Quality of care measurement for patients with ovarian cancer in Japan.

AIM: Quality of care is important to reduce disease progression, and improve both survival and quality of life. The Japan Society of Gynecologic Oncology has published treatment guidelines to promote standardized high-quality care for ovarian cancer in Japan. We developed quality indicators based on the guideline recommendations and used them on large datasets of health service use to examine the quality of ovarian cancer care. METHODS: A panel of experts developed the indicators using a modified Delphi method. Adherence to each indicator was evaluated using data from a hospital-based cancer registry of patients diagnosed in 2018. All patients receiving first-line treatment at participating facilities were included. The adherence rates were returned to participating hospitals, and reasons for nonadherence were collected. A total of 580 hospitals participated, and the study examined the care received by 6611 patients with ovarian cancer and 1879 with borderline tumors using 11 measurable quality indicators. RESULTS: The adherence rate ranged from 22.6% for "Estrogen replacement within 6 months of operation" to 93.5% for "Bleomycin, etoposide, and cisplatin for germ cell tumor more than Stage II." Of 580 hospitals, 184 submitted the reasons for nonadherence. CONCLUSIONS: The quality of ovarian cancer care should be continuously assessed to encourage the use of best practices. These indicators may be a useful tool for this purpose.

2023 Japan Society of clinical oncology clinical practice guidelines update for antiemesis.

BACKGROUND: The Japan Society of Clinical Oncology Clinical Practice Guidelines for Antiemesis 2023 was extensively revised to reflect the latest advances in antineoplastic agents, antiemetics, and antineoplastic regimens. This update provides new evidence on the efficacy of antiemetic regimens. METHODS: Guided by the Minds Clinical Practice Guideline Development Manual of 2017, a rigorous approach was used to update the guidelines; a thorough literature search was conducted from January 1, 1990, to December 31, 2020. RESULTS: Comprehensive process resulted in the creation of 13 background questions (BQs), 12 clinical questions (CQs), and three future research questions (FQs). Moreover, the emetic risk classification was also updated. CONCLUSIONS: The primary goal of the present guidelines is to provide comprehensive information and facilitate informed decision-making, regarding antiemetic therapy, for both patients and healthcare providers.

Non-pharmacological treatments for anticipatory nausea and vomiting during chemotherapy: a systematic review and meta-analysis of the Clinical Practice Guidelines for Antiemesis 2023.

BACKGROUND: Anticipatory chemotherapy-induced nausea and vomiting (CINV) is a conditioned response influenced by the severity and duration of previous emetic responses to chemotherapy. We aimed to evaluate the efficacy of non-pharmacologic interventions for anticipatory CINV among patients with cancer. METHODS: We conducted a systematic search in databases, including PubMed, the Cochrane Library, CINAHL, and Ichushi-Web, from January 1, 1990, to December 31, 2020. Randomized controlled trials, non-randomized designs, observational studies, or case-control studies that utilized non-pharmacological therapies were included. The primary outcomes were anticipatory CINV, with an additional investigation into adverse events and the costs of therapies. The risk-of-bias for each study was assessed using the Cochrane risk-of-bias tool, and meta-analysis was performed using Revman 5.4 software. RESULTS: Of the 107 studies identified, six met the inclusion criteria. Three types of non-pharmacological treatments were identified: systematic desensitization (n = 2), hypnotherapy (n = 2), and yoga therapy (n = 2). Among them, systematic desensitization significantly improved anticipatory CINV as compared to that in the control group (nausea: risk ratio [RR] = 0.60, 95% confidence interval [CI] = 0.49-0.72, p < 0.00001; vomiting: RR = 0.54, 95% CI = 0.32-0.91, p = 0.02). However, heterogeneity in outcome measures precluded meta-analysis for hypnotherapy and yoga. Additionally, most selected studies had a high or unclear risk of bias, and adverse events were not consistently reported. CONCLUSIONS: Our findings suggest that systematic desensitization may effectively reduce anticipatory CINV. However, further research is warranted before implementation in clinical settings.

Cost-effectiveness analysis of hospital treatment volume and survival outcomes in endometrial cancer in Japan.

OBJECTIVE: Hospital treatment volume affects survival in patients with endometrial cancer; notably, initial treatment at high-volume centers improves survival outcomes. Our study assessed the effect of hospital treatment volume on cost-effectiveness and survival outcomes in patients with endometrial cancer in Japan. METHODS: A decision-analytic model was evaluated using the following variables and their impact on cost-effectiveness: 1) hospital treatment volume (low-, intermediate-, and high-volume centers) and 2) postoperative recurrent risk factors based on pathological findings (high- and intermediate-risk or low-risk). Data were obtained from the Japan Society of Obstetrics and Gynecology database, systematic literature searches, and the Japanese Diagnosis Procedure Combination database. Quality-adjusted life years (QALY) was used as a measure of effectiveness. The model was built from a public healthcare perspective and the impact of uncertainty was assessed using sensitivity analyses. RESULTS: A base-case analysis showed that the incremental cost-effectiveness ratio at high-volume centers was below a willingness-to-pay (WTP) threshold of ¥5,000,000 with a maximum of ¥3,777,830/4.28 QALY for the high- and intermediate-risk group, and ¥2,316,695/4.57 QALY for the low-risk group. Treatment at the high-volume centers showed better efficiency and cost-effectiveness in both strategies compared to intermediate- or low-volume centers. Sensitivity analyses showed that the model outcome was robust to changes in input values. With the WTP threshold, treatment at high-volume centers remained cost-effective in at least 73.6% and 78.2% of iterations for high- and intermediate-risk, and low-risk groups, respectively. CONCLUSION: Treatment at high-volume centers is the most cost-effective strategy for guiding treatment centralization in patients with endometrial cancer.

Trends in gynecologic cancer in Japan: incidence from 1980 to 2019 and mortality from 1981 to 2021.

BACKGROUND: In Japan, comprehensive cancer statistics data have been collected through national cancer registries, but these data are rarely summarized and reported in research articles. METHODS: Here, we compiled the national registry data on malignant tumors originating from gynecologic organs (ovary, corpus uteri, cervix uteri) in Japan. RESULTS: The number of new patients in 2019 was 13,380, 17,880, and 10,879, respectively, and the number of deaths in 2021 was 5081, 2741, and 2894, respectively. Compared with 40 years ago, the incidence of ovarian cancer has tripled, the incidence of uterine corpus cancer (mainly endometrial cancer) has increased eightfold, the mortality rate of uterine corpus cancer has tripled, and the incidence of cervical intraepithelial cancer has increased ninefold in data standardized by the world population. Compared with the United States, the incidence rate of ovarian cancer has overtaken and the mortality rate of uterine corpus cancer is the same, while both the incidence and mortality rates of cervical cancer are higher in Japan. CONCLUSION: The incidence of gynecologic cancer is increasing significantly in Japan.

Current status of head and neck sarcomas in Japan in 2016-2019: an analysis using the national cancer registry.

BACKGROUND: Head and neck sarcomas are especially rare in Asia, leading to limited clinical evidence. This study aimed to investigate the incidence, clinical features, treatment status, and outcome of these sarcomas using data from the National Cancer Registry in Japan. METHODS: All head and neck sarcomas diagnosed between 2016 and 2019 and recorded in the National Cancer Registry were analyzed. Data on sex, age, primary site, histological type, stage, treatment modality, and prognostic information were collected. Age-adjusted incidence and 3-year survival rates of patients with head and neck sarcomas were calculated. RESULTS: Overall, 635 head and neck sarcoma patients were identified. Head and neck sarcoma occurred more frequently in men and patients in their 70 s. The age-adjusted annual incidence rate was 0.125 per 100,000 patients in the 2015 Japanese model or 0.089 per 100,000 patients in the world population model. The nasal cavity and paranasal sinuses were the most frequent primary sites, with rhabdomyosarcoma as the most common histologic type. Treatment typically involved chemotherapy and/or radiation therapy for rhabdomyosarcoma and Ewing's sarcoma, whereas surgical approaches for other types. Three-year survival rate of head and neck sarcoma patients was 64.8%. CONCLUSIONS: Head and neck sarcomas occurred rarely, but most frequently in the nasal cavity and paranasal sinuses in Japan. Poor outcomes were observed for sarcoma patients than for non-sarcoma head and neck cancer patients.

The accuracy and characteristics of gastric cancer treatment information in the national data of the hospital-based cancer registry.

OBJECTIVE: The hospital-based cancer registry is used extensively for research to support cancer control activities by providing an overview of how cancer treatments are provided nationwide. This study aimed to shed light on the quality and characteristics of treatment data in the hospital-based cancer registry using the linked dataset on gastric cancer. METHODS: Using the nationally linked data of the hospital-based cancer registry and the health services utilization data, the treatment data in the hospital-based cancer registry for patients who were newly diagnosed with gastric cancer in 2016 and 2017 and received the first course of treatment at their own institutions were examined. The agreement rates between registry data and utilization data were analyzed by stage, treatment, age, period from the date of diagnosis to the date of treatment and hospital type. RESULTS: The sensitivity of open surgery, laparoscopic surgery and endoscopic treatment tended to decrease in advanced stages, whereas the sensitivity of chemotherapy and radiation therapy increased. Specificity was high for all treatments and stages, at ˃90%. Sensitivity by age was slightly different for chemotherapy and radiation therapy, but specificities did not differ.For all treatments, the longer the time from diagnosis to treatment implementation, the higher the coverage rate. CONCLUSIONS: The hospital-based cancer registry recorded the treatment performed appropriately. It is necessary to interpret the data from the hospital-based cancer registry whilst keeping in mind that, chemotherapy and radiation therapy are registered less frequently than surgical treatments administered.

Retroperitoneal sarcoma: a 10-year follow-up analysis using hospital-based cancer registry data in Japan.

OBJECTIVES: We sought clinical characteristics, survival outcomes, and prognostic factors for overall survival of retroperitoneal sarcoma in Japan. METHODS: A Japanese hospital-based cancer registry database with a pivotal 10-year follow-up was used to identify and enroll patients, registered from 106 institutions, diagnosed with retroperitoneal sarcoma in 2008-2009. Treating hospitals were divided by hospital care volume; high-volume hospitals and low-volume hospitals were defined as ≥ 4 and < 4 cases/year, respectively. RESULTS: A total of 91 men and 97 women were included, with a median age of 64 years. The most common histological type was liposarcoma in 101 patients, followed by leiomyosarcoma in 38 patients. The 5-year and 10-year overall survival rates were 44.1 and 28.3%. The majority of patients (n = 152, 80.9%) were treated at low-volume hospitals. High-volume hospital patients had higher 10-year overall survival rates than low-volume hospital patients (51.2% vs 23.2%, P = 0.026). Multivariate analysis revealed age over 60 years, treatment in low-volume hospitals and chemotherapy were independent predictors of unfavorable survival while treatment with surgery was an independent predictor of favorable survival. CONCLUSIONS: The possibility of surgical removal was suggested to be the most important prognostic factor for retroperitoneal sarcoma. Better survival was shown in patients treated at high-volume hospitals in our series.

Adult genitourinary sarcoma: analysis using hospital-based cancer registry data in Japan.

BACKGROUND: Genitourinary sarcomas are rare in adults and few large-scale studies on adult genitourinary sarcoma are reported. We aimed to elucidate the clinical characteristics, survival outcomes, and prognostic factors for overall survival of adult genitourinary sarcoma in Japan. METHODS: A hospital-based cancer registry data in Japan was used to identify and enroll patients diagnosed with genitourinary sarcoma in 2013. The datasets were registered from 121 institutions. RESULTS: A total of 116 men and 39 women were included, with a median age of 66 years. The most common primary site was the kidney in 47 patients, followed by the paratestis in 36 patients. The most common histological type was liposarcoma in 54 patients, followed by leiomyosarcoma in 25 patients. The 5-year overall survival rates were 57.6%. On univariate analysis, male gender, paratestis as primary organ, and histological subtype of liposarcoma were predictive of favorable survival while primary kidney, bladder, or prostate gland location were predictive of unfavorable survival. On multivariate analysis, primary paratestis was an independent predictor of favorable survival while primary kidney, bladder, or prostate gland were independent predictors of unfavorable survival. CONCLUSIONS: This is the first report showing the clinical characteristics and survival outcomes of adult genitourinary sarcoma in Japan using a real-world large cohort database.

The prognostic impact of treatment centralization in patients with testicular germ cell tumors: analysis of hospital-based cancer registry data in Japan.

BACKGROUND: To identify the prognostic impact of treatment centralization in patients with testicular germ cell tumors (TGCT). METHODS: We used a hospital-based cancer registry data in Japan to extract seminoma and non-seminoma cases that were diagnosed in 2013, histologically confirmed, and received the first course of treatment. To compare the 5-years overall survival (OS) rates of patients stratified by institutional care volume, we performed a Cox proportional hazards regression analysis using inverse probability of treatment weighting (IPTW) method to adjust patient backgrounds. RESULTS: A total of 1767 TGCT patients were identified. The 5-years OS rates for stage II and III TGCT patients treated at low-volume institutions (< 7 cases) were significantly worse than high-volume institutions (≥ 7 cases) (91.2% vs. 83.4%, p = 0.012). Histological stratification revealed that 5-year OS rates for stage II and III seminoma patients in the low-volume group were significantly worse than the high-volume group (93.5% vs. 84.5%, p = 0.041). Multivariate OS analysis using an IPTW-matched cohort showed that institutional care volume was an independent prognostic factor (hazard ratio 2.13 [95% confidence interval: 1.23-3.71], p = 0.0072). CONCLUSION: Our results indicate that stage II and III TGCT patients experience lower survival rates at low-volume institutions and would benefit from treatment centralization.

Treatment Patterns and Postoperative Activities of Daily Living in Patients with Non-small Cell Lung Cancer: A Retrospective Study Using Nationwide Health Services Utilization Data in Japan.

BACKGROUND: The number of older patients with cancer has been increasing. This study aimed to determine the proportion of postoperative decline in activities of daily living (ADL), hospital mortality rate, home healthcare services use, and adjuvant chemotherapy treatment patterns of patients with early-stage non-small cell lung cancer (NSCLC) across age groups. METHODS: We analyzed health service utilization data of patients aged ≥ 40 years diagnosed with clinical stage I or II NSCLC in 2015 who underwent thoracoscopy or thoracotomy. The Barthel index was used to determine the proportions of patients aged 40-64, 65-74, ≥ 75 years who experienced a decline in the ADL of ≥ 10 points at postoperative discharge compared to the ADL at admission. RESULTS: Overall, 19,780 patients were analyzed. The proportion of patients with ADL decline slightly increased with increasing age: 1.1%, 1.6%, and 3.5% after thoracoscopic surgery, and 1.4%, 2.8%, and 4.8% after thoracotomy among those aged 40-64, 65-74, and ≥ 75 years, respectively. The hospital mortality rate and proportion of home healthcare services use was fewer than 10 cases, or < 2%. The unexpected readmission rate was slightly higher among those aged ≥ 75 years (3.7% for thoracoscopic surgery, 4.7% for thoracotomy) than among those aged 40-64 years (1.8% for thoracoscopic surgery, 2.5% for thoracotomy). CONCLUSION: The difference in the proportion of patients with ADL decline between those aged 40-64 and ≥ 75 years was approximately 3%. This study provides practical information for clinicians involved in the care of older patients who undergo thoracic surgery.

A retrospective study of sentinel lymph node biopsy for skin cancer in Japan: Comparison with breast cancer and evaluation of factors related to its use.

BACKGROUND: Sentinel lymph node biopsy (SLNB) underuse has been reported for skin cancers; however, actual performance rates have not been compared. The objective of this study was to investigate the SLNB performance rate in skin cancers covered by health insurance in Japan and compare it with that in breast cancer. METHODS: This was a retrospective study of the SLNB performance rate in SLNB-eligible patients with breast or skin cancer from 2018 to 2019, utilizing a database linked to the Hospital-Based Cancer Registry and Diagnosis Procedure Combination survey. Demographic and tumor characteristics were analyzed using logistic regression. RESULTS: A total of 71,652 patients were included in this study. SLNB was performed in 86.4% (57,904/67,036) of the patients with breast cancer, 44.7% (694/1552) with melanomas, 3.1% (89/2849) with squamous cell carcinomas (SCCs), and 13.5% (29/215) with Merkel cell carcinomas (MCCs). The performance rate of SLNB was significantly lower for skin cancers than for breast cancers (odds ratio [OR], 0.03; p < 0.001). In addition, the performance rates of SLNB were significantly lower for SCCs and MCCs than for melanomas (SCC: OR, 0.04; p < 0.001; MCC: OR, 0.19; p < 0.001). Factors associated with SLNB performance included age, sex, year of incidence, primary tumor site, T stage, and number of hospital beds. CONCLUSIONS: SLNB is underutilized for skin cancer. Further investigation is required to explore the reasons for its underutilization so that it may be implemented more universally.

Activities of daily living after surgery among older patients with gastrointestinal and hepatobiliary-pancreatic cancers: a retrospective observational study using nationwide health services utilisation data from Japan.

OBJECTIVES: The effectiveness and impact of any treatment on patients' physical functions, especially in older patients, should be closely considered. This study aimed to evaluate activities of daily living (ADLs) after oncological surgery in patients with gastrointestinal and hepatobiliary-pancreatic cancers by age groups in Japan. DESIGN: Retrospective observational study using health services utilisation data from 1 January 2015 to 31 December 2016. SETTING: Data for patients with gastrointestinal and hepatobiliary-pancreatic cancers diagnosed in 2015 from 431 hospitals nationwide in Japan. PARTICIPANTS: Patients who underwent endoscopic submucosal dissection (ESD), endoscopic mucosal resection (EMR) and laparoscopic or open surgery were included. OUTCOME MEASURES: The proportion of ADL decline at discharge, death and unexpected readmission within 6 weeks postsurgery was calculated by age groups (40-74, 75-79 and ≥80 years). RESULTS: Data for 68 032 patients were analysed. The difference in the proportion of ADL decline after ESD/EMR between patients aged ≥80 years and <75 years was marginal (0.8%-2.5%), whereas that after laparoscopic (4.8%-5.9%) or open surgery (4.6%-9.4%) was large, except for pancreatic cancer (3.0%). Among patients with gastric cancer who underwent laparoscopic or open surgery, the proportion of unexpected readmission tended to be higher in patients aged ≥80 years than in the remaining younger patients (laparoscopic surgery 4.8% vs 2.3% (p=0.001); open surgery 7.3% vs 4.4% (p<0.001)). The postoperative mortality rate was <3% (<10 cases) across all ages and cancer types. CONCLUSIONS: In ESD/EMR, postoperative ADL decline was almost the same between older and younger patients. Laparoscopic or open surgery is associated with increased rates of ADL decline in older patients, especially in those aged ≥80 years. The potential decline in ADLs should be carefully considered preoperatively to best maintain the patient's quality of life postsurgery.

Epidemiology of skin cancer based on Japan's National Cancer Registry 2016-2017.

Skin cancer is most frequently diagnosed in the White population. However, its subtypes and epidemiology in Japan are understudied. We aimed to elucidate skin cancer incidence in Japan based on the National Cancer Registry, a new nationwide integrated population-based registry. Data from patients diagnosed with skin cancer in 2016 and 2017 were extracted and classified by cancer subtypes. Data were analyzed using the World Health Organization and General Rules tumor classifications. Tumor incidence was calculated as the number of new cases divided by the corresponding total person-years. Overall, 67,867 patients with skin cancer were included. The percentage of each subtype was as follows: basal cell carcinoma, 37.2%; squamous cell carcinoma, 43.9% (18.3% of which, in situ); malignant melanoma, 7.2% (22.1% of which, in situ); extramammary Paget's disease, 3.1% (24.9% of which, in situ); adnexal carcinoma, 2.9%; dermatofibrosarcoma protuberans, 0.9%; Merkel cell carcinoma, 0.6%; angiosarcoma, 0.5%; and hematologic malignancies, 3.8%. The overall age-adjusted incidence of skin cancer was 27.89 for the Japanese population model and 9.28 for the World Health Organization (WHO) model. The incidences of basal cell carcinoma and squamous cell carcinoma were the highest (3.63 and 3.40 per 100,000 persons, respectively, in the WHO model) among skin cancers, whereas the incidences of angiosarcoma and Merkel cell carcinoma were the lowest (0.026 and 0.038 per 100,000 persons, respectively, in the WHO model). This is the first report to provide comprehensive information on the epidemiological status of skin cancers in Japan using population-based NCR data.

Time to Treatment Initiation for Six Cancer Types: An Analysis of Data from a Nationwide Registry in Japan.

BACKGROUND: Delay in the time to treatment initiation (TTI) may adversely affect the survival of patients, but its current status in Japan is unknown. This study aims to describe the TTI for six cancer types: lung, breast, colorectal, stomach, head and neck (H&N), and cervical. Data for this study were derived from a nationwide registry in Japan. METHODS: This observational study employed the national database of hospital-based cancer registries (HBCRs) and health services utilization data. Using HBCR data, we identified all patients with cancer who started their cancer therapy at the same hospitals between January 1 and December 31, 2017. We calculated the TTI for each cancer type and treatment option, stratifying the results by age group and geographical region. RESULTS: The overall median TTI was 33 days, with shorter TTIs for colorectal and H&N cancers and chemotherapy. The TTI was the shortest for younger patients and the longest for the elderly, especially for lung cancer. When categorized by eight Japanese geographical regions, Tohoku and Kanto had the longest TTI. The result remained the same even after adjusting cancer type, treatment, age, and stage information. CONCLUSION: For colorectal and H&N cancers, in which a longer TTI is associated with a poorer prognosis, TTI was found to be particularly shorter. Although we could not discuss our results in light of the patient survival in this study, future research should explore the best balance between thorough evaluation before treatment and necessary time for that.

Baseline cardiac function checkup in patients with gastric or breast cancer receiving trastuzumab or anthracyclines.

BACKGROUND: Although trastuzumab and anthracyclines are frequently used to treat breast cancer (BC) and gastric cancer (GC), cardiotoxicity is a serious concern. The cardiac function assessment is recommended at baseline before initiating treatment. However, the prevalence rates of baseline cardiac checkups are unknown. METHODS: The national database of hospital-based cancer registries linked to the health services-utilization data was used to study patients with newly diagnosed stage IV BC and GC (n = 6271) who received trastuzumab (n = 4324, 69.0%) or anthracyclines between January 2012 and December 2015. The baseline ultrasound echocardiogram (UCG) performance rate and factors related to adequate UCG performance for all patients and those receiving trastuzumab were analyzed. RESULTS: The adequate baseline UCG checkup rate was higher in patients treated with trastuzumab than in those treated with anthracyclines (71.8% vs 44.1%, respectively). Additionally, patients with GC were less likely to receive an adequate baseline UCG performance than those with BC (70.4% vs 75.0%, respectively). After adjusting for potential confounders, patients with anthracycline-treated BC and GC were less likely to receive adequate baseline UCG performance than those with trastuzumab-treated BC (odds ratio [OR]: 0.24, 95% confidence interval [CI]: 0.20-0.28, and OR: 0.07, 95% CI: 0.03-0.16, respectively). Furthermore, patients with trastuzumab-treated GC were less likely to receive adequate baseline UCG performance than those with BC (OR: 0.65, 95% CI: 0.50-0.84). CONCLUSIONS: The baseline UCG was less likely to be performed in patients receiving anthracyclines than in those receiving trastuzumab, as well as in patients with GC than in those with BC.

Differences in the performance of adjuvant chemotherapy between hemodialysis and nonhemodialysis patients.

BACKGROUND: The survival of hemodialysis (HD) patients with cancer is poor, which may be caused by undertreatment due to renal dysfunction. Particularly, adjuvant chemotherapy after surgery may be considered optional because of its preventive nature. This study investigated the current frequency of administration of adjuvant chemotherapy to HD patients compared with non-HD patients in Japan. METHODS: We used data from the Hospital-Based Cancer Registries national database linked to health services utilization data to analyze cases of newly diagnosed colon cancer, gastric cancer, breast cancer, and non-small cell lung cancer (NSCLC) at the stages where adjuvant chemotherapy is generally required. We compared the performance rate of adjuvant chemotherapy and the adjuvant chemotherapy regimens between HD and non-HD patients from October 2011 to December 2017. RESULTS: Of the 99,761 patients who underwent curative surgery, 1207 (1%) were HD patients. HD patients received adjuvant chemotherapy less frequently than non-HD patients (24% vs. 63%, p < 0.001). After adjusting for potential confounders, HD remained negatively related to adjuvant chemotherapy administration for all four cancer types. Among all patients who received adjuvant chemotherapy 0(N = 61,873), HD patients were less likely to receive standard regimens and chemotherapy requiring dose adjustment than non-HD patients (88% vs. 95%, p < 0.001 and 92% vs. 98%, p < 0.001, respectively). This trend was particularly pronounced among patients with gastric cancer. CONCLUSIONS: HD patients were less likely to receive adjuvant chemotherapy with standard regimens than non-HD patients.

Imatinib use for gastrointestinal stromal tumors among older patients in Japan and Taiwan.

Tyrosine kinase inhibitors (TKIs) improve the prognosis of patients with gastrointestinal stromal tumors (GISTs). We conducted a retrospective cohort study using cancer registries linked with health utilization data in Japan and Taiwan to assess TKI usage in older and non-older patients. Patients diagnosed with GIST (2012-2014) were categorized into the following: adjuvant and advanced/metastatic settings. The duration and patterns of imatinib therapy were compared between the older (aged ≥ 75 years) and non-older (< 75 years) groups. We included 232 Japanese and 492 Taiwanese patients in the adjuvant setting, and 235 Japanese and 401 Taiwanese patients in the advanced/metastatic setting. Older patients had higher proportions of starting with lower doses (< 400 mg/day) than the non-older patients (adjuvant: 22.5% vs. 4.3% [Japan]; 22.5% vs. 10.9% [Taiwan]; advanced/metastatic: 29.6% vs. 7.2% [Japan]; 32.6% vs. 8.1% [Taiwan]; all p < 0.01). The median time to stop imatinib was shorter in the older than in the non-older patients (adjuvant: 301 vs. 975 days [Japan], 366 vs. 1028 days [Taiwan]; advanced/metastatic: 423 vs. 542 days [Japan]; 366.5 vs. 837 days [Taiwan]). More older patients with GIST tended to have TKIs at a lower initial dose and a shorter imatinib duration than the non-older patients.