Does the Unexpected Presence of Non-organ-confined Disease at Final Pathology Undermine Cancer Control in Patients with Clinical T1N0M0 Renal Cell Carcinoma Who Underwent Partial Nephrectomy?

Background: A non-negligible proportion of individuals diagnosed with cT1 renal cell carcinoma (RCC) are upstaged to pT3a at final pathology. Few data on oncological outcomes for these patients are available to determine whether partial nephrectomy (PN) might jeopardise cancer control. Objective: To assess, within an international multi-institutional collaboration, whether PN might undermine cancer control relative to radical nephrectomy (RN) in RCC patients with unexpected pT3a disease. Design, setting, and participants: International multi-institutional collaboration including patients with cT1abN0M0-pT3a RCC. Intervention: PN or RN. Outcome measurements and statistical analysis: We used Kaplan-Meier analyses, before and after propensity-score matching, to evaluate differences in metastatic progression (MP) and cancer-specific mortality (CSM) rates during follow-up. Univariable and multivariable Cox regression analyses were used to assess predictors of MP and CSM. Results and limitations: Overall, 309 patients with cT1abN0M0 RCC (cT1aN0M0, n = 107, 34.6%; cT1bN0M0, n = 202, 65.4%) had pT3a disease according to final pathology. Patients were treated with either PN (n = 71, 23%) or RN (n = 238, 77%). MP at 1, 2, and 5 yr was detected in 9.1%, 13.3%, and 24.1% of patients, respectively. CSM was 3.5%, 10.7%, and 18.4% at 1, 2, and 5 yr, respectively. After matching, no difference in terms of MP or CSM was observed between the PN and RN cohorts (both p>0.3). On multivariable analysis, type of surgery (PN vs RN) was not an independent predictor of either MP (p = 0.3) or CSM (p = 0.4). Limitations include the retrospective design. Conclusions: In patients with unexpected pT3a RCC at final pathology, PN does not appear to jeopardise cancer control with regard to MP and CSM. Patient summary: Cancer control is similar between patients treated with removal of the entire kidney and those with only partial removal, even if the final histology examination demonstrates a tumour that is unexpectedly not confined within the kidney. Partial nephrectomy does not undermine cancer control when unexpected pT3a renal cancer is identified at final pathology.