Added value of abdominal CT after treatment of lung cancer

Lung cancer exhibits poor survival outcomes, particularly in cases where distant metastases are identified at the time of diagnosis or following treatment. In instances where there is a heightened risk of distant metastasis, customized postoperative abdominal computed tomography (CT) scans may be beneficial in the early identification of metastatic lung cancer, which holds promise for enhancing survival rates by facilitating prompt initiation of curative interventions. This study aimed to evaluate the effectiveness of additional abdominal CT scans in identifying extrapulmonary and abdominal metastases in lung cancer patients' post-treatment.

A retrospective analysis was conducted on patients diagnosed with lung cancer between January 2015 and December 2017 who underwent at least one follow-up abdominal CT scan after treatment. Cumulative rates of extrapulmonary and isolated abdominal metastasis were analyzed using Kaplan-Meier method and compared with log-rank tests. Cox proportional hazard models were performed to identify risk factors for extrapulmonary and isolated abdominal metastases. The radiation dose for each abdominal CT scan was recorded in volume CT dose index (CTDI_vol) and dose-length product (DLP), and effective dose (ED) was calculated.

A cohort of 396 patients (mean age, 59±8 years; 239 men) was incorporated in the study. The cumulative incidence rates at 3 years of extrapulmonary metastasis and isolated abdominal metastasis were 28.3% and 11.4%, respectively. Significant risk factors for extrapulmonary metastasis included histological subtype, T stage, lymph node metastasis, and size of the largest tumor. Statistical significance was observed in histological subtype, T stage, lymph node metastasis, ALK mutation, squamous cell carcinoma antigen, and size of the largest tumor in cases of isolated abdominal metastasis. The EDs of radiation exposure in non-contrast and contrast-enhanced abdominal CT scanning were 7.2±3.5 and 18.2±6.9 mSv, respectively.

The incorporation of abdominal CT scans into follow-up protocols may be a valuable strategy for the early detection and management of distal metastasis in lung cancer patients with risk factors.