Compared to X-ray, CT lung screening cuts cancer mortality by 51 percent

The risk of lung cancer death in low-risk individuals and nonsmokers who underwent low-dose computed tomography (LDCT) screening, decreased by 51% compared to x-ray screening, according to a study published in the Japanese Journal of Clinical Oncology.

This is the first cohort study regarding the effectiveness of LDCT screening for subjects including non-/light smokers.

An increase in the incidence of lung cancer in non-smokers and increased risk of mortality from passive-smoking-related lung cancer is rapidly increasing in Asian countries, including Japan. According to the results of the National Lung Screening Trial (NLST), lung cancer screening using low-dose computed tomography (LDCT screening) for heavy smokers reduced the lung cancer mortality by 20%.

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The study was primarily conducted in Hitachi city, Japan. In this study, the ‘CT group’ was defined as residents who had undergone LDCT screening at least once between 1998 and 2006 and were aged 50–74 years at the first LDCT screening. The observation period began on the day of the first LDCT screening between 1998 and 2006. On the other hand, the ‘XP group’ was defined as residents who had undergone chest X-ray screening at least once between 2001 and 2006 and were aged 50–74 years at the first screening.

The researchers investigated the lung cancer incidence rate, mortality rate and all-cause mortality rate for both groups from the first lung cancer screening to the end of 2012.

The authors found that the risk of all-cause death in the CT group decreased by 43%. Moreover, Regarding the lung cancer incidence rate, the number of subjects diagnosed with lung cancer in the CT group was 1.23 times greater than that in the XP group. Most lesions detected by LDCT screening in Japan have been lung cancer measuring ≤20 mm in diameter (10–12), most of which were not detectable by X-ray screening.

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“This result suggests a delay in the detection of some lung cancer lesions in the XP group in comparison with early detection in the CT group,” write the authors.

The researchers concluded that the cohort study including non-/light smokers with a mean follow-up of ≥9 years demonstrated the incidence of lung cancer in residents in Hitachi city who underwent LDCT screening increased by 23% in comparison with that in those who underwent X-ray screening and lung cancer screening using low-dose CT for a population including non-/light smokers may be effective.

For full information log on to https://doi.org/10.1093/jjco/hyy185