Stages of lung cancer describe the phase of the disease at the time of diagnosis.
Accurately determining the stage of lung cancer is critically important for deciding on the appropriate treatment.
The stage of lung cancer is determined based on the following four factors:
1. Size of the cancer. For example, tumors smaller than 4 cm are classified as stage 1, those between 4–7 cm as stage 2, and those larger than 7 cm as stage 3 lung cancer.
2. Whether it has spread to lymph nodes: This assesses whether lung cancer has spread to different groups of lymph nodes. In stage 1 lung cancer, no lymph node involvement is present. However, if cancer has spread to the lymph nodes, the cancer is classified as stage 2 or stage 3, depending on the location of the affected lymph nodes.
3. Spread to tissues and organs near the lung. This refers to the tumor extending into structures such as the ribs, diaphragm, blood vessels, heart, or esophagus, rather than spreading through the bloodstream. If any of these conditions are present, the cancer is classified as stage 3.
4. Metastasis to other organs through the bloodstream. If lung cancer has spread to organs like the bones, brain, adrenal glands, liver, or similar, it is classified as stage 4, regardless of the other factors.
What Is Stage 1 Lung Cancer?
Stage 1 lung cancer is the earliest stage where the cancer is detected in its smallest form. At this stage, the tumor is small, and there is no spread to the lymph nodes or other organs.
Stage 1 lung cancer is often discovered incidentally during a routine check-up or imaging. The tumor is smaller than 5 cm and has not spread to any lymph nodes or other locations. It is the earliest stage of lung cancer. Advanced diagnostic tools (such as PET-CT, brain MRI, EBUS, mediastinoscopy) confirm that there is no lymph node or organ involvement. Treatment outcomes for stage 1 lung cancer are better than for all other stages.
What Is Stage 2 Lung Cancer?
Stage 2 lung cancer refers to cases where the tumor size ranges from 5–7 cm, there is spread to lymph nodes within the lung, or the tumor blocks a bronchus.
What Are the Symptoms of Stage 2 Lung Cancer?
Most patients with stage 2 lung cancer do not experience symptoms. However, due to the tumor causing blockages in the airway, the following symptoms may occur:
- Cough
- Bloody sputum
- Recurring pneumonia
- Other respiratory infections
In addition, unrelated symptoms like fatigue, pain in some parts of the body, or swelling in the legs may be observed.
What Is Stage 3 Lung Cancer?
In stage 3 lung cancer, the tumor size is greater than 7 cm. Additionally, tumors causing blockage of the main bronchus, damage to the pleura or ribs, or spreading to lymph nodes outside the lung (mediastinal lymph nodes) are classified as stage 3.
What Is Stage 3A Lung Cancer?
Stage 3A lung cancer is indicated by any of the following:
- Metastasis to mediastinal lymph nodes on the same side of the lung (e.g., the cancer is in the right lung, and lymph node involvement is also on the right side).
- Cancer spreading to nearby tissues (e.g., tumors larger than 10 cm or spreading to the main bronchus or diaphragm).
What Is Stage 3B Lung Cancer?
Stage 3B lung cancer is indicated by any of the following:
- Metastasis to lymph nodes on the opposite side (e.g., the cancer is in the right lung, but lymph node involvement is on the left).
- Metastasis to lymph nodes outside the chest cavity (e.g., neck, armpit, or groin lymph nodes).
- Cancer spreading to tissues such as the spine, esophagus, or heart, making surgical removal impossible.
What Is Stage 4 Lung Cancer?
Stage 4 is the most advanced stage of lung cancer, where the disease has spread (metastasized) to other organs or tissues such as bones, brain, adrenal glands, liver, or soft tissues.
In stage 4 lung cancer, treatment options vary depending on the cancer cell type.
Treatment for Non-Small Cell Stage 4 Lung Cancer
In this stage, since the cancer has spread to other organs, surgery is generally not preferred except in certain cases. The most appropriate treatments include chemotherapy, immunotherapy, and, if needed, radiation therapy for the areas where the cancer has spread.
In cancers other than squamous (epidermoid) cell carcinoma, targeted therapies (smart drugs) can improve treatment success. To determine eligibility for targeted therapies, genetic tests such as EGFR, ALK, and ROS-1 must be performed on the biopsy tissue.
Surgery may be beneficial in very specific situations (e.g., if there is only one metastasis in the brain or adrenal gland, and these are treated or can be treated).
Treatment for Small Cell Stage 4 Lung Cancer
For this group, smart drugs are not used. Immunotherapy can be used in certain cases. Treatment involves:
- Chemotherapy – Drug Therapy
- Radiotherapy – Radiation Therapy
Recommendations for Stage 4 Lung Cancer Patients
- Using targeted therapies can improve treatment outcomes; however, only about one-fourth of patients are eligible for these treatments.
- Encouraging results have been observed with immunotherapy – consult with your oncology specialist.
- Supportive treatments aim to maintain the patient’s quality of life.
- Palliative care should be applied to manage symptoms such as shortness of breath, pain, or severe weight loss.
- Be cautious of alternative treatments, which often provide no benefit and may mislead patients and their families.
What Is the Survival Rate for Stage 4 Lung Cancer?
The most frequently asked question by patients and their families is about the chances of recovery with treatment. Below are statistics from international studies involving a large number of patients:
According to Cancer Research UK (link), the 1-year survival rate for stage 4 lung cancer is approximately 14%.
According to the American National Cancer Institute (link), the 5-year survival rate for stage 4 lung cancer is approximately 1%.
NOTE: These rates are from before the widespread use of smart drugs (targeted therapies) and immunotherapy. With these advancements, survival rates for stage 4 lung cancer patients eligible for these treatments are better than the statistics shown here.
You should consult a medical oncology specialist for the treatment of stage 4 lung cancer.
