Pancoast’s tumour is a rare and challenging type of lung cancer that develops at the very top of the lung, near the shoulder and upper chest. Unlike typical lung cancers that cause coughing or breathing difficulties, this tumour creates distinctive symptoms like severe shoulder pain and arm weakness because of its unusual location. Though once considered universally fatal, modern treatment approaches combining chemotherapy, radiation, and surgery have transformed the outlook for many patients living with this complex disease.

Understanding Pancoast’s Tumour: A Rare Form of Lung Cancer

Pancoast’s tumour, also known as a superior sulcus tumour, is a type of lung cancer that begins in the uppermost part of the lung, technically called the apex. This area sits just above the first rib in the chest. The tumour gets its name from Dr. Henry Pancoast, an American radiologist who first described these unusual cancers in detail during the 1920s and 1930s. What makes this cancer particularly distinct is not what type of cells it grows from, but rather where it grows and how it affects nearby structures.^[1]

The location of a Pancoast tumour is what defines it and creates its unique challenges. Because the tumour sits at the top of the lung, it tends to spread into surrounding tissues quite early in its development. These nearby structures include the uppermost ribs, the upper portion of the spine, important blood vessels that supply the arms, and most significantly, a bundle of nerves called the brachial plexus that controls sensation and movement in the shoulder, arm, and hand. This invasion of neighbouring tissues happens before the tumour grows large enough to cause typical lung cancer symptoms.^[3]

Most Pancoast tumours are classified as non-small cell lung cancer, with the majority being adenocarcinomas. Adenocarcinomas are cancers that start in the mucus-producing gland cells that line the airways and tiny air sacs in the lungs. A smaller portion may be squamous cell carcinomas, another type of non-small cell lung cancer. Only a very small percentage of Pancoast tumours are small cell lung cancers.^[1][4]

How Common Is Pancoast’s Tumour?

Pancoast tumours are considered rare within the already serious landscape of lung cancer. They account for only about three to five out of every one hundred cases of lung cancer. To put this in perspective, lung cancer itself represents roughly 12.8% of all newly diagnosed cancers worldwide, excluding non-melanoma skin cancers. In 2018 alone, this amounted to over 2 million cases of lung cancer globally. Within that large number, Pancoast tumours remain a small but significant subset.^[3][6]

Like most lung cancers, Pancoast tumours occur more frequently in men than in women. The typical age at diagnosis falls within the sixth decade of life, meaning most patients are diagnosed when they are in their 60s. Some sources report the average age of diagnosis as being between 60 and 70 years old. However, cases can occur outside this age range, and younger people are not immune to developing this condition, particularly if they have significant risk factors.^[3][6]

What Causes Pancoast’s Tumour?

The causes and risk factors for developing a Pancoast tumour mirror those of other types of lung cancer. The single most important risk factor is smoking tobacco. The vast majority of patients diagnosed with Pancoast tumours have a history of smoking cigarettes. Tobacco smoke contains thousands of chemicals, many of which are known to damage the cells lining the lungs and airways, eventually leading to cancerous changes.^[1][9]

Exposure to secondhand smoke, also called secondary smoke exposure, is another significant risk factor. People who live or work in environments where others smoke regularly inhale many of the same harmful chemicals found in cigarette smoke, even if they never smoke themselves. This passive exposure can increase the risk of developing lung cancer, including Pancoast tumours.^[1]

Long-term exposure to certain environmental and occupational substances also raises the risk. Asbestos, a material once commonly used in construction and manufacturing, is a well-established cause of lung disease and cancer. Radon gas, which can accumulate in homes built on certain types of soil, is another environmental carcinogen. Industrial workers exposed to heavy metals such as nickel or gold may also face increased risk of lung cancer over time.^[1][15]

While the vast majority of Pancoast tumours are primary lung cancers, it is worth noting that in very rare cases, cancers from other parts of the body can spread to the top of the lung and mimic a Pancoast tumour. Additionally, some non-cancerous infectious or inflammatory conditions involving bacteria such as Pseudomonas, Staphylococcus, or Actinomyces can occasionally cause similar symptoms, though this is uncommon.^[3]

Risk Factors for Developing Pancoast’s Tumour

Understanding who is most at risk for developing a Pancoast tumour can help in early detection and prevention efforts. The primary risk factor remains smoking. People who have smoked for many years, or who smoke heavily, face the highest risk. Even those who quit smoking years ago carry some residual risk, though quitting at any age reduces future cancer risk compared to continuing to smoke.

Age is another important factor. Most people diagnosed with Pancoast tumours are older adults, typically in their 60s or 70s. This likely reflects the many years of cumulative exposure to carcinogens that are often needed before cancer develops.

Occupational exposures play a significant role for certain groups of workers. People who have worked in industries involving asbestos, such as construction, shipbuilding, or manufacturing, face elevated risk. Similarly, workers in mining or industrial settings where they are exposed to radon gas, heavy metals, or other toxic substances may be at higher risk. Personal protective equipment and workplace safety regulations are important in reducing these occupational hazards.

Recognising the Symptoms of Pancoast’s Tumour

The symptoms of a Pancoast tumour are quite different from those of typical lung cancers, which is one reason why diagnosis can be delayed. Most lung cancers cause respiratory symptoms like persistent coughing, shortness of breath, coughing up blood, or chest pain. However, because a Pancoast tumour grows at the very top of the lung in a peripheral location, it often does not affect breathing in the early stages.^[1][6]

Instead, the hallmark symptom of a Pancoast tumour is severe shoulder pain. This pain is often constant and may be mistaken for a muscle strain, rotator cuff injury, or arthritis, leading patients to seek care from orthopaedic doctors or physical therapists initially. The pain typically affects the shoulder on the same side of the body as the tumour. For example, if the tumour is in the right lung, the right shoulder will hurt.^[1][5]

As the tumour grows and presses on or invades the brachial plexus, additional symptoms develop. Pain may radiate down the arm, often following the path of the ulnar nerve, which runs along the inner side of the arm down to the hand, particularly affecting the area near the pinky finger and the wrist. This pain can be sharp, burning, or aching in quality.^[1]

Weakness in the arm and hand is another common symptom. Patients may notice difficulty gripping objects, reduced strength when lifting or carrying items, or a general sense of heaviness in the affected arm. Fine motor skills may decline, making it hard to perform tasks that require dexterity, such as buttoning clothes or writing. Some people experience tingling or numbness in the hand and fingers, similar to the sensation of “pins and needles.”^[1]

Neck pain and pain in the upper ribs or upper back may also occur as the tumour invades the chest wall and nearby bones. In more advanced cases, swelling in the upper arm may develop if the tumour compresses major blood vessels.^[1]

A particularly important constellation of symptoms is called Horner’s syndrome, which occurs when the tumour affects the sympathetic nerves that run up into the neck and head. Horner’s syndrome is present in up to 50% of patients with Pancoast tumours. It causes a characteristic set of signs on the affected side of the face, including a drooping eyelid (called ptosis), a smaller pupil (called miosis), reduced or absent sweating on that side of the face (called anhidrosis), and sometimes flushing of the facial skin. Some patients may also notice that the affected eye appears slightly sunken, though this is often due to the drooping eyelid rather than true displacement of the eyeball.^[1][4]

General cancer symptoms such as fatigue, unexplained weight loss, and loss of appetite may also occur, though these are less specific and can be seen with many other conditions.^[1]

The combination of shoulder and arm pain with Horner’s syndrome is known as Pancoast syndrome or Pancoast-Tobias syndrome. Recognition of this pattern is crucial for healthcare providers, as it should prompt investigation for a tumour at the lung apex.^[1][3]

How Pancoast’s Tumour Is Diagnosed

Diagnosing a Pancoast tumour can be challenging, particularly in the early stages. One of the main reasons for this difficulty is that standard chest X-rays, which are often the first imaging test performed when lung problems are suspected, may not show a Pancoast tumour clearly. The tumour’s location at the very top of the lung, along with overlying bones and other structures, can obscure it on a two-dimensional X-ray image.^[1][4]

When a doctor suspects a Pancoast tumour based on symptoms like persistent shoulder pain, arm weakness, and especially the presence of Horner’s syndrome, they will typically order more advanced imaging tests. A computed tomography (CT) scan of the chest is often the next step. CT scans use multiple X-ray images taken from different angles and combine them using computer processing to create detailed cross-sectional pictures of the inside of the body. This allows doctors to see the tumour more clearly and assess how far it has spread into nearby structures such as ribs, vertebrae, and blood vessels.^[1]

Magnetic resonance imaging (MRI) is another valuable tool for evaluating Pancoast tumours. MRI uses powerful magnets and radio waves to create detailed images of soft tissues. It is particularly useful for assessing whether the tumour has invaded nerves, blood vessels, or the spinal canal, information that is critical for planning treatment.^[1][4]

Positron emission tomography (PET) scans, often combined with CT scans (PET-CT), may also be used. In a PET scan, a small amount of radioactive sugar is injected into the body. Cancer cells, which use more sugar than normal cells, absorb more of this radioactive substance and show up as bright spots on the scan. This test helps determine if the cancer has spread to lymph nodes or distant organs.^[4]

Once imaging suggests a tumour is present, the next step is to obtain a tissue sample, called a biopsy, to confirm the diagnosis and determine what type of cancer it is. There are several ways to perform a biopsy of a Pancoast tumour. A needle biopsy, in which a thin needle is guided into the tumour using imaging guidance, is one common approach. Another option is a biopsy performed during a video-assisted thoracoscopic surgery (VATS), where a small camera and instruments are inserted through small incisions in the chest. In some cases, a small surgical incision in the chest wall, called a thoracotomy, may be needed to obtain tissue.^[4]

Additional tests, such as bronchoscopy (inserting a flexible tube with a camera through the airways), may be performed to examine the airways and take samples if needed, though Pancoast tumours are often located too far out in the lung periphery to be reached this way.^[8]

Because the symptoms of Pancoast tumours can mimic other conditions like rotator cuff injuries, frozen shoulder, cervical disc disease, or nerve problems in the neck, there is often a delay before the correct diagnosis is made. Patients may initially be treated for these other conditions without improvement. Healthcare providers should maintain a high index of suspicion for Pancoast tumour in patients with persistent shoulder or arm symptoms, especially if they have a history of smoking.^[5][6]

Prevention Strategies

Because the causes of Pancoast tumour are similar to those of other lung cancers, prevention strategies focus on the same principles. The single most effective way to reduce the risk of developing a Pancoast tumour is to avoid smoking tobacco. For people who currently smoke, quitting at any age brings immediate and long-term health benefits. The risk of lung cancer begins to decline within years of quitting, and continues to decrease the longer a person remains smoke-free. Smoking cessation programs, medications, and counselling can all help people successfully quit smoking.

Avoiding exposure to secondhand smoke is also important. This means creating smoke-free environments at home and work, and avoiding places where smoking is common. Laws and policies that restrict smoking in public places have been shown to reduce exposure to secondhand smoke and improve public health.

Reducing occupational and environmental exposures to known carcinogens is another key prevention strategy. Workers in industries where asbestos, radon, heavy metals, or other toxic substances are present should use appropriate personal protective equipment and follow workplace safety guidelines. Homes should be tested for radon, especially in areas where radon exposure is known to be a problem, and mitigation systems installed if levels are high.

For people at high risk due to age and smoking history, lung cancer screening with low-dose CT scans may be recommended. This screening can detect lung cancers, including Pancoast tumours, at earlier stages when they may be more treatable. However, screening is not appropriate for everyone, and decisions about screening should be made in consultation with a healthcare provider who can assess individual risk and benefit.

Maintaining overall good health through a balanced diet, regular physical activity, and avoiding excessive alcohol consumption may also contribute to overall cancer prevention, though the evidence is less direct for lung cancer specifically compared to the overwhelming importance of tobacco avoidance.

How Pancoast’s Tumour Affects the Body: Understanding Pathophysiology

The pathophysiology of Pancoast tumour refers to the changes that occur in the body as a result of the cancer’s growth and spread. Understanding these changes helps explain why symptoms occur and how the disease progresses.

A Pancoast tumour begins as an abnormal growth of cells in the uppermost part of the lung tissue. As these cancer cells multiply, they form a mass that grows outward from the lung. Because of the tumour’s location at the lung apex, it quickly encounters important structures that sit just outside the lung itself. Unlike tumours that grow deeper within the lung tissue, Pancoast tumours have a tendency to invade surrounding structures early in their development.^[8]

One of the first structures to be affected is often the pleura, the thin membrane that covers the lung and lines the chest wall. As the tumour grows through the pleura, it invades the chest wall itself. This includes the uppermost ribs, particularly the first and second ribs, as well as the muscles and other soft tissues of the upper chest. This invasion causes pain and can lead to destruction of bone.^[4][8]

The brachial plexus, a complex network of nerves that originates from the spinal cord in the neck and travels down through the upper chest into the shoulder and arm, runs very close to the apex of the lung. When a Pancoast tumour invades or compresses these nerves, it disrupts the signals travelling between the brain and the arm. This leads to pain, which can be severe and burning in quality, as well as weakness, numbness, and loss of coordination in the arm and hand. Different nerves within the brachial plexus control different functions, so the specific pattern of symptoms can vary depending on which nerves are most affected.^[1][3]

Blood vessels that supply the arms, including the subclavian artery and vein, also pass through the upper chest near the lung apex. If the tumour compresses or invades these vessels, it can reduce blood flow to the arm, causing swelling, discoloration, or a feeling of heaviness. In severe cases, blood clots can form.^[4]

The sympathetic nerve chain, which is part of the autonomic nervous system controlling involuntary functions like sweating and pupil size, runs alongside the spine in the upper chest. When a Pancoast tumour involves the sympathetic chain, particularly at the level of a cluster of nerve cells called the stellate ganglion, it causes Horner’s syndrome. The disruption of sympathetic nerve signals to the face results in the characteristic drooping eyelid, smaller pupil, and reduced sweating on that side.^[3][8]

In some cases, the tumour may grow into the bones of the spine, particularly the upper thoracic vertebrae. This can cause severe back pain and, if the spinal cord is affected, neurological problems such as weakness or numbness in other parts of the body.^[6]

Like other cancers, Pancoast tumours can spread beyond their original location through the lymphatic system or bloodstream. Cancer cells can travel to nearby lymph nodes in the chest or neck, or to distant organs such as the brain, bones, liver, or adrenal glands. The stage of the cancer, which describes how far it has spread, is an important factor in determining treatment options and prognosis.^[10]

The bulk of a true Pancoast tumour is often extrathoracic, meaning most of it extends outside the lung into the chest wall and surrounding structures. This is in contrast to many other lung cancers that remain primarily within the lung tissue. This pattern of growth makes surgical removal particularly challenging, as it requires removing not just lung tissue but also parts of the ribs, chest wall, and sometimes blood vessels or nerves.^[8]