Partial nephrectomy vs cryoablation for T1a renal cell carcinoma: A comparison of survival benefit stratified by tumour size.

OBJECTIVE: We compared the impact on survival outcomes of partial nephrectomy (PN) and cryoablation (CA) for patients diagnosed with T1a renal cell carcinoma (RCC). PATIENTS AND METHODS: Among patients diagnosed between 2004 and 2014 in the Surveillance, Epidemiology and End Results program, we identified histologically confirmed T1aN0M0 RCC treated with PN (n = 17644) or CA (n = 868). Propensity score matching (PSM) was performed. Kaplan-Meier method, Cox proportional hazards model were used to calculate cancer specific mortality (CSM) and overall mortality (OM) in the unmatched and matched cohort, and in subgroups based on tumour size (< 2 cm, 2-3 cm, 3-4 cm). Sensitivity analyses were performed. RESULTS: A total of 18512 patients were identified: PN (93.88%) and CA (6.12%). In the propensity-score matched cohort, for tumours ≤ 2 cm, the CA and PN groups had similar CSM (HR: 1.41, 95% CI: 0.32-6.31, p = 0.65) and OM (HR 0.97, 95%CI: 0.47-2.01, p = 0.93). For tumours 2-3 cm, CA was associated with similar CSM (HR 1.64, 95%CI: 0.67-4.03, p = 0.28) but higher OM (HR 2.05, 95%CI: 1.35-3.11, p < 0.001), compared with PN. For tumours 3-4 cm, CA was associated with increased CSM (HR: 3.76, 95% CI: 1.62-8.69, p = 0.002) and OM (HR 2.17, 95%CI: 1.48-3.18, p < 0.001). CONCLUSION: For RCC ≤ 2 cm, PN and CA are equal in survival outcomes. For RCC 2-4 cm, PN may have a possible advantage over CA.