Net survival using regional life table were higher than net survival using national life table (0.1–3.0% point).

Difference in net survival using regional and national life table among good prognosis cancer and elder patients were large.

Longer observation period (person-years) affected the difference in net survival.

National life table is commonly used for estimating cancer net survival. However, the national life table does not reflect condition of people in local area accurately, because there are disparities in cancer mortality rates among the local area in many cases. We investigated magnitude of difference in cancer net survival using the local area in Japan and Japanese life tables.

We analyzed data from 32,942 cancer patients diagnosed between 2010 and 2012 in Aomori prefecture, Japan. Expected survival rates in Aomori (ESA) and Japan (ESJ) were estimated based on the life table of each area. Five-year net survival rates using ESA and the ESJ were estimated using the Pohar-Perme method.

The difference between net survival rates using the ESA (NSA) and the ESJ (NSJ) were larger than in men (0.3－3.0%) than in women (0.1－0.8%). The largest difference in the net survival rate was observed in prostate cancer patients, because the difference in the expected survival in oldest old men was remarkable.

Two factors affected the difference in the net survival rates resulting from the sensitivity analysis. The difference was larger (1) among older patients or (2) with a longer observation period (person-years).

Aomori Cancer Registry

death certificates only

expected survival rate in Aomori

expected survival rate in Japan

net survival rate in Aomori

net survival rate in Japan

Expected survival

Net survival

Life table

Cancer

Population-based cancer registry

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