Trend analysis of cancer incidence in Japan using data from selected population-based cancer registries.

Population-based cancer registries are operated by over 80% of prefectures in Japan. However, only a limited proportion of the registries can provide long-term incidence data. Here, we aimed to establish a method for monitoring cancer incidence trends in Japan using data from selected prefectures. Based on the availability of long-term (≥ 20 years) high-quality data, we collected incidence data from five prefectures (Miyagi, Yamagata, Fukui, Osaka, and Nagasaki), which included an annual average of 54,539 primary cancer cases diagnosed between 1985 and 2004. Cancer mortality data for 1995-2004 were obtained from the vital statistics. Representativeness and homogeneity of the trends were examined by funnel plot analysis of log-linear regression coefficients calculated for the most recent 10 years of data (1995-2004) of age-standardized rates (ASR). The ASR of incidence for five prefectures in total (5-pref total) showed a significant decrease, with an annual percent change (APC) of -1.0 (95% confidence interval [CI] -1.4: -0.6) for males and -0.4 (95% CI -0.8: -0.1) for females. Excluding data from Osaka (4-pref total) reversed the decreasing trend; the corresponding APC was +0.4 (95% CI -0.2: +1.0) for males and +0.7 (95% CI +0.5: +0.9) for females. The APCs for the ASR of mortality for the 4-pref total (males, -1.5; females, -1.3) were more representative of nationwide data (males, -1.4 [95% CI -1.7: -1.2]; females, -1.1 [95% CI -1.4: -0.9]) than those for the 5-pref total (males, -1.7; females, -1.4). We conclude that using data from Miyagi, Yamagata, Fukui, and Nagasaki prefectures, with continuous monitoring of the representativeness of the data, is a provisionally relevant way to evaluate cancer incidence trends in Japan.

Cancer incidence and incidence rates in Japan in 2006: based on data from 15 population-based cancer registries in the monitoring of cancer incidence in Japan (MCIJ) project.

The Japan Cancer Surveillance Research Group estimated the cancer incidence in 2006 as part of the Monitoring of Cancer Incidence in Japan (MCIJ) project, on the basis of data collected from 15 of 32 population-based cancer registries. The total number of incidences in Japan for 2006 was estimated as 664 398 (C00-C96). The leading cancer site was stomach for men and breast for women. Age-standardized incidence rates remained at almost the same level as for the previous 3 years.

Population-based survival of cancer patients diagnosed between 1993 and 1999 in Japan: a chronological and international comparative study.

OBJECTIVE: The purpose of the present study was to collect data from population-based cancer registries and to calculate relative 5-year survival of cancer patients in Japan. We also sought to determine time trends and to compare the results with international studies. METHODS: We asked 11 population-based cancer registries to submit individual data for patients diagnosed from 1993 to 1999, together with data on outcome after 5 years. Although all these registries submitted data (491 772 cases), only six met the required standards for the quality of registration data and follow-up investigation. The relative 5-year survival calculated by pooling data from 151 061 cases from six registries was taken as the survival for cancer patients in Japan. RESULTS: Relative 5-year survival (1997-99) was 54.3% for all cancers (males: 50.0%, females: 59.8%). Survival figures for all sites changed slightly over the 7-year period, from 53.2% for the first 4 years of the study (1993-96) to 54.3% for the last 3 years (1997-99), however, a major improvement was observed in several primary sites. Some overall survival was lower in Japan than in the USA, but similar to that in European countries. Specifically, survival for uterine cancer, prostate cancer, testis cancer, lymphoma and leukemia was much lower in Japan than in other countries. However, survival was better in Japan mainly for cancers of the esophagus, stomach, colon, liver and gallbladder. CONCLUSION: The study suggests an improvement in cancer survival in several primary sites in Japan, which is consistent with the development of treatments and early detection.

Cancer incidence and incidence rates in Japan in 2005: based on data from 12 population-based cancer registries in the Monitoring of Cancer Incidence in Japan (MCIJ) project.

The Japan Cancer Surveillance Research Group estimated the cancer incidence in 2005 as part of the Monitoring of Cancer Incidence in Japan (MCIJ) project, on the basis of data collected from 12 of 30 population-based cancer registries. The total number of incidences in Japan for 2005 was estimated as 646,802 (C00-C96). The leading cancer site was the stomach for men and the breast for women. Age-standardized incidence rates remained almost the same level as the previous 2 years.

Incidence and survival trends for childhood cancer in Osaka, Japan, 1973-2001.

Mortality for childhood cancer has declined in Osaka, as well as all over Japan, since the 1970s, but whether this decline can be explained by trends of incidence or survival of childhood cancer has not been examined. A total of 5960 malignant tumors diagnosed between 1973 and 2001 in children <15 years of age were registered at the Osaka Cancer Registry in Japan. The time trends for childhood cancer were analyzed over 29 years for incidence and 20 years for survival. Leukemia was the most common among childhood cancer for both sexes and accounted for one-third of all cases. The age-standardized annual incidence rate of all tumors was highest in 1988-1992: 155.1 per million for males and 135.9 for females. Five-year survival for all tumors improved from 50.1% in 1978-1982 to 73.0% in 1993-1997 for males and from 52.3% to 76.3% for females. Thus, the constant decline in mortality in childhood cancer was primarily due to improved survival between the 1970s and 1980s and reduced incidence after the 1990s.

Cancer incidence and incidence rates in Japan in 2004: based on data from 14 population-based cancer registries in the Monitoring of Cancer Incidence in Japan (MCIJ) Project.

The Japan Cancer Surveillance Research Group estimated the cancer incidence in 2004 as part of the Monitoring of Cancer Incidence in Japan (MCIJ) project, on the basis of data collected from 14 of 31 population-based cancer registries. The total number of incidences in Japan for 2004 was estimated as 623,275 (C00-C96). The leading cancer site according to the crude and age-standardized incidence rates was the stomach for men and breast for women. The apparent increase in age-standardized incidence rates in 2003 was calmed down in 2004.

Regional differences in population-based cancer survival between six prefectures in Japan: application of relative survival models with funnel plots.

We used new methods to examine differences in population-based cancer survival between six prefectures in Japan, after adjustment for age and stage at diagnosis. We applied regression models for relative survival to data from population-based cancer registries covering each prefecture for patients diagnosed with stomach, lung, or breast cancer during 1993-1996. Funnel plots were used to display the excess hazard ratio (EHR) for each prefecture, defined as the excess hazard of death from each cancer within 5 years of diagnosis relative to the mean excess hazard (in excess of national background mortality by age and sex) in all six prefectures combined. The contribution of age and stage to the EHR in each prefecture was assessed from differences in deviance-based R(2) between the various models. No significant differences were seen between prefectures in 5-year survival from breast cancer. For cancers of the stomach and lung, EHR in Osaka prefecture were above the upper 95% control limits. For stomach cancer, the age- and stage-adjusted EHR in Osaka were 1.29 for men and 1.43 for women, compared with Fukui and Yamagata. Differences in the stage at diagnosis of stomach cancer appeared to explain most of this excess hazard (61.3% for men, 56.8% for women), whereas differences in age at diagnosis explained very little (0.8%, 1.3%). This approach offers the potential to quantify the impact of differences in stage at diagnosis on time trends and regional differences in cancer survival. It underlines the utility of population-based cancer registries for improving cancer control.

Trend in incidence of adenocarcinoma of the esophagus in Japan, 1993-2001.

BACKGROUND: Several studies with population-based cancer registry data have suggested that incidence of adenocarcinoma of the esophagus has been increasing since 1970 in some European and North American countries and Australia. However, data from Asian countries with regard to the incidence of esophageal cancer by histological type based on the population-based cancer registry are lacking. The aim of this study was to describe the incidence of esophageal cancer by histological type in a Japanese population. METHODS: Cancer incidence data for 1993-2001 from 15 population-based cancer registries were collected by the Japan Cancer Surveillance Research Group in 2005. We used data from eight registries corresponding to inclusion criteria for data quality. RESULTS: Squamous cell carcinoma remains the predominant type in all esophageal cancers in Japan. The ratio of squamous cell carcinoma to adenocarcinoma is 26:1. For adenocarcinoma, estimated average annual percentage change was 4.7% (95% confidence interval: 0.7, 8.9) in men and 6.0% (2.4, 9.8) in women. Age-adjusted incidence rate (the world standard population) per 100 000 for 2001 was 0.3 in men and 0.05 in women. Incidence of squamous cell carcinoma was increasing slightly in men and nearly constant in women. Age-adjusted incidence rate for 2001 was 8.2 in men and 1.0 in women. CONCLUSION: No dramatic increase in adenocarcinoma has occurred, and absolute incidence remains low in Japan.

Cancer incidence and incidence rates in Japan in 2002: based on data from 11 population-based cancer registries.

The number of cancer incidences, crude incidence rates, age-standardized incidence rates in 2002 in Japan are estimated. The estimated total number of incidences was 570,598.

Lifetime and age-conditional probabilities of developing or dying of cancer in Japan.

The concepts of lifetime and age-conditional probabilities of developing and dying of cancer are introduced as indexes to understand the risk of cancer. In this paper, we estimated the lifetime and age-conditional probabilities of developing and dying of cancer in 2001 and 2005, respectively, in Japan. It is estimated that one in two Japanese males and one in three females will develop cancer, and one in four Japanese males and one in six females will die of cancer. Moreover, the probabilities of developing cancer within specific decades of age are obtained as the short-term risks.

Hospital procedure volume and survival of cancer patients in Osaka, Japan: a population-based study with latest cases.

BACKGROUND: Recent studies reported that hospital procedure volume (i.e. volume of patients per hospital receiving a particular treatment)was directly proportional to cancer survival; however the degree of association might be different according to the primary tumor site, extent of disease and year of diagnosis. We performed a systematical examination of survivals by hospital procedure volume according to the primary site with inclusion of latest cases in Osaka, Japan. METHODS: Individual data on reported cancer cases with active follow-up information and diagnosis between 1994 and 1998 were retrieved from Osaka Cancer Registry's database. The analysed primary sites included oesophagus, stomach, large bowel, liver, gall bladder, pancreas, lung, breast, uterus, ovary, prostate, bladder and lymphoma. Hospitals were ranked as high-, medium-, low- and very low-volume hospitals for every primary site by dividing the number of cancer patients who received treatment in hospitals into four quartiles. RESULTS: The primary sites could be classified into three categories based on the association between hospital procedure volume and cancer survival: In type 1, a better survival was associated with a higher procedure volume as for oesophagus, liver, lung, ovary, prostate, or lymphoma; in type 2, a better survival was associated with a higher procedure volume but there was no significant difference in survival between high- and medium-volume hospitals as for uterus; and in type 3, there was no significant difference in survival among high-, medium- and low-volume hospitals as for stomach, large bowel, gall bladder, pancreas, breast, or bladder sites. CONCLUSIONS: A higher procedure volume was generally associated with a better survival; however, this association could be classified into three types according to the primary site.

Statistical estimation of the number of breast cancer patients with disabilities resulting from surgery.

BACKGROUND: The prolongation of the post-operative life of cancer patients brings new medical demands. The purpose of this paper is to estimate the total number of women patients with breast cancer who will have disability resulting from surgical treatment from 2000 to 2020 in Japan. METHODS: The estimation was carried out using four indices: the number of cases of women diagnosed with breast cancer, the proportion of surgical operations, the frequency of disability from surgical treatment, and the crude survival rate of the patient group. The crude survival rates of surgically-treated breast cancer patients were estimated by the Weibull model. The frequencies of iatrogenic disabilities were calculated from several reports of complaints of pain in the chest wall or axilla and lymphedema of the arm, and 95% confidence intervals were calculated by the Monte Carlo simulation. RESULTS AND DISCUSSION: The number of women patients with disability from breast cancer treatment from 2000 to 2020 was estimated to be 42,016 (95% CI: 41,236, 42,796) people in 2000 and 72,514 (95% CI: 71,196, 73,832) people in 2020 for pain in the chest wall or axilla, and 22,486 (95% CI: 22,148, 22,823) people in 2000 and 38,692 (95% CI: 38,094, 39,290) people in 2020 for lymphedema of the arm. Treatment supports required for the disability are medication and social support. Cancer patients with disability after treatment need long-term support in their daily life.

Liver cancer and its prevention.

Liver cancer is one of the leading causes of cancer deaths in Asia and Africa. The epidemiology of liver cancer is distinctive in Japan, where chronic infection with hepatitis C virus (HCV) rather than hepatitis B virus (HBV) plays the major role in the etiology. In this paper, together with a brief review of the descriptive epidemiology of liver cancer and its prevention, Japanese experiences of liver cancer occurrence and some epidemiological studies are described, and Japanese national projects directed against hepatitis and liver cancer are presented. Distinctive time-trends have been observed for liver cancer incidence in Japan. The rates for over 55-59 year olds (both sexes) showed a peak in the birth cohort of 1931-1935, while the rates for less than 50-54 year old females indicate a decreasing trend. The extremely high incidences among birth cohorts around 1931-1935 seems to be related to endemic HCV infection in this generation in Japan. Follow-up studies not only of patients with chronic hepatitis C but also of apparently healthy carriers of HCV showed an increased risk of hepatocellular carcinoma (HCC). Cumulative risk of HCC (40-74 years of age) was estimated as reaching 21.6% (males) and 8.7% (females) among anti-HCV positive voluntary blood donors. Retrospective cohort studies indicated interferon (IFN), with or without ribavirin, to be effective for reducing the risk of HCC among patients with chronic hepatitis C. Periodic examination with ultrasonography and measurement of alpha-fetoprotein has become common practice for early detection of HCCs among patients with chronic hepatitis or liver cirrhosis in Japan. A non-randomized controlled study was conducted to evaluate the effect of periodic examination on mortality, but we failed to show any beneficial effects of screening for liver cancer. In the fiscal year 2002, Japanese National Projects directed against hepatitis and HCC were started, in which blood tests for HCV and HBsAg are offered just once at the age of 40, 45, 50, 55, 60, 65 or 70 for five years. Participants are categorized as either HCV carriers or non-carriers. HCV carriers are further examined by liver disease specialists, seeking indications for IFN therapy. Type C chronic hepatitis patients are recommended to receive IFN therapy with or without ribavirin. This project is expected to become a model of liver cancer control in HCV-endemic countries. Recently however, the US Preventive Service Task Force has recommended against routine screening for HCV infection in asymptomatic adults in the general population who are not at increased risk of infection. This divergence of views is also discussed.

Estimation of individualized probabilities of developing breast cancer for Japanese women.

BACKGROUND: Projecting individualized probabilities of developing breast cancer is needed for counseling and chemoprevention for Japanese women, in whom breast cancer incidence has been rapidly increasing. METHODS: We calculated individualized probabilities of developing breast cancer within 10-20 years and until life expectancy for Japanese women by multiplying the relative risk for each risk factor combination by the cumulative risk for the reference group. The risk factors used were age at menarche, age at first delivery, family history of breast cancer, and body mass index (BMI) (in post-menopausal women). The relative risk by menopausal status for each risk factor combination was estimated from a case control study conducted at Osaka Medical Center for Cancer and Cardiovascular Diseases (OMCC), Japan. The cumulative risk of breast cancer for the reference group within 10-20 years and until life expectancy was estimated to divide the corresponding cumulative risk for Japanese women by the weighted average of the relative risk. The weight is an expected proportion of those who have each risk factor combination among the general population. The cumulative risk for Japanese women was estimated using a data file from the Osaka Cancer Registry (OCR). RESULTS: We obtained cumulative risks for any age women within a certain range according to various risk factor combinations by menopausal state. For example, the highest risk group had about a 5 times higher risk probability of developing breast cancer than the general population at initial age 40, within 10-20 years, and until life expectancy. CONCLUSION: The cumulative risk of breast cancer varied according to individuals' risk factors among Japanese women. The availability of concrete individualized risk estimation figures will be of use to health care providers in encouraging Japanese women to seek counseling and to adopt self-control of body weight as a primary preventive measure, as well as to have breast cancer screening.

[Cancer incidence in Japan].

Based on the estimates by the Research Group for Population-based Cancer Registration in Japan, time-trend of cancer incidence in Japan was described and analyzed. During the period of 1975-1998, the annual total cancer incidence increased 111,000-290,000 in males, and 96,000-208,000 among females. The higher incidence was prominent for cancers of the colorectum, lung, liver, gallbladder and extrahepatic bill duct (both sexes), prostate, and breast (female), whereas it was low or negligible for cancers of the stomach (both sexes) and uterus. The increased cancer incidence was globally attributed to the rapid growth of the Japanese aged population. However, a remarkable increase in the age-standardized incidence rate was also observed for cancers of the colorectum (both sexes), prostate, and breast (female). A decline in the age-standardized incidence rate was continuously observed for cancer of the stomach and uterus. A birth cohort analysis has revealed that the cancer incidence in Japan has been highly affected by the generation. Based on the Cancer Incidence in Five Continents Vol. VIII, the cumulative risk of cancer incidence (0-79 years old) was calculated and compared among the Japanese population (6 registries' data), US-Japanese and US-white. Several characteristics were suggested and discussed for Japanese cancer risk.

Do the Japanese feel more suspicious about cancer registration than the British?

BACKGROUND: Cancer registration is indispensable, providing useful statistical measures for the appropriate evaluation of cancer control programs and medical treatment or screening. METHODS: Following the British national survey on attitudes toward cancer registration, we conducted an investigation to correctly evaluate the general opinion of the Japanese population in this regard. We randomly recruited 3000 men and women aged 20-69 years from a research database. RESULTS: Only 4% of all respondents had heard about the cancer registry system before the investigation. However, 77% of respondents thought that cancer registration was useful. Forty-three percent of respondents answered, regardless of the strictness of the data protection, that privacy had been violated if the registration occurred without an individual explanation. Compared with the British survey results, Japanese people seemed to be more suspicious about the largely unknown system of cancer registry. Nonetheless, it is noteworthy that Japanese respondents did not show active opposition to cancer registration; they tended to choose "I don't know" instead of "no" to questions asking if they supported the registry system. Multivariate analysis showed that male sex, older age, and living in the southern region were the factors significantly associated with support for cancer registration. CONCLUSIONS: We can seek society's understanding toward cancer registration by actively utilizing information from cancer registries, by using examples of how data are actually used that have wide appeal, and by educating the public on how the data are treated under the complete privacy policy.