A comparative analysis of various surgical approaches of nephron-sparing surgery and correlation of histopathological grade with RENAL nephrometry score in renal cell carcinoma

Nephron-sparing surgery (NSS) is the standard of care for small renal masses whenever feasible. This study aims to evaluate the perioperative outcomes of NSS performed by open (open partial nephrectomy [OPN]) or laparoscopic (laparoscopic PN [LPN]) or robotic (robotic PN [RPN]) approach over the past 6 years and to study the correlation of histopathological grade of renal cell carcinoma with the RENAL score. Materials and Methods: A retrospective analysis of prospectively collected data of all patients who underwent NSS was done. Results: A total of 135 patients underwent NSS. The mean tumour size was 4.4 cm. About 61 patients underwent OPN, 24 had LPN and 50 had RPN. Although tumour size was larger in OPN group (P = 0.01), tumour complexity based on the RENAL score was similar in OPN and RPN groups (P = 0.15). The OPN group had shorter operative time (P = 0.008) but more blood loss (P = 0.001) and length of hospital stay (P = 0.049) as compared to LPN or RPN group. Maximum radiological diameter of tumour (P = 0.017) appeared to be a significant predictor of operative time, while the open surgical approach (P = 0.003) and tumour stage (P = 0.044) were found to be significant predictors of blood loss. Hilar clamping time was similar in OPN and RPN groups (P = 0.054) but higher in LPN group (P = 0.01). However, post-operative decline in renal function (estimated glomerular filtration rate) (P = 0.08) and margin status were comparable among the three groups. The most common histopathology was clear cell carcinoma (70%), and RENAL score was identified as a significant predictor of histopathological grade of tumour (P = 0.008). Conclusion: Open, laparoscopic and robotic approaches to PN provide similar patient outcomes. OPN was usually preferred for larger tumours. The post-operative decline in renal functions and complications were comparable among the three approaches. RENAL score correlated significantly with histopathological grade and hence could help in predicting tumour behaviour pre-operatively.