Lung cancer is among the most common and deadliest cancers across the globe. It develops when cells grow abnormally in the lungs while smoking cigarettes; poor air quality and exposure to carcinogens like asbestos at the workplace are usually critical factors. Recognising the stages of lung cancer is a must for diagnostic and treatment-planning purposes, as different stages need to be handled using different management techniques.

What is Lung Cancer?

Lung cancer is a malignancy that originates in the lungs, most often in the cells, which cover the air-conducting passages. It displays a series of unchecked proliferations of abnormal cells, contributing to the development of tumours, crowding and disrupting the function of the lungs.

There are two most common types of lung cancer, namely:

(a) Non-small cell lung cancer (NSCLC): This type occurs in 85% of all lung cancer cases, making it the most common. 

(b) Small cell lung cancer (SCLC): This type is less frequently found, accounting for about 10–15% of lung cancer cases. SCLC, in contrast to NSCLC, tends to grow and spread incredibly quickly and is usually caused by smoking.

The main reason for lung cancer is the presence of carcinogens in the environment, which are substances that can cause DNA damage to lung cells and lead to their transformation into cancerous ones. The largest contributing risk factor for lung cancer is tobacco smoke, which consists of active smoking and secondhand smoke inhalation. Other risk factors for lung cancer include radon gas, asbestos, air pollution, some occupational hazards or a family history of lung cancer.

Stages of Lung Cancer

The staging system most commonly used for lung cancer is the TNM system:

1. Stage 0 (carcinoma in situ): Cancer cells are localised only in the top layer of cells present in air passages without spreading to deep-seated tissues. At the given point in time, it is still a non-invasive cancer that may be removed simply and effectively with minimal side effects.

2. Stage I: The cancer is confined to the lung and does not show any signs of metastasis to distant lymph nodes. Stage I lung cancer is divided into two subcategories: IA (small tumours) and IB (large tumours). Surgery is the primary treatment for stage I lung cancer, although radiation therapy or stereotactic body radiation therapy (SBRT) may also be considered in cases where the patient is non-operable.

3. Stage II: Cancer has moved to nearby lymph nodes and is still within the lungs. Like stage I, stage II is also divided into two subgroups (IIA and IIB) according to the size and extent of the tumour. Treatment for stage II lung cancer may include surgery to remove tumours and nearby lymph nodes, followed by either chemotherapy or radiation therapy.

4. Stage III: Cancer has metastasized to the lymph nodes in the chest and to adjacent structures, such as the heart and oesophagus. Stage III lung cancer is subdivided into stages IIIA and IIIB according to the involvement of lymph nodes and tumour size. Treatment for stage III lung cancer mainly consists of a combination of chemotherapy, radiation therapy and possible surgery, depending on the individual case.

5. Stage IV: The disease has progressed from the lung to other organs like the brain, liver, or bones. Stage IV lung cancer is the last stage of the disease and is considered incurable. Yet, different types of treatment, including chemotherapy, targeted therapy, immunotherapy and palliative care, may manage symptoms, improve quality of life and increase survival.

Lung Cancer Symptoms

The features of lung cancer depend on the stage and location of the tumour. Symptoms of early-stage lung cancer may not be evident, or the symptoms might be non-specific and might be attributed to other conditions. Common symptoms of lung cancer include:

• Persistent cough
• Chest pain
• Shortness of breath
• Coughing up blood
• Fatigue
• Unintended weight loss
• Hoarseness
• Wheezing

Lung Cancer Treatment

1. Surgery: The goal of surgical resection is to remove a tumour and adjacent tissue that have already been damaged by cancer. It tends to be applied in the early stages of lung carcinoma but may also be taken into account for locally advanced tumours.

2. Chemotherapy: Chemotherapy can kill cells or prevent them from spreading. It may be applied alone or in conjunction with other treatment types, such as surgery or radiation therapy. Chemotherapy is used in an adjuvant setting in advanced cases or after surgery.

3. Radiation Therapy: Radiation therapy utilises penetrating high-energy X-rays or another high-level form of radiation that is directed at cancer cells to annihilate them. It can be used as a curative for early-stage lung cancer, as a pain alleviation modality in advanced conditions, or as an adjuvant with other modalities.

4. Targeted Therapy: Targeted therapy medication is designed to treat the particular molecular abnormality accountable for the cancer. They can be prescribed for particular types of NSCLC (non-small cell lung cancer) with some specific genetic mutations, for example, EGFR mutations or ALK rearrangements.

5. Immunotherapy: Immunotherapy works through the human immune system, which is made to identify and destroy cancer cells. Immunotherapy has shown better results while blocking proteins that stop the immune system from reacting to the cancer cells in the metastatic stages of lung cancer.

To Sum Up

Understanding lung cancer stages serves as a crucial guide for choosing treatment methods and improving the patient's care. Integrated efforts by oncologists, surgeons, radiation oncologists, and other healthcare professionals from reputed hospitals like Action Cancer Hospital are needed to develop precision therapies that cater to each patient's individual needs through careful consideration of their specific health conditions. New research and innovation in the field of lung cancer therapy are signs of hope that the effectiveness and survival of patients with this kind of disease will be further enhanced.