6 Factors That Can Influence Survival Times

By Lynne Eldridge, MD 

Updated on August 15, 2023

 Medically reviewed by Brian Bezack, DO

There are varying five-year survival rates for stage 3 non-small cell lung cancer (NSCLC), ranging from as high as 33% to as low as 13%.¹ This advanced stage of the disease, in which the primary tumor has begun to invade nearby lymph nodes or structures, is sometimes—but not always—able to be treated with surgery. This plays a significant role in stage 3 lung cancer life expectancy.

Still, there are many variables that can influence survival times. Some are out of your control, but others (like smoking) are modifiable and can increase life expectancy dramatically. By understanding the factors that influence lung cancer survival, you can make informed choices about your health if you are diagnosed with stage 3 NSCLC.

Characteristics of Stage 3 Lung Cancers

Lung cancer staging is primarily used to direct the appropriate course of treatment and predict likely outcome (known as the prognosis).

The staging of non-small cell lung cancer (NSCLC) involves the TNM classification system, which categorizes the disease based on the tumor's size and extent (T), whether lymph nodes are affected (N), and whether cancer has spread, or metastasized, to distant organs (M).²

Stage 3 NSCLC is further divided into three substages:

• Stage 3a lung cancer is classified as locally advanced disease. This means that cancer has spread to lymph nodes on the same side of the lung as the primary tumor. Cancer may also be found in the bronchus, pleura, diaphragm, chest wall, breastbone, backbone, phrenic nerve, pericardium, vena cava, aorta, pharynx, trachea, esophagus, and/or carina (the area where the trachea branches into the bronchi).

• Stage 3b lung cancer is classified as advanced disease. It means that cancer has spread to the opposite side of the chest or to supraclavicular lymph nodes located above the collarbone. Additional tumors may also be found in the same area as the primary tumor.

• Stage 3c lung cancer is considered a progression of stage 3b, with the addition of one or more tumors on the same or separate lobe of the lung. (There are three lobes on the right lung and two on the left.) Cancer may also be found in the same area as the primary tumor.³

Stage 3a

Can often be treated with surgery in much the same way as stage 1 and stage 2 lung cancer, albeit with a greater risk of recurrence³

Stages 3b and 3c

Considered inoperable and are primarily treated with chemotherapy and radiation therapy

Stage 3 Survival Statistics

Life expectancy in people with cancer is typically described in five-year survival rates, defined as the percentage of people who live for at least five years following their diagnosis. Many can live for far longer than this.

The methods by which five-year survival rates are calculated can vary. Some scientists base their estimates on the TNM stage, while others do so based on the extent of the disease in the body. Both methods have their benefits and drawbacks.

Survival Rates by TNM Stage

The current five-year estimates based on the TNM staging system were updated in 2018 with the introduction of the stage 3c classification.¹

While the TNM approach provides a generalized overview of survival times, there is wide variation in how stage 3 lung cancers can progress and are treated. Some basic factors—like the location of the tumor and the degree of airway obstruction—can significantly impact survival times and are not reflected in a system like this.

There is also considerable overlap in the diagnostic criteria. Comparatively, stage 2b and stage 3a lung cancers have similar features and treatment approaches, as do stage 3b and stage 4a lung cancers.

Survival Rates by Disease Extent

To better address the wide variability of lung cancer in all of its stages, the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) Program took a simpler approach, basing survival rates on the progression of the disease rather than the stage.

Under the SEER system, survival rates are based on the extent of the disease in the body, irrespective of the type. Instead of multiple categories and subcategories, there are only the following three.

• Localized: Cancer that is limited to lung tissue only

• Regional: Cancer that has spread to nearby lymph nodes or structures

• Distant: Cancer that has spread to distant organs (metastatic disease)⁴

Under the SEER classification system, stage 3 NSCLC is regarded as regional disease with a five-year survival rate of 31.7%.

One of the drawbacks of the SEER classification system is, again, the overlap of definitions. Stage 3 lung cancer, for example, with a 13% five-year survival rate, falls into the same regional category as stage 2b, even though the latter has a 53% five-year survival rate—a difference of nearly 40%.¹

 How Non-Small Cell Lung Cancer Is Treated

Factors Influencing Survival Rates

Lung cancer is different for everyone. There is no one set course, and survival rates can only provide a rough estimate of the likely outcome. Multiple factors can influence life expectancy, some of which are modifiable and others that are inherent and non-modifiable.

There are six factors known to influence survival rates in people with stage 3 lung cancer.

Age

Lung cancer survival rates in general tend to decrease the older you get. Although the average age of diagnosis is 70, a significant number of people are diagnosed in their 60s, 50s, and even younger.⁵

Not only are people over 70 more likely to be in poorer health, but their immune system will generally be less responsive and less able to temper the growth of cancerous tumors.⁶

In people with regional NSCLC specifically, being 65 or older decreases five-year survival rates by nearly 20% compared to a matched set of adults under 50.⁴

 Treating Lung Cancer in Older Adults

Smoking Status

Smoking affects every stage of lung cancer, from the onset of the disease to the overall survival times. By contrast, the benefits of quitting cigarettes don't only extend to people with early-stage lung cancer but also to those with advanced stage 3 and stage 4 disease.

Studies have shown that smoking not only reduces the response rates to cancer therapy compared to quitting (45% vs. 75%, respectively) but also cuts the two-year survival rates by 41%.⁷

In people with stage 3 NSCLC specifically, heavy smoking (defined as more than 60 pack-years) after the diagnosis decreases the probability of survival by almost 30% compared to quitting.⁸

 10 Reasons to Quit Smoking After Getting Cancer

Sex

Male sex is considered an independent indicator of poorer outcomes in people with lung cancer in general. According to a 2018 study in ESMO Open, women have a 27% decreased risk of death due to NSCLC compared to a matched set of men with the same type of lung cancer.⁹

This is reflected in research from the United Kingdom in which women are approximately 4% more likely to survive for 10 years with lung cancer than men.¹⁰

With stage 3 NSCLC specifically, women have a five-year survival rate of 13.7% compared to 11.6% in men—a 2% difference.¹¹

 How Lung Cancer Differs in Women and Men

Type of Lung Cancer

There are many different types and subtypes of NSCLC, some of which are more aggressive than others. The following types are the three most common.

• Lung adenocarcinoma: The most common type, mainly affecting the outer edges of the lung.

• Squamous cell lung carcinoma: The second most common type, which primarily occurs in the airways of the lung.

• Large cell lung carcinoma: A rare and typically aggressive form that can develop in any part of the lung.¹²

These characteristics generally influence the treatment response rate and survival times in people with NSCLC.¹³

With stage 3 NSCLC specifically, the median survival time for people lung adenocarcinoma is 30 months, and 18 months in those with squamous cell carcinoma, according to a 2016 study in the Asian Pacific Journal of Cancer Prevention.¹⁴

Comorbidities

Comorbidity is a term used to describe co-occurring illnesses. In people with lung cancer, the likelihood of a comorbid condition is high; diabetes, chronic obstructive pulmonary disease, and congestive heart failure are the most common additional diagnoses.¹⁵

A 2015 study from the University of Nebraska reported that 73% of the 5,683 participants with lung cancer had a comorbid illness. Of these, three comorbidities were linked to decreased overall survival in people with regional (stage 3b to stage 3c) disease.¹⁵

Type of Surgery

Lung cancer surgery is indicated only for stage 3a NSCLC. Even so, there is a high risk of recurrence following stage 3 lung cancer surgery, which decreases survival times.

According to 2014 research publishing in Oncology Letters, the median survival time for people with post-surgical recurrence (for all stages) is 21.9 months. For people with stage 3 disease, no less than 33.9% experienced a cancer recurrence.¹⁶

For people undergoing surgery for stage 3a NSCLC, a pre-operative course of chemotherapy (called neoadjuvant chemotherapy) can improve survival times, in part by lowering the risk of lung cancer recurrence.¹⁷

The choice of surgery can also influence survival times. The use of lobectomy (in which a lobe of a lung is removed) tends to afford longer survival times than a pneumonectomy (in which an entire lung is removed).

When used with neoadjuvant chemotherapy, lobectomy is associated with a 33% five-year survival rate in people with stage 3a lung cancer. By contrast, pneumonectomy with neoadjuvant chemotherapy translates to a 20.7% five-year survival rate.¹⁷

 Quality of Life After Lung Cancer Surgery

A Word From Verywell

A stage 3 lung cancer diagnosis can be daunting, but the fact that it is "advanced" does not mean it is untreatable. Certain stage 3 lung cancers can be cured, and others can be effectively be managed with longer progression-free survival time than ever before.

If you are diagnosed with stage 3 lung cancer, try not to focus on survival rates. These statistics are based on people of different ages, some of whom are in good health and others of whom are not. Instead, focus on factors that can improve your chances of survival, including smoking cessation, proper nutrition, and exercise.

The stronger and more fit you are, the more likely you are to tolerate treatment and maintain a good quality of life.

FREQUENTLY ASKED QUESTIONS

What determines the life expectancy of stage three lung cancer?

The life expectancy of a person with stage three lung cancer is influenced by multiple factors, such as how far the cancer has spread to other areas in the body. Removal of a primary tumor before it can spread far will greatly improve life expectancy. Age, sex, type of lung cancer, and smoking status can also affect life expectancy.

What is stage three lung cancer?

Stage three lung cancer is identified by cancerous cells that have spread to areas surrounding the primary tumor. There are three substages, separated into 3A, 3B, and 3C that offer specific information about the severity and reach of the cancer.

What is small cell lung cancer?

Small cell lung cancer (SCLC) is an aggressive type of lung cancer that often spreads quickly. Most cases of SCLC are caused by smoking cigarettes. Symptoms can include chest pain, cough, bloody phlegm, appetite loss, weight loss, shortness of breath, wheezing, and more.¹⁸