The role of the PET-CT in staging of lung cancer

Ki, Sung Ho; Lee, Seung Hee; Hyun, In Young; Lee, Kyung Hee; Cho, Jae Hwa; Ryu, Jeong Seon; Lee, Hong Lyeol; Kwak, Seung Min

Abstract

BACKGROUND: PET-CT can provide both a physiological and anatomical image with the benefits of both PET and CT scanners. This may improve the accuracy of a diagnosis of a mediastinal lymph node metastasis. The aims of this study were to compare PET-CT versus CT on the nodal staging of lung cancer and to determine if it could be used to avoid an invasive diagnostic examination. The benefit of the additional PET-CT as preoperative evaluation of the lung cancer was also assessed.
METHODS
The results of CT and PET-CT scanning in 22 patients with a proven non-small cell lung cancer (NSCLC) were correlated with the pathological findings of lymph node sampling using mediastinoscopy or surgery.
RESULTS
The sensitivity, specificity, accuracy, positive and negative predictive values of CT for detecting metastatic lymphadenopathy were 44%, 77%, 64%, 57%, and 67%, respectively. For PET-CT, these were 78%, 92%, 86%, 88%, and 86%, respectively. The earlier detection of a bone metastasis was obtained by PET-CT in 3 cases, which was not detected in bone scan.
CONCLUSIONS
Better results for nodal staging and higher negative-predictive values by PET-CT (than CT) can avoid the need for invasive mediastinal staging of the lung cancer with negative mediastinal lymph node metastasis. An additional histological evaluation by mediastinoscopy needs to be done when positive findings are detected by PET-CT. PET-CT is also helpful in detecting a distant metastasis and avoiding unnecessary surgery. More accurate diagnostic staging can be expected using the simultaneous execution of PET-CT with a conventional preoperative evaluation of lung cancer.