Perinephric and Sinus Fat Invasion in Stage pT3a Tumors Managed by Partial Nephrectomy.

Introduction: We evaluated the influence of perinephric fat invasion (PFI) compared with sinus fat invasion (SFI) on disease-free survival (DFS) and cancer-specific survival (CSS) after partial nephrectomy (PN) for stage pT3a renal cell carcinoma (RCC).

Materials And Methods: Data were recorded from the consecutive records of patients who had undergone underwent PN for cT1-T2 RCC from 2007 to 2016. Of these patients, 143 had stage pT3a with SFI or PFI found on final pathologic examination. The demographic, perioperative, and pathologic variables were reviewed. DFS and CSS analyses were performed. The factors predicting disease progression in this population were assessed.

Results: After a median follow-up period of 28 months (range 15-41 months), 19 patients (13.3%) had developed recurrence, including 5 local and 14 distant metastases, with 11 cancer-specific deaths (7.7%). No differences were found in DFS (5 years, 60.9% vs. 55.3%; log-rank P = .7) or CSS (5 years, 81% vs. 74.2%; log-rank P = .8) between the SFI and PFI groups. For the pT3a fat invasion population, the 2- and 5-year DFS and CSS rates were 83.6% and 58.6% and 93.6% and 78%, respectively. SFI (P = .5) and positive surgical margins (P = .1) did not predict for progression. On multivariate Cox regression, increased tumor size (hazard ratio, 1.5; 95% confidence interval, 1.1-1.9; P < .01) and higher tumor grade (hazard ratio, 3.6; 95% confidence interval, 1.1-4.6; P = .04) were independent predictors of disease progression in the pT3a fat invasion population.

Conclusion: In our series of patients with pT3a RCC after PN, SFI compared with PFI was not associated with an increased risk of progression or cancer-specific death.