The prognostic value of positron emission tomography/computed tomography in pulmonary metastasectomy.

Background: Although positron emission tomography/computed tomography (PET/CT) findings are prognostic in lung cancer patients, the prognostic value of PET/CT findings in patients with pulmonary metastases has neither been comprehensively investigated nor clarified. The aims of this retrospective study were to evaluate the value of PET/CT and identify novel prognostic indicators for pulmonary metastasectomy.

Methods: Between May 2004 and February 2017, 178 patients underwent PET/CT and resection of pulmonary metastases. After exclusion of patients who underwent biopsy only or duplicate cases, 142 patients were analyzed. Prognostic indicators, including PET/CT findings and outcomes were investigated.

Results: The median follow-up time was 42 months. The primary tumor site was colorectal in 76, kidney in 14, head and neck in 13, breast in 12, stomach in 8, urinary tract in 7, and other organs in 12 patients. The median maximal standardized uptake value (SUVmax ) was 4.6. The optimal cut-off value, determined by receiver operating characteristic (ROC) analysis, identified the following cut-off values: disease-free interval (DFI) (12 months; SUVmax =4.5). Univariable analysis revealed that DFI ≤12 months, incomplete resection, and SUVmax ≥4.5 were significant for poor outcome. Multivariable analysis revealed incomplete resection and SUVmax ≥4.5 were significant for poor outcome. The 5-year survival rates of patients with SUVmax ≥4.5 and SUVmax <4.5 were 51.6% and 74.0%, respectively.

Conclusions: Analysis of patients undergoing pulmonary metastasectomy demonstrated that incomplete resection and an SUVmax ≥4.5 are significant prognostic indicators. PET/CT findings should be included in estimations of these patients' prognosis.