Trends and safety of robot-assisted partial nephrectomy during the initial 2-year period after government approval in Japan: A nationwide database study from 2016 to 2018.

ABSTRACT

OBJECTIVES: To evaluate the trends and safety of robot-assisted partial nephrectomy during the initial 2-year period after government approval for this type of procedure in April 2016. METHODS: This nationwide retrospective study included 3722 received robot-assisted partial nephrectomy cases carried out from April 2016 to March 2018 in 124 participating institutions. The institutions were divided into lower- and higher-volume institutions according to the median of 19 robot-assisted partial nephrectomy cases during the study period. Surgical outcomes between 616 cases from lower-volume institutions and 3106 cases from higher-volume institutions were compared using propensity score matching. RESULTS: During the study period, both the number of robot-assisted partial nephrectomy surgeries and the number of institutions in which the surgery was carried out steadily increased. Overall, the median anesthesia time was 217 min, the median postoperative length of stay was 9 days, and the proportion of blood transfusions, complications and readmissions were 0.8%, 5.1% and 1.0%, respectively. There were no significant differences in anesthesia time, incidence of blood transfusions, and complication rates between the lower-volume and higher-volume institutions. However, a slightly, but significantly, longer postoperative length of stay and a lower incidence of readmission were observed in lower-volume institutions both before and after propensity score matching. CONCLUSIONS: Robot-assisted partial nephrectomy has become widespread during the initial 2-year period after government approval with an acceptable safety profile, regardless of the institutional caseloads. This technique has become a standard of care for stage 1 renal cancer patients in Japan.