Using R.E.N.A.L. nephrometry and preoperative aspects and dimensions employed for anatomical classification to evaluate perioperative outcomes of renal tumors greater than 4 cm in patients who underwent minimally invasive partial nephrectomy in a single center

Purpose: The R.E.N.A.L. (radius, exophytic/endophytic tumor properties, nearness of tumor to deepest portion of collecting system or sinus, anterior/posterior descriptor, and location relative to the polar line) and preoperative aspects and dimensions used for an anatomical (PADUA) (tumor size and position, relationship with the renal sinus or the urinary collecting system, and the grade of deepness into the kidney) nephrometry scoring systems are frequently used in predicting the perioperative outcomes of nephron-sparing surgery (NSS). Minimally invasive NSS on renal masses beyond 4 cm in diameter remains challenging and may result in the significant complications. We aimed to evaluate the associations of both scoring systems with perioperative outcomes for minimally invasive NSS on renal masses larger than 4 cm in diameter. Materials and Methods: We retrospectively reviewed patients who received robot-assisted partial nephrectomy (PN) or laparoscopic PN for renal tumors larger than 4 cm in diameter in our institution between January 2008 and March 2019. Computed tomography scan and magnetic resonance imaging were the standard cross-section imaging modalities done before surgery and both R.E.N.A.L. and PADUA scores were calculated in every case accordingly. The correlation between each scoring system and the perioperative and renal functional outcomes was analyzed by logistic regression models. Results: A total of 93 cases were enrolled in this study. The mean tumor size was 6.1 ± 2.03 cm in the largest dimension. A higher R.E.N.A.L. score was significantly correlated with longer warm ischemia time (WIT) (r = 0.267, P = 0.021), prolonged hospital stays (r = 0.258, P = 0.013), and poorer renal functional outcome at 1 year (r = 0.421, P = 0.003). Meanwhile, a higher PADUA score was significantly correlated with longer operation time (r = 0.255, P = 0.014), longer WIT (r = 0.278, P = 0.016), and poorer renal function after 1 year (r = 0.615, P < 0.001). Neither scoring system correlated with estimated blood loss (P = 0.510 and 0.5466, respectively). The R.E.N.A.L. score, PADUA score, patient age, body mass index, Charlson comorbidity index, tumor size, and American Society of Anesthesiologists score were not associated with surgical complications as well. Conclusion: Both the R.E.N.A.L. and PADUA scoring systems were associated with WIT and renal functional outcomes, but the latter was more relevant. When performing minimal invasive NSS on renal masses beyond 4 cm, both systems can provide valuable risk stratification, but PADUA was found to be superior in the current study.