Volumetric Analysis of Renal Masses as Predictors of Partial Nephrectomy Outcomes

Objective: To examine the role of endophytic tumor volume (TV) assessment (endophycity) on perioperative partial nephrectomy (PN) outcomes. Patients and Methods: Retrospective review of 212 consecutive laparoscopic and open partial nephrectomies from single institution using preoperative imaging and 1-year follow-up. Demographics, comorbidities, RENAL nephrometry scores, and all peri- and postoperative outcomes were recorded. Volumetric analysis performed using imaging software, independently assessed by two blinded radiologists. Univariate and multivariate statistical analysis were completed to assess predictive value of endophycity for all clinically meaningful outcomes. Results: Among those undergoing minimally invasive surgery (MIS), lower tumor endophycity was associated with higher likelihood of trifecta outcome (negative surgical margin, <10% decline in estimated glomerular filtration rate, the absence of complications) irrespective of max tumor size. For MIS, estimated blood loss increased with greater tumor endophycity regardless of tumor size. Among those who underwent open partial nephrectomy, lower tumor endophycity was associated with trifecta outcomes for tumors >4 cm only. On multivariate analysis with log-scaled odds ratios (OR), tumor endophycity and total kidney volume had the strongest correlation with tumor-related complications (OR = 3.23, 2.66). The analysis identified that tumor endophycity and TV on imaging were inversely correlated with of trifecta outcomes (OR = 0.53 for both covariates). Conclusions: Volumetric assessment of tumor endophycity performed well in identifying PN outcomes. As automated imaging software improves, volumetric analysis may prove to be a useful adjunct in preoperative planning and patient counseling.