Information on Lung Cancer
Cancer develops in our cells, the body's basic unit of life. To understand lung cancer, knowing how normal cells become cancerous is helpful.
The body is made up of many types of cells. Usually, cells grow, divide, and produce more cells as needed to keep the body healthy and functioning correctly. Sometimes, however, the process goes astray – cells keep dividing when new cells are unnecessary. The mass of extra cells forms a growth or tumor. These abnormal cells primarily originate when the lungs are exposed to cancer-causing substances (carcinogens), such as those found in cigarette smoke, asbestos, and silica dust. Tumors can be benign or malignant.
Benign lung tumors are not lung cancer. They often can be removed and, in most cases, do not return. Cells in benign tumors do not spread to other parts of the body. Most important, benign tumors are rarely a threat to life.
Malignant lung tumors are lung cancer. Cells in malignant tumors are abnormal and divide without control or order. These cancer cells can invade and destroy the tissue around them. Cancer cells can also break away from a malignant tumor and enter the bloodstream or lymphatic system (the tissues and organs that produce, store, and carry white blood cells that fight infection and other diseases). This process, called metastasis, is how cancer spreads from the original (primary) tumor to form new (secondary) tumors in different body parts.
Mesothelioma, Asbestos and Lung Cancer
There are two major types of lung cancers, non-small and small cell, depending on how the cells look under a microscope. Each type of lung cancer grows, spreads in different ways, and is treated differently.
Lung cancer refers to malignant tumors that originate in the lung itself. A cancer of the lung lining or pleura is called mesothelioma and is a different type of cancer.
Small Cell Lung Cancer
Small cell lung cancer makes up for around 20 out of every 100 lung cancers diagnosed, and it is almost always caused by smoking. The cancer cells are small and filled mainly with the nucleus, which is the control center of cells. It is not typical for someone who has never smoked to develop it. Early spreading is common in small cell lung cancer, so chemotherapy treatment is often recommended by doctors instead of surgery.
There are three types of non-small cell lung cancer. These are grouped because they behave similarly and respond to treatment differently from small-cell lung cancer. The three types are:
- Squamous cell carcinoma
- Adenocarcinoma
- Large cell carcinoma
Asbestos is the primary cause of mesothelioma, which, contrary to popular belief, is not limited to the lungs but can also affect the abdomen, reproductive organs, or the heart.
Secondary cancer is cancer that has spread from somewhere else in the body. There are quite a few different cancers that can spread to the lungs, including breast cancer and bowel cancer.
Knowing what you are dealing with is essential to find the correct information. The choice of cancer treatment depends on where the cancer started. When cancer spreads to the lung from the breast, the cells are breast cancer cells, not lung cancer cells. So, they respond to breast cancer treatments. Cancer that has spread from the bowel should respond to bowel cancer treatments.
Lung Cancer Symptoms
- Bronchoscopy. The doctor puts a bronchoscope (a thin, lighted tube) into the mouth or nose and down through the windpipe to look into the breathing passages. Through this tube, the doctor can collect cells or small samples of tissue.
- A cough that doesn't go away and gets worse over time
- Constant chest pain
- Fluid in lungs, fluid around lungs
- Coughing up blood
- Shortness of breath, wheezing, or hoarseness
- Repeated problems with pneumonia or bronchitis
- Swelling of the neck and face
- Loss of appetite or weight loss
- Fatigue
These lung cancer symptoms like fluid in the lungs may be caused by lung cancer or by other conditions. It is important to check with a doctor.
To help find the cause of lung cancer symptoms, the doctor evaluates a person's medical history, smoking history, exposure to environmental and occupational substances such as asbestos, and family history of cancer. The doctor also performs a physical exam and may order a chest x-ray and other tests. If lung cancer is suspected, sputum cytology (the microscopic examination of cells obtained from a deep-cough sample of mucus in the lungs) is a simple test that may be useful in detecting lung cancer. To confirm the presence of lung cancer, the doctor must examine tissue from the lung. The removal of a small sample of tissue for examination under a microscope by a pathologist can show whether a person has lung cancer. Several procedures may be used to obtain this tissue:
- Bronchoscopy. The doctor puts a bronchoscope (a thin, lighted tube) into the mouth or nose and down through the windpipe to look into the breathing passages. Through this tube, the doctor can collect cells or small samples of tissue.
- Needle aspiration. A needle is inserted through the chest into the lung cancer tumor to remove a sample of tissue.
- Thoracentesis. Using a needle, the doctor removes a sample of the fluid that surrounds the lungs to check for cancer cells.
- Thoracoscopy. Surgery to open the chest is sometimes needed to diagnose lung cancer. This procedure is a major operation performed in a hospital.
Lung Cancer Staging
If the diagnosis is lung cancer, the doctor will want to learn the stage (or extent) of the disease. Lung cancer staging determines whether the cancer has spread and, if so, to what parts of the body. Lung cancer often spreads to the brain or bones. Knowing the lung cancer stage of the disease helps the doctor plan treatment. Some tests used to determine the lung cancer stage and whether the cancer has spread include:
- CAT (CT) scan (computed tomography). A computer linked to an X-ray machine creates a series of detailed pictures of areas inside the body.
- MRI (magnetic resonance imaging). A powerful magnet linked to a computer makes detailed pictures of areas inside the body./li>
- Radionuclide Scanning Scanning can show whether cancer has spread to other organs, such as the liver. The patient swallows or receives an injection of a mildly radioactive substance. A machine (scanner) measures and records the level of radioactivity in specific organs to reveal abnormal areas./li>
- Bone Scan A bone scan, one type of radionuclide scanning, can show whether cancer has spread to the bones. A small amount of radioactive substance is injected into a vein. It travels through the bloodstream and collects in areas of abnormal bone growth. An instrument called a scanner measures the radioactivity levels in these areas and records them on x-ray film./li>
- Mediastinoscopy/Mediastinotomy A mediastinoscopy can help show whether the cancer has spread to the lymph nodes in the chest. Using a lighted viewing instrument called a scope, the doctor examines the center of the chest (mediastinum) and nearby lymph nodes. In mediastinoscopy, the scope is inserted through a small incision in the neck; in mediastinotomy, the incision is made in the chest. The scope is also used in either procedure to remove a tissue sample. The patient receives a general anesthetic.
Non-Small Cell Lung Cancer Staging
Non-small cell lung cancer is staged according to tumor size, level of lymph node involvement, and extent of distant metastases (spread). Stages are identified in the following ways:
- Stage 0 Lung Cancer The cancer is limited to the lining of air passages and hasn't invaded lung tissue. The tumor can usually be eliminated when caught and treated.
- Stage I Lung Cancer The cancer has spread to layers of lung tissue but has not reached the lymph nodes or beyond. There is a 60 percent to 80 percent chance of surviving the disease in 5 years when it's caught and treated at this stage.
- Stage II Lung Cancer The cancer has invaded neighboring lymph nodes or spread to the chest wall. There is a 40 percent to 50 percent chance of surviving the disease in 5 years when it's caught and treated at this stage.
- Stage IIIA Lung Cancer The cancer has spread from the lung to lymph nodes beyond the lung area. Cancer usually isn't treated surgically at this stage. There is a 15 percent to 30 percent chance of surviving 5 years when the disease is caught and treated with radiation or chemotherapy at this point.
- Stage IIIB Lung Cancer The cancer has spread to areas such as the heart, blood vessels, trachea, and esophagus - all within the chest. Cancer can't be treated surgically at this stage. A 10 percent to 15 percent chance of surviving 5 years exists when the disease is treated at this point.
- Stage IV Lung Cancer In Stage 4 lung cancer, the cancer has spread to other parts of the body, such as the liver, bones, or brain. When treated at this stage, there is less than a 2 percent chance of surviving the disease in 5 years.
Lung Cancer Treatment Options
Lung cancer treatment depends on several factors, including the type of lung cancer (non-small or small cell lung cancer), the size, location, and extent of the tumor, and the general health of the lung cancer patient. Many treatments and combinations of treatments may be used to control lung cancer and/or improve quality of life by reducing symptoms.
- Surgery is an operation to remove the cancer. The type of lung cancer surgery a doctor performs depends on the location of the tumor in the lung. A process to remove only a tiny part of the lung is called a segmental or wedge resection. When the surgeon removes an entire lobe of the lung, the procedure is called a lobectomy. Pneumonectomy is the removal of a whole lung. Some tumors are inoperable (cannot be removed by surgery) because of their size or location, and some patients cannot have surgery for other medical reasons.
- Chemotherapy uses anticancer drugs to kill cancer cells throughout the body. Even after cancer has been removed from the lung, cancer cells may still be present in nearby tissue or elsewhere in the body. Chemotherapy may be used to control cancer growth or to relieve symptoms. Most anticancer drugs are given by injection directly into a vein (IV) or using a catheter, a thin tube placed into a large vein, and remain there as long as needed. Some anticancer drugs are given in the form of a pill.
- Radiation Therapy, or radiotherapy, involves using high-energy rays to kill cancer cells. Radiation therapy is directed to a limited area and affects the cancer cells only in that area. Radiation therapy may be used before surgery to shrink a tumor or after surgery to destroy any cancer cells that remain in the treated area. Doctors also use radiation therapy, often combined with chemotherapy, as a primary treatment instead of surgery. Radiation therapy may also relieve symptoms such as shortness of breath. Radiation for the treatment of lung cancer most often comes from a machine (external radiation). The radiation can also come from an implant (a small container of radioactive material) placed directly into or near the tumor (internal radiation).
- Photodynamic therapy (PDT), a type of laser therapy, involves using a particular chemical injected into the bloodstream and absorbed by cells all over the body. The chemical rapidly leaves normal cells but remains in cancer cells longer. A laser light aimed at the cancer activates the chemical, killing the cancer cells that have absorbed it. Photodynamic therapy may be used to reduce symptoms of lung cancer -- for example, to control bleeding or to relieve breathing problems due to blocked airways when the tumor cannot be removed through surgery. Photodynamic therapy may also be used to treat tiny tumors in patients for whom the usual treatments for lung cancer are not appropriate.