Pancoast tumor overview
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Associate Editor(s)-in-Chief: Mazia Fatima, MBBS [2]
Overview
A Pancoast tumor, also known as superior sulcus tumor, defined primarily by its location at the pulmonary apex. The tumor can cause compression of a brachiocephalic vein, subclavian artery, phrenic nerve, recurrent laryngeal nerve, or, compression of a sympathetic ganglion.
Historical Perspective
Pancoast tumor was first described by Hare in 1838. In 1924, Henry K. Pancoast discovered the association between apical chest tumors, characteristic pain distribution, and Horner’s syndrome. In 1954, external beam radiation was used for the treatment of associated pain by Haas and colleagues. In 1990’s a combination of chemotherapy and radiotherapy was found to be associated with better prognosis and treatment outcome.
Classification
The staging of the pancoast tumor is based on the TNM system. Pancoast tumors staging starts at T3 always, as there is an invasion of the chest wall. Invasion of the vertebral body or the subclavian vessels is regarded as T4.
Pathophysiology
Pancoast tumor is the type of lung cancer that is associated with invasion of the apical chest wall. The location of Pancoast tumor in the superior sulcus results in an invasion of adjacent structures and in its characteristic clinical presentation. The progression of Pancoast tumor usually involves spread across the pleural apex to invade the following structures by direct extension into lymphatic vessels in the endothoracic fascia, intercoastal nerves, lower roots of brachial plexus, stellate ganglion, sympathetic chain, adjacent ribs, adjacent vertebra bodies, extension to the spinal cord can result in cord compression, subclavian artery or subclavian vein. The development of Pancoast syndrome is the result of tumors in the superior pulmonary sulcus is characterized by pain along ulnar nerve distribution and Horner syndrome.
Causes
Most common cause of Pancoast tumor is non–small cell lung carcinoma (NSCLC).Common types of non-small cell lung carcinoma (NSCLC) presenting as Pancoast tumor are squamous cell cancer, adenocarcinoma and large cell carcinoma. Less common causes of Pancoast tumor includes small cell cancer as it rarely presents as a peripheral tumor. Pancoast syndrome is classically associated with Pancoast tumor. Rare causes of Pancoast syndrome include desmoid tumor, metastasis, hematologic neoplasms, and infections that may present as a tumor localized to the lung apex.
Differential Diagnosis
Pancoast tumor must be differentiated from other causes of mass located in the apical region of the chest which may present with pain in the shoulder region. Differential diagnosis includes most common other conditions that cause hemoptysis, cough, dyspnea, wheeze, chest pain, shoulder pain, unexplained weight loss, unexplained loss of appetite, and fatigue such as superior vena cava syndrome, thoracic outlet syndrome, cervical disk disease, pneumonia/bronchitis, carcinoid tumor, infectious granuloma and thyroid mass.
Epidemiology and Demographics
Pancoast tumors are a rare type of non-small cell lung cancers (NSCLC), account for fewer than 5% of all lung cancers. In the United States, the age-adjusted prevalence of pancoast tumor is estimated to be 5 per 100,000. The prevalence of lung cancer significantly increases among smokers and individuals with chronic exposure to risk factors for lung cancer. In 2014 the incidence of Pancoast tumor was approximately 3 cases per 100,000. Lung cancer is more common in older adults. It is rare in people under age 45. Males are thought to be more predisposed to the development of lung cancer. This gender discrepancy is often attributed to the historically increased rate of smoking among males compared to females. The male to female ratio for the incidence of lung cancer is approximately 1.4 to 1. There is no racial predilection for Pancoast tumor. The incidence of lung cancer is lower in developing countries than in developed countries. It is unknown whether this decreased incidence is due to decreased cancer rates or decreased detection rates. Western Europe and the U.S. have the highest incidence of lung cancer.
Risk Factors
Common risk factors in the development of Pancoast tumor include asbestos exposure for prolonged period of time, exposure to gold, nickel, smoking, secondary smoke exposure.
Screening
There is insufficient evidence to recommend routine screening for Pancoast tumor.
Natural History, Complications and Prognosis
The patient experiences non-specific symptoms such as cough, hemoptysis, dyspnea, chest pain, dysphonia, dysphagia, lack of appetite, weight loss, and fatigue from 3 weeks to 3 months before seeking medical attention. Without treatment, the patient will develop initial symptoms of cough and chest pain, which may eventually lead to Pancoast syndrome. The symptoms of Pancoast syndrome start as referred pain to the shoulder. Without treatment, the tumor may invade surrounding tissues to cause pain along the ulnar nerve distribution, atrophy of hand muscles and spinal cord compression. The complications associated with Pancoast tumor are breathing difficulties, pneumonia, hemoptysis, pain, pleural effusion,metastasis, Horner's syndrome, superior vena cava syndrome, Compression of the spinal cord and paraplegia (paralysis of the lower half of the body with involvement of both legs) develop when the tumor extends into the intervertebral foramina (opening between two vertebrae). The prognosis of Pancoast tumor depends on the stage of the tumor at diagnosis. The presence of the following is associated with a poor prognosis among patients with Pancoast tumor Horner syndrome, spread to the mediastinal lymph nodes, incomplete resection of tumor, involvement of supraclavicular lymph node, vertebral body invasion, metastasis to the brain.
History and Symptoms
The hallmark of Pancoast tumor is lung cancer located in the apex of the lung. A positive history of shoulder pain and atrophy of hand musculature, Horner's syndrome and forearm edema is suggestive of Pancoast Syndrome. The most common symptoms of Pancoast tumor include cough, hemoptysis, dyspnea, chest pain, lack of appetite, weight loss, fatigue, symptoms of Pancoast Syndrome resulting from Pancoast tumor include shoulder pain along the vertebral border of the scapula, Horner's syndrome and weakness of hand muscles. Less common symptoms of Pancoast syndrome include paraplegia.