What Is a Pancoast Tumor? What Is the Link Between Shoulder Pain and Lung Cancer?

We often experience shoulder pain because of muscle injuries or inflammation in the shoulder joints. Less often, lung cancer may cause shoulder pain as a symptom.

Although shoulder pain is not a common symptom of lung cancer, any unexpected and persistent shoulder pain should prompt a visit to a doctor.

How Does Lung Cancer Cause Shoulder Pain?

Lung cancer can cause pain felt in the shoulder. This means the pain begins in one part of the body but is experienced in another — what medicine calls “referred pain.” Some types of lung cancer, discussed below, are more likely than others to cause this pain.

What Is a Pancoast Tumor?

Pancoast tumors are a relatively rare form of lung cancer. They account for 3–5% of the more than 2 million lung cancers that occur worldwide each year. These tumors develop in the upper part of the lungs, in an area called the superior sulcus. Because the superior sulci are close to the shoulders, they often cause severe pain in the shoulder on the same side of the body as the affected lung. Pancoast tumors are also called “superior sulcus tumors.”

If a Pancoast tumor affects the brachial plexus (a network of nerves above the shoulders), it may cause pain in the shoulder and arm. The pain may also radiate to the head, neck and chest. The person may also experience weakness, pain or tingling in their hands and fingers.

96% of people with Pancoast lung cancer tumors report shoulder pain as one of their first symptoms.

Horner Syndrome

Some people with a Pancoast tumor may also experience a group of symptoms called Horner syndrome, which can cause shoulder pain over time. This syndrome may also cause the following asymmetrical signs:

• A drooping eyelid on the affected side
• A smaller pupil in one eye
• Changes in sweating, such as reduced sweating in part of the face
• One eyeball sinking into its bony socket

Although the signs of Horner syndrome are usually mild, the underlying cause will most likely require timely diagnosis and urgent treatment.

Mesothelioma (Cancer of the Lung Lining)

Mesothelioma is a type of cancer of the thorax/chest area that usually develops after prolonged exposure to asbestos. Its symptoms resemble those of other types of lung cancer. Shoulder pain may also be a symptom of mesothelioma, but there are no clear data on how common this symptom is.

• Related topic: What Is Mesothelioma? Its History and the Latest Developments in Treatment

Other symptoms of mesothelioma include:

• Shortness of breath
• Pain on one side of the chest
• Hoarseness and coughing
• Difficulty swallowing
• Swelling in the face and arms

Mesothelioma is generally a very slow-growing cancer, and symptoms may last for years before the tumor becomes apparent. These symptoms can often be mistaken for arthritis (joint inflammation). Differential diagnosis is difficult because 50% of people aged 65 and older have been diagnosed with arthritis in a joint.

Because mesothelioma and arthritis affect people of similar ages, those experiencing shoulder pain from mesothelioma may mistakenly interpret their symptoms as arthritis. This can delay diagnosis and worsen the outcome.

Metastatic (Stage 4) Lung Cancer

Metastatic lung cancer is cancer that has spread to other parts of the body. Shoulder pain may occur when lung cancer spreads to nearby areas such as bones and lymph nodes.

• Related topic: What Are the Symptoms of Lung Cancer Metastasis?

Metastatic lung cancer can cause a range of symptoms specific to the body system it affects. For example, lung cancer that spreads to the liver can cause signs of jaundice, such as yellow skin.

Other common symptoms of metastatic lung cancer, depending on where the cancer has spread, include:

• Coughing up blood
• Unexpected weight loss
• Fluid around the lungs

Features of Shoulder Pain Caused by Lung Cancer

There is no specific characteristic sign that defines shoulder pain caused by lung cancer.

In a study examining shoulder pain in people with mesothelioma, participants rated their pain intensity on a scale of 10, with an average of 4. However, a few participants experienced more significant symptoms, including reduced mobility.

Some cancer-related shoulder pain, such as pain caused by Pancoast tumors, starts in the shoulder and can spread to the head, neck and chest. Some people with cancer-related shoulder pain may also have pain that travels from the arms toward the hands. There may sometimes be numbness and tingling in the hand and fingers on the affected side.

Other Symptoms

Non-small cell lung cancer (KHDAK) is the most common type of lung cancer. Other symptoms that may occur with KHDAK include:

• A persistent cough
• Coughing with blood or rust-colored mucus
• Hoarseness or wheezing
• Unexplained weight loss
• Shortness of breath
• Chest discomfort or pain
• Respiratory infections, such as bronchitis and pneumonia, that do not clear up or keep returning

What Are Other Common Causes of Shoulder Pain?

Most cases of shoulder pain result from poor posture or muscle strains. The most common causes of this pain include:

• Short-term injuries: These can occur because the shoulder muscles are overstretched or overused. Symptoms are generally confined to the injured joint.
• Pain referred from other parts of the body: Back and neck pain can trigger shoulder pain. Weakness in one muscle can cause the shoulder muscles to compensate, resulting in pain.
• Spinal injuries: These may include herniated discs that press on certain nerves. Some of these nerves cause pain in the shoulder.
• Osteoarthritis: A degenerative condition that progresses as cartilage wears away between the joints.
• Rheumatoid arthritis (RA): RA is a long-term inflammatory condition that can sometimes affect the shoulder. It occurs when the immune system attacks the joints, causing pain and inflammation.
• Rotator cuff tears: This shoulder injury impairs a person's ability to move, rotate and lift their arm.
• Frozen shoulder: An injury that limits shoulder mobility. Underuse of the shoulder, RA and abnormal tissue growth may cause frozen shoulder.
• Poor posture: Spending time hunched over a computer, holding the body in an awkward position for a long time, and cracking the neck can cause shoulder tension and pain. The pain may spread to the neck and back.

Less commonly, various diseases may irritate shoulder nerves and trigger pain. Heart disease, gallbladder disease and liver disease can all cause shoulder pain this way. Nerve pain may cause tingling, numbness or a pins-and-needles sensation in the shoulder. The area of the body affected often changes or expands over time.

Treating Shoulder Pain

In most cases, shoulder pain is temporary and results from overuse, strain and minor injuries. To treat recent shoulder pain, you can try:

• Resting the injured shoulder and avoiding excessive movement or heavy lifting
• Applying ice to reduce pain or heat to reduce stiffness
• Wrapping the area with a bandage or wrap to reduce swelling
• Keeping the painful area elevated

Some people also find that alternating between heat and ice helps increase blood flow, promote faster healing and reduce pain. Gentle stretching, low-impact exercise and nonsteroidal anti-inflammatory drugs such as ibuprofen may also provide relief.

A specialist should be consulted if shoulder pain lasts more than a few days, goes away and then returns, or becomes unbearable. Depending on the cause, a specialist may recommend:

• Physical therapy
• Exercise
• Surgery to correct structural problems or damage
• Alternative treatments such as acupuncture or chiropractic care
• Painkillers to reduce shoulder pain and improve mobility

Long-term shoulder pain can range from mild to disabling. Learning to cope with persistent shoulder pain may help make it more bearable.

People should not stop using the affected shoulder, because this may prevent it from healing. Continuing to move can stop the shoulder from becoming frozen. The person should continue normal activities, taking regular breaks as needed. Some people may consider their sleeping position and add an extra pillow to support the shoulder while sleeping.

Summary

Shoulder pain is not a common symptom of lung cancer. In rare cases, however, it may be an early sign of Pancoast tumors or mesothelioma. In most cases, shoulder pain is temporary and may result from shoulder overuse, strain and minor injuries. Still, it is better to consult a specialist about any persistent and unexplained pain.