Understanding lung cancer staging and survival

Lung cancer is by far the leading cause of cancer-related death in the U.S. It claims more lives annually than breast, colon and prostate cancers combined. About 356 people die of the disease every day. 

What makes lung cancer so deadly is that the related symptoms don’t usually occur until the cancer has reached an advanced stage. But when detected early, outcomes are better because the disease is in its initial stages and easier to cure. 

Experts agree the greatest risk factor for lung cancer is smoking. However, there are other causes, such as exposure to second-hand smoke, radon and air pollution.

A low-dose (CT) lung scan, a relatively easy imaging test, is the best screening method for early detection. And research shows that by screening high-risk individuals, there’s potential to dramatically improve survival rates.  

Types of lung cancer 

According to Dr. Igor Medic, a board-certified oncologist and hematologist affiliated with the David & Donna Long Cancer Center at Sharp Grossmont Hospital, the two most common types of lung cancer are non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). “Differentiating between the two is based on histologic, or tumor tissue, examination,” he says.

One of the primary differences between NSCLC and SCLC is the way the cells appear under a microscope. SCLC cells are smaller and rounder than cancer cells in NSCLC. SCLC also typically grows faster than NSCLC and often spreads to the lymph nodes.

“Given the marked differences in biologic behavior, natural history and response to treatment, this distinction is required for proper staging, treatment and prognosis,” Dr. Medic says.

NSCLC accounts for about 80% to 85% of all lung cancers, and 10% to 15% are SCLC. Both are serious conditions, but SCLC is more aggressive. 

The TNM system 

To classify the various stages of lung cancer, doctors use the TNM system.

• T stands for tumor size and location in the lungs.

• N stands for node and whether cancer has spread to lymph nodes near the lungs. Lymph nodes are small bean-shaped glands found throughout your body, which are part of your immune system and the first line of defense against bacteria or viruses that make you sick.

• M stands for metastasis, or whether the cancer has traveled and spread to other organs or areas of the body. 

“The TNM staging system for lung cancer is an internationally accepted system used to characterize the extent of disease,” says Dr. Medic. “It also provides a description of the extent of lung cancer that can easily be communicated to others, assists in treatment decisions, and serves as a prognostic indicator.”

Doctors use these letters and then get more specific with the numbers I through IV. The higher the number, the bigger the tumor and amount it has spread.

Staging non-small cell lung cancer  

“In general, there are four stages for NSCLC, 1 through 4,” says Dr. Medic. “Stage 1 has the best prognosis, and stage 4 is the most advanced disease — metastatic — meaning the cancer has spread.” 

• Stage 1 and 2: These patients have early-stage disease. Usually, surgical resection offers the best opportunity for cure.

• Stage 3: This stage typically represents tumor masses have spread to surrounding lymph nodes. Surgical resection and chemoradiotherapy, a combination of both chemotherapy and radiation therapy, is the preferred treatment for those with more extensive disease.  

• Stage 4: By contrast, stage 4 patients have advanced disease. The primary lung cancer has traveled to distant organs, such as the liver, bones or other areas. It’s managed with palliative care, which helps provide relief from the symptoms of the illness and can significantly improve a patient’s quality of life.

Staging small-cell lung cancer  

Usually, SCLC is staged into two categories, extensive and limited stages.

For patients with extensive-stage SCLC, Dr. Medic says chemotherapy and immunotherapy are important components of treatment, because SCLC has spread in almost all patients. For individuals with limited-stage disease, thoracic radiation therapy (high-precision radiation therapy to the chest) in combination with chemotherapy are treatment options. 

Surviving lung cancer 

According to the American Lung Association, lung cancer has one of the lowest survival rates because cases are often diagnosed at a later stage. The national average of people alive five years after a lung cancer diagnosis is 25%.

However, it’s important to keep in mind that this is an average. Everyone is different. Your prognosis, or chances of recovery, also depend on how early or late your lung cancer was detected, your overall health and other factors.

Dr. Medic is optimistic about the future, citing incredible advancements in lung cancer therapy just in the last 10 years.

“Even though this is still a very serious disease, with recent advancements in therapy and with our expanded knowledge of the lung cancer genetic landscape, I dare to say that patients with advanced lung cancer have a significantly better prognosis,” he says. “With frequent use of immunotherapy, and agents that target specific genetic mutations in the tumor, we are now seeing more long-term responses with excellent quality of life for patients.”

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