Lung cancer is by far the leading cause of cancer death and has a lower relative survival rate than other types of cancer because most lung cancers are detected at an advanced stage when they are first diagnosed.

Recently, a randomized control trial suggests that low-dose computed tomography (LDCT) enables an early stage detection and it has been increasingly accepted as an efficient screening method for high-risk individuals to reduce lung cancer mortality.

In 2011, The National Lung Screening Trial (NLST) in the U.S. has produced results that screening high-risk smoking groups (who have at least 30 pack-year smoking history and currently smoke or have quit within the past 15 years) aged 55 to 74 years with LDCT reduced lung cancer mortality by 20%.

Based on the evidence, Korean National Cancer Center has developed and published the guideline of lung cancer screening using LDCT for high-risk populations in 2015. The guideline recommends annual LDCT screening for high-risk smoking groups aged 55 to 74 years, with at least 30 pack-year smoking history and current smokers or past smokers who quit smoking within 15 years.

The Korean Lung Cancer Screening project (K-LUCAS), a nationwide, multicenter, prospective study started to evaluate the effectiveness and feasibility of lung cancer screening with LDCT for considering implementation of a national lung cancer screening program in Korea.

◎ Objective

This study is to evaluate the effectiveness and feasibility of lung cancer screening with LDCT for considering implementation of a national Lung Cancer Screening Program in Korea.

◎ Recruiting procedure

K-LUCAS involves 14 general hospitals located nationwide. The participants in K-LUCAS are recruited from the visitors in these hospitals for receiving national cancer screenings or smoking cessation services. The candidates are evaluated based on the questionnaire that is completed in prior to the national cancer screenings or smoking cessation services. Invitations will be sent to those candidates who meet our selection criteria to take part in LDCT lung cancer screening. Advertising to public including the information both of screening benefit and harm will be held in hospitals, newspaper, local bus stations and subways.

In addition to the criteria-based participant selection, a lung cancer risk prediction model will be adopted to improve the effectiveness of participant selection. The lung cancer risk prediction model considers various lung cancer risk factors in addition to age, smoking history and smoking quit duration which are already examined in the inclusion criteria. The model evaluates drinking amount, physical activity, family history of cancer, past history of lung disease and so on, in participant selection.

◎ Screening procedure

If the candidate meets the selection criteria or is approved by risk prediction model, investigators carefully explain the benefits or harms of the LDCT screening and offer them to participate in a LDCT lung cancer screening. If the candidate agrees on screening participation, an informed consent form is obtained and LDCT screening date is scheduled and confirmed. K-LUCAS also provides a smoking cessation counselling to current smokers on revisiting for the result counselling. A follow-up call is made after 6 months from the LDCT screening in order to assess smoking cessation status following LDCT screening.

◎Reporting LDCT results

The LDCT screening results are evaluated by radiologists in accordance with Lung imaging reporting and data system (Lung-RADS).

Network-based computer-aided detection (CAD) system will be used in K-LUCAS to assist reducing diagnostic errors and increasing lung nodule detection sensitivity.

We select participants based on the following criteria.

• Inclusion Criteria (1)

  • Age : 55-74 years old

  • Smoking history of at least 30 pack-years

    1. current smokers
    2. past smokers who quit smoking within 15 years

• Inclusion Criteria (2) The lung cancer risk prediction model considers various lung risk factors in addition to age, smoking history and smoking quit duration. This includes drinking amount, physical activity, family history of cancer, information on lung disease and so on, in participant selection. Following criteria is applied when the lung cancer risk prediction model is used for participant selection.

  • Age : 50-74 years old

  • Smoking history of at least 20 pack-years

    1. current smokers
    2. past smokers who quit smoking within 15 years

• Exclusion Criteria:

  • Lung cancer diagnosed and treated
  • Inability to move without help (ECOG status 2 or higher)
  • Have been treating regularly for tuberculosis, pneumonia and interstitial lung disease
  • Treated for any cancer within the last 5 years (*Exception: Thyroid cancer, Skin cancer)
  • A chest CT examination less than 6 months

High-risk smoking groups of current smokers and past smokers