Lung Cancer.pdf

Role of Clinical Practice Guidelines and Clinical Pathways 87
chest. Intervertebral foraminal extension and extradural spread are more
readily appreciated with magnetic resonance imaging than with CT.
The radiographic findings are evaluated to determine the clinical T status
(a measure of local invasiveness) and N status (a measure of systemic
biological metastatic potential) of the tumor. All lung tumors are potentially
curable with surgery if the mediastinal nodes are not involved. T3
tumors that involve the chest wall, diaphragm, or pericardium are also
potentially curable with surgery. T4 tumors with only limited vertebral
body involvement or limited involvement of the great vessels, heart, or
trachea are also potentially curable with surgery.
Patients who present with a pleural effusion containing tumor cells, a
superior sulcus tumor that extensively involves the brachial plexus more
proximal to the T1 nerve root with loss of motor function of the affected
limb, or a lesion with direct involvement of the esophagus are not considered
candidates for surgery.
Nodal status is often assessed by measuring the cross-sectional diameter
of the nodes under the mediastinal windows on CT. Contrast-enhanced CT
is often helpful in differentiating mediastinal vascular structures from the
surrounding nodes. Nodes 1 cm or larger in diameter are considered radiographically
positive and often necessitate additional pathologic assessment
prior to a major resection. It must be recognized, however, that 15% of nodes
smaller than 1 cm may harbor micrometastatic disease and that 30% of nodes
larger than 2 cm may be benign. Enlarged nodes can be biopsied by an interventional
radiologist using transthoracic or transmediastinal needle biopsy
or can be biopsied surgically through cervical mediastinoscopy, anterior mediastinotomy
(Chamberlain procedure; used to evaluate prevascular and anteroposterior
window nodes), or video-assisted thoracoscopic techniques.
Prior to surgery, all patients undergo spirometry testing with measurements
taken before and after administration of a bronchodilator. Patients
whose forced expiratory volume in 1 second (FEV 1 ) is less than 70% also
undergo xenon ventilation-perfusion scanning, which permits estimation
of the postresection FEV 1 on the basis of the regional distribution of the
nuclear tracer. If the postresection FEV 1 is less than 40%, more detailed exercise
oxygen consumption testing is performed before a final decision is
made regarding whether a given patient is fit for surgery.
Patients with clinical stage I or II disease who have a predicted postresection
FEV 1 of greater than 33% may undergo surgical resection. If the
final pathologic stage is stage I, no further treatment is required, and patients
are placed on a surveillance program after their first postoperative
visit. Patients with positive mediastinal nodes on the final pathology report
are offered radiation therapy to improve future local control; however,
no survival advantage is seen with radiation therapy in this group.
Patients who are found on preoperative mediastinoscopy to have stage
IIIA disease undergo brain and bone scans. If the disease is localized to the
chest only, then combined treatment with neoadjuvant chemotherapy