Staging of Lung Cancer: Pulmonologist Perspective
Dr Hema Yamini, Queen Elizabeth Hospital, Kota Kinabalu

Accurate staging of lung cancer is important to prognosticate as well as to identify the appropriate treatment modalities that can be offered to patients. Staging of lung cancer begins with radiology. In patients with lung cancer without distant metastases, assessment of mediastinal nodal involvement is critical. For nodal staging, the sensitivity, specificity, and diagnostic accuracy of chest CT scan is 68%, 65%, and 66%, respectively. Although PET-CT showed higher diagnostic accuracy than CT alone for mediastinal staging, metastatic lesions less than 1 cm may be reported as false negative. Therefore, histological confirmation is recommended when nodal disease is suspected by radiology.

For patients with tumours measuring less than 3cm and are localized to the outer third of the lung, surgical resection is recommended along with systematic nodal dissection. The prerequisite for this is that no enlarged nodes are seen on CT and PET CT does not demonstrate any uptake within the nodes. For patients with central tumours or N1 nodes, pre-operative mediastinal staging must be done.

The American College of Chest Physicians (ACCP) guidelines for staging of non–small cell lung cancer recommends EBUS (Endobronchial Ultrasound) or endoscopic ultrasound (EUS) as the modality of choice for invasive mediastinal staging. A systematic approach of sampling mediastinal nodes is considered superior to selective sampling of radiographically abnormal nodes. The order of nodal sampling should begin at the level of N3 nodes followed by N2 nodes before ending with N1 nodes.