ABSTRACT
BACKGROUND: We previously demonstrated the applicability of the concept of "platinum sensitivity" in recurrent endometrial cancer. Although immune checkpoint inhibitors have been widely incorporated into endometrial cancer treatment, the debate continues regarding treatment options in patients with recurrent endometrial cancer who have previously received platinum-based chemotherapy. In this study, we assessed the duration of response to secondary platinum-based treatment using pooled data from the SGSG-012/GOTIC-004/Intergroup study. METHODS: Among the 279 participants in the SGSG-012/GOTIC-004/Intergroup study wherein platinum-based chemotherapy was re-administered for managing recurrent endometrial cancer between January 2005 and December 2009, 130 (47%) responded to chemotherapy. We compared the relationship between platinum-free interval and duration of secondary platinum-based treatment using pooled data. RESULTS: In 40 patients (31%), the duration of response to secondary platinum-based treatment exceeded the platinum-free interval. The duration of response to secondary platinum-based treatment exceeded 12 months in 51 patients (39%) [platinum-free interval: < 12 months, 14/48 (29%); 12-23 months, 18/43 (42%); 24-35 months, 8/19 (42%); ≥ 36 months, 11/20 (55%)]. In particular, in eight patients (6%), the duration of response to secondary platinum-based treatment exceeded 36 months [platinum-free interval: < 12 months, 3/48 (6%); 12-23 months, 0/19 (0%); 24-35 months, 2/19 (11%); ≥ 36 months, 3/20 (15%)]. CONCLUSIONS: Re-administration of platinum-based chemotherapy for recurrent endometrial cancer may result in a long-term response exceeding the platinum-free interval in some patients. Even in the current situation, where immune checkpoint inhibitors have been introduced, re-administration of platinum-based chemotherapy is worth considering.
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OBJECTIVE: The study aimed to investigate treatment options for older women with pelvic organ prolapse (POP) and postoperative outcomes based on their long-term care (LTC) status. METHODS: We used the medical and LTC insurance claims databases of Tochigi Prefecture in Japan, covering 2014 to 2019. We included women 65 years and older with POP and evaluated their care status and treatment, excluding women with an observation period <6 months. Among women with a postsurgical interval ≥6 months, we compared care level changes and deaths within 6 months and complications within 1 month postoperatively between those with and without LTC using Fisher exact test. RESULTS: We identified 3406 eligible women. Of the 447 women with LTC and 2959 women without LTC, 16 (3.6%) and 415 (14.0%), respectively, underwent surgery. Among 393 women with a postsurgical interval ≥6 months, 19 (4.8%) required LTC at surgery. Two of the 19 women with LTC (10.5%) and eight of 374 women without LTC (2.1%) experienced worsening care-needs level. No deaths were recorded. Urinary tract infection (UTI) was significantly more frequent in women with LTC than in women without LTC (36.8% vs 8.6%). Other complications were rare in both groups. CONCLUSION: The proportion of patients who underwent surgery for POP was lower in women with LTC than in women without LTC. Postoperative UTI was common and 11% had a worsening care-needs level postoperatively, whereas other complications were infrequent. Further detailed studies would contribute to providing optimal treatment to enhance patients' quality of life.
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BACKGROUND: Progesterone therapy is a relatively inexpensive treatment option for endometrial and breast cancers, with few side effects. Two signaling pathways usually mediate the physiological effects of progesterone, namely genomic and non-genomic actions. Genomic action occurs slowly via the nuclear progesterone receptor (PR), whereas the membrane progesterone receptor (mPR) induces rapid non-genomic action. AIMS: We investigated the effects of progesterone and various PR agonists on ovarian cancer cells. METHODS AND RESULTS: PR expression of six serous ovarian cancer cell lines was examined by western blotting, and mPR expression was examined by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). PR-negative and mPR-positive ovarian cancer cells were exposed to progesterone and seven types of PR agonists (medroxyprogesterone acetate [MPA], dehydroepiandrosterone, dienogest, levonorgestrel, drospirenone, pregnenolone, and allopregnanolone) at 10-400 µM, and viable cell counts after exposure for 30 min were measured using the water-soluble tetrazolium (WST-1) assay. Ovarian cancer cell lines were exposed to 100 µM progesterone, and the expression of BAX, a pro-apoptotic protein, after 1-5 min was examined by western blotting. Western blotting detected no PR expression in the six serous ovarian cancer cell lines. In contrast, RT-qPCR detected mPR expression in all six serous ovarian cancer cell lines. Progesterone and MPA-induced cell death in all tested ovarian cancer cell lines in a concentration-dependent manner, whereas no effect was observed for other PR agonists. Western blotting revealed that pro-apoptotic protein BAX expression occurred 1 min after exposure to progesterone, suggesting that the cytocidal effects are mediated by rapid non-genomic action. CONCLUSION: Progesterone and MPA exhibited a rapid cytocidal effect on PR-negative ovarian cancer cells through non-genomic action. Progesterone and MPA could be novel adjuvant therapies for ovarian cancer.
Subject(s)
Ovarian Neoplasms , Progesterone , Female , Humans , Progesterone/pharmacology , Progesterone/physiology , Receptors, Progesterone/genetics , Receptors, Progesterone/metabolism , bcl-2-Associated X Protein , Progestins/pharmacology , Medroxyprogesterone Acetate/pharmacology , Ovarian Neoplasms/drug therapy , Genomics , Cell DeathABSTRACT
AIM: In Japan, Niraparib maintenance therapy for primary and recurrent ovarian cancer was approved in September 2020 and is expected to improve the prognosis of ovarian cancer. However, the safety of niraparib maintenance therapy in Japanese patients has not been fully evaluated. METHODS: Patients with ovarian cancer (including fallopian tube and peritoneal cancer) treated with niraparib at Jichi Medical University Hospital from September 2020 to August 2022 were enrolled in this study. Patient background, starting dose, rates of interruption, reduction, or discontinuation, adverse events (AEs) during treatment, and estimated glomerular filtration rate (eGFR) trends were retrospectively analyzed. RESULTS: Twenty-nine patients received niraparib maintenance therapy during the study period, including 21 with primary cancer and 8 patients with recurrent cancer. Seventeen patients (58.6%) required dose interruptions and 16 patients (55.2%) required dose reductions. Only two patients (6.9%) discontinued treatment due to fatigue and nausea. The most frequent AE was creatinine increases in 18 patients (62.1%, all grades). Although eGFR levels decreased significantly after niraparib therapy compared to before niraparib therapy (59.3 vs. 50.3 mL/min/1.73 m2 , p < 0.001), the levels returned to pre-niraparib initiation levels after discontinuation of niraparib (64.6 vs. 64.6 mL/min/1.73 m2 , p = 0.96). Multivariate regression analysis showed that diabetes was independently associated with decreased eGFR (p = 0.013). CONCLUSIONS: Niraparib maintenance therapy frequently increased serum creatinine, but the change was reversible. Further studies are needed to determine the effects of niraparib on renal function in Japanese patients.
Subject(s)
Indazoles , Neoplasm Recurrence, Local , Ovarian Neoplasms , Piperidines , Female , Humans , Creatinine , Retrospective Studies , Ovarian Neoplasms/drug therapyABSTRACT
The first prophylactic vaccine against human papillomavirus (HPV) 16 and HPV18 was licensed in Japan in 2009. HPV vaccine effectiveness against high-grade cervical lesions has been demonstrated among young Japanese women, but evidence of its effects on invasive cervical cancer (ICC) is lacking. Using data from two different cancer registries, we compared recent trends of new ICC cases by age group using Poisson regression analysis. We also analyzed time trends in HPV16/18 prevalence among 1414 Japanese women aged <40 years newly diagnosed with ICC in the past decade. Based on the population-based cancer registry, the incidence of ICC among young women aged 20-29 years showed a significant decline from 3.6 to 2.8 per 100 000 women-years during 2016-2019, but no similar decline was observed for older age groups (p < 0.01). Similarly, using data from the gynecological cancer registry of the Japan Society of Obstetrics and Gynecology, the annual number of ICCs among women aged 20-29 years also decreased from 256 cases to 135 cases during 2011-2020 (p < 0.0001). Furthermore, a declining trend in HPV16/18 prevalence in ICC was observed only among women aged 20-29 years during 2017-2022 (90.5%-64.7%, p = 0.05; Cochran-Armitage trend test). This is the first report to suggest population-level effects of HPV vaccination on ICC in Japan. Although the declining trend in HPV16/18 prevalence among young women with ICC supports a causal linkage between vaccination and results from cancer registries, further studies are warranted to confirm that our findings are attributable to vaccination.
Subject(s)
Papillomavirus Infections , Papillomavirus Vaccines , Uterine Cervical Neoplasms , Pregnancy , Female , Humans , Aged , Uterine Cervical Neoplasms/epidemiology , Uterine Cervical Neoplasms/prevention & control , Uterine Cervical Neoplasms/pathology , Human Papillomavirus Viruses , Papillomavirus Vaccines/therapeutic use , Human papillomavirus 16 , Papillomavirus Infections/complications , Papillomavirus Infections/epidemiology , Papillomavirus Infections/prevention & control , Japan/epidemiology , Human papillomavirus 18ABSTRACT
OBJECTIVE: Ovarian vein thrombosis (OVT) after adnexectomy is usually asymptomatic, and pulmonary embolism (PE) has not been reported following this type of OVT. We present the case of a patient with symptomatic OVT after bilateral adnexectomy who experienced PE. CASE REPORT: A 52-year-old woman underwent total laparoscopic hysterectomy and bilateral adnexectomy for early stage endometrial cancer. On the 12th postoperative day, she presented with a fever of 38.7 °C. Computed tomography (CT) revealed bilateral OVT. Anticoagulant and antibacterial therapy was initiated; after five days, the fever subsided. On the 19th postoperative day, CT revealed a decrement in OVT; however, PE was observed. By the 60th postoperative day, PE disappeared. No deep vein thromboses were detected at any time. CONCLUSION: This case highlights that OVT, even after adnexectomy, can cause symptoms and PE can occur after this type of OVT. Anticoagulation therapy may be considered in such cases.
Subject(s)
Pulmonary Embolism , Venous Thrombosis , Female , Humans , Middle Aged , Venous Thrombosis/etiology , Ovary/surgery , Ovary/blood supply , Pulmonary Embolism/etiology , Anticoagulants/therapeutic use , Tomography, X-Ray Computed/methodsABSTRACT
INTRODUCTION: Three randomized controlled trials have resulted in extremely extensive application of the strategy of using neoadjuvant chemotherapy (NAC) followed by interval debulking surgery (IDS) for patients with advanced epithelial ovarian cancer in Japan. This study aimed to evaluate the status and effectiveness of treatment strategies using NAC followed by IDS in Japanese clinical practice. PATIENTS AND METHODS: We conducted a multi-institutional observational study of 940 women with Federation of Gynecology and Obstetrics (FIGO) stages III-IV epithelial ovarian cancer treated at one of nine centers between 2010 and 2015. Progression-free survival (PFS) and overall survival (OS) were compared between 486 propensity-score matched participants who underwent NAC followed by IDS and primary debulking surgery (PDS) followed by adjuvant chemotherapy. RESULTS: Patients with FIGO stage IIIC receiving NAC had a shorter OS (median OS: 48.1 vs. 68.2 months, hazard ratio [HR]: 1.34; 95% confidence interval [CI] 0.99-1.82, p = 0.06) but not PFS (median PFS: 19.7 vs. 19.4 months, HR: 1.02; 95% CI: 0.80-1.31, p = 0.88). However, patients with FIGO stage IV receiving NAC and PDS had comparable PFS (median PFS: 16.6 vs. 14.7 months, HR: 1.07 95% CI: 0.74-1.53, p = 0.73) and OS (median PFS: 45.2 vs. 35.7 months, HR: 0.98; 95% CI: 0.65-1.47, p = 0.93). CONCLUSIONS: NAC followed by IDS did not improve survival. In patients with FIGO stage IIIC, NAC may be associated with a shorter OS.
Subject(s)
Neoadjuvant Therapy , Ovarian Neoplasms , Humans , Female , Carcinoma, Ovarian Epithelial/drug therapy , Carcinoma, Ovarian Epithelial/surgery , Carcinoma, Ovarian Epithelial/etiology , Neoadjuvant Therapy/methods , Ovarian Neoplasms/drug therapy , Ovarian Neoplasms/surgery , Ovarian Neoplasms/pathology , Cytoreduction Surgical Procedures , Neoplasm Staging , Chemotherapy, Adjuvant , Retrospective StudiesABSTRACT
BACKGROUND: Relugolix, an oral gonadotrophin-releasing hormone receptor antagonist, was launched in Japan in 2019. Although there have been several studies on relugolix for leiomyomas, few have focused on submucosal leiomyomas. Submucosal leiomyomas cause bleeding more frequently than leiomyomas in other locations. There is only one case report described a patient treated for a submucosal leiomyoma with relugolix who developed severe hemorrhage. However, it remains unclear which characteristics of submucosal leiomyomas can lead to severe hemorrhage. Thus, the aim of this study was to investigate the characteristics of submucosal leiomyomas that would cause severe hemorrhage when treated with relugolix. METHODS: We retrospectively reviewed records of patients who underwent treatment for submucosal leiomyoma with relugolix (40 mg once daily for up to 6 months) in our institute between December 2019 and September 2021. We evaluated the clinical course and characteristics of submucosal leiomyoma in patients who developed severe hemorrhage. RESULTS: A total of 17 patients were treated for submucosal leiomyoma with relugolix. Two patients developed severe hemorrhage and required emergent surgery and blood transfusions. Only those two of the 17 patients had a submucosal leiomyoma of the International Federation of Gynecology and Obstetrics (FIGO) type 0, which has a stalk. In the remaining 15 patients who had FIGO type 1 or 2 leiomyoma, hemorrhage did not occur. CONCLUSIONS: Our study suggests that the use of relugolix for FIGO type 0 leiomyomas may be associated with a risk of hemorrhage. However, relugolix may be a safe and effective treatment option for patients with FIGO type 1 or 2 leiomyomas.
Subject(s)
Leiomyoma , Uterine Neoplasms , Female , Humans , Pregnancy , Leiomyoma/complications , Leiomyoma/surgery , Phenylurea Compounds/therapeutic use , Retrospective Studies , Uterine Neoplasms/complications , Uterine Neoplasms/surgeryABSTRACT
The revised World Health Organization classification of cervical cancer divides adenocarcinomas into human papillomavirus-associated (HPVa) and -independent (HPVi) types; the HPVi type is represented by the gastric type. The treatment outcomes of locally advanced adenocarcinoma (LaAC), based on this classification, are understudied. We investigated the outcomes of patients with HPVa and HPVi LaACs. Data for all consecutive patients with stage IB3 to IIIC1 adenocarcinoma who received treatment at 12 institutions throughout Japan between 2004 and 2009 were retrieved to analyze progression-free and overall survival. Central pathological review classified 103 and 48 patients as having HPVa and HPVi tumors, respectively. Usual- (84%) and gastric- (90%) type adenocarcinomas were the most frequent subtypes. Surgery was the primary treatment strategy for most patients. Progression-free and overall survival of patients with HPVi were worse than those of patients with HPVa (p = 0.009 and 0.032, respectively). Subgroup analysis by stage showed that progression-free survival was significantly different for stage IIB. The current surgical treatment strategy for LaACs is less effective for HPVi tumors than for HPVa tumors, especially those in stage IIB.
ABSTRACT
Accumulation of T lymphocytes and neutrophils shows inversed association with the prognosis of cancer patients, suggesting infiltration of neutrophils and T cells might be differently regulated in tumor tissue. In this study, we stimulated neutrophils with PMA or LPS to produce neutrophil extracellular traps (NETs) and examined the effects on chemotactic migration of activated T cells to a representative T cell chemokine, CXCL11. Migration of the activated T cells was totally abrogated by PMA-stimulated neutrophils placed either in upper or lower chamber, which was mostly canceled by pretreatment with Catalase. Although LPS-stimulated neutrophils also inhibited T cell migration, depletion of NETs by ultracentrifugation or degradation of NETs with DNAse I restored T cell migration. Western blots showed that LPS-stimulated neutrophils thoroughly degraded CXCL11 with NETs dependent manner. Activated neutrophils inhibit T cell chemotaxis via multiple mechanisms including the release of H2O2 and chemokine degradation by NETs, which may suppress adaptive immunity.
Subject(s)
Extracellular Traps , Neutrophils , T-Lymphocytes , Humans , Chemokine CXCL11/metabolism , Chemokines/metabolism , Extracellular Traps/metabolism , Hydrogen Peroxide/metabolism , Lipopolysaccharides/pharmacology , Lipopolysaccharides/metabolismSubject(s)
Placenta Accreta , Placenta Previa , Pregnancy , Female , Humans , Placenta , Myometrium , Retrospective StudiesSubject(s)
Pelvic Organ Prolapse , Pessaries , Humans , Female , Pelvic Organ Prolapse/surgery , Vagina , SuturesABSTRACT
Although geographical differences in the distribution of human papillomavirus genotypes have been observed worldwide, no studies have reported on national differences in the prevalence of human papillomavirus types in Japan. Here, we report a cross-sectional study to explore regional differences in the prevalence of human papillomavirus types among Japanese women with cervical intraepithelial neoplasia or invasive cervical cancer. Using human papillomavirus genotyping data from the nationwide prospective study on human papillomavirus vaccine effectiveness, we compared the frequency of detection of 15 high-risk and two low-risk human papillomavirus types in each disease category between the women who visited hospitals located in eastern Japan and those who visited hospitals located in western Japan. The risk of cervical intraepithelial neoplasia progression was assessed by calculating a prevalence ratio of each human papillomavirus type for cervical intraepithelial neoplasia grade 2/3 versus grade 1. Among the human papillomavirus types studied, human papillomavirus 52 was detected significantly more frequently in western hospitals than in eastern hospitals in cervical intraepithelial neoplasia grade 1 patients, but was less frequent in cervical intraepithelial neoplasia grade 2/3. The prevalence of particular human papillomavirus types was not significantly different between patients in hospitals in eastern Japan and those in hospitals in western Japan for invasive cervical cancer. In both eastern and western hospitals, a higher risk of cervical intraepithelial neoplasia progression was observed in patients infected with human papillomavirus 16, 31 or 58. In contrast, there was a significantly higher prevalence of human papillomavirus 52 infection in women with cervical intraepithelial neoplasia grade 2/3 than in those with cervical intraepithelial neoplasia grade 1 in eastern hospitals (prevalence ratio, 1.93; 95% confidence interval, 1.48-2.58), but not in western hospitals (prevalence ratio, 1.03; 95% confidence interval, 0.83-1.30). Regional differences of human papillomavirus 52 prevalence in cervical intraepithelial neoplasia lesions may exist and emphasize the importance of continuous monitoring of human papillomavirus type prevalence throughout the country in order to accurately assess the efficacy of human papillomavirus vaccines.
Subject(s)
Alphapapillomavirus , Papillomavirus Infections , Papillomavirus Vaccines , Uterine Cervical Dysplasia , Uterine Cervical Neoplasms , Alphapapillomavirus/genetics , Cross-Sectional Studies , DNA, Viral , Female , Humans , Japan/epidemiology , Papillomaviridae/genetics , Papillomavirus Infections/complications , Papillomavirus Infections/epidemiology , Papillomavirus Infections/pathology , Prevalence , Prospective Studies , Uterine Cervical Neoplasms/pathology , Uterine Cervical Dysplasia/diagnosisABSTRACT
The patient was an unmarried nulliparous 21-year-old female who was referred to our hospital with an abdominal mass. Bilateral ovarian tumors with a solid component were detected and both were suspected to be ovarian cancer. Since the patient strongly wished to preserve fertility, we performed left salpingo-oophorectomy, right cystectomy, and omentectomy. A postoperative histopathological examination revealed that the bilateral ovarian tumors were mucinous borderline tumors. The patient selected oocyte cryopreservation. Oocyte retrieval from the right ovary was performed 2 years after surgery, and six oocytes were obtained. The puncture of a small cyst revealed mucinous fluid, not normal follicular fluid; therefore, puncture fluid cytology was performed. A recurrent mucinous borderline ovarian tumor was suspected. Right salpingo-oophorectomy was performed and a recurrent mucinous borderline ovarian tumor was diagnosed. Puncture fluid properties need to be considered when there is an opportunity for oocyte retrieval after fertility-sparing surgery.
Subject(s)
Fertility Preservation , Neoplasms, Cystic, Mucinous, and Serous , Ovarian Neoplasms , Female , Humans , Neoplasm Recurrence, Local/diagnosis , Neoplasm Recurrence, Local/surgery , Oocyte Retrieval , Ovarian Neoplasms/diagnosis , Ovarian Neoplasms/pathology , Ovarian Neoplasms/surgery , PuncturesABSTRACT
Purpose: Although neutrophil extracellular traps (NETs) are present in various tumors, their roles in tumor biology have not been clarified yet. In this study, we examined how NETs affect the pharmacokinetics and effects of doxorubicin (DOX). Methods: NETs were generated by neutrophils stimulated with phorbol 12-myristate 13-acetate (PMA) or lipopolysaccharide (LPS). DOX was added to NETs and their distribution was observed under fluorescein microscopy, and the diffusion of DOX through 3 µM pores from lower to upper chambers was evaluated with a fluorescence-based assay. Ovarian cancer cells, KOC-2S and SKOV3, were embedded in collagen gel droplets and cultured in 3D way and their apoptosis was examined with flow cytometry. Results: DOX was mostly co-localized with NETs. The transfer of DOX to upper chambers increased over time, which was significantly decreased by the presence of neutrophils stimulated with PMA or LPS in the lower chamber. DOX outside of the gel increased the rates of annexin V (+) apoptotic cells, which were significantly reduced by the addition of LPS-stimulated neutrophils in media both in KOC-2S and SKOV3. The reduced diffusion and apoptosis were mostly restored by the destruction of the NETs structure with 1000 u/ml DNAse I. Conclusion: NETs efficiently trap and inhibit the diffusion of DOX which may attenuate its ability to induce apoptosis of ovarian cancer cells. Degradation of NETs with DNAse I may augment the response of ovarian cancer to DOX.
ABSTRACT
The persistence of antitumor effects has been reported after the completion of treatment with immune checkpoint inhibitors (ICIs) for various types of carcinoma, such as malignant melanoma, exhibiting a durable response. A durable response has also been noted after the discontinuation of treatment at an early stage due to adverse events, including in renal pelvic cancer, pancreatic cancer and intrahepatic cholangiocarcinoma; however, to the best of our knowledge, a similar case report has not yet been published in the malignant gynecological tumor field. The present study described a patient with refractory advanced endometrial cancer in whom the administration of pembrolizumab was discontinued after the completion of the 7th course due to renal dysfunction; however, persistent tumor-reducing effects and decreases in the levels of tumor markers were noted for more than 18 months after the cessation of treatment. Pembrolizumab may be continuously administered to some patients for a long period, whereas a durable response is achieved by others even after its discontinuation at an early stage; therefore, difficulties are associated with selecting an appropriate duration of administration. Further studies are required to search for biomarkers that facilitate high-accuracy effect predictions, and to establish an optimal administration period in consideration of specific adverse reactions to ICIs and cost-effectiveness.
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This study evaluated the feasibility and efficacy of three postoperative adjuvant chemotherapy regimens for endometrial cancer. Endometrioid cancer patients with intermediate-risk stage I and II or high-risk stage III and IV disease were randomly assigned to receive six cycles of either paclitaxel-epirubicin-carboplatin (TEC), paclitaxel-anthracycline (doxorubicin)-carboplatin (TAC), or dose-dense paclitaxel-carboplatin (ddTC). The primary end-point was the completion rate (CRate) of six cycles of treatment. The secondary end-points were progression-free survival (PFS) and overall survival (OS). One hundred and one patients were treated as follows: 33 received TEC, 33 TAC, and 35 ddTC. The CRates for TEC, TAC, and ddTC were 94%, 64%, and 69%, respectively (P = .005). The TEC CRate was significantly higher than for the other two groups. However, the PFS and OS outcomes were not statistically different between the three groups. The 2-year survival rates were 94%, 97%, and 97% for TEC, TAC, and ddTC, respectively. When compared to the current standard treatments for endometrial cancer, TEC is a promising candidate for a phase III trial based on its significantly superior CRate and equivalent PFS and OS. This study is registered with UMIN Clinical Trials Registry (UMIN000008911).
Subject(s)
Antineoplastic Combined Chemotherapy Protocols , Endometrial Neoplasms , Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Carboplatin/adverse effects , Chemotherapy, Adjuvant , Endometrial Neoplasms/drug therapy , Female , Humans , Neoplasm Staging , Paclitaxel/therapeutic useABSTRACT
Since the human papillomavirus (HPV) vaccination program for Japanese girls aged 12-16 years began in 2010, vaccination uptake has been low in women born before 1993 but high (approximately 70%) in those born during 1994-1999. We previously compared the prevalence of vaccine types HPV16 and HPV18 in cervical intraepithelial neoplasia grade 1-3 (CIN1-3) or adenocarcinoma in situ (AIS) between vaccinated and unvaccinated cohorts and found direct protection effects among vaccinated women in Japan. In this study, we focused on changes in HPV16/18 prevalence among "unvaccinated" cohorts with CIN/AIS. We analyzed HPV16/18 prevalence among 5051 unvaccinated women aged <40 years, newly diagnosed with CIN/AIS during 2012-2021 for time trends. Declining trends in HPV16/18 prevalence over 9 years were observed in CIN1 (36.0-10.0%, Ptrend = 0.03) and CIN2-3/AIS (62.5-36.4%, Ptrend = 0.07) among women aged <25 years. HPV16/18 prevalence in CIN1 and CIN2-3/AIS diagnosed at age 20-24 years was lower in 1994-1999 birth cohorts compared with 1988-1993 birth cohorts (4.5% vs. 25.7% for CIN1 and 40.0% vs. 58.1% for CIN2-3/AIS, both p = 0.04). Significant reduction in HPV16/18 prevalence among young unvaccinated women with CIN1 and CIN2-3/AIS suggests herd effects of HPV vaccination in Japan.