Endometrial cancer is the most common gynecological malignancy, affecting 410,000 people per year worldwide and ranking sixth in the number of malignant tumors in women [1]. In Japan, it is the fifth most common malignancy in women, with 18,000 patients reported annually [2]. It is an important disease with a gradually increasing number of patients [3]. Surgery is the primary treatment for endometrial cancer. Although laparotomy has been used, laparoscopic surgery, and more recently, robotic surgery, is being increasingly performed [4, 5]. Regarding minimally invasive surgery for endometrial cancer in Japan, public insurance covered laparoscopic surgery in 2014 and robotic surgery in 2018. Our hospital began introducing robotic surgery in 2019. In a comparison between laparoscopic surgery and robotic surgery, studies have reported that there is no significant difference in surgical outcomes and accuracy of diagnosis and that laparoscopic surgery is superior to robotic surgery in terms of operation time [6, 7, 8, 9, 10, 11]. Most of these reports are based on data from facilities with sufficient physicians and equipment due to the short period since the practical application of robotic surgery.

In contrast, our hospital has only one gynecologic oncologist who is not specialized in laparoscopy; this gynecologic oncologist manages almost all patients with malignant tumors as outpatients and performs operations. For minimally invasive surgery for stage I endometrial cancer to be more prevalent as a safer and higher quality treatment in the future, it must be introduced and sustained even in hospitals with few gynecologists or no specialists in minimally invasive surgery. Therefore, this study aimed to investigate whether robotic or laparoscopic surgery is more useful for sustainable medical treatment at a local facility by comparing the operation time and other indices.

In this retrospective study conducted at our institution, RALH for stage I uterine cancer was performed within a shorter operative time than TLH, with shorter hospitalization days and no obvious complications. In contrast to TLH, RALH was achieved with two operators instead of three. These results indicate that RALH is a sustainable and minimally invasive surgery for stage I uterine cancer.

Minimally invasive surgery has been widely used to treat stage I endometrial cancer, as laparoscopic surgery has advantages in the perioperative course and results in a slight increase in the risk of long-term prognosis compared with laparotomy [13, 14]. Subsequently, reports of better short-term results with fewer complications, less blood loss, and fewer cases of conversion to laparotomy in robotic surgery than in laparoscopic surgery and reports of advantages in obese patients have led to the widespread use of robotic surgery [6, 7, 8, 9, 10, 11, 15, 16, 17, 18]. In this study, no obvious complications or conversions to laparotomy were noted in either laparoscopic or robotic surgery, and blood loss was lower with RALH. We safely achieved good short-term outcomes, as in previous reports.

Previous reports comparing RALH and TLH have often been “studies of data about RALH introduction by operators familiar with TLH”, which may be one reason for the longer operative time with RALH than with TLH [17, 18]. However, it was reported that the learning curve was faster with RALH [19], and it was expected that the operative time would be shorter with RALH if the operator were unfamiliar with laparoscopy [20]. The operative time was reduced to approximately 60 min in this study when we introduced RALH at our institution to an operator unfamiliar with TLH and to approximately 40 min for only lymph node dissection cases.

TLH and RALH were performed under conditions wherein the supporters had the experience of TLH and RALH for benign diseases, but the operator performed the procedure for the first time. This environment seemed similar to that of a local hospital, wherein minimally invasive surgery for malignancy was recently introduced. In this institution, we achieved good short-term outcomes for both TLH and RALH, as noted in previous reports [7, 8, 9, 10, 11, 15, 16]. Furthermore, the operative time was reduced to approximately 40 min in the case of lymph node dissection in RALH compared to TLH. In addition, two operators performed 59% of the RALH procedures, indicating that the number of surgeons required for RALH can be reduced. RALH can be performed by two surgeons because the second assistant surgeon for transvaginal manipulation is usually not necessary. Therefore, since fewer surgeons are needed to perform RALH, RALH is an efficient way of treatment. The hospitalization days for RALH were 1.5 days shorter than that for TLH.

There are many facilities with few gynecologic oncologists or surgeons familiar with laparoscopy to promote the use of minimally invasive surgeries for endometrial cancer in the future. Therefore, it is important to report the introduction of minimally invasive surgery for malignancies in such facilities. This study’s results show that robotic surgery is a sustainable and useful approach in such facilities.

This study had some limitations. First, the number of cases was small. Since this was a retrospective study conducted at a single institution, confounding factors and selection bias could not be eliminated. Many hospitals, such as ours, should ensure the quality of malignant tumor care with a limited number of gynecologists. In addition, it is not easy for hospitals with only 10–15 cases of stage I endometrial cancer per year to achieve technical improvements through intensive operations, as in high-volume centers. Therefore, we first compared the short-term results of robotic surgery in this environment to verify the sustainability of RALH. Further evidence will be accumulated in the future.

Second, when the RALH and TLH groups were compared, significantly more cases of lymph node dissection were noted in the TLH group than in the RALH group. Since the presence or absence of lymph node dissection may have had a significant impact on the results, we also selected cases of lymph node dissection for comparison to ensure the quality of the results. It has recently been shown that lymph node dissection may not affect the prognosis of stage I endometrial cancer at a low risk of recurrence, which explains the difference in the number of patients with and without lymph node dissection [21]. This policy regarding lymph node dissection has changed after the introduction of RALH, resulting in more cases being omitted in the RALH group. In the future, we would like to consider ways to ensure the quality of treatment with or without dissection, in addition to the introduction of RALH.

Third, we lacked an analysis of the long-term prognosis. The 5-year overall survival rate for early-stage endometrial cancer is 88.7% [22]. It has been 4 years since insurance coverage for robotic surgery began and 3 years since RALH began at our hospital. In this study, there were two cases of recurrences in the RALH group and one in the TLH group. However, follow-up at 10-year intervals should be continued, as another report indicated that patients treated with robotic surgery showed recurrence more frequently and earlier and were more likely to die of cancer than those treated with laparoscopy [23].

Fourth, we could not analyze the benefit of cost. To sustain robotic surgery as a normal treatment for endometrial cancer, the matter of cost also has to be advantageous. Robotic surgery is costly and can be disadvantageous from the perspective of hospital costs.[24] In the future, we need to consider the cost efficacy of RALH for endometrial cancer.

In the surgical treatment of stage I endometrial cancer, robotic surgery was associated with a significantly shorter operation time, shorter hospital stay, and no obvious complications. This study proposes that robotic surgery is a promising solution for the sustainable introduction of minimally invasive surgery for stage I endometrial cancer in rural hospitals or hospitals with few gynecologists.

BMI, body mass index; TLH, total laparoscopic hysterectomy; RALH, robotic-assisted laparoscopic hysterectomy.

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.

DH collected and analyzed the data and wrote the manuscript. WI collected the data. AT and ON supervised the whole study. AT, MH, HT, RM, and AF performed medical care on the subjects. AT determined the methods of the operation and supervised all medical procedures. All authors read and approved the final manuscript.

This retrospective study was reviewed and approved by the Human Ethical Committee of the University of Teikyo Hospital (trial registration number: 20-054). This retrospective case-control study was conducted at the Department of Obstetrics and Gynecology, University Hospital Mizonokuchi, Teikyo University School of Medicine. Written informed consent was obtained from the patients for the publication of this report.

This research was supported by the Mizonokuchi Hospital of Teikyo University with regard to the provision of medical information.

This research received no external funding.

The authors declare no conflict of interest.