This article, published by the National Cancer Institute (NCI), focuses on the treatment of non-small cell lung cancer (NSCLC) in detail. This article will focus on NSCLC and its diagnosis.
NSCLC is a malignant tumor of lung cells that originates from lung tissue
The lungs are paired conical respiratory organs in the chest cavity. Its role is to inhale and transport oxygen to other organs of the body and to exhale carbon dioxide, a metabolic waste product, from the body. The lungs are separated into different lobes by connective tissue. The left lung has two lobes and the right lung has three lobes slightly larger than the left lung. The main bronchus divides into left and right bronchi to the left and right lungs, respectively, and they can both become cancerous. Tiny air sacs of alveoli and small official cavities of fine bronchi make up the interior of the lungs.
The respiratory anatomy shows the trachea, the two lung lobes and their lobes, the airways, and also the lymph nodes and mediastinum. Oxygen is drawn into the lungs and into the bloodstream through the membranes of the alveoli.
The pleura is a membrane covering the surface of the lungs and the inner surface of the thoracic wall. The cavity between the two pleura is called the pleural cavity, which often contains a small amount of fluid to serve as a lubricant for the smooth movement of the lungs within the thoracic cavity.
There are two main types of lung cancer: non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC).
Different types of NSCLC
NSCLC has many different types of tumor cells, each with specific growth and spreading patterns. the nomenclature of NSCLC is mainly based on the type and shape of tumor cells observed under the microscope, such as
1. squamous cell carcinoma: the tumor originates from squamous cells, which are thin, flat cells that look like fish scales; this is also known as epithelioid carcinoma.
2. Large cell carcinoma: Tumors arise from many types of large cells.
3. adenocarcinoma: tumors arise from cells along the alveolar wall and can secrete substances, such as mucus. 4.
4. other less common types of NSCLC, such as pleomorphic carcinoma, carcinoid tumor, salivary gland carcinoma, and unclassified tumors.
The main risk factors for lung cancer are the following.
Current or former cigarette, pipe or cigar smoking; exposure to secondhand smoke; family history of lung cancer; history of breast or chest radiation; workplace exposure to asbestos, chromium, nickel, arsenic, soot or tar; exposure to radon in the home or workplace; air pollution where you live; infection with human immunodeficiency virus (HIV); smokers who take beta-carotene supplements; smoking increases the risk of NSCLC .
Smoking cigarettes, pipes or cigars is the most common cause of lung cancer. The earlier, more often, and longer a person smokes in life increases the risk of developing lung cancer. If one quits smoking, the risk of developing the disease decreases as the years pass.
Any factor that increases the risk of developing the disease is called a risk factor. The presence of risk factors does not mean that you will definitely develop tumor, and the absence of risk factors does not mean that you will not develop tumor. If you think you have a risk factor, consult your doctor.
The risk of developing lung cancer increases when smoking and other risk factors interact.
Common symptoms of NSCLC
Symptoms of NSCLC include recurrent coughing fits, shortness of breath, and in some cases, lung cancer without any signs or symptoms, which may be detected during a chest X-ray for other diseases. Signs and symptoms may be caused by lung cancer or other diseases. Please consult your doctor if you have the following symptoms.
Chest discomfort or pain; recurrent cough that gets worse with time; dyspnea; croup; blood in the sputum (sputum coughed up from the lungs); hoarseness; lack of appetite; unexplained weight loss; feeling very tired; difficulty swallowing; facial swelling and/or swelling of the jugular veins.
Common tools for the examination, diagnosis and staging of NSCLC.
A number of tests are usually performed concurrently to detect, diagnose and definitively stage NSCLC, and the following are some of the routine tests that may be used.
1. Physical examination and medical history: Examination of the patient’s general health, including examination of the patient’s signs, such as: masses or anything else that seems abnormal. A history of the patient’s health habits, including smoking and previous employment, illnesses, and treatments received.
2. Laboratory tests: Medical tests test samples of the patient’s tissue, blood, urine, or other substances in the body. These tests help diagnose the disease, plan and direct treatment, or monitor the progress of the disease.
3. chest x-ray: x-rays look at the organs and bones in the chest cavity. x-rays are a beam of energy that penetrates the body and reveals the internal organs of the body.
Chest x-rays are usually used to photograph organs and bones within the chest cavity. x-rays penetrate the body and are developed on film
5. CT (CAT) scan: This test scans and photographs different areas of the body from different viewpoints to obtain a series of detailed pictures of that area, such as the chest. These pictures are taken by a computer with an x-ray machine attached. Often a dye is injected into a vein in the patient’s body or a developer is swallowed to make the organ or tissue appear more clearly. This test is also known as computed tomography, or computed axial tomography. 6.
6. Sputum cytology: This test is performed by looking at a sputum specimen (mucus coughed up from the lungs) under a microscope by a pathologist to check for the presence of cancer cells in the sputum.
7. Fine-needle aspiration (FNA): This diagnostic method requires the aid of CT scan, ultrasound or some other imaging means to locate abnormal tissues and fluids in the lungs, and then aspiration of the tissues and fluids in the lungs with the help of a small needle. The needle is passed into the lung to create a tiny incision on the surface of the body, and X-rays are taken after this test to ensure that no pneumothorax is formed. The needle aspirate specimen is sent to the laboratory for further testing, where the pathologist looks through a microscope and looks for evidence of cancer cells.
The biopsy needle is inserted through the chest wall into the lung mass and a small specimen is removed for microscopic examination.
Bronchoscopy: This test allows direct visualization of abnormal areas in the lungs such as the large airways and bronchi. The bronchoscope is inserted through the nose or mouth into the bronchi and lungs. The bronchoscope is a small, tube-like instrument with a light source and lenses for observation, and it may also have tools for obtaining tissue specimens.
10. Thoracoscopy: This surgical examination allows visualization of abnormal areas of organs in the chest cavity. The thoracoscope is inserted through an incision between the two ribs. A thoracoscope is a thin, tube-like instrument with a light source and lens for viewing. It may come with an instrument to remove tissue or lymph node specimens for further examination under the microscope for signs of cancer. In some cases, this test can be used to remove a portion of the esophagus or lung. If certain tissues, organs or lymph nodes cannot be visualized, a thoracotomy will be performed for further visualization. A larger incision will be made between the ribs and the chest will be opened.
11. Thoracentesis: A fine needle is inserted into the chest cavity to drain the pleural fluid and the pathologist looks at the specimen under a microscope to look for cancer cells.
12. Light and electron microscopy: The cells of the sample tissue are observed in the laboratory through conventional and high-performance microscopes to look for certain cellular changes.
13. Immunohistochemistry: The use of antibodies to examine sample tissues that express specific antigens. Antibodies can often be combined with radioactive substances or dyes to make the tissue glow under the microscope. This method can be used to distinguish between different types of cancer.
Specific factors affecting prognosis (recovery) and treatment options
Prognosis and treatment options depend on the following.
1. the stage of the tumor (size of the tumor and whether it has spread only in the lungs or has spread to other parts of the body).
2. the type of lung cancer.
3. whether the cancer has mutations (changes) in certain genes, such as the epidermal growth factor receptor (EGFR) gene or the mesenchymal lymphoma kinase gene (ALK).
4. the presence or absence of signs and symptoms such as cough and dyspnea
5. The general health status of the patient.
For most patients with NSCLC, current treatments do not cure the cancer. If lung cancer is found, one should consider participating in a clinical trial to improve treatment. Many clinical trials have been conducted in many countries for patients with various stages of NSCLC. More information about ongoing clinical trials can be found on the NCI Web site.
NSLCL Staging
1. After the diagnosis of lung cancer, further tests are done to see if the cancer has metastasized only in the lungs or spread to other organs of the body
2. There are three ways that lung cancer can spread in the body
3. the cancer may have spread from other parts of the body
4. screening tests for NSCLC staging
After a diagnosis of lung cancer is made, further tests are needed to find out if the cancer has metastasized only in the lungs or spread to other organs of the body. The procedure used to determine whether the cancer has spread within the lungs or to other parts of the body is called staging, and the information gathered from this procedure determines the stage of the disease. staging of NSCLC is important because it determines treatment options. Some of the tests used to diagnose NSCLC also help with staging. Other tests and procedures used to stage the disease include the following.
(1) MRI: This test uses a magnetic field, radiation waves and a computer to produce a series of pictures that respond to the inside of the body and benefit the brain. This test is also known as magnetic resonance imaging (NMRI).
(2) CT scan: This test produces a series of detailed pictures of various areas of the body, such as the brain and abdomen, from different viewpoints. The pictures are produced by a computer connected to an X-ray machine. Dye can also be injected into a vein or given orally to help enhance the visualization of organs and make the pictures clearer. This method is also called computed tomography, or computerized axial tomography.
(3) PET scan (positive ion emission tomography): This test can detect malignant tumors in the body. A low dose of radioactive glucose (sucrose) is injected into a vein, and the PET scanner presents a spiral motion outside the body and captures a picture of the sugar-containing organism. Malignant tumors take up higher levels of sugar than normal tissue and therefore appear brighter and more active on the picture.
(4) Mediastinoscopy: This method allows direct visualization of abnormal areas directly in both lungs, such as organs, tissues and lymph nodes. An incision is made above the sternum then the mediastinoscope is inserted into the chest. The mediastinoscope is a thin, tube-like instrument with a light source and lens for visualization. It may also be equipped with tools to remove tissue or lymph node samples, which can then be viewed further under the microscope for signs of tumor.
(5) Radionuclide bone scan: This method can detect rapidly dividing cells, such as cancer cells in bone. A small dose of radioactive material is injected into a vein and distributed to the body via the bloodstream. The radioactive material is concentrated in the bones and is scanned.
(6) Pulmonary Function Test (PFT): This test gives an idea of how well the lungs are functioning. It mainly measures how much air the lungs can hold and how quickly air moves in and out of the lungs. It also measures the utilization of oxygen in breathing and the rate of carbon dioxide release.
(7) Ultrasound endoscopy (EUS): An endoscope is inserted into the body for examination. The endoscope is a thin, tube-like instrument with a light source and lens for viewing. The endoscope is used to bounce high-energy sound waves (ultrasound) off internal tissues or organs and produce echoes that are collected by a probe. The echoes form a picture of the body’s tissues called a sonogram. EUS can be used to assist in guiding fine-needle aspiration (FNA) biopsies of lung tissue, lymph nodes, or other sites.
(8) Anterior mediastinoscopy: This surgical procedure allows visualization of both interstitial lung tissues and abnormal areas between the sternum and the heart. An incision is made next to the sternum and the mediastinoscope is then inserted. The mediastinoscope is a thin, tube-like instrument with a light source and lens for visualization. It may also be equipped with tools to remove tissue or lymph node samples, which are then looked at further under the microscope for signs of tumor. This is also known as a Chamberlain examination.
(9) Lymph node biopsy: The removal of some or all of the lymph nodes for the pathologist to look at the tissue under the microscope to look for cancer cells.
(10) Bone marrow aspiration and biopsy: A puncture needle is inserted into the hip or sternum and a portion of the bone marrow, blood, and a small bone fragment is aspirated, and the pathologist looks at the obtained specimen under a microscope to look for signs of tumor.
There are three main ways for tumors to spread in the body
(1) Tumors can spread through tissues, lymphatic tracts and blood channels.
Tissue: tumor spreads from the primary focus to adjacent tissues by direct spread
Lymphatic tract: the tumor invades from the primary focus to the local draining lymphatic vessels and then enters the lymphatic system to spread to other parts
Blood channel: the tumor invades from the primary focus to the local blood vessels, and then spreads to other parts through the vascular system
(2) Tumor may spread from other parts
Cancer spreading to other parts of the body is called metastasis. Tumors can break through the primary focus and then metastasize through blood and lymphatic tracts.
Lymphatic tract: Cancer cells enter the lymphatic system and spread through lymphatic vessels to form another tumor in other parts of the body (i.e. metastatic tumor).
Bloodway: Cancer cells enter the bloodstream and travel with the blood to other parts of the body to form another tumor (i.e. metastatic tumor).
Metastatic tumors are the same type of tumor as the primary tumor. For example, if non-small cell lung cancer spreads to the brain, the tumor cells in the brain are actually lung cancer cells. This disease is metastatic lung cancer, not brain cancer.
The following are the conventional stages of NSCLC
(1) Occult stage: No tumor is found by both imaging and bronchoscopy, but tumor cells are found in sputum cytology (sputum coughed up by the patient from the lungs) or bronchial lavage fluid (samples from the airways in the lungs) tests, when the tumor may have spread to other parts of the body.
(2) Stage 0 (carcinoma in situ): Stage 0 is also known as carcinoma in situ. In stage 0, abnormal cells may be distributed along the airway. These abnormal cells may malign into tumors or may spread into adjacent normal tissues.
(3) Stage Ⅰ: In stage Ⅰ tumor has been formed, stage Ⅰ can be further divided into stage ⅠA and ⅠB.
ⅠA stage: the tumor is only in the lung, the maximum diameter is less than 3 cm
Stage ⅠB: the tumor has not metastasized to the lymph nodes and meets any of the following: the tumor lesion is larger than 3 cm and smaller than 5 cm; the tumor invades the main bronchus but is larger than 2 cm from the bulge; the tumor involves the dirty pleura; the extension of atelectasis or obstructive pneumonia to the hilum, but does not involve the whole lung.
(4) Stage II
Stage II can be further divided into stages IIA and IIB, which can be subdivided into two parts according to the tumor size, site of discovery and whether or not the lymph nodes are invaded.
Stage II A: The tumor invades the chest wall ipsilateral to the primary site, and the metastatic lymph nodes are located in the lung or adjacent to the bronchus and meet any of the following points: tumor with a maximum diameter greater than 5 cm; involvement of the main bronchus but ≥ 2 cm from the bulge; involvement of the dirty pleura; atelectasis or obstructive pneumonia extending to the hilum, but not involving the whole lung.
Or the tumor does not involve lymph nodes and any of the following points are met: tumor > 5 cm and ≤ 7 cm in maximum diameter; involvement of the main bronchus but ≥ 2 cm from the ramus; involvement of the dirty pleura; extension of atelectasis or obstructive pneumonia to the hilum, but not to the whole lung.
Stage IIB: tumor spread to adjacent lymph nodes in the thorax ipsilateral to the primary site, lymph node metastases in the lung or adjacent bronchi, and any of the following points are met: tumor larger than 5 cm and smaller than 7 cm; tumor involving the dirty pleura; atelectasis or obstructive pneumonia extending to the hilum, but not involving the whole lung.
or the tumor does not invade the lymph nodes and any of the following points are met: tumor larger than 7 cm; tumor spreads to the main bronchus (and less than 2 cm from the bulge), chest wall, diaphragm
The tumor invades the pericardium, wall pleura, pulmonary atelectasis or obstructive pneumonia in the whole lung, and single or multiple satellite foci in the same lobe as the primary foci.
(5) Stage III
Stage IIIA: The tumor can be further divided into 3 parts according to its size, site of discovery and invaded lymph nodes
Tumor invades intra-thoracic lymph nodes ipsilateral to the primary focus, such as: parasternal lymph nodes or intrapulmonary lymph nodes, or any size tumor; partial (bulging) or total atelectasis or inflammatory pneumonia; there may be one or more isolated foci of tumor in the same lobe; tumor may invade any of the following areas: main bronchus without involvement of bulge; chest wall; diaphragm and phrenic nerve; dirty pleura or wall pleura; pericardium
Tumor invades intrathoracic lymph nodes ipsilateral to the primary site, metastatic lymph nodes located in or adjacent to the bronchi, or tumors of any size; total pulmonary atelectasis or inflammatory pneumonia; one or more isolated foci of tumor in any lobe of the lung Tumor may invade any of the following sites: main bronchi without involvement of the ridge; chest wall; diaphragm and phrenic nerve; dirty or wall pleura; heart or pericardium; large vessels along or originating from the heart The tumor does not invade the lymph nodes.
3) The tumor does not invade lymph nodes or any tumor of any size. The tumor may involve any of the following structures: heart; large blood vessels along or from the heart; trachea; esophagus; recurrent laryngeal nerve; sternum or thoracic vertebrae; bulge.
Stage IIIB: The tumor can be further divided into 2 parts according to the size, location and involvement of lymph nodes.
Tumor spread to the supraclavicular lymph node ipsilateral to the primary site or to the contralateral supraclavicular lymph node: tumor of any size; partial (bulging) or total lung atelectasis or inflammatory pneumonia; one or more isolated foci of tumor in any lobe; tumor may invade any of the following structures: main bronchus; chest wall; diaphragm or phrenic nerve; dirty or wall pleura; heart or pericardium; great vessels along or from the heart; trachea; esophagus ; laryngeal recurrent nerve; sternum or thoracic vertebrae; augmentation.
The tumor invades the intrathoracic lymph nodes ipsilateral to the primary focus, metastatic lymph nodes located in the parasternal or hilum, or any size tumor; there may be isolated tumor foci in different lung lobes; the tumor may invade any of the following sites: heart; large blood vessels along or originating from the heart; trachea; esophagus; laryngeal regurgitant nerve; sternum or thoracic vertebrae; augmentation.
(6) Stage IV
Stage IV any tumor size and has involved lymph nodes, meeting any of the following conditions: one or more tumors in both lungs; tumor cells found in pleural effusion or pericardial effusion; tumor spread to other parts of the body such as brain, liver, adrenal glands, kidneys or bones.