Lung Cancer

Lung cancer is now the most common form of cancer diagnosed in the United States and a major cause of death. Lung cancer accounts for 14% of all cancers and 28% of all cancer deaths. Cigarette smoking is responsible for an estimated 87% of lung cancer deaths, or seven out of eight. Male heavy smokers (one or more packs of cigarettes daily) have a lung cancer mortality 15 to 25 times higher than male nonsmokers. In female heavy smokers. The risk is two to five times greater than nonsmokers.

Understanding the Cancer Process:

All types of cancer develop in our cells, the body’s basic unit of life. To understand cancer, it is helpful to know how normal cells become cancerous. The body is made up of many types of cells. Normally, cells grow, divide, and produce more cells as needed to keep the body healthy and functioning properly. Sometimes, however, the process goes astray- cells keep dividing when new cells are not needed. The mass of extra cells forms a growth or tumor. Tumors can be benign or malignant.

Benign tumors are not cancer. They often can be removed and in most cases they do not come back. Cells in benign tumors do not spread to other parts of the body.

Malignant tumors are cancer. Cells in malignant tumors are abnormal and divide without control. These cancer cells can invade and destroy the tissue around them. Cancer cells can also break away form 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 form the original (primary ) tumor to form new (secondary ) tumors in other parts of the body.

Lungs

The lungs, a pair of sponge-like, cone-shaped organs, are part of the respiratory system. The right lung has three sections, called lobes: it is a little larger than the left lung, which has two lobes. When we breathe in the lungs take in oxygen, which our cells need to live and carry out their normal functions. When we breathe out, the lungs get rid of carbon dioxide, which is a waste product of the body’s cells.

Lung Cancer:

Lung cancers are divided into two major groups, which make up more than 90% of all lung cancers cases; small cell lung cancer and non-small cell lung caner. Other less common lung tumors are carcinoid tumor, bronchioalveolar cancer.

Small Cell Cancer: (15% of lung cancers)

This cancer makes up about 15% of all lung cancer cases. This is also sometimes call oat cell cancer. The tumor is most often found in the bronchial submucosa and is more likely to have metastasized (spread) at the time of diagnosis than other types of lung cancer. Small cell lung cancer is separated from other cell types due to its rapid growth rate, Symptoms are of brief duration prior to diagnosis. Eighty percent of small cell lung cancer is centrally and 20% is in the periphery of the lung. Histological verification by a pathologist of small cell cancer is mandatory because treatment is significantly different from non-small cell cancer.

Non-small Cell Cancer: (75%-80% of lung cancers)

Squamous Cell Tumor:

This is the one of the most common form of lung cancer worldwide, accounting for 40%-45% of lung cancers. This tumor usually starts in the large bronchi and very often stays in the chest, without spreading, for longer periods of time than other lung cancers. There is a strong association with smoking. Treatment is surgical removal whenever possible and 5year survival over 50% when no evidence of lymph node spread.

Adenocarcinoma:

This tumor is increasing in frequency and now accounts for 40%-50% of all lung cancers. These tumors are often found along the outer edges of the lungs and under the lining of the bronchi. Progression rate is average and inclination to spread average. There is a strong relationship to smoking. Bronchioalveolar carcinoma is a subtype of adenocarcinoma. Treatment is surgical removal whenever possible but this is less likely then with squamous cell cancer. Five year survival rate is less than 10%.

Large Cell Carcinoma:

This tumor makes up about 15% of lung tumors and most often found in the smaller bronchi. There is a strong relationship to smoking. Treatment is surgical removal whenever possible but tumor spreads early and thus not always able to treat surgically. Five year survival of patient is less then 10%.

Carcinoid Carcinoma:

This tumor accounts for less then 20% of lung cancers. The tumor arises from glands near the bronchi. These tumors can have some endocrine function. Treatment is surgical removal.

Lung Cancer: Who’s at Risk:

Cigarettes. Smoking cigarettes causes lung cancer. Harmful substances, called carcinogens, in the tobacco damage the cells in the lungs. Over time, the damaged cells may become cancerous. The likelihood that a smoker will develop lung cancer is affected by the age at which smoking begins, how long the person has smoked, the number of cigarettes smoked per day and how deeply the smoker inhales. Stopping smoking greatly reduces a person’s risk for developing lung cancer.

Cigars and Pipes. Cigar and pipe smokers have a higher risk of lung cancer than nonsmokers.

Environmental Tobacco Smoke. The chance of developing lung cancer is increased by exposure to second hand smoke.

Radon. Radon is an invisible, odorless, and tasteless radioactive gas that occurs naturally in soil and rocks. It can cause damage to the lungs that may lead to lung cancer. People who work in mines may be exposed to radon and, in some parts of the country, radon is found in houses.

Asbestos. Asbestos is the name of a group of minerals that occur naturally as fibers and are used in certain industries. Asbestos fibers tend to break easily into particles that can float in the air and stick to clothes. When the particles are inhaled, they can lodge in the lungs, damaging cells and increase the risk for lung cancer.

Pollution. This relationship has not been clearly defined.

Lung Disease. Certain lung diseases, such as tuberculosis (TB), increase a person’s chance of lung cancer developing.

Recognizing Symptoms:

Common signs and symptoms of lung cancer include:

• A cough that doesn’t go away and gets worse over time
• Constant chest pain
• Coughing up blood
• Shortness of breath, wheezing, or hoarseness
• Repeated problems with pneumonia or bronchitis
• Swelling of the neck and face
• Fatigue

Diagnosing Lung Cancer:

To help find the cause of symptoms, the doctor evaluates a person’s medical history, smoking history, exposure to environmental and occupational substances, and family history of cancer. Usually a chest x-ray is taken to view the lungs. To confirm the presence of lung cancer, the doctor must try to examine tissue from the lung. A biopsy- the removal of a small sample of tissue for examination under a microscope by a pathologist – can show whether a person has cancer. A number of 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 tumor to remove a sample of tissue. This is usually done with CT guidance.

Thoracentesis. Using a needle, the doctor removes a sample of the fluid that surrounds the lung to check for cancer cells.

Thoracoscopy/Thoracotomy. Either through a small scope or a surgical incision tissue is obtained to be examined.

Different Stages of Lung Cancer

The stage of a cancer is a term used to describe its size and whether it has spread beyond its original site. Knowing the extent of the cancer and the grade (see below) helps the doctor to decide on the most appropriate treatment. General cancer is divided into four stages, from small and localized (stage one) to cancer that has spread into surrounding structures (stages two or three) or to other parts of the body (stage four). If the cancer has spread to distant parts of the body this is known as metastatic cancer. The staging is different for small cell and for non-small cell cancers of the lung.

Small Cell Lung Cancer:

Small cell lung cancers are divided into just two stages. This is because small cell lung cancer often spreads outside the lung quite early on. Even if the doctor cannot see any spread of the cancer on your scans, it is likely that some cancer cells will have broken away and traveled through the bloodstream or lymph system. To be safe, small cell lung cancers are usually treated as though they have spread, whether any secondary cancer can be seen or not.

The two stages of small cell lung cancer are:

Limited disease: the cancer cells can be seen only in one lung, or in fluid around the lung.

Extensive disease: the cancer has spread outside the lung within the chest area or the other parts of the body.

Non-Small Cell Lung Cancer:

Stage 1 is very localized cancer with no cancer in the lymph nodes.

Stage 2 cancer has spread to the lymph nodes close to the affected lung.

Stage 3 cancer has spread into the tissue around the lung near to where the cancer started. This can be into the chest wall, the covering of the lung, the middle of the chest (mediastinum) or other lymph nodes.

Stage 4 cancer has spread to another part of the body.

Staging the Disease

If the diagnosis is cancer, the doctor will want to learn the stage (or extent) of the disease. Staging is done to find out whether the cancer has spread and, if so, to what parts of the body. Lung cancer often spreads to the bone or brain. Some tests to determine if the cancer has spread include:

CAT (or CT) scan (computer 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.

Bone scan. A bone scan 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 radioactive levels in these areas and records them on and x-ray film.

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 the mediastinoscopy the scope is inserted through a small incision in the neck; in mediastinotomy, the incision is made in the chest. In either procedure, the scope is also used to remove a tissue sample. The patient receives a general anesthetic.

PET ( positron emission tomography) scan. A PET scan uses low-dose radioactive sugar to measure the activity of cells in different parts of the body. a very small amount of radioactive substance is injected into a vein in your arm. A scan is then taken. Areas of cancer are usually more active than surrounding tissue so they take up more of the radioactive substance and show up on the scan.

Types of Treatment for Lung Cancer

Treatment depends on a number of factors, including the type of lung cancer (non-small or small cell cancer), the size, location, and extent of the tumor, and the general health of the patient. Many different 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 surgery a doctor performs depends of the location of the tumor in the lung. An operation to remove only a small 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 an entire lung. Some tumors are inoperable ( cannot be removed by surgery) because of the size or location, and some patients cannot have surgery for other medical reasons.

Chemotherapy is the use of 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 the 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 or by means of a catheter, a thin tube that is placed into a large vein and remains there as long as it is needed. Some anticancer drugs are given in the form of a pill.

Radiation therapy, also called radiotherapy, involves the use of 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 primary treatment instead of surgery. Radiation therapy may also be used to relieve symptoms such as shortness of breath. Radiation for 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).

Treatment of Lung Cancer

Small Cell Lung Cancer: Chemotherapy is the main treatment for small cell lung cancer. In many People chemotherapy for small cell lung cancer will enable them to live for longer with better control of symptoms. Chemotherapy may be given on its own, or before radiotherapy. Surgery is not usually used to treat this caner, except in very early cases. This is because the cancer has usually spread to other parts of the body before being diagnosed, even if it cannot be seen on a scan. The scans and tests you had to diagnose the cancer may be repeated later to see how well the cancer is responding to treatment. In advanced lung cancer, radiotherapy may also be used very effectively to relieve symptoms, such as pain.

Non-small Cell Lung Cancer: Early stage (1 and 2) non-small cell lung cancer can often be removed with surgery. If people have other medical problems or are not fit enough to have surgery, radiotherapy may be given to the lung tumor, instead. Chemotherapy is sometimes given before surgery and/or radiation. This is called neo-adjuvant chemotherapy. Chemotherapy is also sometimes used after surgery (adjuvant chemotherapy), to reduce the risk of the cancer coming back. If the tumor has spread into the tissue close to the lung or the lymph nodes it may be treated with: just radiotherapy, radiotherapy and chemotherapy, or just surgery.

Carcinoid Tumor: Treatment is similar to non-small cell lung cancer listed above.

Side Effects of theTreatments

Surgery: This is a major operation requiring a thoracotomy (incision in the chest) and general anesthesia. The usual surgery is a lobectomy ( removal of one of the lobes of the lung). Occasionally a pneumonectomy (removal of the entire lung on the side of the tumor) or a wedge resection (removal of the tumor with only a small amount of lung tissue) will be done. After lung surgery , air and fluid tend to collect in the chest. Chest tubes will be placed at surgery to remove this fluid. These tubes will be removed in 3-7 days. Patients need to cough and deep breath to help expand the lung. Pain medication will be given for post operative chest pain. The hospitalization is usually 7-10 days but it will take about 6-8 weeks to get back to normal strength.

Chemotherapy: The chemotherapy affects normal as well as cancerous cells. Side effects depend largely on the specific drugs and the dose (amount of drug given). Common side effects of chemotherapy include nausea and vomiting, hair loss, mouth sores, and fatigue.

Radiation Therapy: Like chemotherapy, radiation therapy affects normal as well as cancerous cells, Side effects of therapy depend mainly on the part of the body that is treated and the treatment dose. Common side effects of radiation therapy are a dry, sore throat, difficulty swallowing, fatigue , skin changes at the site of treatment, and loss of appetite.

Follow-up Care

Follow-up care after treatment for lung cancer is very important. Regular checkups ensure that changes in health are noticed, and if the cancer returns Or a new cancer develops, it can be treated as soon as possible. Checkups may include physical exams, chest x-rays, CT scans, PET scans, and lab tests. Between scheduled appointments, people who have had lung cancer should report any health problems to their doctor as soon as the appear.