Interim analysis of robot-assisted radical hysterectomy in Japan: a multicenter, prospective interventional single-arm clinical trial.

Objective: To investigate the efficacy and safety of robot-assisted radical hysterectomy (RARH) as a minimally invasive procedure in patients with cervical cancer that is curable by surgery.

Materials and methods: This study was a multicenter, open-label, single-arm clinical trial. The short-term outcome of open radical hysterectomy was used as the historical control. The primary endpoint was successful surgery with minimal blood loss (300 mL or less) and negative surgical margins. Secondary endpoints included surgical outcomes, recurrence-free survival (RFS), and overall survival (OS) rates.

Results: Overall, 101 cases were enrolled in this study at 10 participating medical institutions and 100 underwent RARH. Among these cases, 89 met the primary endpoint, exceeding the threshold of 0.75 set by the lower limit. At 2 years postoperatively, 17 cases had recurrences, 4 were classified as International federation of Obstetrics and Gynecology Stage IB1 or lower, while 13 as IB2 or higher. There were three deaths, including one in Stage IB1 and two in Stage IIB in the second postoperative year, all of which had lymph node metastasis. The oncological outcomes for all cases showed RFS and OS rates of 82.7% and 96.9%, respectively, over a median observation period of 37 months. For cases with Stage IB1, RFS and OS were 94.1% and 98.5%, respectively.

Conclusion: RARH demonstrated a significant reduction in blood loss while ensuring radicality, indicating the safety and efficacy of this procedure compared to conventional RH. Although it is conceivable that the results of this oncological analysis could change, as the data collection has not been fully completed, we plan to further evaluate the oncologic outcomes of RARH in future studies.

Trial registration: UMIN-CTR: UMIN000022278, registered on 11th May 2016.