Achievement of trifecta in minimally invasive partial nephrectomy correlates with functional preservation of operated kidney: a multi-institutional assessment using MAG3 renal scan

Purpose: To validate and compare the values of "MIC" and "trifecta" as predictors of operated kidney functional preservation in a multi-institutional cohort of patients undergoing minimally invasive PN. Methods: We retrospectively reviewed records of consecutive cases of minimally invasive PN performed for cT1 renal masses in 4 centers from 2009 to 2013. Inclusion criteria consisted of availability of a renal scan obtained within 2 weeks prior to surgery and follow-up renal scan 3-6 months after the surgery. The primary endpoint of the study was to compare the degree of ipsilateral renal function preservation assessed by MAG3 renal scan in relation to achievement of MIC and trifecta. Results: Total of 351 patients met our inclusion criteria. The rates of trifecta achievement for cT1a and cT1b tumors were 78.9 and 60.6 %, respectively. The rate of MIC achievement for cT1a tumors and cT1b tumors was 60.3 and 31.7 %, respectively. On multivariable linear regression model, only the degree of tumor complexity assessed by R.E.N.A.L nephrometry score [coefficient B -1.8 (-2.7, -0.9); p < 0.0001] and the achievement of trifecta [coefficient B 6.1 (2.4,9.8); p = 0.014] or MIC (coefficient B 7.2 (3.8,0.6); p < 0.0001) were significant clinical factors predicting ipsilateral split function preservation. Conclusions: Achievement of both MIC and "trifecta" is associated with higher proportion of split renal function preservation for cT1 tumors after minimally invasive PN. Thus, these outcome measures can be regarded not only as markers of surgical quality, but also as reliable surrogates for predicting functional outcome in the operated kidney.