Symptoms of Small Cell Lung Cancer

man coughing while doctor checks, a symptom of small cell lung cancer

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Small cell lung cancer symptoms can be similar to symptoms of other forms of lung cancer, but can also be different in several ways. Symptoms such as a cough or shortness of breath may point to the lungs, but symptoms such as headaches, seizures, new onset stretch marks, or difficulty swallowing may have you and your doctor looking for an unrelated condition initially. We will look at how small cell lung cancers can cause a variety of signs and symptoms depending on their location, if they have spread, and if they secrete substances that cause sometimes odd symptoms (paraneoplastic symptoms).

Small cell lung cancers may have symptoms similar to the more common non-small cell lung cancers, but there are important differences as well. People who have non-small cell lung cancer often experience symptoms for many months (or even years) before the diagnosis is made, while symptoms related to small cell lung cancer are usually present for only a short while before a diagnosis is made.

Symptoms Related to Location of the Tumor

Small cell lung cancers tend to grow near the central airways of the lungs, and as such, create symptoms early on by irritating the airways or obstructing air flow. They also tend to spread (metastasize) early, and it isn’t uncommon for the first symptoms of small cell lung cancer to be related to its effect on other organs, such as the brain. Some common symptoms include:

Symptoms Due to Spread to the Mediastinum

Small cell lung cancers tend to spread to the area between the lungs (the mediastinum) fairly early on in the course of the disease. When cancer spreads to the mediastinum, it can place pressure on structures in this area, such as:

  • The esophagus: Pressure can lead to difficulty swallowing or the sensation that something is stuck in your throat
  • The trachea (windpipe): This can cause shortness of breath and a whistling sound while breathing in. Of note is that wheezing is usually most "noisy" when breathing out or during exhalation.
  • The heart: Small cell lung cancers can sometimes cause fluid to build up in the tissues that line the heart (a pericardial effusion). If sufficiently large, the effusion can compress the heart leading to symptoms such as shortness of breath when lying down, especially when lying flat on your back, or discomfort behind your breastbone (sternum).

Symptoms Related to Superior Vena Cava Syndrome

Small cell lung cancer can also result in symptoms referred to as superior vena cava syndrome (SVC syndrome). When a tumor is present in the mediastinum, it can press on the superior vena cava (the large blood vessel in the chest that returns blood to the heart), causing symptoms such as swelling of the face, neck, and upper chest that can sometimes be dramatic.

SVC syndrome is more common with small cell lung cancer than with other forms of lung cancer and may be the first symptom of the disease. Symptoms such as superior vena cava syndrome with lung cancer are a good reminder to talk to your doctor about any unexplained symptoms you are experiencing, as sometimes they are not what people would ordinarily expect.

Paraneoplastic Syndromes

Small cell lung cancer can also result in a broad variety of symptoms due to paraneoplastic syndromes , and In some cases, paraneoplastic symptoms may be the first symptoms of the disease. Paraneoplastic symptoms are caused either by substances secreted by a tumor, or released by the body in response to a tumor. Some of these include:

  • Muscle weakness in the upper limbs, vision changes, and difficulty swallowing (Lambert-Eaton myasthenic syndrome)
  • Weakness, fatigue, and a low sodium level in the blood (syndrome of inappropriate antidiuretic hormone secretion (SIADH))
  • Loss of coordination and difficulty speaking (paraneoplastic cerebellar degeneration)
  • Weight gain, high blood pressure, mental changes, and skin changes such as stretch marks on the abdomen and a darkening of the skin (Cushing Syndrome)
  • Clubbing (rounding) of the fingernails

Symptoms When Lung Cancer Spreads

Since small cell lung cancer spreads (metastasizes) early in the course of the disease, the first symptoms may be related to effects cancer has on distant organs. Some of these symptoms may include:

  • Symptoms due to brain metastases: It's not uncommon for small cell lung cancer to spread to the brain before it is diagnosed, with the resulting symptoms related to brain metastases being the first symptoms. Brain metastases can cause symptoms such as headaches, dizziness, weakness of one side of the body, speech difficulties, or other neurological symptoms.
  • Symptoms due to bone metastasis: Bone metastases can cause symptoms such as back pain or other bones. When metastases in the spine compress the spinal cord, it can lead leg pain and weakness and sometimes bowel or bladder dysfunction (malignant spinal cord compression). Bone metastases may also weaken bones so that fractures occur with minimal or no trauma (pathological fractures).
  • Symptoms due to spread to the liver: Liver metastases may result in abdominal pain, itching (that can be severe), nausea and vomiting, abdominal bloating, and yellowing of the skin.

General Symptoms

Small cell lung cancers can also cause general symptoms of cancer, such as fatigue, loss of appetite, and unexplained weight loss. The syndrome of cancer cachexia, consisting of unintentional weight loss along with muscle wasting, is also far too common and can reduce the quality of life as well as survival.

Bottom Line

The symptoms of small cell lung cancer differ from non-small cell lung cancer in that people rarely look back and realize that they have had symptoms for a long time. The diagnosis of small cell is often made shortly after symptoms arise. And also unlike non-small cell lung cancer, the first symptoms may be neurological, such as headaches, seizures, or weakness related to brain metastases.

Paraneoplastic symptoms are also more common with small cell lung cancer (though they may occur with the type of non-small cell lung cancer known as squamous cell carcinoma). These symptoms can vary tremendously and don't necessarily point at the lungs as the source of the problem. 

A Word From Verywell

The fact that small cell lung cancer can sometimes present with symptoms that don't immediately point to the lungs as a source is a reminder that people should talk to their doctors about any unexplained symptoms they have. As with most cancers, outcomes are often better when small cell lung cancer is diagnosed earlier. It's also important to be persistent and be your own advocate if you have symptoms that aren't explained. Continuing to ask questions, and getting a second (or third) opinion when needed, are important no matter what your symptoms or potential diagnosis.

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