Screening for Lung Cancer Using Low-dose Chest Computed Tomography in Korean Long-term Colorectal Cancer Survivors

The National Lung Screening Trial (NLST) and NELSON trial showed that low-dose chest computed tomography (LDCT) screening significantly reduced the mortality form lung cancer. Although cancer survivors are known to have high risk for second malignant neoplasm (SMN), the usefulness of LDCT screening for lung cancer in cancer survivors is not clear.

Between August 2016 and August 2017, 633 long-term colorectal cancer (CRC) survivors visited the survivorship clinic in Cancer Prevention Center, Yonsei Cancer Center, Seoul, Republic of Korea. We surveyed the smoking status and recommended LDCT screening to ever-smoking CRC survivors aged 55-80 years. The participants were classified into three risk groups: risk group 1 (RG1) who met the NLST criteria (Age 55-74 years, ≥ 30 pack-years of smoking, smoking cessation < 15 years); risk group 2 (RG2) who would not meet the NLST criteria but were at increased 6-year risk of lung cancer (PLCO_M2012 ≥ 0.0151); risk group 3 (RG3) who did not meet any of the criteria above.

Among 176 ever-smoking CRC survivors, 173 (98.3%) were male, 32 (18.2%) were current-smoker, and median age was 66 years (range, 55-79 years). We found 38 positive findings (non-calcified nodule ≥ 4 mm), 8 clinically significant findings, 66 minor abnormalities, and 64 negative findings on LDCT. Positive findings were identified in 15 of 79 (19.0%) of RG1, in 9 of 36 (25%) of RG2, and in 14 of 61 (23.0%) of RG3. Second primary lung cancers were found in 2 patients of RG2, and in 1 patient of RG3. SMN was most frequently found in RG2 (11 of 36 patients, 30.6%), compared with RG1 (12.7%) or RG3 (9.8%) (P = 0.016).

LDCT screening for lung cancer in Korean CRC survivors is feasible. Well-designed clinical trial for defining high risk patients for lung cancer among CRC survivors is needed.