Occupational class differences in pancreatic cancer survival: A population‐based cancer registry‐based study in Japan

Abstract

Background Little is known about occupational class differences in pancreatic cancer survival. Methods Using a population‐based cancer registry in Japan, 3 578 patients with incident pancreatic cancer (1970‐2011) were followed up for 5 years (median follow‐up time 0.42 years). We classified patients into four occupational classes based on their longest‐held jobs: white‐collar (professional and managers), service, blue‐collar, and those not actively employed. Using white‐collar class as the reference group, hazard ratios (HRs) and 95% confidence intervals (CIs) for overall death were estimated by Cox proportional hazard model. Covariates included age, sex, and year of diagnosis. Prognostic variables (pathology, stage, and treatment) and smoking behaviors were additionally adjusted as possible mediating factors. Results Overall survival was poor in this population (median, 0.50 and 0.33 years in white‐collar and service classes, respectively). Compared with white‐collar patients, survival was significantly poorer across all occupational classes, most pronounced in the service worker group: mortality HRs ranged from 1.11 (95% CI 1.00‐1.24) in blue‐collar workers to 1.24 (95% CI 1.12‐1.37) in service workers. Even after controlling for potential mediating factors, service workers showed worse survival. Conclusion We documented occupational class disparities in pancreatic cancer survival in Japan. Even in the setting of lethal prognostic cancer with universal health coverage, high‐occupational class groups may enjoy a health advantage.

Sex‐specific analysis of renal cell carcinoma histology and survival in Japan: A population‐based study 2004 to 2016

“…Despite these limitations, the strengths of our study included the size, as this is one of the most extensive studies conducted for evaluating sex differences in RCC histology in the non‐Western setting. Our distribution of the clear cell subtype (88.2%) estimated with population‐based data was similar to the SEER data, suggesting our reduced bias compared with nonpopulation‐based studies . In addition, while previous population‐based studies did not include SES or smoking habits, we were able to take account of these characteristics in our study.…”

“…A large, population‐based data set (2004‐2016) of Kanagawa Cancer Registry (KCR), a survey of over nine million people in Kanagawa prefecture that covers approximately 7% of the Japanese population, was used for analysis. Details of the study database have been previously described elsewhere . Briefly, Kanagawa Prefecture, a metropolitan prefecture located next to Tokyo, is the second largest prefecture in Japan, and KCR is one of the largest local cancer registries in Japan.…”

“…Additionally, clinicopathological variables were included in survival analyses as potential mediating variables, ie, these variables do not confound the association between sex and RCC survival, but rather, they may help to explain the observed differences. Our clinicopathological variables of interest included the following: WHO pathological grade (grades 3 or 4 [high‐grade] vs grades 1 or 2 [low‐grade]), the Union for International Cancer Control TNM stage (stages III and IV [late stage] vs stages I and II [early stage]), and any performed surgeries including radical/partial nephrectomy (yes/no), as well as SES (high SES [with the longest‐held occupational class of managerial or professional workers] vs low SES) and smoking habits (never/ever).…”

Occupational disparities in bladder cancer survival: A population‐based cancer registry study in Japan

“…Additionally, KCR partly collected occupational and smoking history at diagnosis among the bladder cancer patients during 1970‐2011. However, on average, only 15% of the annually registered bladder cancer patients completed occupational information, and 19% completed smoking information; these data were no longer collected after 2016 due to the change of data management practice . KCR automatically updates dates of death/last follow‐up with population registers and death certificates, and previous diagnostic codes are updated to be consistent with changes in coding practice .…”

“…However, in this regression analysis among the 3593 study subjects, records included a large number of missing data: 88.1% (3165 patients) of stage information, 12.5% (448 patients) of pathological type, 79.2% (2846 patients) of pathological grade, 1.6% (57 patients) of treatment, and 72.3% (2596 patients) of smoking behaviors. We conducted multiple imputation for missing data among the 3593 study subjects with all variables used for analysis, and 20 imputed data sets were generated . Additionally, we estimated HRs and 95% CIs with multiple imputation among all 23 906 bladder cancer patients registered in KCR in the study period.…”