我が国の先駆的低線量CT検診―長野県における歩み

Pioneering low-dose CT screening in Nagano

長野県は全国でも屈指の「長寿県」として知られており，中でも，肺がん死亡率が都道府県別で最低であることは大いに注目されている。この理由については必ずしも十分解明されているわけではないが，本稿ではその背景について，長野県の住民検診における低線量肺がんCT検診（以下，CT検診という）の歴史と現状および課題をCT検診の実務者の立場から紹介し，考察する。

In 2017, 235（13.6％）of 1722 municipalities in Japan performed lung cancer CT screening. In Nagano Prefecture, 61 out of 75 municipalities（81.3％）implemented the program. One of the reasons for the widespread use of CT screening in Nagano Prefecture is the CT screening（Nagano Program）, which was started in 1996 by Emeritus Professor Shusuke Sone of Shinshu University. From 2000 to 2010, Dr. Sone performed LDCT examinations on 88,758 Nagano citizens. The prevalence rate of lung cancer was 504 per 100,000 subjects. According to a paper published by Sone et al. in 2014, in general, annual repeat screening for smokers and biennial screening for non-smokers appear to be appropriate for detecting the majority of lung cancers measuring＜14mm.

It is necessary to secure reading physicians to ensure the stable operation of low-dose CT screening. The cooperation of general physicians, respiratory physicians, respiratory surgeons, and radiologists is essential.