The most common initial symptoms of SCLC are a worsening cough and shortness of breath. However, this type of lung cancer often doesn’t cause symptoms until it’s in the later stages.

Lung cancer is made up of two primary categories called small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC).

SCLC is much less common than NSCLC. It makes up about 13% of lung cancers compared to 84% for NSCLC. Despite being less common, it tends to be more aggressive and is associated with a poorer outlook.

SCLC often doesn’t cause symptoms in the early stages so it can be harder to diagnose early. Nearly 60% of people diagnosed with SCLC have late-stage cancer that has spread to distant body parts by the time they receive their diagnosis. When symptoms do appear in the early stages, they often include respiratory symptoms like a cough or trouble breathing.

Keep reading to learn more about the potential early signs and symptoms of SCLC.

SCLC often isn’t diagnosed until the late stages. A lack of specific symptoms in the early stages is one of the main obstacles to early detection.

In a 2021 study, researchers found that 24.7% of a group of 267 people with lung cancer were diagnosed incidentally after receiving imaging for an unrelated condition and had no previous lung cancer symptoms. Over half of people with cancer limited to the lung or surrounding tissue had no symptoms.

SCLC symptoms can develop from the invasion of lung tissue by cancer cells or from a tumor that compresses structures in your chest. The most common initial symptoms in people with SCLC are a worsening cough and shortness of breath.

Other signs and symptoms that may appear in the early stages include:

Metastasized SCLC

Metastasized cancer is when cancer spreads to distant body parts. It’s also referred to as stage IV cancer. The most common places SCLC spreads to are:

  • lymph nodes
  • other parts of your lung
  • bone
  • brain
  • liver
  • adrenal glands

Symptoms of metastasized cancer depend on where the cancer spreads. Here’s a look at potential symptoms by location.

lymph nodes · often no symptoms
· swollen or painful lymph node
· blood clots
bone · bone pain
· bone fracture
· urinary or bowel incontinence
· muscle weakness
· high levels of calcium in the blood
· nausea
· vomiting
· constipation
· confusion
brain · headaches
· seizures
· arm or leg weakness
· loss of balance
· memory loss
· speech disturbances
· behavior or personality changes
· vision problems
· limb numbness
· hearing problems
liver· loss of appetite
· weakness
· fever
· itchy skin
· jaundice
· abdominal bloating
· leg swelling
· pain in upper right part of abdomen
adrenal glands · weight loss
· loss of appetite
· nausea
· vomiting
· abdominal pain
· weakness
· fatigue
· fever
· lethargy
· confusion
· electrolyte imbalances
· adrenal insufficiency
other parts of the lung · similar to SCLC

Paraneoplastic disorders

SCLC is a solid cancer most likely to cause paraneoplastic syndromes. These syndromes occur when cancer cells produce excessive hormones or when they trigger an abnormal immune response where your immune system attacks healthy nerve cells.

The most common neoplastic syndromes in people with SCLC are:

  • Syndrome of inappropriate antidiuresis (SIADH): SIADH is characterized by the excessive production of an antidiuretic hormone that causes your body to retain excess water. It affects 15% to 40% of people with SCLC.
  • Ectopic Cushing syndrome: Ectopic Cushing syndrome is characterized by the excessive production of adrenocorticotropic hormone by cancer cells that results in elevated cortisol levels. It affects 2% to 5% of people with SCLC.
  • Lambert-Eaton myasthenic syndrome: Lambert-Eaton myasthenic syndrome is characterized by problems with your muscles and weakness in your arms and legs. It occurs in about 3% of people with SCLC.

SCLC symptoms by stage

You may not have any symptoms in the early stages. Some people develop symptoms earlier than others.

Stage IStage I lung cancer is contained in your lung. There’s a good chance you won’t have symptoms at this stage. Paraneoplastic disorders can develop at any stage.
Stage IIStage II lung symptoms may have spread into your lymph nodes, this stage has a greater chance of causing symptoms.
Stage IIIStage III lung cancer may produce breathing problems or general symptoms such as unintentional weight loss.
Stage IVStage IV lung cancer has spread to distant organs and may cause symptoms affecting distant body parts like your liver or brain.
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Limited stage vs. extensive stage

In addition to the stage 1 through stage IV classifications described in the table above, doctors commonly use a simpler staging of SCLC: limited vs. extensive.

  • Limited stage: In this stage, cancer is just on one side of the chest, typically contained to one lung and lymph nodes on the same side as the affected lung.
  • Extensive stage: In this stage, cancer has spread throughout both lungs, to lymph nodes on both sides of the chest, and other parts of the body, including bone marrow.

SCLC is thought to be primarily caused by DNA damage to lung cells by chemicals found in tobacco smoke. Only 2% of SCLCs develop in people who have smoked less than 100 cigarettes. Certain gene mutations you receive from your parents can also increase your risk of developing SCLC.

Other potential causes may include exposure to:

  • chloromethyl ethers, used in manufacturing
  • asbestos
  • radon
  • air pollution

Doctors start the diagnostic process by performing a physical exam and taking your medical history. Imaging tests can identify tumors in your lungs or other parts of your body. You may receive:

A lung needle biopsy can help doctors understand what type of cancer you have. A biopsy is when a small tissue sample is removed for laboratory analysis. Your biopsy may be taken with a long, thin needle through your chest or with a flexible tube with a camera that goes down your throat.

Learn more about the diagnostic process for lung cancer here.

Treatment for small cell lung cancer depends on how far the cancer has progressed. You may receive some combination of:

Learn more about SCLC treatment here.

SCLC generally has a poor outlook since it’s often spread to distant tissue by the time it’s diagnosed. The American Cancer Society lists the 5-year relative survival rate as:

Stage5-year relative survival rate
All stages26%

The 5-year relative survival rate measures how many people with the disease are alive 5 years later compared to people without the disease.

These numbers can give you a rough idea of what to expect, but your actual chances of survival depend on factors such as:

  • your age
  • your overall health
  • the subtype of your cancer
  • your response to treatment
  • genetic factors

What can you do to prevent getting lung cancer?

The top risk factor for lung cancer is exposure to tobacco smoke. Avoiding smoking, or quitting if you currently smoke, can help you lower your risk of developing SCLC. Avoiding potentially harmful chemicals like radon in your home may also help.

Can NSCLC develop into SCLC?

NSCLC can potentially develop into SCLC. In a 2020 study, researchers noted that the transformation of adenocarcinoma, a type of NSCLC, into SCLC is well-documented after treatment with tyrosine kinase inhibitors.

However, this study only involved one person. Further research is needed to learn more about the transformation of NSCLC to SCLC.

Learn more about this transformation here.

What other types of lung cancers are there?

The most common category of lung cancer is called non-small cell lung cancer. Other lung cancers include:

If you stop smoking, does your risk for SCLC go away?

In a 2018 study, researchers found evidence that lung cancer risk drops in heavy former smokers within 5 years compared to people who continue to smoke. The risk stays 3 times higher in former smokers than in people who have never smoked even after 25 years.

Can quitting smoking improve your outlook if you’ve been diagnosed with lung cancer?

In a 2021 study, researchers found evidence that quitting smoking after lung cancer diagnosis improved overall survival and disease progression in current smokers with early-stage lung cancer.

SCLC often doesn’t cause symptoms in the early stages and more than half of people have cancer that has spread to distant organs by the time they’re diagnosed.

If you have symptoms that could be from lung cancer, it’s important to see your doctor as soon as possible. Getting an early diagnosis and treatment can give you the best chance of having a good outlook.