The Role of Computed Tomography in Detection of Lung Metastases in Patients with Colorectal Carcinoma

Objective: At the time of diagnosis, 20% of colorectal carcinomas (CRC) are metastatic, and 1-9% of these metastatic patients have lung metastasis. Current guidelines recommend thoracic computed tomography (TCT) for preoperative staging, but this is costly and involves significant radiation exposure. Additionally, in most cases, the treatment plan does not change. Therefore, a comparison between chest X-ray (CXR) and computed tomography (CT) in patients with CRC was conducted. Material and Method: In this study, 630 patients admitted to our hospital between May 2019 and May 2023 for CRC were retrospectively screened. According to follow-up records, the presence of lung metastasis was confirmed based on biopsy, CT, and/or PET/CT results. Thirteen patients with lung metastasis were classified as Group 1, and 31 patients without lung metastasis, identified using propensity score matching, were classified as Group 2, totaling 44 patients for analysis. Results: Preoperative screening revealed that metastatic lesions were detected by CXR in 4 out of 13 patients in Group 1, with an average lesion diameter of 1.5 cm (min: 0.5, max: 5.0 cm). The average diameter of lesions detected by TCT in the remaining 9 patients, which were not visible on CXR, was 7 mm. The sensitivity and specificity of TCT and CXR were found to be 30.77% and 100%, respectively (Table 2). The positive predictive value and negative predictive value of CXR were 100% (39.76%-100%) and 77.50% (70.57%-83.19%), respectively. Conclusion: Although current guidelines recommend TCT for screening, our study found that TCT did not lead to a change in the treatment plan for patients. The use of TCT in the staging of CRC patients may need to be reconsidered.