Symptoms of Small Cell Lung Cancer

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Small cell lung cancer (SCLC) doesn't always cause symptoms, but the effects of the disease can worsen rapidly within just a few weeks. This type of cancer can cause respiratory distress due to its presence in the lung, and may also cause issues like seizures or pain due to metastasis (spread of the tumor). SCLC can also produce paraneoplastic syndromes as a result of tumor-induced stimulation of distant organs. You can't necessarily know whether you have SCLC based on symptoms alone, but if you're diagnosed with this type of cancer it can be helpful for you to recognize its common symptoms.

Pulmonary Symptoms

Typically, SCLC tends to develop near the central airways of the lungs, and as such, can induce pulmonary effects early on by irritating the airways or obstructing airflow. You can begin to experience symptoms that seem to persist or worsen.

If you're a current or former smoker with chronic respiratory issues for years, it can be easy to ignore the symptoms of SCLC. But it's important to get medical attention as soon as possible because this lung cancer can worsen quickly.

Symptoms of SCLC in the lungs may include:

Early on, SCLC might not cause respiratory problems. But if the tumor enlarges within the lungs or if additional lesions develop in the lungs, inflammation and bleeding can result. With increased lung damage, these pulmonary symptoms may worsen, causing more distress for you.

Mediastinal Symptoms

SCLC tends to grow into and metastasize within the mediastinum (the area between the lungs) fairly early on in the course of the disease.

When cancer spreads to the mediastinum, it can place pressure on structures in this area, producing a variety of symptoms.

SCLC in the mediastinum can affect:

  • The esophagus: Pressure can lead to difficulty swallowing or the sensation that something is stuck in your throat. Cancer that invades the esophagus can cause vomiting, hemoptysis, iron deficiency anemia (low red blood cells) due to blood loss, and weight loss.
  • The trachea (windpipe): This can cause pain, discomfort, shortness of breath, or a whistling sound while inhaling or talking.
  • The heart: SCLC can sometimes cause pericardial effusion (inflammatory fluid in the tissues that line the heart). An effusion can compress the heart and nearby structures, leading to chest discomfort or shortness of breath, especially when lying flat on your back.

Superior Vena Cava Syndrome

Face, neck, or upper chest swelling can occur if SCLC causes superior vena cava (SVC) syndrome. This type of cancer can metastasize near the superior vena cava, which is the large blood vessel in the chest that returns blood from the head to the heart.

Pressure on or inside this blood vessel can inhibit blood from the head, neck, and upper chest from returning to the heartpo, tentially resulting in discomfort and swelling.

SVC syndrome can be a medical emergency if it causes severe edema (fluid accumulation) in the throat or the brain.

SVC syndrome is more common with small cell lung cancer than with other forms of lung cancer. And while SVC syndrome isn't usually one of the early effects of this lung cancer, it may develop if the disease advances.

Paraneoplastic Syndromes

Paraneoplastic symptoms occur when distant organs are targeted by antibodies (immune proteins) or by substances secreted by the tumor.

A broad variety of manifestations due to paraneoplastic syndromes can occur at any stage of SCLC. In some cases, paraneoplastic symptoms may be the first effects of the disease.

Paraneoplastic syndromes caused by SCLC include:

  • Lambert-Eaton myasthenic syndrome (LEMS): This causes weakness of the arms, trouble swallowing, and vision changes. It is caused by impairment of the neuromuscular junction, which is the small area between a nerve and a muscle.
  • Syndrome of inappropriate antidiuretic hormone secretion (SIADH), which causes a low sodium level, weakness, and fatigue. SIADH occurs when too much antidiuretic hormone (ADH) is produced, disrupting kidney function.
  • Paraneoplastic cerebellar degeneration: This causes severe problems with physical coordination, manifesting with jerking movements, difficulty walking, and a shaky voice. It happens when the tumor secretes antibodies that damage the cerebellum.
  • Cushing syndrome, which causes weight gain, edema, hypertension, and skin changes. It occurs when SCLC produces adrenocorticotrophic hormone (ACTH) that overstimulates the adrenal glands.
  • Humoral hypercalcemia of malignancy (HHM), which causes elevated calcium levels and dehydration due to bone breakdown and parathyroid stimulation

Paraneoplastic syndromes may be associated with antibodies or markers in the blood. These can be detected with blood work even before the tumor is visible on an imaging test.


Most of the time, SCLC is not completely curable and may recur and metastasize even after treatment. Sometimes SCLC metastasizes early in the course of the disease, and the first symptoms may be related to its invasion in distant organs.

Effects of SCLC metastases may include:

A Word From Verywell

Because it's a fairly aggressive tumor, SCLC can cause a wide variety of early and late-stage effects on your health and quality of life. Your medical team will work with you to help get your symptoms under control with strategies aimed at treating the tumor, as well as symptom control to improve your overall sense of well-being.

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