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.
I. NSCLC is a malignant tumor of lung cells originating 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
There are many different types of tumor cells in NSCLC, each type of tumor cells has a special way of growth and spread. the naming 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 originate from many types of large cells.
Adenocarcinoma: Tumors arise from cells along the alveolar wall and can secrete substances, such as mucus.
4. Other less common NSCLC, such as pleomorphic carcinoma, carcinoid tumor, salivary gland carcinoma, and unclassified tumors.
3. The main risk factors for lung cancer are as follows.
Current or former smoking, 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, the greater the risk of lung cancer. If one quits smoking, the risk of developing the disease decreases as the years go by.
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.
When smoking and other risk factors interact, the risk of lung cancer increases.
Common symptoms of NSCLC
Symptoms of NSCLC include recurrent cough and shortness of breath. Some lung cancers do not have any signs and symptoms and may be detected by chest radiographs 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 jugular vein swelling
V. Common tools for screening, diagnosis and staging of NSCLC.
A number of tests are usually performed simultaneously to detect, diagnose and clarify the staging of NSCLC, 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 a lump 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 primarily test samples of the patient’s tissue, blood, urine, or other substances in the body. These tests help diagnose the disease, plan and guide treatment, or monitor the progress of the disease.
3, chest x-ray: x-rays are used to visualize organs and bones in the chest cavity. x-rays are a type of beam energy that penetrates the body and can visualize the internal organs of the body.
4. Chest X-rays are usually used to photograph organs and bones in the chest cavity, and the 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 computerized axial tomography.
6.Sputum cytology: This test is performed by a pathologist who observes the sputum specimen (mucus coughed up in the lungs) under a microscope to check whether cancer cells are present 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 fluid in the lung, and then a fine needle to aspirate the tissues and fluid in the lung. 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.
9.Bronchoscopy: This test allows direct observation of abnormal areas in the lungs such as the large airways and bronchi. The bronchoscope is a small, tube-like instrument with a light source and lenses for observation, and it may come with 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.Thoracocentesis: A fine needle is used to penetrate into the chest cavity to drain the pleural fluid, and the pathologist will look at the specimen under the microscope to find 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.
Immunohistochemistry: Using 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.
VI. Specific factors affecting prognosis (recovery) and treatment options
Prognosis and treatment options depend on the following points.
1. The stage of the tumor (size of the tumor and whether it has spread only in the lung or has spread to other parts of the body).
2. the type of lung cancer.
3.Whether the cancer is in certain genetic mutations (changes), such as the epidermal growth factor receptor (EGFR) gene or the mesenchymal lymphoma kinase gene (ALK).
4. Whether there are 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 clinical trials 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.
VII. NSLCL Staging.
1. after the diagnosis of lung cancer, further tests to see if the cancer has metastasized only in the lungs or spread to other organs of the body.
2. there are three ways for lung cancer to spread in the body.
3.Cancer may have spread from other parts of the body.
4.Checking means of NSCLC staging.
After the diagnosis of lung cancer is confirmed, further tests are needed to find out whether the cancer cells have metastasized only in the lungs or spread to other organs in the body. The procedure used to determine whether the cancer has spread within the lungs or to other parts of the body becomes 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 reflect what is going on inside the body, for the benefit of the brain. This test is also known as magnetic resonance imaging (NMRI).
(2) CT scan.
This test produces a series of detailed pictures of areas inside 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 method 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 allows examination of 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 provides an understanding of the function of the lungs. 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. An 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 the interstitial tissue between the two lungs 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.
Part or all of the lymph nodes are removed 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 bone or sternum to aspirate part of the bone marrow, blood and a small bone fragment, and the pathologist observes the obtained specimen under the microscope to look for signs of tumor.
VIII. There are three main ways for tumor to spread in body.
1.Tumor may spread through tissues, lymphatic tracts and blood channels.
2. Tumors may spread from other parts of the body.
The spread of cancer to other parts of the body is called metastasis. The tumor can break through the primary focus and then metastasize through blood and lymphatic tracts.
Metastatic tumor is 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.
IX. 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 become malignant and become tumors, or may spread to adjacent normal tissues.