, and year of diagnosis. Results At a median follow-up of 64 months, the 5-year rates of CSM and OCM were 6.7% and 24%, respectively. At CRR predicting CSM, surgery (hazard ratio [HR] 0.46; P < .0001) and year of diagnosis (HR 0.96; P < .0001) were associated with lower CSM risk. Conversely, age (HR 1.05; P < .0001), CCI (HR 1.07; P < .0001), and tumor size (HR 1.03; P < .0001) were associated with higher CSM risk. At CRR predicting OCM, surgery (HR 0.66; P < .0001), female gender (HR 0.83; P < .0001), Other race (HR 0.82; P < .0001), and year of diagnosis (HR 0.95; P < .0001) were associated with lower OCM risk. Conversely, age (HR 1.06; P < .0001), African American race (HR 1.16; P < .01), CCI (HR 1.17; P < .0001), and acute kidney injury or chronic kidney disease (HR 1.35; P < .0001) were associated with higher OCM risk. Conclusion The benefit of surgery over observation was more pronounced in younger and healthier patients with larger tumors. The proposed model can aid in clinical decision-making, providing crucial information on CSM and OCM risk after either treatment modality.