Introduction and Objective: Robot-assisted radical nephrectomy (RRN) is increasingly utilized as an alternative to laparoscopic radical nephrectomy (LRN), but there are concerns over costs and objective benefit. In the setting of very large renal masses (>10 cm), comparison between techniques is limited and it is unclear whether a robotic approach confers any perioperative benefit over LRN or open radical nephrectomy (ORN). In this study, perioperative outcomes of RRN, LRN, and ORN for very large renal masses are compared. Methods: Using the National Cancer Database, patients were identified who underwent radical nephrectomy for kidney tumors >10 cm diagnosed from 2010 to 2015. Patients were analyzed according to surgical approach. Perioperative outcomes, including conversion to open, length of stay, readmission rates, positive surgical margins, and 30- and 90-day mortality were compared among cohorts. Results: A total of 9288 patients met inclusion criteria (RRN = 842, LRN = 2326, ORN = 6120). Compared with ORN, recipients of RRN or LRN had similar rates of 30-day readmission and 30- and 90-day mortality. Length of hospital stay was significantly shorter in RRN (-1.73 days ±0.19; p < 0.0001) and LRN (-1.40 days ±0.12; p < 0.0001) compared with ORN. LRN had a higher rate of conversion to open compared with RRN (odds ratio 1.48; 95% confidence interval 1.10-1.98; p = 0.0087). Conversion to open from RRN or LRN added 1.3 additional days of inpatient stay. Over the study period, RRN use increased from 4.1% to 14.8%, LRN from 20.9% to 25.6%, whereas ORN use decreased from 75% to 59.6%. Conclusions: Minimally invasive approaches are increasingly utilized in very large renal masses. RRN has lower rates of conversion to open but produces comparable perioperative outcomes to LRN. Minimally invasive approaches have a shorter length of inpatient stay but otherwise report similar surgical margin status, readmission rates, and mortality rates compared with ORN.

Initiation is a highly regulated, rate-limiting step in transcription. We used a series of approaches to examine the kinetics of RNA polymerase (RNAP) transcription initiation in greater detail. Quenched kinetics assays, in combination with gel-based assays, showed that RNAP exit kinetics from complexes stalled at later stages of initiation (e.g., from a 7-base transcript) were markedly slower than from earlier stages (e.g., from a 2- or 4-base transcript). In addition, the RNAP-GreA endonuclease accelerated transcription kinetics from otherwise delayed initiation states. Further examination with magnetic tweezers transcription experiments showed that RNAP adopted a long-lived backtracked state during initiation and that the paused-backtracked initiation intermediate was populated abundantly at physiologically relevant nucleoside triphosphate (NTP) concentrations. The paused intermediate population was further increased when the NTP concentration was decreased and/or when an imbalance in NTP concentration was introduced (situations that mimic stress). Our results confirm the existence of a previously hypothesized paused and backtracked RNAP initiation intermediate and suggest it is biologically relevant; furthermore, such intermediates could be exploited for therapeutic purposes and may reflect a conserved state among paused, initiating eukaryotic RNA polymerase II enzymes.