# Occupational Disparities in Cancer Survival Among the Working Population in Japan: 10‐Year Survival Analysis Using the Kanagawa Cancer Registry

## TL;DR

This study found that workers in lower nonmanual, manual, and primary industry jobs in Japan have worse long-term cancer survival rates compared to those in upper nonmanual professions.

## Contribution

The study provides new evidence of occupational disparities in cancer survival among working-age populations in Japan using a 10-year follow-up analysis.

## Key findings

- Manual workers had a 38% higher all-cause mortality rate compared to upper nonmanual workers.
- Adjusting for cancer stage and treatment reduced but did not eliminate survival disparities.
- Occupational disparities were observed across common cancer sites like stomach, lung, colorectal, and breast cancers.

## Abstract

Limited data exist on occupational disparities in long‐term cancer mortality among the working‐age population in Japan. We examined occupational disparities in long‐term cancer survival, focusing on 10‐year survival outcomes among working‐age populations.

This retrospective observational study used data from the Kanagawa Cancer Registry of 41,632 patients with cancer aged 20–65 years who were diagnosed between 1992 and 2015, with a 10‐year follow‐up. Patients were classified into four occupational classes based on their longest‐held occupations (upper nonmanual, lower nonmanual, manual, and primary industry). The primary outcome was all‐cause mortality, and cancer‐specific mortality was the secondary outcome. Poisson regression was used to estimate the mortality rate ratios (MRRs) and 95% confidence intervals (CIs) for each occupational class, adjusted for sex, age, and year of diagnosis. Additional analyses were performed for common cancer sites (stomach, lung, colorectal, and breast).

MRRs for all‐cause mortality were higher in lower nonmanual (MRR = 1.14, 95% CI 1.10–1.18), manual (MRR = 1.38, 95% CI 1.32–1.43), and primary industry workers (MRR = 1.19, 95% CI 1.09–1.31) than in upper nonmanual workers (professional and managerial occupations). Similar patterns were observed across common cancer sites and cancer‐specific mortality. Adjusting for cancer stage and treatment attenuated these disparities but did not eliminate them, particularly among manual workers.

We observed occupational disparities in long‐term cancer mortality among working‐age populations in Japan, with manual workers experiencing worse survival outcomes. Promoting targeted interventions, healthy lifestyles, and early cancer detection for cancer survivors in the workplace are crucial for mitigating these disparities.