What is Stage 4 Lung cancer

Stage 4 lung cancer, the most advanced stage of lung cancer, in which cancer metastasizes from its point of origin to other body tissues or organs.

A tumor spreads to other body parts through lymph nodes or blood vessels. In this way, cancer cells move to other organs like the brain, liver, adrenal gland, and bones. 

Furthermore, since these metastatic tumors originated from lung cancer cells, they are also regarded as lung cancer.

Types of Stage 4 Lung Cancer

The main types of stage 4 lung cancer are non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC).

1. Non-Small Cell Lung Cancer (NSCLC)

About 80-85% of stage 4 lung cancer is non-small cell cancer. In stage 4 lung cancer, non-small cell cancer is metastatic and dispersed beyond the site of origin. 

Based on the extent to which the cancer has spread, it is further classified as 4A and 4B NSCLC.

Stage 4A: In stage 4A, cancer cells spread only to one other area outside its starting point.

Stage 4B: In stage 4B, tumor cells get dispersed to multiple other body organs such as the brain, bones, and liver.

2. Small Cell Lung Cancer (SCLC)

Small cell cancer accounts for approximately 10-15% of all lung cancer. It is more widespread and has a lower survival rate as compared to non-small cell lung cancer.

Furthermore, it is classified as limited or extensive-stage lung cancer based on how widely it spreads.

Symptoms of Stage 4 Lung Cancer

Symptoms can occasionally lead to the discovery of advanced lung cancer. The following symptoms of lung cancer can appear at any stage, though these symptoms become more prominent as the disease advances:

• Persistent cough often, coughing up blood

• Shortness of breath  

• Chest pain or chest infection

• Disturbance in appetite

• Frequent weight loss

• Hoarse voice

• Fatigue or weakness

Symptoms may differ from individual to individual. Furthermore, symptoms also vary depending on the location of lung cancer in the body. 

Lung cancer symptoms can vary based on the spot of occurrence. This includes;

• Joint swelling and pain are common symptoms if lung cancer spreads to the bones. 

• Nausea, jaundice, and bloating can occur if lung cancer spreads to the liver.

• Vision loss, headaches, or even seizures are the most common symptoms if lung cancer spreads to the brain. 

Stage 4 Lung Cancer Testing 

Healthcare providers use various testing and scanning procedures to diagnose lung cancer. The most commonly used methods for diagnosing lung cancer include;

1. Magnetic Resonance Imaging (MRI): To find out if lung cancer has spread to other parts of the body, like the liver or brain, an MRI scan is performed on the body.

2. Computed Tomography (CT) Scans: Like MRI, CT scans also determine where the cancer cells are located in the body. In addition, CT scans provide us with information about the tumor size.

3. Biopsy: A biopsy involves removing a small sample of tissue and examining it for tumor cells. Thus, it offers a reliable method for determining cancer.

Treatment Options for Stage 4 Lung Cancer

Treating advanced-stage lung cancer that has metastasized is very challenging.  Even in some cases, treatment seems to be working. However, some cancer cells may remain because the tumor cells are continuously spreading. 

Therefore, the goal of treatment for stage 4 lung cancer is to reduce symptoms and stop the disease from spreading. Treatment options may include;

1. Surgery: Cancer cells can be surgically removed. But whether it works, depends on the patient’s age, physical fitness, type, stage, and size of the tumor.

2. Chemotherapy: In chemotherapy, anti-cancer medications or drugs are used to prevent the rapid growth of tumor cells. Sometimes, systemic chemotherapy is given, delivering the drug via blood. However, regional chemotherapy is used to target specific organs.

3. Immunotherapy: Immunotherapy aims to increase your immune system's sensitivity to foreign substances, like tumor cells. Thus, it involves boosting a person’s immune system to detect and destroy cancer cells. 

4. Radiotherapy: Using high-energy X-rays cancer cells are killed or destroyed. It is primarily used to reduce the tumor size before surgery and is frequently used to eradicate any cancer cells that may remain after surgery.

Stage 4 Lung Cancer Survival Rate

As lung cancer advances, it becomes more dangerous and challenging to treat. All types of metastatic lung cancer typically have low survival rates.

A five-year relative survival rate indicates the probability of a person surviving for at least five years with lung cancer following the diagnosis compared to those without cancer.

• Metastatic Non-Small Cell Lung Cancer (Stage 4)

The five-year relative survival rate with stage 4 NSCLC, for regionally dispersed cancer, is about 37% and if spreads to distant organs, then the survival rate is almost 8% 

• Metastatic Small Cell Lung Cancer (Stage 4)

If the cancer has dispersed regionally, the five-year relative survival rate with stage 4 SCLC is 18%. In cases where lung cancer is widespread, the survival rate is roughly 3%.

Conclusion

Stage 4 lung cancer, is the most advanced form of the disease. Thus, it presents significant treatment challenges due to its widespread metastasis. Cancer cells spread to other body organs, such as the brain, liver, or even glands, making treatment more complex.

The lower survival rate for stage 4 lung cancer, highlights the importance of early detection. Awareness about the symptoms and types of lung cancer helps in an early diagnosis, hence more successful treatment can be achieved.