Pancoast tumor

Pancoast tumor is a rare form of lung cancer that arises at the apex of the lung, involving structures in the thoracic inlet. Due to its unique location, it often presents with distinct clinical features and poses specific challenges in diagnosis and management. Understanding its anatomy, pathology, and clinical presentation is crucial for effective treatment.

Definition and Classification

Definition

A Pancoast tumor, also known as a superior sulcus tumor, is a malignant neoplasm located at the apex of the lung that invades adjacent tissues such as the chest wall, ribs, vertebrae, brachial plexus, and subclavian vessels. Unlike other lung cancers, its location leads to early involvement of surrounding structures, producing characteristic pain and neurological symptoms.

Histological Types

• Squamous Cell Carcinoma: The most common histological type associated with Pancoast tumors, often linked to a history of smoking.
• Adenocarcinoma: Less common, typically arising from peripheral lung tissue near the apex.
• Other Rare Types: Includes large cell carcinoma and small cell carcinoma, which are infrequently observed in superior sulcus tumors.

Anatomy and Location

Thoracic Apex

The thoracic apex is the uppermost portion of the lung, bordered by the first rib, clavicle, and upper vertebral bodies. Pancoast tumors originate in this region and can infiltrate the surrounding structures of the superior sulcus, which contributes to their distinctive clinical presentation.

Adjacent Structures

• Brachial Plexus: The lower cervical and upper thoracic nerve roots are susceptible to compression or invasion, resulting in neurological symptoms.
• Sympathetic Chain: Involvement can lead to Horner’s syndrome, characterized by ptosis, miosis, and anhidrosis on the affected side.
• First Rib and Vertebral Bodies: Tumor invasion into bone structures causes localized pain and may complicate surgical management.
• Pleura and Lung Parenchyma: Direct extension into lung tissue can produce respiratory symptoms such as cough and hemoptysis.

Pathophysiology

Local Invasion

Pancoast tumors tend to grow locally rather than causing early widespread metastasis. Their apical location allows them to invade adjacent structures, including the chest wall, ribs, vertebrae, brachial plexus, and subclavian vessels. This local extension is responsible for the characteristic shoulder and arm pain, neurological deficits, and musculoskeletal involvement observed in patients.

Metastasis

Although Pancoast tumors primarily exhibit local invasion, they can also spread regionally and distantly. Regional metastasis often involves mediastinal and supraclavicular lymph nodes. Distant metastases may occur in the liver, adrenal glands, brain, and bones, particularly in advanced stages, affecting prognosis and treatment decisions.

Clinical Presentation

Pain Syndromes

Shoulder and arm pain are hallmark features of Pancoast tumors. The pain is often severe, persistent, and may radiate along the distribution of the ulnar nerve due to brachial plexus involvement. Pain typically precedes respiratory symptoms and can be mistaken for musculoskeletal or neurological conditions.

Neurological Manifestations

• Horner’s Syndrome: Involvement of the sympathetic chain produces ptosis, miosis, and anhidrosis on the affected side of the face.
• Motor Deficits: Weakness or atrophy of the hand muscles may occur due to invasion of the lower brachial plexus.
• Sensory Changes: Numbness, tingling, or paresthesia along the medial arm and forearm can result from nerve compression.

Respiratory Symptoms

Respiratory manifestations such as cough, hemoptysis, and shortness of breath are usually late findings. Because the tumor originates in the lung apex, pulmonary symptoms may be minimal initially, leading to delayed diagnosis in some cases.

Diagnostic Evaluation

Imaging

Accurate diagnosis of Pancoast tumors relies heavily on imaging studies, which help assess tumor size, local invasion, and metastatic spread.

• Chest X-ray: Often the initial imaging modality, may show an apical mass or rib destruction, but early tumors can be missed.
• Computed Tomography (CT) Scan: Provides detailed visualization of the lung apex, chest wall, and adjacent structures, helping in staging and surgical planning.
• Magnetic Resonance Imaging (MRI): Particularly useful for evaluating involvement of the brachial plexus, spinal canal, and subclavian vessels.
• Positron Emission Tomography (PET) Scan: Helps identify metabolic activity, assess lymph node involvement, and detect distant metastases.

Histopathological Confirmation

Definitive diagnosis requires tissue sampling and histological examination. Biopsy techniques are chosen based on tumor location and patient factors.

• CT-Guided Needle Biopsy: Commonly used for accessible apical lesions, providing adequate tissue for diagnosis.
• Bronchoscopic Biopsy: May be utilized if the tumor involves central airways or is adjacent to bronchi.
• Surgical Biopsy: Reserved for cases where percutaneous or bronchoscopic methods are inconclusive.
• Immunohistochemistry: Helps differentiate histological subtypes and guide treatment decisions.

Staging

Staging of Pancoast tumors is essential for determining prognosis and planning treatment. The TNM classification system is commonly used.

• T Stage: Describes the size and extent of primary tumor, including invasion of chest wall, brachial plexus, or vertebrae.
• N Stage: Assesses involvement of regional lymph nodes such as mediastinal, supraclavicular, and hilar nodes.
• M Stage: Indicates the presence or absence of distant metastases, which significantly affects treatment options and outcomes.

Accurate staging requires a combination of imaging, histopathology, and sometimes invasive procedures such as mediastinoscopy or endobronchial ultrasound-guided biopsy.

Treatment

Multimodal Approach

Management of Pancoast tumors typically involves a combination of therapies due to the tumor’s complex location and tendency for local invasion. A multimodal approach improves resectability and overall survival.

• Neoadjuvant Chemoradiation: Preoperative chemotherapy and radiation are often administered to shrink the tumor, facilitate surgical resection, and reduce the risk of local recurrence.
• Surgery: Surgical resection is performed after neoadjuvant therapy if the tumor is deemed operable. Approaches may include posterolateral thoracotomy or extrapleural techniques depending on tumor extent.
• Adjuvant Therapy: Postoperative radiation or chemotherapy may be used to eliminate residual microscopic disease and reduce recurrence risk.

Surgical Considerations

Surgery for Pancoast tumors is technically challenging due to the proximity of critical structures. Complete resection often requires removal of involved ribs, vertebral bodies, or portions of the subclavian vessels. Careful preoperative planning and intraoperative navigation are essential to minimize complications and preserve neurological function.

Non-Surgical Management

For patients with unresectable tumors or those who are poor surgical candidates, definitive chemoradiation may be employed. Palliative care, including analgesics and supportive therapies, is crucial for symptom control and quality of life.

Prognosis

The prognosis of Pancoast tumors depends on several factors, including tumor stage, histology, extent of local invasion, and response to therapy. Early detection and a multimodal treatment approach significantly improve survival rates.

• Five-year survival is higher in patients who undergo complete surgical resection following neoadjuvant chemoradiation.
• Histological type influences outcome, with squamous cell carcinomas generally showing better local control.
• Advanced tumor stage, extensive brachial plexus or vertebral involvement, and distant metastases are associated with poorer prognosis.

Complications

Pancoast tumors and their treatment can lead to a range of complications that affect both short-term recovery and long-term outcomes. Awareness of these potential issues is critical for patient management and counseling.

• Postoperative Complications: Include bleeding, infection, respiratory difficulties, and wound healing problems. Neurological deficits may occur if the brachial plexus or sympathetic chain is affected during surgery.
• Local Recurrence: Despite complete resection, residual microscopic disease can lead to recurrence at the tumor site, necessitating additional therapy.
• Metastatic Spread: Pancoast tumors may metastasize to distant organs such as the liver, adrenal glands, or brain, especially in advanced stages or if initial treatment is delayed.
• Radiation-Related Complications: Chemoradiation may cause esophagitis, pneumonitis, or cardiac toxicity depending on the radiation field and dose.

References

1. Pancoast HK. Superior Pulmonary Sulcus Tumors. J Thorac Surg. 1932;1(3):223-235.
2. Rusch VW, Giroux DJ, Kraut MJ. Pancoast Tumor. In: Shields TW, LoCicero J, Reed CE, Feins RH, editors. General Thoracic Surgery. 8th ed. Philadelphia: Lippincott Williams & Wilkins; 2019. p. 1253-1270.
3. van Klaveren RJ, et al. Imaging of Superior Sulcus Tumors. Radiol Clin North Am. 2018;56(2):213-228.
4. Socinski MA, et al. Treatment of Pancoast Tumors: A Multidisciplinary Approach. J Clin Oncol. 2017;35(20):2340-2348.
5. Detterbeck FC, Lewis SZ. Diagnosis and Management of Pancoast Tumors. Chest. 2016;150(5):1223-1235.
6. Rusch VW. Surgery for Superior Sulcus Tumors. Thorac Surg Clin. 2015;25(4):365-373.
7. National Comprehensive Cancer Network. NCCN Guidelines: Non-Small Cell Lung Cancer. Version 2.2025. Available from: https://www.nccn.org
8. Mountain CF, Dresler CM. Regional Lymph Node Classification for Lung Cancer Staging. Chest. 2018;154(1):201-212.
9. Horner’s Syndrome in Lung Cancer. Oncol Rev. 2020;14(1):438.