Lung Cancer: Types, Symptoms, Risk Factors, Diagnosis, Treatment, Prevention

Lung cancer is a type of cancer that begins in the lungs. Lungs are subjected to numerous harmful elements through inhalation, including tobacco and pollution, which is why lung cancer is so prevalent. Lung cancer accounts for the majority of cancer-related deaths globally, with men and women experiencing the highest mortality rates. Lung cancer is one of the common cancers globally, affecting both men and women.

Types of lung cancer:

• Non-small cell lung cancer – the most common type accounting for the majority of cases (80-85%), grows slowly when compared to SCLC.
• Small cell lung cancer– It is a neuroendocrine tumour that indicates nearly 15 percent of all lung cancers. SCLC behaves differently from most types of non-small cell lung cancer by its rapid growth, advanced stage of presentation and the early development of metastases.

Symptoms:

• Cough with occasional blood in sputum.
• Chest pain
• Breathlessness
• Hoarseness of voice
• Facial puffiness and dilatation of veins over chest and neck.
• Back pain, headache, seizures in case of metastatic disease.

Risk factors:

• Smoking is the most important risk factor for the development of lung cancer, accounting for 90% of the cases. Secondhand smoke also causes lung cancer. Tobacco smoke contains nearly 70 cancer-causing substances (carcinogens). In India, the most common tobacco products are cigarettes, gutkha, khaini, zarda, etc. Smoking also causes oral, throat, esophageal, stomach, colorectal and bladder cancers.
• Occupational exposure to asbestos, arsenic, chromium, beryllium, nickel, soot, or tar.
• Radon gas exposure in the home or workplace.
• Air pollution: exposure to diesel exhaust is associated with an increased risk of lung cancer.

Diagnosis: Once the lung cancer is suspected, imaging has to be done to know the location of the tumour and to know the stage of cancer.

• Computed Tomography (CT scan)
• MRI scan
• Bone scan
• PET CT scan

1. Tissue Biopsy

To confirm the lung cancer, a tissue biopsy has to be done. Various modalities are available for getting a tissue biopsy.

• Image-guided biopsy:
• During a fine-needle aspiration biopsy of the lung, the patient will lie on a table that slides through a computed tomography (CT) machine. A biopsy needle will be inserted through the chest wall and into the tumour, and a small piece of tissue will be removed through the needle. This piece of tissue will then be checked under a microscope to confirm whether or not cancer is present.
• Endoscopic ultrasound:

Endoscopic ultrasound-guided fine-needle aspiration biopsy is a medical procedure used to examine the lymph nodes near the esophagus. The procedure involves inserting an endoscope, which has an ultrasound probe and a biopsy needle, through the mouth and into the esophagus. The ultrasound probe bounces sound waves off body tissues to create an image of the lymph nodes. A small piece of tissue is then removed from the lymph node using the biopsy needle and examined to identify any abnormalities.

• Bronchoscopy:

During a bronchoscopy, a thin, tube-like instrument called a bronchoscope is inserted through the mouth, trachea, and major bronchi into the lung to look for a tumour. The bronchoscope is equipped with a light and a lens for better visualization, and it may also have a cutting tool. During the procedure, the doctor may take tissue samples, which will be examined under a microscope for diagnostic purposes.

• Liquid Biopsy: It is a minimally invasive blood test that detect circulating tumour cells (CTCs) and fragments of tumour DNA (ctDNA) that are shed into the blood from lung or any metastatic site. It allows molecular profiling of cancer which helps direct targeted therapy and detect any new mutations.

Treatment:

Treatment is based on the type of cancer, molecular profiling, how much it has spread, patient comorbidities and performance status.

1. Surgery: The primary method of treating early-stage lung cancer (i.e., when the tumour is limited to the lung and has not spread to other organs or lymph nodes) is through surgical removal of the tumour. This can be done through procedures such as lobectomy, segmentectomy, or wedge resection. In cases where surgery is not feasible, radiation therapy or stereotactic body radiation therapy (SBRT) may be used as the primary treatment.

• Wedge resection involves removing a small section of the lung that contains the tumour along with a margin of healthy tissue.

• Segmental resection involves removing a major portion of the lung but not an entire lobe.

• Lobectomy involves removing the entire lobe of one lung.

• Pneumonectomy is to remove an entire lung.

2. Radiotherapy

Radiation therapy utilizes high-powered energy beams from X-rays and protons to destroy cancer cells. In locally advanced cancer, radiation is combined with chemotherapy and given. For advanced lung cancers, radiation therapy may help relieve symptoms such as pain.

Newer leading-edge modalities of radiotherapy include

• Cyberknife stereotactic radiosurgery- option for people with small lung cancers where surgery is not feasible. It may also be used to treat limited brain metastasis.
• Image-guided radiotherapy (IGRT)
• Intensity-modulated radiotherapy (IMRT)
• Proton therapy

3. Chemotherapy is the most commonly used treatment modality as the majority of lung cancer patients present in the advanced stages where surgery and radiotherapy are not useful. Chemotherapy uses cancer drugs that circulate throughout the body to destroy cancer cells. The chemo side effects include vomiting, diarrhea, mucositis, neutropenia etc.

4. Targeted therapy:

NSCLC harbours specific genetic alterations (mutation) leading to uncontrolled signalling and growth of the tumour. Target therapy is a treatment modality that targets those cancer’s specific genes and proteins thereby stopping the growth and spread of cancer cells and limits damage to normal healthy cells. The most common side effects are rash, diarrhoea, fatigue, etc.

4. Immunotherapy

The treatment known as immunotherapy fights cancer by utilizing the patient’s own immune system. Immunotherapy can alter or strengthen the immune system’s function to enable it to recognize and combat cancerous cells. Knowing what to expect and how immunotherapy works can frequently help you make educated decisions about your care and help you be ready for treatment, if that’s part of your treatment plan.

5. Photodynamic therapy (PDT)

This is a cancer treatment that uses a drug and a specific type of laser light to eliminate cancerous cells. The drug collects more in cancerous cells, compared to normal cells. Fiberoptic tubes are then used to carry the laser light to the cancerous cells, where the drug becomes active and destroys them. When the tumour is located in the airways, PDT is administered directly to the tumour through an endoscope. It is indicated in a palliative setting to relieve airway obstruction.

Prevention:

In the high-risk population, lung cancer early detection can greatly increase the chances of successful treatment and improve outcomes. The primary screening procedure for lung cancer is low-dose computed tomography (LDCT).

Omega offers the latest and most advanced lung cancer treatment in India. We provide comprehensive cancer care services through a dedicated team of doctors specialized in oncology.