受益者指向の施設間保健医療介護情報のオンライン流通基盤

研究期間:平成13-15年度 ; 研究種目:基盤研究B2 ; 課題番号:13480105原著には既発表論文の別刷を含む

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

Cancer survival trends in Osaka, Japan: the influence of age and stage at diagnosis.

BACKGROUND: Five-year survival is an important index for evaluating the overall effectiveness of cancer diagnosis and treatment. The aim of this study was to monitor trends in 5-year cancer survival in Osaka, Japan, during 1975-94, with adjustment for trends in age and stage at diagnosis. METHODS: Five-year crude survival was estimated for cancers of the stomach (39,697 patients), lung (17,400 patients) and breast (11,988 women) in four consecutive 5-year periods, with adjustment for age and/or stage, using the age and stage distribution of cases diagnosed during 1975-79 as standard weights. We estimated the impact of adjusting for either age or stage alone by their proportionate impact on the trend in fully (age- and stage-) adjusted survival. RESULTS: The absolute increase in unadjusted 5-year survival over 20 years was about 20% for stomach cancer, 14% for breast cancer and 5% for lung cancer. Lack of age adjustment would have caused proportionate under-estimation of these trends by 13-14% (stomach), 7% (breast), 14% (lung, men) and 4% (lung, women). Lack of adjustment for the trend toward earlier stage would have caused proportionate over-estimation (152%, men: 133%, women) of stomach cancer survival trends, which seemed more influenced by earlier diagnosis than more effective treatment. For breast cancer, the 31% over-estimation of trend from lack of stage adjustment suggests the impact of earlier diagnosis, while the improvement of survival after additional adjustment for age may be due to more effective treatment. Failure to adjust for stage led to a proportionate 21% under-estimation of lung cancer survival trends for men, and 4% over-estimation for women. CONCLUSION: This study confirms the importance of adjusting for trends in age and stage distribution when evaluating time trends in cancer survival

Trends in 'cure' fraction from colorectal cancer by age and tumour stage between 1975 and 2000, using population-based data, Osaka, Japan.

Since the 1960s, Japan has experienced a striking increase in the incidence of colorectal cancer, now the second most common cancer in the country. Meanwhile, the management of colorectal cancer has changed dramatically with the implementation of, for example, screening, endoscopy and adjuvant chemotherapy. It is therefore of interest to monitor the long-term trends in population 'cure' in Japan. We analysed 33 885 colorectal cancer cases diagnosed between 1975 and 2000 in Osaka. We applied the multivariable mixture cure model to estimate cure fraction and median survival time (MST) for 'uncured' patients, by sex, age, stage, period at diagnosis and subsite. For colon cancer, the cure fraction increased by about 25%, while MST for the uncured was prolonged from 8 to 12 months. The cure fraction was 5% higher in men than in women, while MST was similar in both. The cure fraction also increased for localized and regional tumours. For rectal cancer, the cure fraction increased by about 25-30%, but remained lower than for colon cancer. From the late 1970s, the cure fraction for colorectal cancer increased dramatically due to better management of detection and care for colorectal cancer. This improvement was obtained at the cost of shorter MST for uncured patients

Complete Workplace Indoor Smoking Ban and Smoking Behavior among Male Workers and Female Nonsmoking Workers’ Husbands: A Pseudo Cohort Study of Japanese Public Workers

A pseudo cohort study using national cross-sections (2001, 2004, 2007, and 2010) was conducted to examine differences in smoking prevalence under different smoking ban policies such as a complete workplace indoor smoking ban (early or recent implementation) and a partial smoking ban among male public workers and husbands of female nonsmoking public workers. The effectiveness of smoking bans was estimated by difference-in-differences (DID) with age group stratification. The results varied considerably by age and implementation period. Although DID estimates (positive value of DID estimate represents smoking cessation percentage) for both smoking bans on total male smoking were not significant, the over-40 age group indicated a significant DID estimate of 5.0 (95% CI: 0.2, 9.8) for the recent smoking ban. For female workers' husbands' smoking, the over-40 age group indicated positive, but not significant, DID estimates for the early and recent smoking bans of 7.2 (−4.7, 19.2) and 8.4 (−2.0, 18.7), respectively. A complete indoor workplace smoking ban, particularly one recently implemented among public office workers aged over 40, may reduce male workers' smoking and female workers' husbands' smoking compared with a partial smoking ban, but the conclusion remains tentative because of methodological weaknesses in the study