Prediction Of Pentafecta Achievement Following Laparoscopic Partial Nephrectomy:Implications For Robot-assisted Surgery Candidates

Objective:Due to the advantages of robotic surgical system,for most tumors,robot-assisted partial nephrectomy(RAPN)can achieve more favorable perioperative outcomes compared to laparoscopic partial nephrectomy(LPN).However,previous studies denied the benefit of RAPN in treating tumors<4cm,Moreover,because of the expensive equipment,the direct cost of RAPN is much higher than LPN.Hence,we aim to evaluate surgical outcomes,assess the individual benefit from LPN to RAPN,which can guide clinical decision-making.Materials and Methods:We included the patients with localized renal cell carcinoma(RCC)undergoing LPN or RAPN between Jan 2013 and Dec 2016 in our hospital.The baseline demographics,anatomic features,surgical,pathologic and functional outcomes were collected.After performing propensity-score matched analysis(1:1),the perioperative,pathologic and functional outcomes were compared between LPN and RAPN groups.The pentafecta achievement[negative margin,no perioperative complication,ischemia time?25 min,return of glomerular filtration rate(eGFR)to>90%from baseline at last follow-up,and no chronic kidney disease upstaging]was used to evaluate surgical outcomes.Univariable and multivariable logistic regression analyses were applied to explore the predictors of pentafecta achievement following LPN.Using regression coefficients from the multivariable analysis,a nomogram for predicting the probability of pentafecta was established.A locally weighted,scatterplot smoothing method was used to graphically explore the observed pentafecta rate against the predicted probability of pentafecta.Results:A total of 1,393 patients were included,790 of them underwent LPN,603 of them underwent RAPN.For baseline variables,more patients in LPN group had a history of diabetes(16.2%vs.11.9%,P = 0.025).For patients in RAPN group,the surgical complexity is higher,the median maximum diameter of tumor is larger(3.3cm vs.2.8cm,P<0.001),the complexity of RENAL score is higher(P<0.001),the rate of hilar tumor is higher(13.8%vs.7.7%,P<0.001).After matching,there is no significant difference for preoperative variables(P>0.05).Compared to RAPN,LPN group had a more estimated blood loss(50ml vs.40ml,P = 0.007),a longer renal artery clamping time(20min vs.18min,P<0.001),a longer postoperative hospital stay(6days vs.5days,P<0.001),a less direct cost(?33461 vs.?72923,P<0.001).There is no significant difference between LPN and RAPN in terms of operative time,rate of transfusion,rate of conversion,perioperative complications,and positive surgical margin(P>0.05).Pathological results showed that most of them were malignant tumors,and clear cell RCC was the most common type.There is no significant difference for histology(P = 0.826),pathologic T stage(P = 0.152),Fuhrman grade(P =0.174),tumor necrosis(P = 0.062).After surgery,the percentage of eGFR decline was higher in the LPN group at day 1(12.3%vs.19.2%,P<0.001)and the latest follow-up(4.3%vs.6.4%,P<0.001).For pentafecta achievement,the rate of ischemia time?25 min(P<0.001),and return of eGFR to>90%from baseline at last follow-up is higher in RAPN group,there is no significant difference for other three components.Moreover,RAPN group had a significantly higher pentafecta achievement(54.6%vs.41.1%,P<0.001).Logistic regression analyses identified that tumor size,preoperative eGFR and distance of tumor to collecting system or sinus were independent predictors of pentafecta after LPN.According to these three variables,the nomogram for predicting pentafecta after LPN was established.The calibration performed well and the C-index was 0.66.All patients can benefit from LPN to RAPN(P<0.001).When RAPN was chose over LPN,the increase in the probability of pentafecta achievement was greatest in intermediate-probability patients.With the increase or decrease of the probability of pentafecta achievement,the benefit of RAPN decreases.Conclusions:For localized RCC,compared to LPN,RAPN can achieve more favorable perioperative outcomes(estimated blood loss,renal artery clamping time,and postoperative hospital stay),and early renal functional preservation,but need a more direct cost.When pentafecta achievement are evaluated,the benefit of choosing RAPN is not the same in all patients.Specifically,patients at intermediate-probability of pentafecta in case of LPN may benefit the most from RAPN and represent ideal RAPN candidates.The predictive model is helpful for clinical decision-making.