Stage 4 Lung Cancer Life Expectancy

Questions about life expectancy are often the first ones asked when someone is diagnosed with stage 4 non-small cell lung cancer (NSCLC). This is the most advanced stage of the disease in which cancer has spread (metastasized) from the primary tumor to distant organs.

The median survival time for those with stage 4 lung cancer is around four months. That means that 50% of patients will still be alive four months after their diagnosis.

As distressing as this statistic may be, it is important to remember that stage 4 lung cancer has no set course. Many will live for months and even years longer than this.

Multiple factors can influence survival times, some of which (like smoking) are modifiable. Newer targeted therapies and immunotherapies are also helping people with stage 4 cancer live longer with fewer side effects and a better quality of life.

This article discusses stage 4 lung cancer life expectancy and what factors may influence the outcome of a diagnosis.

Characteristics of Stage 4 Lung Cancers

Lung cancer is staged to classify the severity of the disease. The staging of NSCLC helps doctors choose the most appropriate course of treatment based on the likely outcome or prognosis.

The stage of lung cancer is determined using the TNM classification system, which categorizes the severity of the disease based on three conditions:

• The size and extent of the primary tumor (T)
• Whether nearby lymph nodes have cancer cells in them (N)
• Whether distant metastasis has occurred (M)

With stage 4 lung cancer, all three of these conditions will have occurred. With that said, the extent of metastasis can vary along with the prognosis.

For this reason, the 2018-released TNM classification system broke down stage 4 NSCLC into two substages:

• Stage 4a lung cancer, in which cancer has spread within the chest to the opposite lung; or to the lining around the lungs or the heart; or to the fluid around the lungs or heart (malignant effusion)
• Stage 4b lung cancer, in which cancer has spread to one or multiple places in one or more distant organs, such as the brain, adrenal gland, bone, liver, or distant lymph nodes

Stage 4 Survival Statistics

Stage 4 lung cancer life expectancy is typically gauged using five-year survival rates. These estimate the percentage of people who will live for at least five years following the initial diagnosis.

Epidemiologists classify five-year survival rates in one of two ways.

Survival Rates by TNM Stage

The first approach is based on the TNM stage. Statistical survival times are matched to the stage of the disease.

By contrast, the one-year survival rate for stage 4 lung cancer was reported in one study to be between 15% and 19%. This means this portion of patients with metastatic disease lived for at least a year.

Survival Rates by Disease Extent

A second method estimates survival rates based on the extent of cancer in the body. This is the approach used by the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) Program. The SEER system classifies cancer in one of three broader categories:

• Localized: Cancer limited to the lungs
• Regional: Cancer that has spread to nearby lymph nodes or structures
• Distant: Metastatic cancer

The one drawback to the SEER approach is that stage 4a and 4b lung cancer are melded into one category. This generalized approach returns a much lower five-year survival estimate (5.8%). It also fails to reflect the wide variability in stage 4 survival rates, particularly in people with limited metastases.

Factors Influencing Survival Rates

The variability in survival rates highlights one key reality about stage 4 lung cancer: no two people have the same disease. Arguably more than any other stage of the disease, stage 4 lung cancer survival is influenced by multiple factors. Some of these are fixed (non-modifiable) and others can be changed (modifiable).

There are seven factors known to influence survival times in people with stage 4 NSCLC.

Age

Older age is linked to poorer outcomes in people with lung cancer irrespective of their lung cancer stage. This is due to the fact that people over 70 are often in poorer general health and have immune systems that are less able to suppress tumor growth.

Older age not only influences the progression of the disease but survival rates as well. If you are under age 50 at the time of your diagnosis, you are more likely to live for at least five years compared to someone 65 and older.

Based on SEER data, the five-year survival rate for people with stage 4 lung cancer is 14.2% for those under 50. This drops to 5.6% for those 65 and over.

Sex

Male sex is independently associated with poorer outcomes in people with lung cancer in general. Men are not only more likely to get lung cancer than women but are more likely to die as a result of the disease. These factors contribute to the disparity in the overall five-year survival rate in women and men.

Concerning stage 4 NSCLC, the five-year survival rates are 5.6% and 8.6% for men and women, respectively. Research suggests that men are at a genetic disadvantage. Compared to women, men are less likely to have "treatable" gene mutations—those that are responsive to newer targeted therapies used for stage 4 disease.

Interestingly, men prescribed drugs like Keytruda (pembrolizumab) tend to have lower survival overall but higher overall progression-free survival (i.e., the length of time in which the condition does not worsen) than women.

Performance Status

People with stage 4 NSCLC tend to be symptomatic. This doesn't mean, however, that all people will be equally ill or disabled. There can be significant variations in the ability to function in everyday life, which doctors refer to as performance status (PS).

There are several ways that PS is measured. The most common is called the Eastern Cooperative Oncology Group (ECOG) PS Score, which rates PS on a scale of 0 to 5. Under the ECOG system, a score of 0 means that you are fully functional, while a score of 5 indicates death.

Research suggests that around half of all people diagnosed with stage 4 lung cancer will have "good" PS, defined as an ECOG score of 0 to 2. Almost without exception, people with a PS in this range will survive longer than those with a PS of 3 or 4.

Using the ECOG PS Score, lung cancer survival rates and times (for all stages) break down as follows.

Smoking Status

It is never too late to stop smoking. Even among people with stage 4 lung cancer, quitting cigarettes before starting chemotherapy can increase survival time by as much as six months, according to research published in the Brazilian Journal of Pneumonology.

With that said, the consequences of smoking cessation—namely, nicotine withdrawal—may outweigh the benefits in heavy smokers with poor performance status and advanced stage 4 disease.

The decision to quit is ultimately a personal one, but something that should always be discussed prior to the start of cancer treatment.

Location and Type of Lung Cancer

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

• Lung adenocarcinoma, the most common form of the disease that mainly develops in the outer edges of the lungs
• Squamous cell lung carcinoma, accounts for 25% to 30% of lung cancer cases and develops mainly in the airways
• Large cell lung carcinoma, an uncommon type of NSCLC that can develop anywhere in the lungs and tends to be more aggressive than other types

Research shows that the differences between these types influence survival rates. Moreover, the location of the tumor—whether in the airways (as with bronchioloalveolar adenocarcinoma) or in lung tissues themselves—can also have an impact on survivability.

While research on each NSCLC type in stage 4 is limited, survival rates are generally lower than the reported overall five-year survival rates, consistent with previous data reported.

Comorbidity

Roughly three of every four people with advanced lung cancer have another chronic health condition, referred to as a comorbidity. Having one or more comorbidities not only complicates lung cancer treatment but significantly impacts life expectancy.

Overall, some of the most common comorbidities in people with lung cancer include chronic obstructive pulmonary disease, diabetes, and congestive heart failure.

Among people with stage 4 lung cancer specifically, there are two comorbidities that most directly influence survival times.

Genetic Mutations

The treatment of stage 4 NSCLC has evolved dramatically in recent years with the introduction of targeted therapies approved specifically for the treatment of metastatic lung cancer.

Unlike traditional chemotherapy drugs, these medications don't attack all fast-replicating cells. Instead, they recognize and attack cancer cells with specific "treatable" mutations. Because of this, there is less collateral damage to normal cells and fewer side effects.

Not everyone has these genetic mutations, but, if they do, the drugs can significantly improve survival times. The three most common mutations are:

• EGFR mutations, which respond to targeted drugs like Iressa (gefitinib), Tarceva (erlotinib), and Gilotrif (afatinib)
• ALK rearrangements, which respond to Xalkori (crizotinib), Zykadia (ceritinib), and Alecensa (alectinib)
• ROS1 mutations, which also respond to Xalkori (crizotinib) and Zykadia (ceritinib) as well as Lorbrena (lorlatinib) and Rozlytrek (entrectinib)

The effect of these drugs on survival times has been impressive. A 2019 study published in the Journal of Thoracic Oncology followed 110 people with stage 4 NSCLC from 2009 to 2017, each of whom was treated with Xalkori in first-line therapy along with chemotherapy drugs.

Similar results have been seen in people with EGFR or ROS1 mutations, although the effectiveness of treatment can vary considerably by the location of the metastases.

Summary

Stage 4 NSCLC is an advanced form of lung cancer in which cancer has spread from the lungs to distant organs or areas of the body. The median survival time for stage 4 lung cancer is about four months.

Research shows that factors such as age, sex, smoking status, and type of cancer may influence survival rates. But overall, survival rates are improving due to advancements in treatment methods.

A Word From Verywell

Stage 4 lung cancer remains a serious diagnosis, but it is important to remember that it is not the same disease it was just 20 years ago. Survival rates are ever-increasing, and newer medications can now personalize treatment in ways that were once unheard of.

Try not to let survival statistics overwhelm you. Instead, learn as much as you can about your specific cancer and the treatment options available to you.

If you have any doubts about treatment recommendations, do not hesitate to seek a second opinion, ideally from a specialist in one of the 71 National Cancer Institute-designated treatment centers in the United States. Their practitioners are more likely to be on top of the current research and treatment strategies.