Symptoms of Small Cell Lung Cancer

Small cell lung cancer (SCLC) doesn't always present with symptoms at the time of diagnosis, but that can change quickly as the disease has a tendency to worsen rapidly. Because it's a fairly aggressive malignancy, SCLC can have a wide variety of effects on your health and quality of life. Your medical team will work to treat the tumor and help you manage symptoms in an effort to improve your overall sense of well-being.

man coughing while doctor checks
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Spectrum of Effects

It's important to know that you can't necessarily recognize SCLC based on symptoms alone, and the emergence of symptoms doesn't follow a predictable path or timeline. Depending on the activity of the tumor within the lungs and its systemic spread, the signs and symptoms can start in the absence of metastasis (spread) or may begin after the cancer has invaded distant regions of the body.

This type of cancer can cause respiratory distress due to its presence in the lung and may also cause non-pulmonary issues like seizures or pain due to metastasis.

SCLC can also produce paraneoplastic syndromes as a result of tumor-induced stimulation of distant organs. These effects can occur when the tumor is small and confined to the lung or may begin when it spreads.

For example, you might have paraneoplastic effects without any pulmonary symptoms until several months down the road, or you might not ever have pulmonary symptoms of your SCLC. Similarly, a range of metastatic effects can emerge at any time in the course of the disease.

If you're diagnosed with this type of cancer, it can be helpful to aware of the signs of disease progression so you can recognize them—particularly since SCLC does not follow a scripted path.

Pulmonary Symptoms

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

Symptoms of SCLC in the lungs may include:

As the tumor enlarges within the lungs or if additional lesions develop, inflammation and bleeding can result. With increased lung damage, pulmonary effects may become noticeable or more significant, causing you to experience substantial distress.

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

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 heart, potentially 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

The symptoms and effects of SCLC are wide-ranging and are not specific to the condition. If you experience any of these symptoms, diagnostic testing can identify whether they are caused by SCLC or another condition. For the best outcome, it is vital that you seek medical attention, even for mild symptoms.

And if you are diagnosed with SCLC, knowing the effects that the disease can have will help you recognize signs that your condition might be worsening, so you can get medical attention and a treatment plan to help manage your disease and its impact on your quality of life.

7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Lynne Eldridge, MD
 Lynne Eldrige, MD, is a lung cancer physician, patient advocate, and award-winning author of "Avoiding Cancer One Day at a Time."