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# Cancer mortality gap across Japanese prefectures moved north between 1995 and 2023
- URL: https://www.coios.me/cancer-mortality-gap-across-japanese-prefectures-moved/
- Published: 2026-11-08T13:02:18.000Z
- Updated: 2026-11-08T14:12:19.000Z
- Description: As cancer mortality fell, Japan's prefectural excess moved from liver cancer in the west to several cancers in the north.
- Author: Daniel Ryan
- Tags: Health today, Cancer, Japan, #peer-reviewed, #refines, #item, #source-2026-11, #score-62

This nationwide ecological study compared age-standardised cancer mortality across all 47 Japanese prefectures in 1995 and 2023\. Using vital statistics, each prefecture's excess mortality was measured against a leave-one-out national reference. All-cancer mortality fell everywhere, and the gap between prefectures narrowed from 69·6 to 55·0 per 100,000\. The 1995 excess lay in western Japan, particularly Osaka and Fukuoka, and came largely from liver cancer. By 2023 it was led by Aomori at 32·6 per 100,000, and spread across colorectal, lung and stomach cancer. Because it compares area-level data for only two years, the study cannot identify the causes of the shift.

*Why it is interesting: Mortality fell everywhere, yet the prefectures carrying the excess changed and the cancers behind it broadened. A western excess led by liver cancer was replaced by a northern one, rather than simply removed.*

Source

[Japanese Journal of Clinical Oncology, 5 November 2026](https://doi.org/10.1093/jjco/hyag190?ref=coios.me)

Paper

Northward shift in cancer mortality inequality across Japanese prefectures, 1995–2023, a nationwide ecological study

Authors

Jamil H, Abubakar AK, Tanaka H, Katanoda K

DOI

10.1093/jjco/hyag190

Type

Peer-reviewed article

Design

Nationwide ecological study of age-standardised cancer mortality across all 47 Japanese prefectures, vital statistics for 1995 and 2023, excess mortality against a leave-one-out national reference, decomposed by cancer site

Verdict

Refines prior evidence

Driver

[Cancer](https://www.coios.me/d-cancer/)

Abstract — the authors' own words, CC BY

Abstract

Background

Cancer has been the leading cause of death in Japan since the 1980s, with known variation across prefectures, but evidence on how this pattern has changed over time is limited.

Methods

We analysed age-standardized cancer mortality across all 47 Japanese prefectures in 1995 and 2023 using vital statistics data. For each prefecture, excess mortality was calculated relative to a leave-one-out national reference and standardized to the 1995 national population. Excess mortality was decomposed by cancer site. We also compared prefectures’ age-standardized mortality rates (ASMRs) between the two years.

Results

All-cancer ASMR declined in every prefecture. In 2023, excess mortality ranged from 32·6 per 100 000 (95% CI 26·8 to 38·4) in Aomori to −22·4 (−26·1 to −18·6) in Nagano, a gap of 55·0 deaths per 100 000, with 30 prefectures differing significantly from the national reference. The geographic pattern shifted between 1995 and 2023\. In 1995, excess mortality was concentrated in western Japan, particularly Osaka and Fukuoka, and was largely driven by liver cancer. By 2023, excess mortality had shifted to northern prefectures, led by Aomori and Hokkaido, and was distributed across multiple cancer types, including colorectal, lung, and stomach cancer. The overall gap narrowed from 69·6 to 55·0 per 100 000.

Conclusions

Geographic inequality in cancer mortality persisted in Japan, but its pattern changed substantially. The findings suggest that national cancer control should monitor subnational inequality directly and support regionally targeted strategies.