Published papers

Objectives: The initial learning curve is a barrier to introducing robotic surgery. Evidence regarding appropriate simulation programs that allow for a smooth introduction of gynecological robotic surgery remains limited. Materials and Methods: We retrospectively analyzed 149 patients who underwent robotic surgery for gynecologic diseases. Before their first procedure, the surgeons completed a robotic surgery training program. Assistant surgeons also completed simulation programs, including setup procedures and manipulation of the robotic arm. Results: The mean (± standard deviation) operative, setup, and console times were 170 ± 54 min, 22 ± 8 min, and 126 ± 51 min, respectively. No patient required blood transfusion or conversion to laparoscopy or laparotomy. Patients undergoing surgery by the same surgeon were divided into three groups (first-third, middle-third, and last-third of patients undergoing surgery) to assess chronological changes. No statistically significant differences were found between the operative and console times among these groups. The setup times for the middle and last third of patients were 20 ± 7 min and 18 ± 7 min, respectively, which were statistically significantly shorter than those for the first third of patients. No significant differences in the operative and console times done by five physicians who completed programs were observed between the first 75 and the latter 74 procedures; however, the setup times of the latter 74 procedures were significantly shorter than those of the first 74 procedures (25 ± 9 min vs. 19 ± 6 min; P < 0.001). Conclusion: The setup time was influenced by clinical experience. An appropriate simulation program allowed a safe implementation of robotic surgery.

While the fallopian tube epithelium (FTE) is known to be composed of various differentiated cells such as secretory and ciliated cells, the upstream regulatory mechanisms of cell differentiation that are essential for tissue homeostasis remain under investigation. In this study, we established human FTE organoids and identified quiescent cells within the early organoid formation by observing cellular proliferation heterogeneity. We also analyzed two single-cell transcriptomic data to trace the differentiation trajectory in human FTE, and found that the gene LCN2 serves as a marker gene of early stage of the trajectory. Genetically manipulated FTE organoids indicated that LCN2 inhibits ferroptosis and promotes cell survival under oxidative stress. In addition, the FTE organoids introduced p53 dysfunction, the common genetic characteristics of high-grade serous carcinoma, showed upregulated LCN2 expression and enhanced ferroptosis resistance. This study provides insights into the LCN2-mediated protective mechanism of human FTE quiescent cells and its potential role in tumorigenesis.

Objective: This study aimed to assess the prognostic significance of para-aortic lymphadenectomy (PALX) and para-aortic lymph node metastasis in endometrial cancer (EC) patients at risk of post-operative recurrence. Methods: Japanese Gynecologic Oncology Group (JGOG) 2043 was a randomized controlled trial assessing the efficacy of adjuvant chemotherapy in EC patients at risk for postoperative recurrence. A retrospective analysis included patients who underwent pelvic lymphadenectomy (PLX) alone or both PLX and PALX in JGOG2043. Data on positive lymph nodes and other clinicopathological risk factors were collected. Results: PLX and PALX were performed on 402 patients, while PLX alone was conducted on 250 patients. Evaluating the effect of PALX on survival was challenging through a comparison of the outcomes of the 2 cohorts since PALX was predominantly administered to higher-risk patients. Patients with 2 or more metastases in para-aortic nodes exhibited significantly poorer overall survival than those with no or 1 metastasis, respectively (p<0.001, p=0.031). Multivariate analysis revealed that 2 or more metastases in para-aortic nodes is independent risk factors for disease-free survival (hazard ratio [HR]=1.72; 95% confidence interval [CI]=1.10–2.72; p=0.019) and are marginally significant for overall survival (HR=1.58; 95% CI=0.92–2.72; p=0.096) compared to no or a single metastasis. Conclusion: The clinical relevance of PALX was challenging to evaluate in the JGOG2043 cohort; however, the presence of 2 or more para-aortic node metastases was identified as an independent unfavorable prognostic factor in EC patients at risk of recurrence.

Claudin 18.2 (CLDN18.2), a tight junction protein isoform, is an emerging therapeutic target in oncology. CLDN18 is well-characterized in gastric cancer, but its pan-cancer expression profiles and isoform distributions are poorly documented. In the present study, we analyzed CLDN18 expression in patients with solid tumors enrolled in the MONSTAR-SCREEN-2 study using immunohistochemistry (IHC, n = 349) and whole-transcriptome sequencing (WTS, n = 2191). A splice junction analysis algorithm characterized isoform distribution patterns in WTS data and evaluated temporal changes using paired pre- and postchemotherapy specimens. IHC detected CLDN18.2 (≥ 40% of tumor cells showing any staining intensity) in 16.3% of patients, with highest prevalence in gastric (54.5%), biliary tract (21.7%), pancreatic (20.7%), and small intestinal (18.2%) cancers. WTS and IHC findings were significantly correlated (p < 0.001). WTS analysis with optimized transcript thresholds (n = 2191) demonstrated the CLDN18-high population to be 13.8%, with highest proportions in gastric (64.5%), small intestinal (40.0%), pancreatic (37.8%), and biliary tract (20.0%) cancers. Isoform analysis of 364 patients revealed CLDN18.2 predominance (mean 18.2/18.1 proportion 0.945), with CLDN18.1 predominance observed in only 4.9% of patients. Longitudinal analysis of 27 paired gastric cancer samples revealed a significant reduction in CLDN18 expression and a nonsignificant decrease in the CLDN18.2 proportion following chemotherapy. This analysis validates WTS as a complementary approach to IHC for CLDN18 assessment and demonstrates significant CLDN18 expression across multiple cancer types. The predominance of CLDN18.2 supports the expansion of targeted therapeutic approaches beyond gastric cancer and indicates the potential of RNA-based screening.

Objective: Cervical cancer rates in Japan (16.0/100,000) exceed the global average rate (11.3/100,000, according to the High/Very-High Human Development Index in 2020). This necessitates the evaluation of care quality and the quality indicators (QIs) for cervical cancer that were developed in 2013 to serve this purpose. This study updated these indicators using current evidence and consensus while longitudinally examining trends in practice patterns. Methods: The revision involved reviewing existing QIs and patterns of care indicators and incorporating new indicators using the modified Delphi method. Adherence to these indicators was assessed using a linked hospital-based cancer registry-based diagnostic procedure combination database covering approximately 70% of patients with cancer in Japan. The longitudinal trends of the existing indicators were evaluated using the linear probability model. Results: Seven new indicators were added to the existing twelve. Two of the new indicators mainly focused on early-stage surgical intervention, while one focused on advanced-stage bevacizumab combination therapy, with adherence rates of 81.7%, 0.8%, and 45.9%. Longitudinal analyses revealed significant improvements with the use of cisplatin in concurrent chemoradiotherapy for advanced-stage cervical cancer (+1%/year), oral anticancer agents as maintenance therapy after primary treatment for early-stage cervical cancer (−0.8%/ year), and hysterectomy for adenocarcinoma in situ in patients above 44 years old (−2%/year). Conclusion: The QIs for cervical cancer in Japan have been revised based on 2022 evidence. The existing and new indicators should be continually evaluated to correspond to the latest knowledge. This will facilitate the standardization and promotion of bottom-up improvements in cervical cancer care.

Hereditary breast and ovarian cancer syndrome (HBOC) is traditionally associated with mutations in the BRCA1 and BRCA2 genes, predominantly impacting breast, ovarian, pancreatic, and prostate cancers. However, recent research suggests that these mutations may also predispose carriers to a broader spectrum of malignancies, including biliary tract, cervical, colorectal, endometrial, esophageal, and gastric cancers. This review presents findings from extensive datasets, including a significant study from a nationwide Japanese biobank that examined cancer risks in 63,828 patients and 37,086 controls. Our review highlights notable associations, such as an increased risk of uterine and cervical cancers in BRCA1 mutation carriers and increased risk of esophageal and gastric cancers in BRCA2 mutation carriers. These emerging associations underscore the necessity of revisiting and potentially expanding current clinical guidelines to incorporate these additional risks. These findings advocate a comprehensive approach to genetic counseling and underscore the importance of tailored cancer surveillance strategies in populations carrying BRCA mutations. This expanded understanding could significantly influence preventive, diagnostic, and therapeutic strategies, promoting personalized approaches to manage and potentially prevent these malignancies in genetically susceptible populations.

In this study, we identified prognostic biomarkers that predict treatment outcome in patients receiving fertility-preserving high-dose medroxyprogesterone acetate (MPA) therapy through comprehensive multigene panel testing. A total of 38 patients (20 atypical endometrial hyperplasia and 18 stage IA G1 without myometrial invasion) who received first-line MPA therapy were enrolled. Genomic DNA was extracted from formalin-fixed paraffin-embedded samples, and PleSSision-Rapid multigene panel testing was performed. Of the 38 patients, 31 (82%) achieved complete response (CR), 2 (5%) had stable disease (SD), and 5 (13%) had progressive disease (PD) following initial treatment. The median duration to achieve tumor disappearance was 7 months (range: 4–14 months). Following initial treatment, 25 of 32 patients (78%) experienced recurrence, with a median recurrence-free survival (RFS) of 21 months (range: 2–84 months). The most frequently observed actionable gene mutations were PTEN (68.4%), CTNNB1 (55.2%), and PIK3CA (33.3%). Patients harboring PTEN mutations in EMG1 required a significantly longer duration to achieve tumor disappearance (p = 0.011). In addition, the presence of PIK3CA mutations in AEH was significantly associated with shorter RFS (p = 0.048). Molecular classification identified 34 patients (89%) with no specific molecular profile (NSMP), 1 patient (3%) with POLE mutation, and 3 patients (8%) with deficient mismatch repair (d-MMR). Most patients undergoing MPA therapy were classified as having NSMP. Genetic alterations, specifically mutations in PTEN and PIK3CA, were significantly associated with treatment outcomes, highlighting their potential as prognostic biomarkers.

Objective: To investigate clinical characteristics and in vitro fertilization (IVF) outcomes in patients after radical abdominal trachelectomy (RAT) for early-stage cervical cancer. Design: A retrospective cohort study of patients who underwent IVF after RAT between January 2009 and December 2022, with comparison to age-matched controls. Subjects: Forty-one patients who underwent RAT for early-stage cervical cancer and subsequently sought IVF, compared with 82 age-matched controls. Exposure: Radical abdominal trachelectomy as a fertility-sparing surgery for early-stage cervical cancer, followed by IVF. Main Outcome Measures: Embryological outcomes, clinical pregnancy rates, live birth rates, and factors influencing IVF success, including age at first oocyte retrieval, ovarian response parameters, number of oocytes retrieved, presence of cervical stenosis, and endometrial thickness at embryo transfer (ET) were compared between the RAT and control groups. Results: The RAT group had similar anti-mullerian hormone levels and embryological outcomes compared with controls. In the RAT group, clinical pregnancy and live birth rates were 68.3% (28/41) and 58.5% (24/41) per patient and 20.8% (37/178) and 15.7% (28/178) per ET, respectively. These rates were comparable to those in the control group, which were 62.2% (51/82) and 50.0% (41/82) per patient and 25.4% (80/314) and 16.6% (52/314) per ET, respectively. In the RAT group, live birth outcomes were associated with younger age at first oocyte retrieval, higher number of oocytes retrieved, fewer cases of cervical stenosis, and greater endometrial thickness at ET. An endometrial thickness of 9.2 mm was identified as the optimal statistical boundary for predicting both clinical pregnancy and live birth. Conclusion: The live birth rate in the RAT group was comparable to that in the age-matched control group, indicating that RAT does not negatively impact assisted reproductive technologies outcomes. Age at first oocyte retrieval, number of oocytes retrieved, presence of cervical stenosis, and endometrial thickness at ET may influence IVF outcomes after RAT.

In recent years, advances in organ transplantation medicine have led to an increase in pregnancies and births following transplantation. Pregnancy after organ transplantation is considered high-risk, and its impact on both the recipient and the child must be carefully evaluated. In this review, we summarize the current landscape of pregnancy and childbirth after organ transplantation, with a particular focus on uterus transplantation (UTx). Traditionally, organ transplants have involved vital organs; however, UTx, developed for women with absolute uterine factor infertility, represents a novel approach. Although the number of births following UTx remains limited, it is expected to grow due to the international expansion of this procedure. Importantly, the concept of pregnancy and delivery following UTx is fundamentally different from that of other organ transplants. UTx is a life-enhancing, non-vital, and temporary transplant uniquely intended to enable the creation of new life. Pregnancy after UTx carries specific risks such as a higher incidence of miscarriage, preterm birth, hypertensive disorders of pregnancy, and gestational diabetes. All deliveries are performed via cesarean section, and conception is typically allowed after a relatively short period following transplantation, given the temporary nature of the graft and the goal to minimize recipient burden, with generally good neonatal outcomes. As pregnancies after both solid organ transplantation and UTx continue to rise worldwide, the development of standardized, organ-specific perinatal management strategies, particularly for UTx, is essential. Multidisciplinary collaboration will be critical to supporting these high-risk pregnancies and ensuring the best possible maternal and neonatal outcomes.

Splenic metastases from solid tumors are rare, particularly when they occur after a long postsurgical interval. We report the case of a 69-year-old woman who developed a splenic metastasis from endometrial carcinoma, presenting as a hemorrhagic splenic cyst, 17 years after her initial surgery. Laparoscopic splenectomy achieving R0 resection was successfully performed; however, the patient subsequently developed multiple liver metastases. This case highlights the importance of periodic evaluation for recurrence, including monitoring for symptoms and elevated tumor markers, in patients with a history of endometrial carcinoma or other solid tumors.

Objectives: ARID1A mutation is frequently found in clear cell ovarian cancer (CCC) and endometrioid ovarian cancer (EC). Anti-PD-1 monotherapy has been found to have limited efficacy in epithelial ovarian cancer; however, anti-PD-1 therapy showed significant clinical benefit in some CCC. We sought to define the relationship of ARID1A mutation/ARID1A expression to the immunogenic profile of different histologic subtypes of ovarian cancer. Methods: We performed next-generation sequencing of 160 cancer-related genes. Also, we analyzed the immunohistochemical status of ARID1A, PD-L1, and CD8 with survival in different histologic subtypes of ovarian cancer in a total of 103 cases. Results: ARID1A mutation was found in 0% of the high-grade serous ovarian cancer (HGSC) (n = 36), 41.5% of the CCC (n = 41), 45.0% of the EC (n = 20), and 33.3% of the mucinous ovarian cancer (MC) (n = 6) cases. ARID1A loss was found in 19.4% of the HGSC, 75.6% of the CCC, 60.0% of the EC and 0% of the MC cases. ARID1A mutation was found to be associated with high PD-L1 (p < 0.001) or CD8 levels (p < 0.001) in CCC but not in other histologic subtypes. Meanwhile, ARID1A loss was associated with high PD-L1 or CD8 levels in CCC (p < 0.001) and HGSC (p < 0.001) but not in EC and MC. In addition, ARID1A mutation was associated with high tumor mutation burden in CCC (p = 0.006). Conclusions: ARID1A mutation/ARID1A expression is associated with immune microenvironmental factors in CCC but not in EC. ARID1A status can be a biomarker for selecting candidates for immune checkpoint blockade in CCC.

Objectives: The aim of this study was to elucidate the clinicopathological features of ovarian granulosa cell tumors (GCTs) and to identify the prognostic factors. Methods: The Japanese Society of Gynecologic Oncology (JSGO) conducted an observational retrospective cohort study of women with GCTs enrolled in the Gynecological Tumor Registry of the Japan Society of Obstetrics and Gynecology (JSOG) between 2002 and 2015. Clinicopathological features, including lymph node metastasis, were evaluated. In addition, we performed a prognostic analysis of patients between 2002 and 2011 for whom survival data were available. Kaplan–Meier and multivariate Cox proportional hazards analyses were performed. Results: We identified 1426 patients with GCTs. Of the 222 patients who underwent lymph node dissection, 10 (4.5%) had lymph node metastasis. The incidence of lymph node metastasis in patients with pT1, pT2, and pT3 was 2.1%, 13.3%, and 26.7%, respectively (p < 0.001). Prognostic analysis was performed on 674 patients. In the multivariate Cox regression analysis, residual disease after initial surgery (hazard ratio (HR) = 10.39, 95% confidence interval (CI) = 3.15–34.29) and lymph node metastasis (HR = 5.58, 95% CI = 1.62–19.19) were independent risk factors for cancer-specific survival. Conclusions: In the initial surgery for GCTs, lymph node dissection can be omitted if the operative finding is pT1. In cases of pT2 or higher, lymph node dissection should be considered. Debulking is critical for achieving no gross residual tumor at the end of the surgery.

Atypical polypoid adenomyoma (APA) is an intrauterine tumor for which hysteroscopic tumor resection allows for fertility preservation. Complete resection is important because of the high recurrence rate of APA, but is difficult due to the lack of characteristic hysteroscopic findings. We previously reported a case in which photodynamic diagnosis (PDD) was useful for detection of APA. Here, we report two additional cases of APA treated by hysteroscopic resection with PDD. The procedure was approved by the ethical committee. Case 1: A 35-year-old female who underwent hysteroscopic surgery for a submucosal tumor suspected to be APA with hypermenorrhea. Case 2: A 37-year-old female in whom hysteroscopic surgery was performed for a residual APA lesion after hormone therapy. In Case 1, PDD identified the tumor borders and this enabled as complete resection as possible. In Case 2, lesions could not be identified clearly under white light, but some areas were PDD-positive and were excised. Among 19 specimens from these two cases and the previously reported case, all PDD-positive specimens were pathologically diagnosed as APA. The sensitivity and specificity of PDD for APA were 76.9% and 100%, respectively. These results suggest that PDD can contribute to identification of APA.

Objective: This multicenter study aimed to evaluate the accuracy of the one-step nucleic acid amplification (OSNA) assay in diagnosing lymph node metastasis (LNM) in patients with cervical and endometrial cancers. Methods: Surgically removed LNs from patients with cervical and endometrial cancer were sectioned at 2-mm intervals along the short axis direction and alternately examined using the OSNA assay and conventional histopathological examination. Ultrastaging (200-μm LN sections) was performed for metastatic LNs using hematoxylin and eosin staining and immunostaining with an anti-CK19 antibody in cases where the OSNA assay and histopathological examination (performed using 2-mm LN sections) results showed discordance. Results: A total of 437 LNs from 133 patients were included; 61 patients (14%) showed metastasis by histopathological examination, with a concordance rate of 0.979 (95% confidence interval [CI]: 0.961–0.991) with the OSNA assay. The sensitivity and specificity of the OSNA assay were 0.918 (95% CI: 0.819–0.973) and 0.989 (95% CI: 0.973–0.997), respectively. Discordance between the two methods was observed in nine LNs (2.1%), and allocation bias of metastatic foci was identified as the major cause of discordance. Conclusions: The OSNA assay showed equally accurate detection of LN metastasis as the histopathological examination. We suggest that the OSNA assay may be a useful tool for the rapid intraoperative diagnosis of LN metastasis in patients with cervical and endometrial cancers.

Background: Japan’s health insurance covers multigene panel testing. This study aimed to determine the potential availability and utility of gene panel testing clinically in gynecologic oncology. Methods: We analyzed the characteristics of patients with gynecologic cancer who underwent gene panel testing using FoundationOne® CDx or OncoGuide™ NCC Oncopanel between November 2019 and October 2022. Results: Out of 102 patients analyzed, 32, 18, 43, 8, and 1 had cervical, endometrial, ovarian cancers, sarcoma, and vaginal cancer, respectively. Druggable gene alteration was found in 70 patients (68.6%; 21 with cervical cancer, 15 with endometrial cancer, 28 with ovarian cancer, 5 with sarcoma, and 1 with other). The most common druggable gene alteration was PIK3CA mutation (n = 21), followed by PTEN mutation (n = 12) and high tumor mutation burden (TMB-H) (n = 11). TMB-H was detected in 5 patients with cervical cancer, 5 with endometrial cancer, and 1 with endometrial stromal sarcoma. Eleven patients (10.8%) received molecularly targeted therapy according to their gene aberrations. Gene panel testing was mostly performed when the second-line treatment was ineffective. Of all 102 patients, 60 did not have recommended treatment, and 15 died or had worsened conditions before obtaining the test results. Conclusion: Through multigene panel testing, although many patients had druggable gene alterations, 10.8% of them received the recommended treatment. TMB-H was mainly observed in cervical/endometrial cancer, suggesting its potential as a therapeutic biomarker of immune checkpoint inhibitors. Furthermore, patients’ prognosis and performance status should be considered before performing the test.

Objective: In this study, we collected data over 8 years (2012–2019) from the Japan Society of Obstetrics and Gynecology (JSOG) tumor registry to determine the status of endometrial cancer in Japan, and analyzed detailed clinicopathological factors. Methods: The JSOG maintains a tumor registry that gathers information on endometrial cancer treated at the JSOG-registered institutions. Data from the patients whose endometrial cancer treatment was initiated from 2012 to 2019 were analyzed retrospectively. Results: A total of 82,969 patients with endometrial cancer underwent treatment from 2012 to 2019. Chemotherapy alone or in combination with hormonal therapy is more common among endometrial cancer patients under 40 years compared with those over 40 years. The number of patients with endometrial cancer, treated with laparoscopic or robot-assisted surgery was observed to have increased yearly. Small cell carcinomas and undifferentiated carcinomas were more likely to be diagnosed at an advanced stage. Lymphadenectomy was most commonly performed for stage IIIC2 disease, whereas positive peritoneal washing cytology was most common for stage IVB and serous carcinoma. Conclusion: Multi-year summary reports provided detailed clinicopathological information regarding endometrial cancer that could not be obtained in a single year. These reports were useful in understanding treatment strategies and trends over time based on age, histology, and stage.