Time trend analysis of rare cancer incidence 2011-2018: Nationwide population-based cancer registries in Japan.

Rare cancers collectively account for a significant proportion of the overall cancer burden in Japan. We aimed to describe and examine the incidence of each rare cancer and the temporal changes using the internationally agreed rare cancer classification. Cancer cases registered in regional population-based cancer registries from 2011 to 2015 and the National Cancer Registry (NCR) from 2016 to 2018 were classified into 18 families, 68 Tier-1 cancer groupings, and 216 single cancer entities based on the RARECAREnet list. Crude incidence rates and age-standardized incidence rates (ASR) were calculated for Tier-1 and Tier-2 cancers. The annual percent change and the 95% and 99% confidence limits for annual ASR for each of the 68 Tier-1 cancers were estimated using the log-linear regression of the weighted least squares method. The differences in ASRs between 2011 and 2018 were evaluated as an absolute change. A total of 5,640,879 cases were classified into Tier-1 and Tier-2 cancers. The ASRs of 18 out of 52 Tier-1 cancers in the rare cancer families increased, whereas the ASR for epithelial tumors of gallbladder decreased. The ASRs of 6 out of the 16 Tier-1 cancers in the common cancer families increased, whereas those of epithelial tumors of stomach and liver decreased. There was no significant change in the incidence of the other 40 Tier-1 cancers. The incidence of several cancers increased due to the dissemination of diagnostic concepts, improved diagnostic techniques, changes in coding practice, and the initiation of the NCR.

Increased incidence of rare cancers and varied age distributions by cancer group: A population-based cancer registry study in Hiroshima Prefecture, Japan.

BACKGROUND: Epidemiological characteristics of many types of rare cancers are limited especially in Asia. Therefore, this study aimed to describe the burden and changing time trends of rare cancers in Hiroshima, Japan. METHODS: The internationally agreed RARECAREnet list of rare cancers was used to identify patients diagnosed with cancers from 2005 to 2015 who were registered in the Hiroshima Prefecture Cancer Registry. Quality indicators specific to rare cancers were assessed by cancer grouping. Crude incidence rates (IRs) and age-standardized rates (ASRs) were calculated for 216 single cancers (rare and common) included in the list. A joinpoint regression was used to analyze age distribution and time trends in the ASRs for 12 internationally agreed rare cancer families. Quality indicators, ASRs, and IRs in Japan were identified to examine IR differences and the effects on data accuracy. RESULTS: The 231,328 cases were used to calculate the IRs of each cancer. Epithelial tumors in rare families increased with age, but nonepithelial tumors occurred at any age. The proportion of rare cancer families to total cancers was stable. The time trend for families of head and neck cancers (annual percent change and 95 % confidence interval: 2.4 %; 1.2-3.7 %), neuroendocrine tumors (6.6 %; 5.1-8.1 %), and hematological cancers (4.3 %; 3.2-5.5 %) markedly increased. CONCLUSION: The ASRs of several rare cancers increased because of increased knowledge of these diseases, improved diagnostic techniques, and aggressive diagnoses.

Novel Algorithm for the Estimation of Cancer Incidence Using Claims Data in Japan: A Feasibility Study.

PURPOSE: We developed algorithms to identify patients with newly diagnosed cancer from a Japanese claims database to identify the patients with newly diagnosed cancer of the sample population, which were compared with the nationwide cancer incidence in Japan to assess the validity of the novel algorithms. METHODS: We developed two algorithms to identify patients with stomach, lung, colorectal, breast, and cervical cancers: diagnosis only (algorithm 1), and combining diagnosis, treatments, and medicines (algorithm 2). Patients with newly diagnosed cancer were identified from an anonymized commercial claims database (JMDC Claims Database) in 2017 with two inclusions/exclusion criteria: selecting all patients with cancer (extract 1) and excluding patients who had received cancer treatments in 2015 or 2016 (extract 2). We estimated the cancer incidence of the five cancer sites and compared it with the Japan National Cancer Registry incidence (calculated standardized incidence ratio with 95% CIs). RESULTS: The number of patients with newly diagnosed cancer ranged from 219 to 17,840 by the sites, algorithms, and exclusion criteria. Standardized incidence ratios were significantly higher in the JMDC Claims Database than in the national registry data for extract 1 and algorithm 1, extract 1 and algorithm 2, and extract 2 and algorithm 1. In extract 2 and algorithm 2, colorectal cancer in male and stomach, lung, and cervical cancers in females showed similar cancer incidence in the JMDC and national registry data. CONCLUSION: The novel algorithms are effective for extracting information about patients with cancer from claims data by using the combined information on diagnosis, procedures, and medicines (algorithm 2), with 2-year cancer-treatment history as an exclusion criterion (extract 2).

Validation of HPV triage in cytology-based cervical cancer screening for ASC-US cases using Japanese data.

OBJECTIVE: In Japan, cervical cancer screening consists of a cytology examination performed once every 2 years. We verified whether the risk of cervical intraepithelial neoplasia (CIN) 3 disease or higher (CIN3+) was equivalent to that of cytology negative cases (negative for intraepithelial lesion or malignancy [NILM]) for patients with a cytological diagnosis of "atypical squamous cells of undetermined significance (ASC-US)" who tested negative for human papillomavirus (HPV). METHODS: Data from a total of 22,925 cases who had undergone cervical cancer screening at least twice or who had completed follow-up examinations after cervical screening at a single facility between April 2013 and April 2018 were analyzed. The cumulative incidence of CIN3+ was calculated for each category of initial cytology finding and HPV result (NILM, > ASC-US, ASC-US/HPV (unknown), ASC-US/HPV+, and ASC-US/HPV-). The statistical analysis was conducted using the Cox proportional hazards model. RESULTS: The hazard ratio for the cumulative incidence of CIN3+ in 2 years relative to that for NILM cases was 2.7 (95% confidence interval=1.0-7.8) for > ASC-US cases, 0.5 (0.1-1.7) for ASC-US/HPV (unknown), 0.8 (0.3-2.4) for ASC-US/HPV+ cases, and 0.3 (0.1-1.0) for ASC-US/HPV- cases. CONCLUSION: Because the cumulative incidence of CIN3+ at 2 years for the ASC-US/HPV- cases was sufficiently low, compared with that of the NILM cases, we considered it reasonable and safe to perform HPV triage for ASC-US cases and to allow HPV-negative cases to return for their next screening in 2 years, which is the same follow-up schedule as that for NILM cases.

Suicide, other externally caused injuries, and cardiovascular disease within 2 years after cancer diagnosis: A nationwide population-based study in Japan (J-SUPPORT 1902).

BACKGROUND: This study aimed to investigate the risk of death by suicide, other externally caused injuries (ECIs), or cardiovascular disease for patients with cancer. METHODS: We used data from the National Cancer Registry, which include the entire population in Japan. Patients diagnosed with cancer from January 1 to December 31, 2016 were included, and their follow-up period was set to 2 years. The standardized mortality ratio (SMR) of death by suicide, other ECIs, and cardiovascular disease was calculated compared with the general population. Multivariate Poisson or negative binomial regression analysis was used to quantify the adjusted relative risks of factors of interest. RESULTS: We evaluated 1,070,876 patients with cancer. The 2-year follow-up SMR was 1.84 (95% confidence interval [CI]: 1.71-1.99) for suicide, 1.30 (95% CI: 1.24-1.37) for other ECIs, and 1.19 (95% CI: 1.17-1.21) for cardiovascular disease. The SMR was higher with shorter follow-up periods but was significant 13-24 months after cancer diagnosis. The SMRs at 0-1 month and 13-24 months, respectively, were 4.40 (95% CI: 3.51-5.44) and 1.31 (95% CI: 1.14-1.50) for suicide; 2.27 (95% CI: 1.94-2.63) and 1.27 (95% CI: 1.18-1.37) for other ECIs; and 2.38 (95% CI: 2.27-2.50) and 1.07 (95% CI: 1.04-1.10) for cardiovascular disease. The multivariate analyses showed that patients with cancers other than localized tumors had significantly high relative risks of death for each cause. CONCLUSION: Suicide prevention countermeasures for patients with cancer, especially those with advanced disease immediately after diagnosis, are warranted.

Difference in net survival using regional and national life tables in Japan.

BACKGROUND: National life table is commonly used for estimating cancer net survival. However, the national life table does not reflect condition of people in local area accurately, because there are disparities in cancer mortality rates among the local area in many cases. We investigated magnitude of difference in cancer net survival using the local area in Japan and Japanese life tables. METHODS: We analyzed data from 32,942 cancer patients diagnosed between 2010 and 2012 in Aomori prefecture, Japan. Expected survival rates in Aomori (ESA) and Japan (ESJ) were estimated based on the life table of each area. Five-year net survival rates using ESA and the ESJ were estimated using the Pohar-Perme method. RESULTS: The difference between net survival rates using the ESA (NSA) and the ESJ (NSJ) were larger than in men (0.3－3.0%) than in women (0.1－0.8%). The largest difference in the net survival rate was observed in prostate cancer patients, because the difference in the expected survival in oldest old men was remarkable. CONCLUSION: Two factors affected the difference in the net survival rates resulting from the sensitivity analysis. The difference was larger (1) among older patients or (2) with a longer observation period (person-years).

Status of cervical cancer screening among adolescents and young adults (AYA) in Japan.

Cervical cancer ranks high among the cancers that affect people in their 20s and 30s. Cervical cancer is characterized by the presence of precancerous lesions, which can be detected by cancer screenings; some precancerous lesions are amenable to treatment, which can halt the progression to invasive cancer. As a result, cervical cancer screening has been shown to reduce the incidence of invasive cancer and its mortality. On the other hand, many precancerous lesions do not progress to invasive cancer, but stagnate or disappear spontaneously. In Japan, there is a nationwide cytological screening program for residents, and the screening is performed every two years after the age of 20. There are also screening programs provided by the workplaces in Japan. According to the National Health Survey 2019, the checkup rates of any type of cervical cancer screenings are low: 15.1% for those aged 20-24, 36.6% for those aged 25-29, and 49.4% for those aged 30-34. Statistics are reported every year for the nationwide screening, and according to them, the positive screening rate is 2.1% for all ages, but 4.5% and 3.2% for those in their 20s and 30s, respectively. On the other hand, the percentage of people with positive test results who undergo follow-up examinations or confirmatory tests should be at least 90%, but it is 72.1% for all ages, 72.0% for those in their 30s, and even lower for those in their 20s, at 67.1%. Improving the rate of people getting screenings and subsequent examinations is a challenge even among the young.