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Clinical Management of Lung Cancer:
Lessons from the Cleveland Clinic Tumor Board
Online Monograph




Pancoast Tumor

Sonali Sethi, MD

 

Case Presentation

A 56-year-old female with a significant smoking history presented to the emergency department with a productive cough. She has no history of fevers, chills, or hemoptysis. She has mild pain in her right scapula/shoulder with radiation into the right arm but without neuropathy. She denies any dyspnea. Her appetite is good and weight is stable.

A chest radiograph reveals a large right upper lobe lung mass measuring approximately 9 cm in diameter, with no focal infiltrates or pleural effusion. A CT scan shows a right upper lobe mass with enlarged right hilar lymph node. A percutaneous needle biopsy reveals a thyroid transcription factor-1 (TTF-1) positive adenocarcinoma. Subsequent PET/CT reveals fludeoxyglucose avidity of the primary mass and right hilar lymph node. A brain MRI shows no evidence of metastatic disease. A neck MRI reveals that the mass is in close proximity to the brachial plexus. Pulmonary function tests found an FEV1 of 2.36 L (77% predicted) and a DLCO of 71% predicted. She is referred for a multidisciplinary evaluation.

Case Discussion

The terms Pancoast tumors, superior sulcus tumors, and superior pulmonary sulcus tumors have been applied to neoplasms located at the apical pleuropulmonary groove. In 1924, Henry K. Pancoast, MD, described a patient afflicted with a carcinoma occupying the apical thoracic cavity that was associated with a constellation of symptoms that included shoulder pain radiating down the arm, atrophy of the hand muscles, and Horner’s syndrome.1 Since then, it has become widely accepted that the term Pancoast syndrome can be applied to any clinical condition in which a neoplasm in the apex of a lung is accompanied by shoulder or arm pain.

Anatomically, the definition includes any tumor invading through the parietal pleura at the level of the first rib and above. The pulmonary sulcus refers to the costovertebral gutter extending from the first rib to the diaphragm. The superior pulmonary sulcus is therefore analogous to the superior most portion of this recess. The first rib is at the base of the thoracic inlet. The thoracic inlet contains the subclavian vein anteriorly, the subclavian artery, phrenic nerve and trunks of the brachial plexus medially, and the nerve roots of the brachial plexus and the stellate ganglion posteriorly. The bony thorax in the superior sulcus includes the upper ribs and the associated vertebral bodies. It is invasion of this complex anatomical area that accounts for the classic symptoms of the Pancoast tumor.

Superior sulcus carcinomas have the same biologic behavior as lung carcinomas located in the lung parenchyma. Consequently, their diagnosis, staging, and treatment follow the same principles as for any other lung cancer. The unique characteristics of Pancoast tumors are related to the anatomy of the region where these tumors occur (thoracic inlet) and not to their biologic behavior.

Epidemiology
Pancoast tumors are a relatively rare subset of non-small cell lung cancers (NSCLC), accounting for fewer than 5% of all lung cancers. At least 50% of cases are adenocarcinomas, while the rest are squamous cell and large-cell carcinomas. Small cell carcinoma occurs rarely.2

Patients often present with complaints of pain distributed to the upper anterior chest wall. These tumors may manifest with signs and symptoms related to the compression or infiltration of the middle and lower trunks of the brachial plexus such as shoulder and arm pain (in the distribution of the C8, T1, and T2 dermatome). The peripheral location of these tumors minimizes standard lung cancer symptoms such as cough, hemoptysis, and dyspnea and is the main reason why patients with Pancoast tumors present at a later stage of diagnosis.

Diagnosis

Pancoast tumors are diagnosed through history and physical examination, chest radiographs, and tissue biopsy. CT scan with intravenous contrast and PET scanning have become the initial radiologic evaluations for these tumors. The major benefits of CT scanning relate to its ability to identify a tumor mass as distinct from apical pleural thickening and to assess the presence of bone destruction and invasion of the chest wall and root of the neck. Magnetic resonance angiography (MRA) and MRI are important diagnostic tools that may delineate the tumor’s extension to the brachial plexus, phrenic nerve, or epidural space. They also provide better soft tissue differentiation than CT scans, thus allowing superior depiction of chest wall invasion. MRI imaging of the thoracic inlet is necessary to help plan for surgery with curative intent in order to exclude invasion of the vascular structures, brachial plexus above the level of T1, or the epidural space.3,4

Diagnosis is established through biopsy of the mass. Given their location, these lesions are amenable to CT or ultrasound-guided fine-needle aspiration. Because of the peripheral location of the tumor, fiberoptic bronchoscopy is only able to establish the diagnosis in less than 30% of cases (unless there is nodal involvement). A tissue diagnosis via video-assisted thoracoscopy (VATS) may be indicated when other investigations are negative and to eliminate the possibility of pleural metastatic disease. Axillary minithoractomy is an alternative to VATS to obtain a tissue diagnosis of the mass in small apical tumors.

As with other lung carcinomas located in the lung parenchyma, it is imperative to stage the mediastinum with Pancoast tumors. Metastases to the mediastinal nodes is a major negative prognostic factor — 5-year survival rates in the presence of N2 disease are below 10%.4 According to the 2013 ACCP guidelines,4 before surgery for Pancoast tumors, an endobronchial ultrasound with transbronchial needle aspiration or a cervical mediastinoscopy is warranted to exclude N2/N3 disease, even in the absence of involved nodes in CT or PET scans.

Staging
Pancoast tumors are by definition T3 or T4 tumors. Most of the lesions are classified as T3 tumors because they invade only the chest wall and/or the sympathetic chain. The rest invade brachial plexus, vertebral bodies, and vascular structures, and are classified as T4 tumors. According to the new staging system for lung cancer developed by the International Association for the Study of Lung Cancer (IASLC),5 their final stage, in the absence of distant metastases, depends on the N status of the tumor:

  • IIB if T3NO,
  • IIIA if T3N1-2, or T4NO-1,
  • IIIB if T3N3 or T4N2-3.

Therefore, even the earliest of these lesions are staged at least IIB. Invasion of the ipsilateral supraclavicular nodes in the setting of lung cancer is classified as N3 disease. In superior sulcus carcinomas the importance of supraclavicular node involvement is quite different because it is considered to represent a locoregional lymph node extension.

Treatment
The primary prognostic factors in the treatment of superior sulcus tumors are the T stage, the N stage, and the ability to perform a complete resection. Modern treatment of these tumors is with a trimodal combination of radiation, chemotherapy, and surgery.

The results of multimodal treatment for stage IIIa (N2 disease) lung cancer led to the development of the Southwest Oncology Group (SWOG) and the Japan Clinical Oncology (JCO) group. The high rates of pathologic response to chemoradiotherapy were associated with increased rates of complete resection, with the overall 5-year survival reaching 46% (SWOG)6 and 61% (JCO).7 Therefore, the standard of care for Pancoast tumors is currently induction chemoradiotherapy followed by surgical resection.

Chemoradiotherapy. Induction chemoradiotherapy is the standard of care for any potentially resectable Pancoast tumor. There is substantial variability in the induction chemoradiotherapy protocols between different institutions. Mortality from induction chemoradiation was reported to be 2.7% and 1.3% in the SWOG and JCO prospective phase II trials.6,7 In addition, 5% of the recruited patients in both trials did not complete the induction therapy protocol due to the toxicity of the treatment.

Once patients have completed their induction chemoradiation, careful re-evaluation needs to be performed. Radiographic evaluation should include repeat CT and PET scan. Patients with borderline cardiopulmonary fitness should undergo repeat pulmonary function evaluation. In addition, re-evaluation of the mediastinum is essential.

Surgical therapy. The ideal time for surgery is 3 to 6 weeks after the end of chemotherapy and radiation. This allows adequate time for tumor regression but not enough time for formation of excessive fibrosis and scarring that can hamper the surgery. Resection can be made through a variety of anterior and posterior approaches to the thoracic inlet. A combined thoracic-neurosurgical approach is necessary to treat tumors that invade the brachial plexus and/or the spine. The goal of surgery is to completely resect the disease through a combined resection of lung parenchyma en bloc with the adjacent invaded structures of the thoracic inlet, such as the apical chest wall, the vertebrae, the ulnar component of the brachial plexus, the sympathetic chain/stellate ganglion, and the subclavian vessels.8,9

Surgery for Pancoast tumors is associated with a 5% mortality rate, and the complication rate varies from 7% to 38%.8,9 The overall 2-year survival rate after induction chemoradiotherapy and resection varies from 55% to 70%, while the 5-year survival for RO resections is 54% to 77%.

The main factors that affect prognosis in patients with Pancoast tumors who undergo treatment with curative intent are the T-status of the tumor and, particularly, invasion of the spine, the response to induction treatment (better for complete responders), and, most importantly, the completeness of resection.

The data for patients with N2 disease undergoing surgery are less optimistic. Those rare patients with N2 disease who clear the mediastinum with induction therapy are still at high risk for recurrence, making the indication for surgery in this group uncertain. This group may be better treated with curative intent combination chemotherapy and radiation.

Case Recommendation

This patient has a locally advanced superior sulcus adenocarcinoma, probable T4 tumor with N1 nodal involvement suggested on PET/CT. She has a good performance status, pulmonary function, and minimal comorbidities. After discussion, she was interested in taking an aggressive approach to treatment of her lung cancer and was deemed to be a candidate for tri-modality therapy incorporating induction chemoradiation therapy, followed by surgery with the goal of attaining a complete resection. She was referred to thoracic surgery for invasive mediastinal staging prior to developing a final treatment plan.

Learning Points

  • Pancoast tumors are a relatively rare subset of NSCLC, accounting for fewer than 5% of all lung cancers.
  • Patients often present with complaints of pain distributed to the upper anterior chest wall, shoulder, and arm pain.
  • As with other lung carcinomas located in the lung parenchyma, it is imperative to stage the mediastinum with Pancoast tumors.
  • Although staging of Pancoast tumors is the same as NSCLC, even the earliest of these lesions is staged at least T3NO, making them stage IIB.
  • For patients with no metastatic disease, concurrent chemoradiotherapy as the initial step is recommended. This is followed by surgical resection if there is no evidence of distant metastases or local progression (N2 or N3).
  • For patients who are medically inoperable or who have locally advanced, unresectable disease, definitive chemoradiotherapy is recommended.

Multimedia Feature

Abbreviations

ACCP = American College of Chest Physicians; CT = computed tomography; DLCO = diffusion capacity of carbon monoxide; FEV1 = forced expiratory volume in 1 second; JCO = Japan Clinical Oncology; PET = positron emission tomography; MRI = magnetic resonance imaging; NSCLC = non-small cell lung cancer; RO = surgical margins after resection negative for tumor; SWOG = Southwest Oncology Group; VATS = video-assisted thoracoscopic surgery.

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