Small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC) are the two main types of lung cancer. Although these two types share similar causes and symptoms, there are several important differences that can affect your care and lung cancer treatment options.

Learning more about the differences between these types of cancer can help you better understand your diagnosis and treatment. In this article, we’ll explore the key differences between SCLC and NSCLC so that you can feel more confident discussing next steps with your cancer care team.

How Are Small Cell Lung Cancer and Non-Small Cell Lung Cancer Different?

SCLC and NSCLC are both cancers that begin in the lungs. One of the most obvious differences between these two cancers is right in the name. Under a microscope, cancer cells from an SCLC tumor look smaller than NSCLC cells. SCLC cells can also appear round and flat, like rolled oats. That’s why SCLC is also referred to as oat-cell cancer.

Each type differs in how it grows, spreads, and responds to treatment. Understanding the differences can give you a clearer picture of what to expect and help guide informed conversations with your healthcare provider.

1. NSCLC Is the Most Common Type of Lung Cancer

The American Cancer Society (ACS) estimates that more than 226,000 people will be diagnosed with lung cancer in the United States in 2025. Most of these people diagnosed with lung cancer will have NSCLC. Between 80 percent and 85 percent of all lung cancer diagnoses are NSCLC. In contrast, between 10 percent and 15 percent of people with lung cancer will be diagnosed with SCLC.

2. SCLC and NSCLC Have Different Subtypes

NSCLC is divided into several subtypes based on the types of cells in which the cancer starts. The most common subtypes of NSCLC are:

• Adenocarcinoma — This is the most common subtype of NSCLC. It usually develops in the cells that line the surface of the lungs and tends to grow slowly compared to other types of NSCLC.
• Squamous cell carcinoma — This subtype of NSCLC begins in squamous cells, which line the airways. It often develops in the central part of the lungs near the main bronchi (airways).
• Large cell carcinoma — This is the least common subtype of NSCLC. It can develop in any part of the lung and often grows more quickly than other subtypes.

Between 10 percent and 15 percent of people with lung cancer will be diagnosed with SCLC.

SCLC is also broken down into two different subtypes:

• Small cell carcinoma — The most common SCLC subtype
• Combined small cell lung cancer — An SCLC subtype where the tumor is made up of a combination of small cell carcinoma cells and non-small cell carcinoma cells

3. SCLC Is Usually More Aggressive Than NSCLC

SCLC is known as the most aggressive type of lung cancer. In general, SCLC tends to grow and spread more quickly than NSCLC. Because of this, people with SCLC often have a poor prognosis (outlook). Even with treatment, most people with SCLC die within two years of their diagnosis.

The prognosis for people with NSCLC depends on the exact subtype, cancer stage, and overall health. However, one subtype of NSCLC, called large cell neuroendocrine carcinoma (LCNEC), tends to grow quickly and can behave like SCLC.

4. SCLC Is Almost Always Linked to Smoking

Smoking cigarettes is a risk factor for both NSCLC and SCLC. Overall, about 80 percent of lung cancer deaths are thought to be linked to smoking. However, SCLC is almost always associated with smoking.

Since SCLC grows aggressively, people with this type often have a poor prognosis. For people with NSCLC, prognosis depends on their exact subtype, cancer stage, and overall health.

People who don’t smoke can also develop lung cancer. When they do, it’s most often NSCLC, especially the adenocarcinoma subtype. According to the journal Oncotarget, among nonsmokers, this type is more common in women with Asian ancestry.

5. Symptoms May Be More Severe for People With SCLC

Both SCLC and NSCLC can cause symptoms such as:

• A cough that gets worse over time
• Chest pain
• Shortness of breath
• Coughing up blood
• Wheezing
• Hoarse voice
• Tiredness or weakness
• Unexplained weight loss
• Loss of appetite
• Difficulty swallowing
• Swollen face
• Swollen veins in the neck

SCLC tends to grow and spread to other parts of the body more quickly. That means that by the time you notice symptoms, the cancer may be more advanced, and you’re more likely to have more severe symptoms of advanced lung cancer, such as:

• Bone pain
• Back pain
• Confusion
• Seizures
• Headaches
• Balance problems
• Jaundice (yellowing of the skin and whites of the eyes)
• Swollen lymph nodes

6. SCLC Only Has Two Stages

With many cancers, including NSCLC, doctors assign a stage using the TNM staging system. This system uses the size of the tumor, lymph node involvement, and whether the cancer has spread to other parts of the body to determine the cancer stage. In the TNM system, cancers are given a stage from stage 0 to stage 4. In general, the lower the stage, the less the cancer has spread.

Although healthcare providers can use the TNM staging system for SCLC, most use a different two-stage system to help select the best treatment options. The two stages of SCLC are limited stage and extensive stage.

Limited-stage SCLC means that the cancer is found in only one lung and is confined to a small area. In some cases, cancer has spread to the lymph nodes on the same side of the chest. About 30 percent of people are diagnosed with SCLC when it’s still in this early stage.

Extensive-stage SCLC is when the cancer has spread to both lungs or other parts of the body. About 70 percent of people are diagnosed with SCLC after it’s already spread to other parts of the body.

7. Surgery Is More Often Used for Early-Stage NSCLC

Surgery is the treatment with the best chance of curing lung cancer. However, lung cancer surgery is usually only helpful for people with early-stage lung cancer. When lung cancer hasn’t spread widely, a surgeon can remove the tumor, affected lymph nodes, and surrounding tissue. Since about 30 percent of people with NSCLC are diagnosed with early-stage cancer, surgery is more likely to be an option in this form of lung cancer. For some people with stage 1 NSCLC, surgery may be the only treatment they need.

Surgery is used to treat early-stage lung cancer. Since more people with NSCLC are diagnosed at an early stage, surgery is a more common treatment than it is for SCLC.

Lung cancer surgery is not usually part of the treatment plan for people with SCLC. That’s because most people are diagnosed with SCLC after it’s already spread. Fewer than 5 percent of people diagnosed with SCLC have a single tumor that hasn’t spread to the lymph nodes or other parts of the body.

8. SCLC Often Responds to Chemotherapy and Radiation Therapy

Cancer treatments like chemotherapy and radiation therapy work by targeting fast-growing cells. Since SCLC grows quickly, these treatments are often helpful for people with SCLC. In limited-stage SCLC, radiation therapy can be combined with chemotherapy to help shrink a localized lung tumor.

Once SCLC advances to the extensive stage, cancer has usually spread too far for local radiation therapy to be helpful, though it can still be used in some cases to treat symptoms. In this case, immunotherapy treatments can be combined with chemotherapy to help shrink the tumor and help people live longer. Unfortunately, SCLC often returns after treatment.

People with NSCLC may have additional treatment options available, including radiofrequency ablation, immunotherapy, and targeted therapy drugs. The best treatment plan depends on the cancer stage, lung function, and overall health. Learn more about NSCLC treatment options.

Talk With Others Who Understand

On MyLungCancerTeam, the social network for people with lung cancer and their loved ones, members come together to ask questions, offer support and advice, and connect with others who understand life with lung cancer.

Have you or a loved one been diagnosed with small cell or non-small cell lung cancer? Share your story in the comments below or by posting on your Activities page.