Objective: The incidence and mortality rates of endometrial cancer are increasing globally, including in Japan. Quality of cancer care is promoted through guideline adherence. This study aimed to establish quality indicators (QIs) for endometrial cancer and explore the factors contributing to treatment nonadherence. Methods: QIs and pattern-of-care indicators (PCIs) were developed using the Research and Development/University of California Los Angeles modified Delphi method. QIs reflect desirable healthcare patterns, whereas PCIs address treatment areas with lacking evidence.Data from the Hospital-Based Cancer Registry and Diagnosis Procedure Combination Survey were used. Patients diagnosed or treated between January 1 and December 31, 2020 were included. The reasons for nonadherence were collected. Logistic regression was used to analyze the factors influencing adherence, including age, body mass index, comorbidities, facilities, and recurrence risk. Results: Of the 35 proposed QI candidates, 8 QIs and 9 PCIs were selected, predominantly focusing on surgical aspects. Adherence rates varied, with peritoneal lavage cytology being the highest (93.1%), and postoperative hormone replacement therapy (HRT) for patients aged <45 years being the lowest (30.9%), when focusing on process indicators. Reasons for nonadherence included patient preference and medical comorbidities as significant factors. Multivariate analysis highlighted age, clinical stage, and Barthel index as significant contributors to nonadherence. Conclusion We developed QIs to comprehensively assess endometrial cancer treatment.Adherence rates are favorable; however, HRT has a low adherence rate. Factors leading to nonadherence include advanced age and incomplete activities of daily living, particularly in advanced stages.

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.