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).
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 attaches to the bronchus). 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.
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.
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)
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.
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.
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%.
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.
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.
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.
With stage 3 NSCLC specifically, women have a five-year survival rate of 13.7% compared to 11.6% in men—a 2% difference.
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.
These characteristics generally influence the treatment response rate and survival times in people with NSCLC.
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.
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.
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.
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.
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.
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.
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