Practice Essentials
Pancoast syndrome (sometimes termed Pancoast-Tobias syndrome) typically results when a malignant neoplasm of the superior sulcus of the lung leads to destructive lesions of the thoracic inlet and involvement of the brachial plexus and cervical sympathetic nerves (stellate ganglion). [1, 2, 3] This produces the following clinical manifestations:
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Severe pain in the shoulder region radiating toward the axilla and scapula, with later extension along the ulnar aspect of the arm to the hand
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Atrophy of hand and arm muscles
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Compression of the blood vessels with edema
Most Pancoast tumors are non–small cell lung cancer (NSCLC])—specifically, squamous cell carcinoma (SCC) or adenocarcinomas; only 3-5% are small cell carcinomas. Squamous cell carcinoma occurs more frequently, although large cell and undifferentiated types are also common. Very rarely, tumors in this location may have metastasized from other sites. [4, 5]
Once universally fatal, Pancoast tumors are currently treatable with outcomes similar to those of
Pathophysiology
Pancoast tumors are a subset of lung cancers that invade the apical chest wall. Because of their location in the pleural apex, they invade adjoining tissue. Although other tumors may have a similar clinical presentation because of their location at the thoracic inlet, the most common cause is believed to be a bronchogenic carcinoma arising in or near the superior sulcus and invading adjacent extrathoracic structures by direct extension. Location, rather than pathology or histology of origin, is significant in producing the tumor’s characteristic clinical manifestations. [7]
The bulk of a true Pancoast tumor is extrathoracic, originating in an extreme peripheral location with a plaquelike extension over the lung apex and principally involving the chest wall structures rather than the underlying lung parenchyma. Bronchogenic carcinomas occurring in the narrow confines of the thoracic inlet invade the lymphatic vessels in the endothoracic fascia and include, by direct extension, the following structures:
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Intercostal nerves
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Lower roots of the brachial plexus
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Stellate ganglion
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Sympathetic chain
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Adjacent ribs and vertebrae.
Carcinomas in the superior pulmonary sulcus produce Pancoast syndrome, with pain in the shoulder and along the ulnar nerve distribution of the arm and hand. [8] These carcinomas can also cause Horner syndrome. These apical lung tumors tend to be locally invasive early. Nevertheless, in the absence of metastases and regional nodal involvement, many Pancoast tumors can be successfully treated.
The tumor may invade the bony structures of the chest, including the first or second thoracic vertebra or the first, second, or third rib. In a review of 60 patients with Pancoast tumors, Maggi et al found radiographic evidence of rib erosion in 50%; an almost equal percentage demonstrated involvement of the first or second rib, and 20% had involvement of the third rib. One patient had involvement of all 3 ribs. [9]
The tumor can also invade the first or second thoracic vertebral bodies or intervertebral foramina. From this point, it can extend to the spinal cord and result in cord compression. The subclavian vein or artery may also be invaded.
Involvement of the phrenic or recurrent laryngeal nerve or superior vena cava obstruction is not representative of the classic Pancoast tumor.
Etiology
The overwhelming majority of cases of Pancoast syndrome result from non–small cell lung carcinoma (NSCLC), with more than 95% located in the superior sulcus. The most common varieties are squamous cell carcinoma and adenocarcinoma; large cell carcinoma has also been reported. Small cell carcinoma accounts for fewer than 5% percent of cases in most series; more typically, small cell lung cancer manifests in a central rather than a peripheral location. [9]
Although NSCLC is by far the most common cause of Pancoast syndrome, the list of differential diagnoses is broad. Because of the wide variety of diseases that can produce Pancoast syndrome, a histologic diagnosis is mandatory before definitive treatment is initiated.
Rare causes include the following:
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Desmoid tumors [10]
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Hemangiopericytoma [11]
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Adenoid cystic carcinoma [12]
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Lymphoma [13]
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Thyroid carcinoma [14]
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Vascular aneurysms
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Amyloid nodules
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Cervical rib syndrome
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Inflammatory pseudotumor (plasma cell granuloma)
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Mycotic subclavian artery aneurysm
Risk factors are similar for almost all lung cancers and include the following:
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Tobacco smoking
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Secondary smoke exposure
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Prolonged asbestos exposure
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Exposure to industrial elements (eg, gold, nickel)
Epidemiology
Overall, Pancoast tumors are much less common than other lung cancers, accounting for fewer than 5% of these cancers (1-3% in various previous series). [21, 22] Originally deemed universally fatal, Pancoast tumors are currently often amenable to curative treatment because of improvements in combined modality therapy and development of new techniques for resection.
Prognosis
The prognosis for patients with Pancoast syndrome is stage dependent. Adverse prognostic factors include the following:
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Presence of Horner syndrome
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Involvement of mediastinal lymph nodes
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Incomplete resection
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Involvement of supraclavicular lymph node
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Vertebral body invasion
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Anterior location of tumor [23]
Distant disease limits survival. Treatment failure is especially frequent in patients with involvement of the brain. The authors recommend careful surveillance for brain metastasis during and after the therapy. The authors also recommend obtaining brain imaging prior to surgery in patients receiving induction therapy for the primary tumor.
Mortality and survival
A 2007 study by Rusch et al in 110 patients with superior sulcus NSCLC treated with trimodality therapy reported 5-year survival of 44% for all patients and of 54% in patients with complete resection, with no difference between T3 and T4 tumors. [24] A Dutch study of 123 patients with superior sulcus NSCLC treated with trimodality therapy from 2002-2017 reported 10-year overall survival of 48.1% and disease-free survival of 42.6%. [25]
Tables
Stage |
T(Tumor) |
N (Nodes) |
IIB |
T3 |
N0 |
IIIA |
T3 |
N1 |
IIIB |
T3 |
N2 |
IIIC |
T3, T4 |
N3 |
