Lung cancer usually starts in the lining of the bronchi, 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. In 2006, 174,470 new cases of lung cancer are expected, according to the American Cancer Society.
Lung cancers are believed to develop over a period of many years
Lung cancers are generally divided into two types
Non-small cell lung cancer is more common than small cell lung cancer. The main kinds of non-small cell lung cancer are named for the type of cells in the tumor:
Squamous cell carcinoma, also called epidermoid carcinoma , is the most common type of lung cancer in men. 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 women and in people who have never smoked.
Lung cancer has now become the main cancer killer in both men and women ,reflecting the changing smoking habits in women that have occurred since the early 1950s and the long exposure required for the development of this malignancy ,the rate in women is rising at an alarming pace.
The prognosis of lung cancer is stage-dependant,and is influenced by the size and location of the tumor (T status),the presence or absence of lymph nodes metasteses(N status),and the presence or absence of distant metasteses (M status).For this reason, the initial clinical staging of the tumor is important not only for prognosis but also for decision about treatment .
.The staging of ca. of the lung is by the TNM approach so the summary of staging
Occult stage ---malignant cells in sputum,bronchial wash but tumor not visualized by imaging studies or bronchoscopy.
Stage 0---ca. in situ.
Stage IA---tumor <3cm arising more than 2cm distal to the carina (T1N0).
Stage IB---tumor>3cm with involvement of visceral pleura arising more than 2cm from carina(T2N0).
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:
A risk factor is anything that may increase a person's chance of developing a disease.
It may be an activity such as smoking, diet, family history, or many other things.
Different diseases, including cancers, have different risk factors.
Although these factors can increase a person's risk, they do not necessarily cause the disease. Some people with one or more risk factors never develop the disease, while others develop disease and have no known risk factors
second-hand smoke - breathing in the smoke of others.
smoking marijuana cigarettes, which:
contain more tar than tobacco cigarettes.
are inhaled very deeply.
are smoked all the way to the end where tar content is the highest.
Because marijuana is an illegal substance, it is not possible to control whether it contains fungi, pesticides and other additives.
recurring inflammation, such as from tuberculosis and some types of pneumonia.
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.
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 include:
chest x-ray - to look for any mass or spot on the lungs.
other special x-rays and scans (such as the CT (computed tomography) scan) - can provide more precise information about the size, shape, and position of a tumor.
sputum cytology - a study of phlegm (spit) 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 - a fiberoptic flexible, lighted tube is passed through the mouth or nose into the bronchi to help find centrally located tumors or blockages, and gather samples of tissue or fluids to be examined under a microscope.
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.
positron emission tomography (PET) scan - radioactive-tagged glucose (sugar) is injected into the bloodstream. Tissues that use the glucose more than normal tissues (such as tumors) can be detected by a scanning machine. PET scans can be used to find small tumors or to check if treatment for a known tumor is working.
Magnetic resonance imaging(MRI ),it differentiates vascular from solid structures and demonstrates hilar, mediastinal and parenchymal anatomy in both coronal and sagittal planes.
Thoracoscopy .thoracoscopic staging of lung cancer has been demonstrated to be safe and effective in selected patients .
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.
Three main types of surgery are most often used in lung cancer treatment. The choice depends on the size and location of the tumor, the extent of the cancer, the general health of the patient, and other factors.
segmental or wedge resection - to remove only a small part of the lung
lobectomy - removal of an entire lobe of the lung
pneumonectomy - removal of an entire lung
radiation therapy (also called radiotherapy ) - the use of high-energy rays to damage cancer cells and stop them from growing and dividing.
chemotherapy - the use of drugs to kill cancer cells
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
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 .
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
The solitary pulmonary nodule(SPN) (acoin lesion);has been defined to be an abnormal density up to 4cm in diameter rounded or ovoid in appearance,surrounded by azone of lung tissue on x-ray,and free of cavitation or associated lung infiltrates .
The differential diagnosis of an SPN includes :pulmonary hamartoma,granuloma,pulmonary AVfistula,pulmonary infarction and several benign and malignant tumors.
Other Lung Ttumor :Carcinoid Tumor,Tumor of bronchial gland origin,Carcinosarcoma