LUNG CANCER ( Definition, cause , Stages , Clinical feature, investigation, differential diagnosis, management)

LUNG CANCER 

 What is lung cancer? 

• Lung cancer, also known as lung carcinoma, is a malignant lung tumor characterized by uncontrolled cell growth in tissues of the lung.
• Lung cancer is a type of cancer that begins in the lungs. It occurs when abnormal cells in the lung grow and divide uncontrollably, forming a tumor. Lung cancer can spread to other parts of the body, such as the lymph nodes, bones, and brain. 
• This growth can spread beyond the lung by the process of metastasis into nearby tissue or other parts of the body.
•  Most cancers that start in the lung, known as primary lung cancers, are carcinomas.

What is the CAUSES OF LUNG CANCER? 

• The main cause of lung cancer is exposure to tobacco smoke, either through smoking cigarettes, using other forms of tobacco, or being exposed to secondhand smoke. In fact, about 85% of lung cancer cases are caused by smoking. The risk of developing lung cancer increases with the amount and duration of tobacco smoke exposure.

Other known risk factors for lung cancer include:

1. Exposure to radon gas: Radon is a naturally occurring radioactive gas that can be found in some homes and buildings.
2. Exposure to certain chemicals and pollutants: such as asbestos, certain metals, diesel exhaust, and air pollution.
3. Personal or family history of lung cancer: Having a parent, sibling, or child with lung cancer increases the risk of developing the disease.
4. Having a history of lung diseases like Chronic Obstructive Pulmonary Disease (COPD)
5. Age: The majority of lung cancer cases are -diagnosed in people over the age of 55.

How many Types of lung cancer? 

1.SCLC ( small cell lung cancer)

2.NSCLC( Non small cell lung cancer )

1. SCLC 

• Small cell lung cancer (SCLC) is a type of lung cancer that is characterized by small, round cells that look abnormal under a microscope.
•  It accounts for about 10-15% of all lung cancers. 
• SCLC is also known as "oat cell" cancer because of the way the cells look under a microscope.
• SCLC is a highly aggressive and rapidly growing cancer that tends to spread early to other parts of the body, such as the lymph nodes, brain, and bones. 

2.NSCLC

• Non-small cell lung cancer (NSCLC) is the most common type of lung cancer. 
• It is called "non-small" because the cancer cells do not look small and round under a microscope, unlike small cell lung cancer (SCLC) cells. NSCLC accounts for about 85% of all lung cancers.

NSCLC is divided into subtypes based on the type of cells that make up the cancer:

1. Adenocarcinoma is the most common subtype and usually begins in the outer part of the lung.
2. Squamous cell carcinoma begins in the cells that line the airways within the lung.

• Large cell carcinoma can occur in any part of the lung and can look like any of the other subtypes under a microscope.
• NSCLC tends to grow and spread more slowly than small cell lung cancer (SCLC), but it can still spread to other parts of the body if not treated early.

How many STAGE'S OF LUNG CANCER ? 

Lung cancer is typically divided into four stages:

• Stage 1: The tumor is small and has not spread to nearby lymph nodes.
• Stage 2: The tumor is larger and may have spread to nearby lymph nodes.
• Stage 3: The tumor has spread to other parts of the lung or to nearby structures, such as the chest wall or diaphragm.
• Stage 4: The tumor has spread to distant parts of the body, such as the bones or liver.

What is the clinical feature of lung cancer? 

 1. SCLC  

• Small cell lung cancer (SCLC) is a fast-growing type of lung cancer that typically presents with symptoms such as cough, chest pain, shortness of breath, and weight loss. 
• Other common clinical features of SCLC include the presence of symptoms such as fatigue, weakness, and hoarseness.

2.NSCLC-

• Common clinical features of NSCLC include:

A persistent cough

• Chest pain
• Shortness of breath
• Fatigue
• Weight loss
• Hoarseness
• Recurrent lung infections (such as pneumonia or bronchitis)
• Coughing up blood etc 

What is Diagnosis method LUNG CANCER? 
There are several investigations that can be used to diagnose and stage lung cancer, including:

1.Radiology/Imaging tests: These include X-ray, computed tomography (CT) scans, positron emission tomography (PET) scans, and magnetic resonance imaging (MRI) scans, which can help identify the size, location, and spread of the tumor.

2.Bronchoscopy: This procedure uses a thin, flexible tube with a light and camera on the end to look inside the airways and take samples of suspicious tissue.

3.Biopsy: A sample of tissue is taken from the lung using a needle or during surgery and examined under a microscope to confirm the diagnosis of lung cancer.

4.Blood tests: These tests can measure the levels of certain biomarkers, such as tumor markers, that can indicate the presence of lung cancer.

5.Lung function tests: These tests measure how well the lungs are working, which can help determine if a person is able to tolerate certain treatments.

6.Additional test may be required to find out the stage of the cancer, like CT of brain, bone scan etc.

(It is important to note that the specific tests and procedures used to investigate lung cancer will depend on the individual case, including the patient's symptoms, medical history, and results of initial tests.)

What is DIFFRENTIAL DIAGNOSIS OF LUNG CANCER ? 

• Some of the differential diagnoses of lung cancer include:

1. Bronchitis: Inflammation of the bronchial tubes, which can cause cough, chest pain, and shortness of breath.
2. Pneumonia: An infection of the lungs that can cause fever, cough, and difficulty breathing.
3. Tuberculosis: A bacterial infection that can cause a chronic cough, chest pain, and weight loss.
4. Pulmonary fibrosis: A condition that causes thickening and scarring of the lungs, leading to difficulty breathing and a dry cough.
5. Asthma: A chronic inflammatory disease of the airways that can cause wheezing, chest tightness, and shortness of breath.
6. Emphysema: A lung disease that causes damage to the air sacs, leading to difficulty breathing and a chronic cough.
7. Lung abscess: A pus-filled infection in the lung that can cause fever, cough, and chest pain.
8. Pleural effusion: A buildup of fluid in the pleural space, which can cause difficulty breathing and chest pain.

(It's important to have a thorough examination, proper imaging tests and a biopsy to confirm the diagnosis of lung cancer. A multidisciplinary team approach and a patient's history, symptoms, physical examination, and test results will all be taken into account to make an accurate diagnosis.)

How to MANAGEMENT OF LUNG CANCER? 

• The management of lung cancer depends on the stage and type of the cancer, as well as the patient's overall health and preferences. 

Treatment options may include ;

1.Surgery, ;

Surgery for lung cancer ;

• Surgery is a common treatment option for lung cancer, particularly for early-stage non-small cell lung cancer. 
• The type of surgery performed depends on the size and location of the tumor, as well as the overall health of the patient. 
• The most common types of surgery for lung cancer are lobectomy, which involves removing a lobe of the lung, and pneumonectomy, which involves removing an entire lung.
•  Other surgical options include segmentectomy and wedge resection. The goal of surgery is to remove as much of the cancerous tissue as possible while minimizing damage to healthy tissue.
•  It may be done alone or in combination with other treatments such as radiation therapy and chemotherapy.

2. Radiation therapy, :

•  It uses high-energy beams, such as X-rays or protons, to kill cancer cells or shrink tumors. 
• The radiation is delivered externally, using a machine called a linear accelerator, or internally, using a small radioactive source placed inside the body near the tumor. 
• The goal of radiation therapy for lung cancer is to destroy as many cancer cells as possible while minimizing damage to healthy tissue

3.Chemotherapy, :

• It involves using drugs to kill cancer cells or stop them from growing and dividing. Chemotherapy can be administered intravenously or orally, and it can be given alone or in combination with other treatments such as surgery or radiation therapy. 

4.Targeted therapy, or a combination of these.

• In early-stage lung cancer, surgery may be the best option.
• while in advanced-stage cancer, a combination of treatments may be used.
•  Palliative care may also be provided to alleviate symptoms and improve quality of life for patients with advanced-stage cancer. 
• The management plan should be developed by a team of specialists, including -

 A.Thoracic surgeon, 

B.Medical oncologist, 

C. Radiation oncologist.