Primary Lung Cancer
Primary lung cancer is a serious and often fatal respiratory malignancy that begins in the airways and air sacs of the lungs.
What is going on in the body?
ancer of the lung can begin in the lining of the trachea or its larger branches (bronchi), in the smaller airways, or in the tiny air sacs.
Lung cancer is classified into two major types. Non-small cell lung cancer, or NSCLC, accounts for 70% to 80% of lung cancers. Small cell lung cancer (SCLC, also known as "oat cell" carcinoma) , accounts for the remainder.
Both types of lung cancer are fatal more often than not. They invade surrounding tissue and can spread to other parts of the body through the lymph nodes and bloodstream.
Lung cancer accounts for more deaths in the United States -- about 160,000 deaths each year - than any other cancer. When it was first reconized in the 1920s and 1930s, lung cancer was mostly a disease of men, but women, who began to smoke cigarettes several decades later than men, have closed much of the gap. In the U.S. more women die from lung cancer than from breast cancer.
Thanks to the success of tobacco control efforts, the lung cancer rate for men peaked in the 1980s and has continued downward, while that for women crested in the mid-1990s and has remained level.
Most types of lung cancer are aggressive, spreading early in their course. Lung cancer can cause life threatening complications in the chest and spread to distant sites throughout the body, causing death by any of a number of mechanisms. A person also may have symptoms either because a tumor has pushed another organ out of position, or because the tumor cells have produced a toxic chemical. The latter phenomenon is known as a paraneoplastic syndrome.
What are the causes and risks of the disease?
Inhaling tobacco smoke probably causes at least 90% of all lung cancer. Smokers have an estimate 10 to 30 times greater risk compared to lifetime nonsmokers.
A person's risk for lung cancer depends on how many packs of cigarettes he or she smokes each day and for how many years. When a person quits smoking, his or her risk decreases steadily but remains elevated above that of a never-smoker for life.
People exposed to radiation, radon, asbestos, second-hand tobacco smoke, and probably heavy metal are also at risk.
Lung cancer occurs if the cells lining the airways of the lungs are constantly exposed and stimulated by cancer-causing substances over several decades. This changes the genetic DNA, makeup of cells and results in the uncontrolled growth of abnormal cells.
Although it is rare, some people who have not been exposed to cigarette smoke or radiation may develop lung cancer.
What can be done to prevent the disease?
This best way to prevent this cancer is not to smoke and to avoid exposure to second-hand smoke. People who want to quit smoking
- behavior modification programs
- support groups
- nicotine chewing gum
- nicotine patches
- bupropion medication
- alternative approaches such as biofeedback, hypnosis, and acupuncture
Educating young people about the dangers of smoking is a key preventive strategy. Radon is a cancer-causing substance that should also be avoided. It is sometimes found in the home. If present, it can be reduced to acceptable levels by various means, such as caulking and creating more ventilation.
Workplace exposure to asbestos and other toxic substances can be minimized by following appropriate occupational health guidelines.
Early diagnosis may help in reducing some deaths, however, lung cancer tends to spread early. There are no reliable screening blood tests or sputum tests. Screening chest X-rays or CT scans have not been shown to be cost effective on a population-wide basis.
How is the disease diagnosed?
The disease is diagnosed by taking a tissue sample of the lung. There are many ways to collect a tissue sample. Biopsies are obtained wherever the cancer is most accessible. A needle puncture, brush or pinch biopsy is frequently all that is needed.
Various ways to collect tissue include:
- needle aspiration of pleural fluid through the chest wall
- pleural biopsy
- needle biopsy of a liver mass
- biopsy of tissue from a peripheral lymph node obtained either through needle biopsy or a surgical incision
- biopsy of a mass in any location of the body
Through this tissue sample, doctors can tell if the cancer is small cell or non-small cell. Small cell is an aggressive lung cancer deriving from the neuroendocrine cells. It usually has spread cancer cells throughout the body at the time of diagnosis. A bone marrow biopsy may be performed to see if it has spread to the marrow.
Staging for small cell lung cancer is generally divided into limited disease versus extensive disease. Non-small cell lung cancer can include all kinds of different cells. Some are flat and scaly, while other disguise themselves as lung cells. These cancers are categorized or staged differently than small cell cancer because non-small cell lung cancer may be curable.
In order to evaluate whether removing all or part of the lung may be feasible, more tests are needed. This includes blood tests, MRI scan of the chest, bronchoscopy, bone scan, liver scan, CT scans, and PET scans.
Diagnostic staging is somewhat complex.
- Stage I consists of a small lung mass that has not invaded the chest wall, trachea, or lymph nodes.
- Stage II can involve the lymph nodes in the area where the windpipe branches into the two lungs, but not the center of the chest around the heart.
- Stage III consists of involvement of lymph nodes in the hilum, which is an area at the root of the lungs (III-A), or a locally invasive tumor (III-B).
- Stage IV involves any tumor in the lung that has spread to the other lung or outside of the chest.
At many times exact staging is not known until the chest is opened for surgery.
Long Term Effects
What are the long-term effects of the disease?
Stage I cancers are considered curable by surgical removal 50 to 90% of the time.
Stage II tumors are curable, less than 50% of the time. Curability drops off rapidly in later stage disease.
People with stage III-B and IV usually have an average survival of less than 1 year.
Small cell lung cancer with bulky metastatic disease has a survival of less than 1 year as well. Some patients with grossly limited small cell lung cancer can survive for more than 2 years with aggressive treatment with combination chemotherapy and radiation therapy.
What are the risks to others?
Others are not put at risk since this type of cancer is not considered contagious.
What are the treatments for the disease?
Small cell lung cancer spreads throughout the body. It can be sensitive to chemotherapy and radiation therapy. Surgery to remove the cancer where it started is usually not helpful.
Multiple agent chemotherapy is given with limited or extensive small cell lung cancer. Response rates are good initially and some complete remissions are attainable; however, the cancer almost always returns. Chemotherapy is often followed or combined with radiation therapy to the primary cancer site. Radiation to the brain has been used with small cell lung cancer because this is where it often spreads, even after treatment has been finished.
Chemotherapy drugs that are used include etoposide, cisplatin, carboplatin, doxorubicin, vincristine, cyclophosphamide, vinorelbine or paclitaxel.
Limited stage (I and II) non-small cell cancers are considered candidates for surgery with the intention to cure. Treatment includes the partial removal of the lung and the removal of lymph nodes in the chest cavity. This is followed up with radiation therapy. Radiation therapy may be useful in patients who are not able to have surgery because of other medical conditions. Chemotherapy in addition to the radiation may or may not be helpful, this is dependent on the stage of the tumor. Pre- or postoperative chemotherapy have been given along with complete surgical removal.
People with higher stages of cancer are not likely to benefit from extensive surgery. They are treated with radiation and/or chemotherapy to relieve symptoms and improve quality of life. Radiation therapy can be given from the outside of the body or through the windpipe.
Chemotherapy drugs that have given response include vinblastine, vincristine, cisplatin, etoposide, and 5-fluorouracil (5-FU). People whose cancer has spread to the brain may benefit from whole brain irradiation and corticosteroids to reduce brain swelling. Stereotactic brain irradiation or surgical removal of a solitary brain metastases may also be of value. Radiation and/or chemotherapy may relieve other symptoms including painful enlarged liver, bone pain caused by metastases from the lung cancer, or generally failing health
Fluid in the chest containing malignant cells is treated with needle or chest tube drainage followed by instillation of chemotherapy into the space within the chest that holds the lungs. This will dry up any fluid and improve symptoms. Normal lung is very sensitive to radiation damage, so a complete lung cannot be exposed to radiation.
Experimental therapies are available for treatment of all stages of this disease since it has been so common and since standard therapies have had such minimal impact on survival.
Development of new drugs and other treatments will benefit the hundreds of thousands of people who have yet to develop this disease.
People with this disease often suffer from too much calcium in the blood. High calcium is treated with corticosteroids, diphosphonate medicine, or primary treatment of the cancer.
A team of medical experts is often needed to manage lung cancer. This includes thoracic surgeons, radiation oncologists, medical oncologists, lung specialists, and radiologists.. Terminal care can be provided by a hospice-based team.
What are the side effects of the treatments?
When surgery is done to remove part of a lung, it can result in a decreased amount of functioning lung. Before surgery, it is important to test the uninvolved lung to see if it has enough capacity to sustain the person after surgery. Opening the chest cavity for any reason is major surgery, and can sometimes cause significant illness or and even death
Side effects of radiation include:
- skin redness
- redness, swelling, and pain in the lining of the esophagus, a condition called esophagitis
- injury to the lungs
Chemotherapy also has many side effects. The drugs that are used will cause:
- hair loss
- lowered blood counts and risks of infections
- potential need for transfusions
- abnormal bleeding or blood clotting
- damage to nerves, kidneys, and liver
People who receive radiation to the brain can have:
- problems with short-term memory losses
- difficulty walking
- coordination problems
- loss of brain cells
Because some of the lung capacity is removed by surgery or damaged by radiation, patients might need daily oxygen even if they did not use it before treatment.
Lung cancer can recur in spite of any or all of the above treatments. As with most cancers, the prospect of survival after a recurrence is poor.
What happens after treatment for the disease?
After treatment, people will be followed for lung function, any delayed or prolonged side effects of the treatments, and for recurrence of the disease.
How is the disease monitored?
Frequent visits to the healthcare provider must continue for several months to a few years. Physical exams, laboratory tests, chest CT, abdominal CT, and sometimes bronchoscopy are needed.