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Robotic Versus Laparoscopic Pelvic Lymphadenectomy for Endometrial Cancer Under the Japanese Public Health Insurance System

HIKARU IMATAKE, KANA KAWAI, YUKA MATSUMOTO, YURI SUMINAGA, CHIHIRO NAKAI, YURIKO TANABE, NAOYA KISHIMOTO, IKUKO EMOTO, YASUAKI AMANO and KAORU ABIKO
In Vivo September 2025, 39 (5) 2794-2800; DOI: https://doi.org/10.21873/invivo.14078

Abstract

Background/Aim: Surgery is the preferred treatment modality for endometrial cancer. In recent years, minimally invasive surgery (MIS) has become increasingly popular, and in Japan, robotic surgery has been covered by national insurance in addition to laparoscopic surgery for apparent stage IA cases since 2018. We conducted a comparative analysis of laparoscopic and robotic surgeries, including pelvic lymphadenectomy for stage IA endometrial cancer, with the aim of evaluating the efficacy of robotic surgery.

Patients and Methods: A retrospective analysis was conducted for patients who underwent MIS pelvic lymphadenectomy between January 2018 and December 2023. Sixty-nine patients who underwent robotic surgery and 29 who underwent laparoscopic surgery were included in the study. All the patients underwent total hysterectomy and pelvic lymph node dissection, with preoperative diagnosis of stage 1A and G1-G2 endometrial cancer.

Results: Operative time was longer in the robotic group (median=316 vs. 272 min in the laparoscopic group, p=0.02). Intraoperative blood loss and postoperative hospital stay were lower in the robotic group (median blood loss: 0 vs. 50 ml for the laparoscopic group, p<0.01; median postoperative hospital stay: 5 vs. 8 days for the laparoscopic group, p<0.01). No statistically significant differences were found in the incidence of complications and recurrence between the two groups.

Conclusion: This retrospective analysis suggests that robotic surgery is a feasible and safe procedure for total hysterectomy and pelvic lymph node dissection in patients with preoperative diagnosis of stage IA and G1-G2 endometrial cancer.

Keywords:

Introduction

The number of patients diagnosed with endometrial cancer in Japan has continued to increase, reaching 17,779 in 2020 (1). Surgical treatment remains the primary treatment option for endometrial cancer, and in recent years, minimally invasive surgery (MIS) has been gaining ground (2). Since 2018, robotic surgery for patients with apparent stage IA endometrial cancer has been covered by national insurance in Japan, in addition to laparoscopic surgery. In the United States, data between 2017 and 2020 showed that 16.7% of uterine cancer surgeries were performed via laparotomy, 19.0% via laparoscopy, and 64.3% via robotic surgery (3). In contrast, in Japan, due to the delayed insurance approval for robotic surgery compared with laparoscopic surgery, there are few domestic reports comparing the two approaches (4). Furthermore, sentinel-node navigation surgery for endometrial cancer is not covered by national insurance; therefore, only select institutions perform the procedure in Japan. Therefore, many institutions in Japan perform pelvic lymph node dissection for patients with early-stage endometrial cancer. In this study, we aimed to investigate the utility of robotic surgery in community hospitals using real-world data by retrospectively comparing laparoscopic and robotic surgeries, including pelvic lymphadenectomy for apparent stage IA endometrial cancer at our hospital.

Patients and Methods

Study design and patients. A single-center retrospective study was conducted. Patients who underwent laparoscopic simple total hysterectomy and pelvic lymph node dissection or robotic-assisted laparoscopic simple total hysterectomy and pelvic lymph node dissection for preoperative diagnosis of stage IA uterine cancer and G1 or G2 endometrioid carcinoma histology between January 2018 and December 2023 at the Kyoto Medical Center were included in this study. Robotic surgery was performed using the Da Vinci Si or Xi Surgical System® (Intuitive Surgical Inc., Sunnyvale, CA, USA). Data were collected from electronic medical records, including patient age at surgery, body mass index (BMI), preoperative diagnosis, intraoperative blood loss, operative time, number of lymph nodes dissected, postoperative diagnosis, postoperative adjuvant therapy, complications, and recurrence. Recurrence and complications were followed-up until August 2024.

Data analysis. The Mann–Whitney U-test was used for age, BMI, operative time, intraoperative blood loss, number of lymph nodes dissected, and postoperative hospital stay, while Fisher’s exact probability test was used to compare the number of complications, postoperative adjuvant chemotherapy, and recurrence. Spearman’s rank correlation coefficients were used to examine the correlations between operative time and age, BMI, intraoperative blood loss and number of lymph nodes dissected.

Ethical considerations. This study was approved by the Institutional Review Board of Kyoto Medical Center (approval number: 20-083).

Results

The year 2020 was the transitional period from laparoscopic to robotic surgery at Kyoto Medical Center, and after 2021, most surgeries for stage IA endometrial cancer with G1 and G2 endometrioid histology were performed by robotic surgery (Figure 1).

Figure 1.
Figure 1.

Annual trend of patients eligible for surgery by type. Robotic surgery has been performed for most patients since the year 2021.

We included 29 patients in the laparoscopic group and 69 in the robotic group (Table I). There were no significant differences in age or BMI between the two groups (median age was 57 vs. 55 years in the robotic group and the laparoscopic group, respectively, p=0.86; median BMI was 24.5 vs. 23.0 kg/m2, respectively, p=0.10). Operative time was significantly longer in the robotic group (median of 316 vs. 272 min respectively, p=0.02). Intraoperative blood loss and postoperative hospital stay were significantly lower in the robotic group (median blood loss was 0 vs. 50 ml, respectively, p<0.01; median postoperative hospital stay: 5 vs. 8 days, respectively, p<0.01). There was no significant difference in the number of lymph nodes resected (median of 18 vs. 21, respectively, p=0.06).

View this table:
Table I.

Comparison of laparoscopic and robotic groups.

There was no increase in complications with robotic surgery compared with laparoscopic surgery. Intra-operative complications included one patient with external iliac vein injury in the laparoscopic group, which was sutured intraoperatively. Postoperative complications in the robotic group included one patient with postoperative infection, one with wound hematoma, one with bowel obstruction, and one with postoperative atelectasis, pulmonary edema, and acute renal failure. In the laparoscopic group, there were two patients with urinary tract stenosis, one with postoperative infection, and one with pulmonary embolism. All patients with complications fully recovered after adequate intervention. There were no cases converted to laparotomy in either group.

We also examined the correlation between operative time and age, BMI, intraoperative blood loss, and number of lymph nodes resected using Spearman’s rank correlation coefficient. We found positive correlations of operative time with BMI and intraoperative blood loss (Figure 2).

Figure 2.
Figure 2.

Correlation of operative time with other characteristics in patients undergoing robotic or laparoscopic surgery. Correlation between operative time and age (A), body mass index (BMI) (B), intraoperative blood loss (C), and number of lymph nodes resected (D). BMI and intraoperative blood loss were statistically significantly associated with operative time. Rs: Spearman’s rank correlation coefficient.

We compared laparoscopic surgery with robotic surgery in obese patients with BMI ≥25 kg/m2 only (Table II). No statistically significant difference in operative time was found (median of 294 min in the robotic group vs. 363 min in the laparoscopic group, p=0.078), and no increase in blood loss or complications was observed. Postoperative hospital stay was also significantly shorter in the robotic group (median of 5 vs. 8 days, respectively, p=0.001).

View this table:
Table II.

Comparison of laparoscopic and robotic groups in patients with a body mass index (BMI) of ≥25 kg/m2.

Oncological prognosis is shown in Table III. Post-operative histological diagnosis was changed from the preoperative diagnosis of endometrial carcinoma G1 or G2 for one (3.4%) patient in the laparoscopic group (endometrial carcinoma G3) and four (5.8%) in the robotic group (endometrial carcinoma G3 in two patients, serous carcinoma in one, and cervical adenocarcinoma in one). Two (6.9%) patients in the laparoscopic group (one with stage IB and one with stage IIIC) and four (5.8%) in the robotic group (one with stage IB, two with stage II, and one with stage IIIC) had advanced disease beyond stage IA. Postoperative adjuvant chemotherapy was administered to seven patients in the robotic group and two in the laparoscopic group. Two recurrences were observed in the robotic group, but there was no difference between the two groups. The site of recurrence was vaginal and pelvic in one patient, and pelvic peritoneal dissemination in the other. Both recurrences were treated with chemotherapy, but the disease progressed, and one patient died of the original disease 11 months postoperatively, whilst the other patient was alive with disease at 1 year and 4 months postoperatively.

View this table:
Table III.

Comparison of oncological prognosis between laparoscopic and robotic groups.

Discussion

In this study, the robotic surgery group had longer operative time than the laparoscopic group, but intraoperative blood loss and postoperative hospital stay were reduced, and there were no significant differences in the number of complications or recurrences. Previous studies have reported that MIS for early-stage endometrial cancer reduces complications and postoperative hospital stay, with no difference in oncologic outcome between laparoscopic and robotic surgeries compared with open surgery (2, 5, 6). Furthermore, although robotic surgery increases operative time, surgical complications and oncological outcomes are similar as those of laparoscopic surgery (7). The present study and previous reports suggest that robotic surgery can be safely performed for early-stage endometrial cancer and reduce blood loss and postoperative hospital stay (6, 8). Factors that may contribute to prolonged operative time include the time required for roll-in and docking, and the fact that in laparoscopic surgery, the assistant’s forceps move simultaneously, whereas in robotic surgery, the operation is performed with the third arm fixed. In robotic surgery, the forceps are articulated, allowing for more detailed movements, and the three-dimensional magnified field of view may have contributed to the reduction in blood loss.

Although there was no statistically significant difference in surgery for patients with obesity in our study, there was also no increase in complications or postoperative hospital stay for robotic surgery; however, robotic surgery may prolong operative time in obese patients compared with laparoscopic surgery. Obesity has been implicated as a risk factor for uterine cancer (9-11), and patients with obesity have a higher surgical risk than those without (10). In this study, the median BMI of patients with obesity was approximately 30 kg/m2, and there were few patients with severe obesity. However, previous reports from overseas have reported that laparoscopic and robotic surgeries have fewer complications than open surgery for obesity-associated uterine cancer (12, 13), and that robotic surgery is associated with fewer complications conversions to laparotomy than laparoscopic surgery (14-16), implying robotic surgery for endometrial cancer can be performed safely without increased complications, even in patients with obesity.

Between 2017 and 2020 in the United States, 16.7% of surgeries for endometrial cancer were open, 19.0% were laparoscopic, and 64.3% were robotic (3), while in Japan, robotic surgery for endometrial cancer was covered by national insurance from 2018, and the introduction of robotic surgery has been delayed. In Japan, of uterine cancer surgeries performed in 2021, 62.8% were open surgery, 23.5% laparoscopic surgery, and 14.8% robotic surgery (17). Furthermore, in Japan, MIS is covered by national insurance only in stage IA cases. Sentinel node navigation surgery is not covered by national insurance either; therefore, many IA G1-2 cases undergo pelvic lymph node dissection instead of sentinel node detection. Although MIS and sentinel node navigation surgery for stage I-II endometrial cancer is widely accepted worldwide, large-scale studies of the real-world Japanese situation are limited. This study provides real-world evidence of national insurance-restricted practice widely accessible in Japan.

At our hospital, robotic surgery is also performed by junior physicians under the guidance of gynecological oncologists and Board-certified endoscopists. The present study suggests that robotic surgery for early-stage endometrial cancer can be performed safely, even while the use of robotic surgery continues to increase in Japan, as does the number of surgeons at community hospitals and surgeons with different years of experience.

Study limitations. Limitations of this study include the limited number of patients in a single institution and the retrospective nature of the study, as well as the difference in surgeon skill for each operation. Additionally, evaluation of long-term oncological prognosis is difficult due to the short follow-up period. In contrast, the strength of this study is that the period during which both laparoscopic and robotic surgeries were performed was short; therefore, there was minimal bias in the choice of surgical technique. There was no difference in surgeon skill between laparoscopic and robotic surgeries, and no patient underwent both surgeries.

As the use of robotic surgery is expected to continue increasing in the future, the usefulness and safety of robotic surgery for endometrial cancer should be further investigated by examining a larger number of cases at multiple centers. Additionally, although we reviewed surgeries between 2018-2023 in this study, the 2018 edition of the Japanese Guidelines for the Treatment of Uterine Cancer states that pelvic lymph node dissection is necessary to accurately determine the stage of surgical progression of endometrial cancer (18) and pelvic lymph node dissection was performed as standard treatment in our hospital. Since lymph node metastasis is rarely detected in stage IA endometrial cancer with G1-2 endometrioid histology, the 2023 edition of the guidelines for the treatment of endometrial cancer suggests that pelvic lymph node dissection should be omitted (19). Our study also indicated a low frequency of pelvic lymph node metastasis in patients with apparent stage IA G1-2 endometrioid histology. Comparison of robotic versus laparoscopic surgeries for cases omitting lymphadenectomy should be planned in the future.

Conclusion

Robotic surgery for early-stage endometrial cancer is safe and effective in community hospitals, with minimum intraoperative blood loss and no increase in complications, although it takes longer than laparoscopic surgery. Additionally, robotic surgery is considered safe for the treatment of early-stage endometrial cancer associated with obesity.

Footnotes

  • Authors’ Contributions

    Conception and design: HI and KA; data curation; HI, YS and KA; formal analysis; HI and KA; investigation: HI, KK, YM, YS, CN, YT, NK, EI, YA and KA; article writing: HI and KA; final approval of article: all Authors.

  • Conflicts of Interest

    The Authors declare no conflicts of interest related to this manuscript.

  • Funding

    No funding was received for the completion of this study or the preparation of this manuscript.

  • Artificial Intelligence (AI) Disclosure

    During the preparation of this manuscript, a large language model (DeepL and DeepL Write, DeepL) was used solely for language editing and stylistic improvements in select paragraphs. No sections involving the generation, analysis, or interpretation of research data were produced by generative AI. All scientific content was created and verified by the authors. Furthermore, no figures or visual data were generated or modified using generative AI or machine-learning-based image enhancement tools.

  • Received May 14, 2025.
  • Revision received June 6, 2025.
  • Accepted June 11, 2025.

This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY-NC-ND) 4.0 international license (https://creativecommons.org/licenses/by-nc-nd/4.0).

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Robotic Versus Laparoscopic Pelvic Lymphadenectomy for Endometrial Cancer Under the Japanese Public Health Insurance System
HIKARU IMATAKE, KANA KAWAI, YUKA MATSUMOTO, YURI SUMINAGA, CHIHIRO NAKAI, YURIKO TANABE, NAOYA KISHIMOTO, IKUKO EMOTO, YASUAKI AMANO, KAORU ABIKO
In Vivo Sep 2025, 39 (5) 2794-2800; DOI: 10.21873/invivo.14078
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