What's The Difference Between Small Cell and Non-Small Cell Lung Cancer?


Small Cell vs. Non-Small Cell Lung Cancer: What’s the Difference?

Lung cancer begins in the lungs, but not all lung cancers are the same. Most can be sorted into two categories, which require very different treatments: small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC). NSCLC is far more common; in fact, the American Lung Association estimates that 80 to 85% of all lung cancer cases are non-small cell lung cancer, with 10 to 15% falling into the small cell lung cancer category. And while these two types of lung cancer do have a few things in common, it’s important to understand where they diverge, too.

Take a closer look at small cell vs. non-small cell lung cancer.

Small cell and non-small cell lung cancer have a few similarities. For one, they’re both characterized by malignant cells that grow inside the lungs. Another similarity: coughing and shortness of breath are the early signs of both types of lung cancer. Smokers are at greater risk for developing these kinds of cancer, as are people who are exposed to secondhand smoke, certain chemicals in the workplace, air pollution, and certain kinds of radiation.

When it comes to the nitty gritty details, they start to diverge. There are several kinds of non-small cell lung cancers and two main kinds of small cell lung cancer. Each kind is named for the different types of cells which produce the malignant tumors.

Small cell lung cancer typically starts near the center of the chest, around the bronchi. The two types of small cell lung cancer are:

  • Combined small cell carcinoma

  • Small cell carcinoma

NSCLC can start in several areas. The three main kinds of non-small cell lung cancer are:

  • Adenocarcinoma, which begins in the lining of the alveoli, in the cells that secrete mucus

  • Large cell carcinoma, which is a fast-growing carcinoma that can grow in many different kinds of large cells

  • Squamous cell carcinoma, which tend to grow in the thin, flat cells in the central part of the lung or in the main airway

There are a few other kinds of non-small cell lung cancer, including adenosquamous carcinoma and sarcomatoid carcinoma, but they are much less commonly diagnosed.

The staging classifications are different.

After your oncologist determines which type of lung cancer you have, then they’ll do a deeper dive to determine the correct staging for your cancer, which will help determine the course of your treatment. However, it’s crucial to know that just as the two different types of lung cancer aren’t the same, the staging for small cell lung cancer and non-small cell lung cancer is not the same, either.

The two stages for small cell lung cancer are:

  • Limited stage, which describes the cancer while it’s either still located in the lungs or may have spread to the lymph nodes above the collarbone or the space between the lungs

  • Extensive stage, which describes cancer that’s spread to other parts of the body

Meanwhile, the stages for non-small cell lung cancer are:

  • Stage 0

  • Stage 1

  • Stage 2

  • Stage 3

  • Stage 4

As you might surmise, stage 0 is the earliest stage, when abnormal cells are found in the lining of your airways. As you move up the scale, the tumors may get larger and begin to spread. Stages 1, 2, 3, and 4 are further subdivided into categories that explicitly classify the cancer by size and spread of the tumors. Stage 4 is the most advanced form.

Small cell lung cancer tends to grow more quickly.

Small cell lung cancer is known for being fairly aggressive. According to the American Lung Association, SCLC tends to grow and spread faster than NSCLC. By the time it’s diagnosed in about 70% of cases, it’s already spread beyond the lungs to places as far as the brain and bones. It can also metastasize in the liver and adrenal glands.

Both kinds of cancer are known to recur. Some research suggests that 30 to 55% of patients with NSCLC whose tumor is completely removed via surgery will experience a recurrence within five years. But recurrence is far more common with small cell lung cancer. In fact, the majority of people with small cell lung cancer will experience a recurrence–and it’s often within just a year or two. However, new treatments are changing these statistics, and more are being introduced to offer myriad effective options to patients.

Treatment options vary.

You can’t treat these kinds of cancer in the exact same way, but you have a variety of options.

According to the National Cancer Institute, there are six standard treatment options for small cell lung cancer:

  • Chemotherapy

  • Radiation therapy

  • Immunotherapy

  • Laser therapy

  • Surgery to remove the cancer and nearby lymph nodes

  • Endoscopic stent placement

Many patients undergo combinations of treatments for small cell lung cancer.

With non-small cell lung cancer, you have nine types of standard treatment available to you, depending on the type of NSCLC and the stage it’s in:

  • Chemotherapy

  • Radiation therapy

  • Immunotherapy

  • Laser therapy

  • Surgery to remove tumors and possibly also part or all of a lung

  • Targeted therapy, which may include monoclonal antibodies and other agents

  • Photodynamic therapy

  • Cryosurgery

  • Electrocautery

And as with small cell lung cancer, non-small cell lung cancer often warrants combinations of therapies, too, which will vary by type and stage.

Your doctor can talk to you about which options are appropriate for your particular kind (and stage) of cancer.

The five-year survival rates are different.

One question that is surely at the top of mind for anyone diagnosed with lung cancer is “what’s the long-term prognosis for someone like me?”

Of course, it can vary from person to person, depending on your specific type of cancer, your overall health, and how well you respond to treatment.

overall, the five-year survival rates are higher for people with non-small cell lung cancer than they are for people with small cell lung cancer.

The overall five-year survival rate for NSCLC is 25%, according to the American Society of Clinical Oncology. If you have non-small cell lung cancer that hasn’t spread beyond your lungs, you’re looking at an overall five-year survival rage of 63%. Even if the cancer has spread to nearby areas, the five-year survival rate is still 35%. It drops to 7% when the cancer has metastasized in other parts of your body.

By comparison, the overall five-year survival rate for SCLC is 7%. It is a bit higher for people with localized small cell lung cancer that hasn’t begun to spread beyond the lung: about 27%. It drops to 16% for regionalized cases and 3% for people whose small cell lung cancer has metastasized to distant parts of their bodies. Keep in mind: five-year survival rates are determined based on people who received treatment at least five years ago. Newer therapies for both SCLC and NSCLC are changing the outlook for many people with these types of cancer, and every patient is different.

“Small Cell vs. Non-Small Cell Lung Cancer: What's the Difference?” CNN, Cable News Network, 3 Dec. 2021, https://healthguides.cnn.com/treating-early-lung-cancer/small-cell-vs-non-small-cell-lung-cancer-whats-the-difference?did=t1_rss7. 

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