Stage 4 Lung Cancer Life Expectancy

7 Factors That Can Influence Survival Times

In This Article

If you or a loved one has been diagnosed with stage 4 non-small cell lung cancer, one of the first questions that may come to mind is, "What is the life expectancy?" As the most advanced stage of the disease—in which cancer has spread (metastasized) from the primary tumor to distant organs—stage IV lung cancer has a median survival time of around four months. This means that 50% of people with stage 4 cancer will still be alive four months after their diagnosis. Many will live for months and even years longer.

As distressing as this statistic may be, it is important to remember that stage 4 lung cancer has no set course. Multiple factors can influence survival times, some of which (like smoking) are modifiable. Newer targeted therapies and immunotherapies are also helping people with stage IV cancer live longer with fewer side effects and a better quality of life.

Lung Cancer Staging

Lung cancer is staged to classify the severity of the disease. The staging of non-small cell lung cancer (NSCLC) helps doctors choose the most appropriate course of treatment based on the likely outcome, referred to as the 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, stage 4 NSCLC was broken down into two substages with the release of the new TNM classification system in 2018.

  • Stage 4a lung cancer, in which cancer has spread within the chest and/or has spread to one area outside of the chest
  • Stage 4b lung cancer, in which cancer has spread to multiple places in one or more distant organs, such as the brain, adrenal gland, bone, liver, or distant lymph nodes.

Stage 4 lung cancer is incurable. Treatments, therefore, are focused on slowing the progression of the disease, minimizing symptoms, and maintaining an optimal quality of life.

Stage 4 Survival Statistics

Stage 4 lung cancer life expectancy is typically measured using five-year survival rates, which estimates 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. The first approach is based on the TNM stage in which statistical survival times are matched to the stage of the disease.

5-Year Survival Rates by TNM Stage
Lung Cancer Stage 5-Year Survival Rate
IVa 10%
IVb Less than 1%

By contrast, the one-year survival rate for stage 4 lung cancer is between 15% and 19%, meaning that 15% to 19% of people with metastatic disease will live for at least a year.

lung cancer survival rates
Illustration by Hetal Rathod, Verywell

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: Metastasic cancer

Under the SEER classification system, "distant" disease and stage 4 cancer are synonymous.

The one drawback to the SEER approach is that stage 4a and 4b lung cancer are melded into one category. This generalized approach not only returns a much lower five-year survival estimate (5.8%) but fails to reflect the wide variability in stage 4 survival rates, particularly in people with limited metastases.

SEER 5-Year Survival Rates
Stage at Diagnosis Percent (%) Surviving
Localized 59%
Regional 31.7%
Distant 5.8%
Unstaged 8.3%

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 which are fixed (non-modifiable) and others of which can be changed (modifiable).

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

variables that affect stage 4 lung cancer survival
Illustration by Emily Roberts, Verywell

Age

Older age is linked to poorer outcomes in people with lung cancer irrespective of the 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 temper tumor growth.

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

5-Year Survival Rate by Age Group
Stage at Diagnosis Under 50 Ages 50-64 65 and Over
Localized 83.7% 67.4% 54.6%
Regional 47.7% 36.6% 28.3%
Distant 11% 7% 4.7%
Unstaged 32.1% 15.4% 6%

Based on SEER data, the five-year survival rate for people with stage 4 lung cancer is 11% for those under 50, dropping to 4.7% 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- and 10-year survival rates in women and men.

Lung Cancer Survival Rates by Sex
Sex 5-Year Survival Rate 10-Year Survival Rate
Women 19% 11.3%
Men 13.8% 7.6%
Overall 16.2% 9.5%

With respect to stage 4 NSCLC specifically, men are also at a genetic disadvantage. Compared to women, men are less likely to have "treatable" gene mutations responsive to newer targeted therapies used for stage 4 disease.

As a result, men prescribed drugs like Keytruda (pembrolizumab) tend to have lower overall and progression-free survival than women.

Performance Status

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

There are several ways that PS is measured, the most common of which is called the Eastern Cooperative Oncology Group (ECOG) PS Score that 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 higher PS will survive longer than those with a lower PS.

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

Lung Cancer Survival by Performance Status
Performance Status 5-Year Survival Rates Median Overall Survival
0 45.9% 51.5 months
1 18.7% 15.4 months
2 5.8% 6.7 months
3 0% 3.9 months
4 0% 2.4 months
5 Not applicable Not applicable

Among people with stage 4 lung cancer. an ECOG score of 0 translates to no less than an 11-fold increase in six-month survival rates compared to an ECOG score of 4, says to a 2015 study published in PLoS One.

Smoking Status

It is never too late to stop smoking. Even among people with stage 4 lung cancer, quitting cigarettes prior to the start of chemotherapy can increase survival times 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 who have poor performance status and advanced stage 4b disease. The decision to quit is ultimately a personal one, but something that should always be discussed prior to the start of cancer treatment.

Cancer Type and Location

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, which accounts for 25% to 30% of lung cancer case 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 the other types

These characteristics can influence survival times in people with stage 4 NSCLC. Moreover, the location of the tumor—whether in the airways (as with bronchioloalveolar adenocarcinoma) or in lung tissues themselves—can make a big difference in how long a person survives.

Survival Rates by Stage IV NSCLC Type
Cancer Type 1-Year Survival Rate 5-Year Survival Rate
Bronchioloalveolar adenocarcinoma 29.1% 4.4%
Non-bronchioloalveolar adenocarcinoma 18% 1.5%
Squamous cell lung carcinoma 14.6% 1.6%
Large cell lung carcinoma 12.8% 1.1%

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 comorbidity not only complicates lung cancer treatment but significantly impacts survival times.

Overall, the most common comorbidities in people with lung cancer are chronic obstructive pulmonary disease (COPD), diabetes, and congestive heart failure (CHF).

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

Stage 4 NSCLC Comorbidity and Survival
Comorbid Condition Reduction in Overall Survival
Congestive heart failure Reduction of 19%
Cerebrovascular diseases (such as stroke,
aneurysm, or vascular malformation)
Reduction of 27%

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 Xalkora in first-line therapy along with chemotherapy drugs.

According to the research, the median survival time for people treated with Xalkori was 6.8 years, meaning that 50% were still alive by 6.8 years. By contrast, only 2% of those not on Xalkori were still alive after five years.

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).

A Word From Verywell

As distressing as the diagnosis of stage 4 lung cancer can be, 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.

Don't 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. They are more likely to be on top of the current research and treatment strategies.

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