What is lung cancer?
Lung cancer is cancer that usually starts in the lining of the bronchi (the main airways of the lungs), but can also begin in other areas of the respiratory system, including the trachea, bronchioles, or alveoli.
It is the leading cause of cancer death in both men and women. For 2009, more than 219,440 new cases of lung cancer were expected, according to the American Cancer Society.
Lung cancers are believed to develop over a period of many years.
Nearly all lung cancers are carcinomas, a cancer that begins in the lining or covering tissues of an organ. The tumor cells of each type of lung cancer grow and spread differently, and each type requires different treatment. About 85 percent to 90 percent of lung cancers belong to the group called non-small cell lung cancer.
Lung cancers are generally divided into two types:
- Small cell lung cancer – sometimes called oat cell cancer because the cancer cells may look like oats when viewed under a microscope – grows rapidly and quickly spreads to other organs. There are two stages of small cell lung cancer:
- Limited – cancer is generally found only in one lung. There may also be cancer in nearby lymph nodes on the same side of the chest.
- Extensive – cancer has spread beyond the primary tumor in the lung into other parts of the body.
- Non-small cell lung cancer (NSCLC) is much more common than small cell lung cancer. The three main kinds of non-small cell lung cancer are named for the type of cells in the tumor:
- Squamous cell carcinoma is also called epidermoid carcinoma. It often begins in the bronchi and usually does not spread as quickly as other types of lung cancer.
- Adenocarcinoma usually begins along the outer edges of the lungs and under the lining of the bronchi. It is the most common type of lung cancer in people who have never smoked.
- Large cell carcinomas are a group of cancers with large, abnormal-looking cells. These tumors may begin anywhere in the lungs.
It is important to find out what kind of lung cancer a person has. The different types of carcinomas, involving different regions of the lung, may cause different symptoms and are treated differently.
A cancerous tumor of the mesothelium is called a malignant mesothelioma, but this is often shortened to just mesothelioma. Learn more about mesothelioma.
Tumors of the mediastinum
Mediastinal tumors are growths that form in the area that separates the lungs. Learn more about mediastinal tumors.
A risk factor is anything that increases a person’s chance of getting a disease such as cancer. Different cancers have different risk factors. Several risk factors make a person more likely to develop lung cancer:
- Smoking is the leading cause of lung cancer, with nearly 90 percent of lung cancers thought to be a result of smoking.
- Secondhand smoke – breathing in the smoke of others
- Asbestos exposure
- Talcum powder – While no increased risk of lung cancer has been found from the use of cosmetic talcum powder, some studies of talc miners and millers suggest a higher risk of lung cancer and other respiratory diseases from their exposure to industrial grade talc. Talcum powder is made from talc, a mineral which, in its natural form, may contain asbestos, although, by law, all home-use talcum products (baby, body, and facial powders) have been asbestos-free since 1973.
- Cancer-causing agents in the workplace, including:
- Radioactive ores such as uranium
- Vinyl chloride
- Nickel chromates
- Coal products
- Mustard gas
- Chloromethyl ethers
- Radon – a radioactive gas that cannot been seen, tasted, or smelled. It is produced by the natural breakdown of uranium.
- Personal or family history of lung cancer
- Vitamin A deficiency – People who do not get enough vitamin A are at increased risk of lung cancer. Taking too much vitamin A may also increase lung cancer risk.
- Air pollution – In some cities, air pollution may slightly increase the risk of lung cancer.
The following are the most common symptoms for lung cancer. However, each individual may experience symptoms differently.
Lung cancer usually does not cause symptoms when it first develops, but they often become present after the tumor begins growing. A cough is the most common symptom of lung cancer. Other symptoms include:
- Constant chest pain
- Shortness of breath
- Recurring lung infections, such as pneumonia or bronchitis
- Bloody or rust colored sputum
- A tumor that presses on large blood vessels near the lung can cause swelling of the neck and face
- A tumor that presses on certain nerves near the lung causing pain and weakness in the shoulder, arm, or hand
- Fever for unknown reason
Like all cancers, lung cancer can cause:
- Loss of appetite
- Loss of weight
- Pain in other parts of the body not affected by the cancer
- Bone fractures
Other symptoms can be caused by substances made by lung cancer cells – referred to as a paraneoplasticsyndrome. For example, certain lung cancer cells produce a substance that causes a sharp drop in the level of sodium in the blood, which can cause many symptoms, including confusion and sometimes even coma.
None of these symptoms is a sure sign of lung cancer. Only a physician can tell whether a patient’s symptoms are caused by cancer or by another problem. Consult your physician for a diagnosis.
In addition to a complete medical history to check for risk factors and symptoms, and a physical examination to provide other information about signs of lung cancer and other health problems, procedures used to diagnose lung cancer may include:
- Chest x-ray – to look for any mass or spot on the lungs.
- Positron Emission Tomography (PET scan): Positron emission tomography (PET) uses small amounts of radioactive materials called radiotracers, a special camera and a computer to help evaluate your organ and tissue functions. By identifying body changes at the cellular level, PET may detect the early onset of disease before it is evident on other imaging tests.
- Computed tomography scan (CT or CAT scan.) – a diagnostic imaging procedure that uses a combination of x-rays and computer technology to produce cross-sectional images (often called slices), both horizontally and vertically, of the body. A CT scan shows detailed images of any part of the body, including the bones, muscles, fat, and organs. CT scans are more detailed than general x-rays.
- Sputum cytology – a study of phlegm (mucus) cells under a microscope.
- Needle biopsy – a needle is guided into the mass while the lungs are being viewed on a CT scan and a sample of the mass is removed and evaluated in the pathology laboratory under a microscope.
- Bronchoscopy – the examination of the bronchi (the main airways of the lungs) using a flexible tube (bronchoscope) passed down the mouth or nose. Bronchoscopy helps to evaluate and diagnose lung problems, assess blockages, obtain samples of tissue and/or fluid, and/or to help remove a foreign body.
- Mediastinoscopy – a process in which a small cut is made in the neck so that a tissue sample can be taken from the lymph nodes (mediastinal nodes) along the windpipe and the major bronchial tube areas to evaluate under a microscope.
- X-rays and scans of the brain, liver, bone, and adrenal glands - to determine if the cancer has spread from where it started into other areas of the body.
Other tests and procedures may be used as well.
Specific treatment for lung cancer will be determined by your physician based on:
- Your age, overall health, and medical history
- Extent of the disease
- Your tolerance for specific medications, procedures, or therapies
- Expectations for the course of the disease
- Your opinion or preference
Lung cancer may be treated with surgery, chemotherapy or other medications, radiation therapy, laser therapy, or a combination of treatments. “Combination treatment” or “multimodality treatment” refers to having more than one type of treatment.
Treatment for lung cancer includes one or more of the following:
- Surgery- Three main types of surgery are most often used in lung cancer treatment. The choice depends on the size and location of the tumor in the lung, the extent of the cancer, the general health of the patient, and other factors.
- Segmental or wedge resection – removal of only a small part of the lung.
- Lobectomy – removal of an entire lobe of the lung.
- Pneumonectomy - removal of an entire lung.
- Radiation therapy- Radiation therapy is the use of high-energy radiation to kill cancer cells and to shrink tumors. Radiation may also be used with chemotherapy to treat lung cancer. There are two ways to deliver radiation therapy, including the following:
- External radiation (external beam therapy) – a treatment that precisely sends high levels of radiation directly to the cancer cells. The machine is controlled by the radiation therapist. Since radiation is used to kill cancer cells and to shrink tumors, special shields may be used to protect the tissue surrounding the treatment area. Radiation treatments are painless and usually last a few minutes.
- Internal radiation (brachytherapy, implant radiation) – radiation is given inside the body as close to the cancer as possible. Substances that produce radiation, called radioisotopes, may be swallowed, injected, or implanted directly into the tumor. Some of the radioactive implants are called “seeds” or “capsules.” Internal radiation involves giving a higher dose of radiation in a shorter time span than with external radiation. Some internal radiation treatments stay in the body temporarily. Other internal treatments stay in the body permanently, though the radioactive substance loses its radiation within a short period of time. In some cases, both internal and external radiation therapies are used.
- Chemotherapy – The use of anticancer drugs to treat cancerous cells. In most cases, chemotherapy works by interfering with the cancer cell’s ability to grow or reproduce. Different groups of drugs work in different ways to fight cancer cells. The oncologist will recommend a treatment plan for each individual. Chemotherapy may be given before other treatments, after other treatments, or alone for lung cancer.
- Photodynamic therapy (PDT) – A type of laser treatment that involves injecting photosensitizing chemicals into the bloodstream. Cells throughout the body absorb the chemicals. The chemicals collect and stay longer in the cancer cells, than in the healthy cells. At the right time, when the healthy cells surrounding the tumor may already be relatively free of the chemical, the light of a laser can be focused directly on the tumor. As the cells absorb the light, a chemical reaction destroys the cancer cells. For lung cancer, the light is delivered through a bronchoscope (a small, flexible tube with a light on the end) that is inserted through the mouth or nose.
- Targeted therapy - As cancers grow, they form new blood vessels which nourish them. Research aimed at blocking the growth of these blood vessels has led to the development of medications called antiangiogenesis medications. Bevacizumab (Avastin) is one of these medications. It has been found to be helpful in prolonging the survival of patients with advanced lung cancer. It is used with the standard chemotherapy regimen. Medications with other specific targets, such as erlotinib (Tarceva) and cetuximab (Erbitux), may also be useful.
- Stereotactic body radiotherapy (stereotactic radiosurgery, SRS, SBRT) – a relatively new technology, used to deliver high doses of radiation very accurately to tumors. This results in outcomes similar to that of a surgical procedure, without the use of open surgical techniques
There are specific names for the order in which treatment is given. Neoadjuvant treatment refers to having radiation or chemotherapy before surgery. Having one or both of these before surgery may help shrink the tumor – a smaller tumor is easier to take out in surgery.
Chemotherapy or radiation soon after surgery is called adjuvant treatment. The goal of adjuvant treatment is to kill any cancer cells that may be left after the surgery. Even if there is no sign of cancer cells, your physician may suggest adjuvant treatment, as it lowers the risk that the cancer may come back or spread.
Immunotherapy with medications like Nivolumab (Opdivo) and Pembrolizumab (Keytruda) augments our body’s immune system to attack the cancer cells resulting in dramatic treatment response in select group of patients with improved survival.
Clinical trials are being conducted on prevention and treatment options for lung cancer, including photodynamic therapy and chemoprevention.
Respiration is the act of breathing:
- Inhaling (inspiration) – taking in oxygen
- Exhaling (expiration) – giving off carbon dioxide
The respiratory system is made up of the organs involved in the interchanges of gases, and consists of the:
- Mouth (oral cavity)
- Pharynx (throat)
- Larynx (voice box)
- Trachea (windpipe)
The upper respiratory tract includes the:
- Nasal cavity
- Ethmoidal air cells
- Frontal sinuses
- Maxillary sinus
- Sphenoidal sinus
The lower respiratory tract includes the:
- Airways (bronchi and bronchioles)
- Air sacs (alveoli)
The lungs function in two ways:
- They take in oxygen, which the body’s cells need to live and carry out their normal functions.
- The lungs also get rid of carbon dioxide, a waste product of the cells.
The lungs are a pair of cone-shaped organs made up of spongy, pinkish-gray tissue. They take up most of the space in the chest, or the thorax (the part of the body between the base of the neck and diaphragm).
The lungs are enveloped in a membrane called the pleura.
The lungs are separated from each other by the mediastinum, an area that contains the following:
- Heart and its large vessels
- Trachea (windpipe)
- Lymph nodes
The right lung has three sections, called lobes. The left lung has two lobes.
When you breathe, the air:
- Enters the body through the nose or the mouth
- Travels down the throat through the larynx (voice box) and trachea (windpipe)
- Goes into the lungs through tubes called main-stem bronchi
- One main-stem bronchus leads to the right lung and one to the left lung
- In the lungs, the main-stem bronchi divide into smaller bronchi
- And then into even smaller tubes called bronchioles
- Bronchioles end in tiny air sacs called alveoli
Source: Adapted from content provided by StayWell Custom Communications. Always consult a physician about specific medical problems.