Lung cancer screening policy in Japan

Japan has a long history of lung cancer screening. A national chest X-ray (CXR) screening programme for lung cancer was introduced in 1987. Now in its 36^th year, it offers annual screening for lung cancer to people aged 40 years or older.^1-3

Guidelines for lung cancer screening were first developed in 2003. However, the last update in 2018 did not recommend population-based screening via LDCT. The responsibility of developing cancer screening guidelines now lies with the National Cancer Center.¹

Instead, LDCT screening in Japan is commonly performed on a voluntary (opportunistic) basis. People interested in being screened for lung cancer can be referred in the community or during the mandatory workplace or annual medical check-ups.³

Because of the widespread uptake, the Japanese Lung Cancer Society publishes annual guidelines to ensure quality of LDCT screening.^{3 4} In addition, the Japanese Society of CT Screening (JSCTS) offers accreditation for healthcare professionals using LDCT. In 2022, there were around 1,500 physicians and radiologists accredited in Japan.^{4 5}

Survey snapshot of the widespread use of LDCT screening in Japan (2000–2009) ³

Results from the Quality Control Group of the Japanese Society of CT Screening 2009 nationwide survey.

Three decades of LDCT screening implementation research

LDCT screening was first piloted in Japan in 1993 as part of the Anti-Lung Cancer Association (ALCA) project in Tokyo – the first centre in the world to do so.⁵ The ALCA project targeted people aged 40–79 who smoke and demonstrated that 76.2% of people diagnosed with lung cancer via LDCT screening were still alive after five years.⁶

Building on these results, a mobile CT unit delivered three rounds of annual LDCT screening to 5,480 people aged 40–74 living in Matsumoto (Nagano prefecture).^{7 8} This pilot found that 88% percent of people detected to have lung cancer were diagnosed at stage I of the disease and 10-year survival in this group was 86% (83% when considering all-cause mortality).

Another well-known example of mass LDCT screening took place in Hitachi (Ibaraki prefecture). The Hitachi city pilots were one of the largest cohorts in Japan to demonstrate that LDCT screening can result in a dramatic reduction of lung cancer deaths.^{9 10} Between 1998 and 2006, over 25,000 people aged 50–69 were selected to participate at two centres in the city, which was estimated to represent around 30% of the total population in this age group.³

The future of LDCT screening in Japan

A nationwide randomised controlled trial for LDCT screening (JECS) was set up by the Ministry of Health, Labour and Welfare in 2010. People aged 50–70 who currently smoke or used to smoke undergo two LDCT scans over a 10-year study period, whereas a control group is offered a single CXR scan through the annual and workplace health check-ups. By 2021, over 20,000 participants had enrolled from across 25 prefectures in Japan, including the Tokyo metropolitan area, and follow-up is expected to end in 2035.

Studies of opportunistic screening have also provided valuable lessons for the implementation of an organised LDCT screening programme. In 2020, an observational study of people who underwent LDCT screening between 2004 and 2012 concluded that the opportunity to detect approximately 70% of lung cancer cases at an early stage of the disease may be missed if Japan were to adopt LDCT screening using criteria from the US National Lung Screen Trial (NLST).¹²

Instead, it was recommended that people who have never smoked and those who had smoked less heavily (<30 pack-years) should be eligible for screening. More recently, one study also concluded that LDCT screening was more cost-effective than no screening and CXR when it came to detecting lung cancer in people who have never smoked.¹³ Other pilot studies targeting people who have never smoked in South Korea (LEADER), Taiwan (TALENT) and Kazakhstan may offer further learning of how to target people in Japan who have never smoked for LDCT screening.

The Lung Cancer Policy Network is publishing brief case studies of countries that have implemented LDCT screening; you can read other examples here.

We will also continue to build the extensive implementation research in Japan into the second edition of the map.

View the interactive map