Understanding Lung Cancer: Different Stages & Survival Rates

Cancer is a disease where abnormal cells divide uncontrollably and destroy different body tissues. The cells spread from one organ to other body parts by metastasis. When cancer develops in the lung, it is referred to as lung cancer which mostly affects people who smoke. However, non-smokers can also develop lung cancer which can be classified into 4 main types :

1. Small cell lung cancer (SCLC)

2. Non-small cell lung cancer(NSCLC)

3. Lung nodules

4. Mesothelioma
   
   

NSCLC is the most common type of lung cancer that begins at the cellular level and gradually causes abnormal lung cell growth with symptoms like persistent cough and shortness of breath. 

However, SCLC is the most aggressive form that originates in breathing tubes or bronchi and further spreads to healthy body parts. This mostly affects smokers causing symptoms like cough, chest pain, bloody phlegm and shortness of breath.

Importance of Understanding Survival Rates

Lung cancer survival rates are usually much lower than cancer in other organs like breast, colorectal or prostate. According to reports, the five-year survival rate for lung cancer is nearly 56-60% for cases detected when the disease is still confined within the lungs. 

However, early diagnosis occurs in only 16 % of lung cancer-affected patients while the rest are diagnosed later when the cancer has become metastatic, thus reducing the survival rate to 5 %. 

Due to such failure of diagnosis, more than 50 % of patients with lung cancer die within one year of being diagnosed.

Explanation of Different Stages of Lung Cancer

Lung cancer can be divided into the following stages:

1. Occult Stage: This is the primary or initial stage when cancer cells are found in the mucus of the cough. However, the tumour cannot be seen on biopsy or imaging scans and thus this stage is called hidden cancer.

2. Stage 0: At this stage, the tumour is very small and cancer has not spread to deeper lung tissues or outside the lungs.

3. Stage 1: Cancer is in the lung tissues but not the lymph nodes near the lungs.

4. Stage 2: The disease may have spread to the lymph nodes near the lungs.

5. Stage 3: The disease has spread to the lymph nodes and middle of the chest.

6. Stage 4: Cancer has spread to distant body parts like bones, liver or brains by metastasis.
   
   

Stage 1 Lung Cancer Survival Rates

Stage 1 is the earliest stage of the disease and thus lung cancer survival rates of patients at this stage are quite promising.  Current statistics suggest that 70-90% of the people detected with stage 1 lung cancer can expect to live for at least 5 years or more following diagnosis. Additionally, recently developed therapies are enhancing the likelihood of longer survival in patients.

There are different strategies to calculate survival rates. Some scientists estimate survival rates based on the stage of the disease that uses the TNM classification system, i.e. the extent of the main tumour (T), the number of nearby lymph nodes affected (N) and whether cancer metastasized to different organs. 

While other scientists calculate survival rates based on the extent of disease progression i.e. whether cancer is localised (restricted in lungs), regional (spread in nearby lymph nodes) or distant (metastasized).

Overall Survival Rate

Lung cancer affects the older population mostly (people aged over 65). However, people of all ages can be affected by their immune health. The overall survival rate at this stage is nearly 60-90%.

Five-Year Survival Rate

The five-year survival rate of patients in stage-1 can be grouped based on age as follows:

1. Under 50 years - 83.7%

2. 50-64 years: 67.4%

3. 65 and older:54.6%
   
   

Stage 2 Lung Cancer Survival Rates

Stage 2 is an intermediate stage in which the malignancy has begun to extend or spread from the primary tumour site to the surrounding tissues and is still highly treatable. Certain factors positively impact the survival rate, and thus making those lifestyle changes can augment the chance of disease-free survival.

According to recent reports, the survival rate of Stage 2 lung cancer patients is nearly 53-60%. However, this rate may vary based on a person's lifestyle changes and immune health. 

Overall Survival Rate

The survival rate of people with Stage 2 lung cancer ranges from 50-80%, with men more likely to get affected and die than women. Women have a survival rate of 60% or more, which drops to 50% in men.

Five-Year Survival Rate

The five-year survival rate of patients in stage-2 can be classified based on age and extent of disease progression as follows:

Stage 3 Lung Cancer Survival Rates

Stage 3 is the last stage before metastasis. Cancer has already reached the nearby tissues and lymph nodes at this stage and is thus referred to as locally advanced or advanced stage based on its subtypes. 

This stage demands immediate treatment, like surgery to remove the tumour followed by chemotherapy and radiation. The life expectancy and survival rate at this stage is nearly 36%. However, this can decrease up to 26% or as low as 1% depending on the disease progression.

Overall Survival Rate

The overall survival rate of Stage 3 lung cancer differs on the basis of subcategories of its stages which are stage 3A, 3B or 3C. It also depends on the patient's overall health and response to treatments.

Five-Year Survival Rate

According to reports, one in three people diagnosed with stage 3A (locally advanced stage) lung cancer can live for at least 5 years post-diagnosis. Thus the survival rate is 36% at this stage. 

For stage 3B (advanced), the average lung cancer survival rate is nearly 26%, which drops to 13% for stage 3C.

Stage 4 Lung Cancer Survival Rates

4th stage lung cancer is the last stage, where cancer has already spread to different areas of the other lung, fluid surrounding it and other distant body parts via the bloodstream. Patients face numerous emotional anxieties along with headaches, dizziness, muscle weakness and other symptoms. 

The stage 4 lung cancer survival rate is very less among the population. Nearly 8% of people survive for 5 years post-diagnosis if proper treatments are given and the body responds promptly.

Overall Survival Rate

The stage 4 lung cancer survival rate ranges from 3-8% in people due to higher cancer spread in different body parts and thus less chance of recovery.

Five-Year Survival Rate

The five-year survival rate for this stage can be classified based on the two cancer types that affect the lungs. People with distant non-small cell lung cancer have a 5-year survival rate of 8%. While people having distant small cell lung cancer have a survival rate of 3%.

Factors Influencing Survival Rates in Lung Cancer

Many factors influence the survival rates of lung cancer. These are briefly mentioned below:

Age and General Health of the Patient

Many studies have found that older people have less chance of survival than younger ones due to poor immune health and the ability to withstand chemotherapy and other treatments.

Smoking History and Exposure to Carcinogens

Smoking increases the likelihood of cancer incidence and progression. Quitting smoking and less exposure to carcinogens (cancer-causing substances) increases the chance of survival in cancer patients.

Genetic Factors and Biomarkers

Several genetic mutations may lead to cancer in people. According to reports, epidermal growth factor receptor (EGFR) gene mutation may lead to lung cancer in women and non-smokers. Mutations in different microRNAs can also lead to lung cancer. However, targeted drug therapies can effectively treat EGFR and other gene mutations, thus enhancing survival rates.

Treatment Approaches and Advancements

Recent discoveries of advanced treatments make it much easier to curb cancer progression. However, the survival rate depends upon the ability of a person to respond to the cancer treatment. If a person can respond well, there is a higher chance of survival.

Supportive Care and Multidisciplinary Treatment

In hospitals, supportive care is provided by a multidisciplinary team of specialists who plan the treatment suitable for the patient. The team includes a surgeon who specialises in lung cancer and an oncologist who specialises in radiotherapy, chemotherapy and targeted therapies. 

Their decision can help a patient get the best treatment and thus increase the survival rate.

Importance of Early Detection and Screening

Early detection is necessary in any type of lung cancer to prevent metastasis and cancer spread.

Benefits of Early Lung Cancer Detection

The benefits of early detection are:

1. Better treatment outcomes.

2. Prevention of disease progression or metastasis

3. Reduction of the risk of complications

4. Better long-term health

Screening Methods and Guidelines

The only recommended screening method for lung cancer is low-dose computed tomography (also called a low-dose CT scan, or LDCT). During an LDCT scan, an X-ray machine uses a low dose (amount) of radiation to make detailed images of the lungs. The scan takes a few minutes and is not painful. Yearly lung cancer screening with LDCT is recommended for people who:

1. Smokes for the past 20 years

2. Smokes now or has quit smoking within the past 15 years

3. Are between 50 and 80 years old.

Role of Imaging Techniques and Biomarkers

Imaging techniques for lung cancer are chest X-ray, MRI, CT scan, biopsy and sputum cytology. These tests help to understand the area and extent of cancer progression; thus, treatments can be provided accordingly.

On the other hand, biomarker testing identifies genes, proteins and other substances that can provide information about cancer. A large number of genetic alterations are associated with lung cancer and these tests help to understand the genomic profile of the unique tumour briefly.

Early Intervention and Treatment Options

Treatment options mainly include surgery when cancer is restricted to a particular place. But if it has started spreading and the tumour is large, chemotherapy or radiation therapy is used to kill the malignant cells before surgery.

Conclusion

Lung cancer is one of the most common and serious types of cancer with no signs and symptoms in the early stages. Many people are diagnosed with the condition every year and the survival rate is almost 56% for cases detected when the cancer is still localized. 

Additionally, age, overall health, sex, and smoking habits can impact the overall survival rate in patients. However, recent advances in treatment are being made every day and survival rates are increasing.

Frequently Asked Questions 

How do Tumor Size and Location Impact Survival Rates?

Tumour size significantly affects survival rates. A study showed that the survival rate was nearly 81.4% for patients with tumour size less than or equal to 2 cm, while it is 63.2 % in those with tumours larger than 2 cm. The location of the cancer is also important as when cancer spreads more or becomes metastatic, the survival rate automatically decreases.

Does Histological Type Affect the Prognosis of Lung Cancer?

Small cell lung cancer, which is typically caused due to tobacco smoking, is the most aggressive form of lung cancer. Thus histological type can affect the severity of lung cancer.

What Advancements in Treatment have Positively Influenced Survival Rates?

1. The CyberKnife System is a recently discovered radiation therapy routinely used to treat lung cancers and metastasis.

2. Atezolizumab is an approved immune checkpoint inhibitor effectively used to treat non-small cell lung cancer cells post-surgery.

3. In 2023, the FDA approved pembrolizumab as an adjuvant treatment and platinum-based chemotherapy for treating Stage 3 lung cancer.

How Does a Patient's Age and Overall Health Affect Survival Rates?

The survival rate for patients with younger age and good overall health is much higher than patients above 65 as their immune system is compromised and the body loses its ability to adapt to severe treatments. 

What Role Does Lymph Node Involvement Play in Lung Cancer Survival?

When cancer spreads to lymph nodes, it is easier for them to metastasize to different organs through lymph and blood and form tumours in distant parts. This causes a reduction in the survival rate in patients.