Practice Essentials
Pancoast tumors are neoplasms of pulmonary origin located at the apical pleuropulmonary groove (superior sulcus).[1, 2] By direct extension, Pancoast tumors typically involve the lower trunks of the brachial plexus, intercostal nerves, stellate ganglion, adjacent ribs, and vertebrae. As a result, patients may present with severe pain, often of neuropathic characteristics radiating toward the ipsilateral upper extremity and accompanied with sympathetic symptoms (eg, the Horner syndrome) caused by invasion of the cervicothoracic sympathetic ganglion. These manifestations may appear months before the diagnosis of the underlining disease.[3, 4, 5, 6]
Pancoast syndrome is characterized by ipsilateral shoulder and arm pain, paresthesias, paresis and atrophy of the thenar muscles of the hand, and Horner syndrome (ptosis, miosis, and anhidrosis).[7]
More than 95% of Pancoast tumors are non–small cell carcinomas, most commonly squamous cell carcinomas (52%) or adenocarcinomas and large cell carcinomas (approximately 23% for each subtype).[1] Small cell carcinomas are seen in fewer than 5% of cases.[8]
Staging of Pancoast tumor involves the tumor, node, and metastasis (TNM) classification system, in which T indicates site and size of the primary tumor, N is related to nodal involvement according to site, and M indicates the presence or absence of distant metastases. These tumors are, at a minimum, T3N0M0 (T3 for chest wall invasion, stage IIB), and they are considered T4 lesions if the brachial plexus, mediastinal structures, or vertebral bodies are involved at the time of presentation. When supraclavicular nodes are involved, they are designated as N3 nodes, although they may be the first nodal station involved. Metastatic tumor in the ipsilateral nonprimary-tumor lobe of the lung or metastases to other organ systems is considered M1.[9]
(Pancoast tumors and their associated morbidities are presented in the images below.)
View Image | Pancoast tumor. A 53-year-old man with a 50 pack-year history of smoking began experiencing upper back pain for several weeks. PA chest radiograph sho.... |
View Image | Pancoast tumor. Axial nonenhanced CT image of the upper dorsal spine demonstrates a soft-tissue mass destroying the vertebra on the right and the righ.... |
View Image | Pancoast tumor. Sagittal fast spin-echo T2-weighted MRI shows collapsed vertebrae and cord compression at C7, T1, and T2 caused by a soft tissue mass..... |
Imaging modalities
Magnetic resonance imaging (MRI) is more accurate than computed tomography (CT) scanning and radiography in identification of the extent of tumor involvement and detection of invasion of adjacent organs (eg, vertebral bodies, brachial plexus, subclavian vessels).[10, 11, 12, 13] Histologic diagnosis is made in 95% of the cases by means of percutaneous transthoracic needle biopsy with fluoroscopic, ultrasonographic, or CT scan localization.[5, 14, 15] Among other considerations, CT scanning or MRI of the brain is recommended in the initial evaluation, because distant metastases to the brain are not infrequent, and diagnosis of these metastases is necessary for staging.[6, 7, 16]
Noninvasive preoperative evaluation of the mediastinum with CT or MRI is limited by substantial false-positive and false-negative results (30-40%, depending on the criteria used to define enlarged lymph nodes and the patient population). Positron emission tomography (PET) scanning and, possibly, surgical assessment of the mediastinum with lymph node sampling should be strongly considered before curative surgery is attempted.
Intervention
Preoperative radiation therapy at doses of 2000-6500 cGy, followed by surgical resection, is the most common form of treatment for Pancoast tumors. The overall 5-year survival rate in patients treated with preoperative radiation therapy and surgery is reported to be 20-35%.[1, 6, 7, 17, 18]
Radiation therapy at a dose of 6000 cGy or greater has been used as a primary treatment modality for inoperable tumors, with successful palliation of pain in as many as 90% of patients. The reported 5-year survival rate is 0-29% in these patients, which is likely a result of extensive disease involvement at initial presentation.
The routine use of intraoperative and postoperative radiation therapy is not currently recommended, except in patients in whom unresectable tumors are found at the time of surgery.
Radiography
Posteroanterior (PA) chest radiographs may show unilateral apical opacity (as seen in the first image below), pleural thickening, asymmetry of the apices greater than 5 mm (see the second image below), or a large mass, depending on the tumor stage during diagnosis. Although it is less accurate than CT, chest radiography can show a peripheral lesion and its size. Local rib destruction and/or tracheal deviation can sometimes be observed. Mediastinal enlargement can be seen as well. Lordotic chest views can be beneficial, but the findings can also be misleading. In the early stages, Pancoast tumors are difficult to detect on PA chest radiographs because of the difficulty in interpreting overlying shadows at the apices.[19]
(See the images below.)
View Image | A 74-year-old male with Pancoast tumor. A chest radiograph shows a right apical soft-tissue speculated mass. Erosion of the adjacent ribs is not evide.... |
View Image | Pancoast tumor. A 53-year-old man with a 50 pack-year history of smoking began experiencing upper back pain for several weeks. PA chest radiograph sho.... |
Computed Tomography
CT and MRI are the most accurate imaging modalities in the identification and staging of Pancoast tumors, but CT is more economical and available. For T staging, CT is the most common modality and can help identify proximity to surrounding blood vessels, infiltration of the esophagus and trachea, and mediastinal invasion. Although CT can aid in detecting chest wall invasion, MRI has greater specificity and sensitivity in doing so.[20]
CT scanning is the best imaging modality for demonstrating bony destruction (see the first image below). In a study of 31 patients with superior pulmonary sulcus tumors,[10] CT scanning had a sensitivity of 60% and a specificity of 65%, with an overall accuracy of 63% in identification of extent of disease. Furthermore, contrast-enhanced CT has a reported sensitivity of 68-85% in detecting liver metastases.[21]
(See the images below.)
View Image | Pancoast tumor. Axial nonenhanced CT image of the upper dorsal spine demonstrates a soft-tissue mass destroying the vertebra on the right and the righ.... |
View Image | A 74-year-old male with Pancoast tumor. An axial CT scan at the level of the lung apices shows a soft-tissue mass lesion of 5.3 cm in the right apex. |
View Image | A 74-year-old male with Pancoast tumor. An axial CT scan at the level of the lungs apices at a different level shows erosion of the right second rib (.... |
View Image | A 50-year-old male with Pancoast tumor. An axial CT scan at the level of the apices demonstrates a soft-tissue mass with central necrosis and microcal.... |
View Image | A 50-year-old male with Pancoast tumor. A coronal reformat of the above CT scan shows further relations with the adjacent structures without definite .... |
Magnetic Resonance Imaging
MRI provides superior delineation of the normal anatomy of the brachial plexus because of its multiplanar capabilities. Advantages of MRI include the identification of the absence of streak artifact from bone and the accurate identification of blood vessels. It also provides superior soft-tissue contrast enhancement, and it is more accurate than other methods in documenting or excluding brachial plexus involvement by tumor.[22]
In a study of 31 patients with Pancoast tumors, MRI had a sensitivity of 88%, a specificity of 100%, and an overall accuracy of 94%.[10]
Compared to other techniques, MRI is more accurate in the evaluation of extension of tumor to the vertebral body, spinal canal, brachial plexus, and subclavian artery. This ability is important because invasion of the vertebral body, spinal canal, or upper brachial plexus is a contraindication to surgical resection. Also CT scanning appears to be superior to MRI in detecting chest wall invasion. The anatomy above the lung apex is better demonstrated on multiplanar MRI because the nerves of the brachial plexus and blood vessels follow a horizontal and parallel course, meeting above the apex of the lung.
(See the images below.)
View Image | Pancoast tumor. Sagittal fast spin-echo T2-weighted MRI shows collapsed vertebrae and cord compression at C7, T1, and T2 caused by a soft tissue mass..... |
View Image | Pancoast tumor. Sagittal gradient-echo T2-weighted MRI demonstrates a soft-tissue mass involving C7, T1, and T2, with collapse of the vertebrae and mo.... |
View Image | Pancoast tumor. Axial T1-weighted image shows cord compression caused by a large, enhancing mass. The right subclavian artery is not involved. |
Ultrasonography
Some researchers have suggested that all patients with Pancoast tumors should undergo ultrasonographic examination of the ipsilateral scalene area and that percutaneous biopsy should be performed on nodes with a transverse diameter greater than 1 cm. The purpose of these studies is to assist in staging of the disease. The use of a sector ultrasonographic unit with a supraclavicular approach has been useful in guiding needle aspirations, with a yield for pathologic diagnosis in 91% of cases.[5, 14, 15]
Furthermore, ultrasonography can also be used to identify chest wall invasion. In one study, ultrasonography had a higher sensitivity (89%) than CT scanning (42%) and had a similar specificity in assessing chest wall invasion by lung tumors.[23]
Ultrasonography is also used in the detection of liver metastasis from lung tumors.[21]
Nuclear Imaging
Althought positron emission tomography (PET) is widely used in evaluating lung cancer patients, some research has revealed that it not suitable for all patients. The significance of PET greatly depends on clinical settings. For instance, PET is most useful in identifying patients with a high risk of metastasis (M1). It is also used in cases in which it is difficult to specify through other modalities whether a tumor is in N2 or N3 nodal involvement. [24]
PET is superior to CT imaging in detecting mediastinal and hilar node metastases. A meta-analyses compared detection of mediastinal nodal involvement by PET and CT imaging in patients with non–small cell lung cancer. The study showed that CT had a sensitivity and specificity of 60% and 77%, respectively, whereas PET had a sensitivity and specificity of 79% and 91%, respectively, concluding that PET is superior in mediastinal staging.[25] However, integrated PET-CT provides greater information in staging, with one study showing that PET-CT had greater diagnostic accuracy in staging of non–small cell lung cancer than either imaging modality used individually.[26]
(See the images below.)
View Image | A 74-year-old male with Pancoast tumor. A PET scan shows an FDG-avid right-upper-lobe speculated mass inseparable from pleura and chest wall. |
View Image | A 50-year-old man with Pancoast tumor. A PET scan shows an FDG-avid left-upper-lobe mass with no definite evidence of invasion of the adjacent structu.... |
Author
Javed Ahmad, MBBS, Consultant Radiologist, Abdominal Section, King Faisal Specialist Hospital and Research Centre, Saudi Arabia
Disclosure: Nothing to disclose.
Coauthor(s)
Fazal Hussain, MD, MPH, Director of Research Operations, Department of Medicine, University of Texas Health Science Center at San Antonio, Joe R and Teresa Lozano Long School of Medicine
Disclosure: Nothing to disclose.
Omar Ahmad, MD Candidate, Alfaisal University College of Medicine, Saudi Arabia
Disclosure: Nothing to disclose.
Specialty Editors
Bernard D Coombs, MB, ChB, PhD, Consulting Staff, Department of Specialist Rehabilitation Services, Hutt Valley District Health Board, New Zealand
Disclosure: Nothing to disclose.
Chief Editor
Eugene C Lin, MD, Attending Radiologist, Teaching Coordinator for Cardiac Imaging, Radiology Residency Program, Virginia Mason Medical Center; Clinical Assistant Professor of Radiology, University of Washington School of Medicine
Disclosure: Nothing to disclose.
Additional Contributors
Judith K Amorosa, MD, FACR, Clinical Professor of Radiology and Vice Chair for Faculty Development and Medical Education, Rutgers Robert Wood Johnson Medical School
Disclosure: Nothing to disclose.
Melanie Guerrero, MD, Consulting Staff, Department of Pulmonary and Critical Care Medicine, Walter Reed Army Medical Center
Disclosure: Nothing to disclose.
Scott C Williams, MD, Section Chief, Nuclear Medicine Associate Attending Radiologist, Advanced Radiology Consultants, Bridgeport Hospital
Disclosure: Nothing to disclose.
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