Management of localized kidney cancer: calculating cancer-specific mortality and competing risks of death for surgery and nonsurgical management.

BACKGROUND: For elderly individuals with localized renal cell carcinoma (RCC), surgical intervention remains the primary treatment option but may not benefit patients with limited life expectancy.
OBJECTIVE: To calculate the trade-offs between surgical excision and nonsurgical management (NSM) with respect to competing causes of mortality. DESIGN, SETTING, AND PARTICIPANTS: Relying on a cohort of Medicare beneficiaries, all patients with nonmetastatic node-negative T1 RCC between 1988 and 2005 were abstracted. INTERVENTION: All patients were treated with partial nephrectomy (PN), radical nephrectomy (RN), or NSM. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Cancer-specific mortality (CSM) and other-cause mortality (OCM) rates were modeled through competing-risks regression methodologies. Instrumental variable analysis was used to account for the potential biases associated with measured and unmeasured confounders. RESULTS AND LIMITATIONS: A total of 10 595 patients were identified. In instrumental variable analysis, patients treated with PN (hazard ratio [HR]: 0.45; 95% confidence interval [CI], 0.24-0.83; p=0.01) or RN (HR: 0.58; 95% CI, 0.35-0.96; p=0.03) had a significantly lower risk of CSM than those treated with NSM. In subanalyses restricted to patients ≥ 75 yr, the instrumental variable analysis failed to detect any statistically significant difference between PN (HR: 0.48; p=0.1) or RN (HR: 0.57; p=0.1) relative to NSM with respect to CSM. Similar trends were observed in T1a RCC only.
CONCLUSIONS: PN or RN is associated with a reduction of CSM among older patients diagnosed with localized RCC, compared with NSM. The same benefit failed to reach statistical significance among patients ≥ 75 yr. The harms of surgery need to be weighed against the marginal survival benefit for some patients. Crown