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Lung Cancer Diagnosis

Lung cancer can cause a number of symptoms, including:

  • a nagging cough
  • chest, shoulder or back pain, which feels like a constant ache that may or may not be related to coughing
  • shortness of breath
  • fatigue
  • weight loss
  • repeated pneumonia or bronchitis
  • coughing up blood
  • hoarseness
  • swelling of the neck and face due to the tumor compressing the superior vena cava, the main vein that drains the upper body

Because of the large size of the lungs, cancer may grow for many years, undetected, without causing symptoms. In fact, lung cancer can even spread outside the lungs without causing any symptoms.

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It is difficult to diagnose lung cancer at an early stage. Repeated chest x-rays have not been proven to be effective at increasing survival for people with lung cancer. Frequently, people do not have symptoms, or symptoms are vague or they are attributed to other ailments, such as stress, bronchitis, pulled muscles or pneumonia.

Some studies have demonstrated that a new kind of CT scan, called spiral CT, can detect small nodules (early-stage disease) poorly visible on chest x-rays. An advantage of spiral CT is the speed of the test compared to traditional CT. An entire scan can be completed in about 15 seconds. This type of technology, however, is still being tested as a screening test and is not widely available yet. The disadvantage of this testing is it often finds tiny nodules that are not cancerous, yet require additional testing or even major surgery to prove they are benign.

When lung cancer is suspected, a series of tests are conducted to confirm the disease and to determine how widely the cancer has spread (staging). The major tests include:

X-rays: A chest x-ray is frequently ordered as a first step in diagnosis. An x-ray is a two-dimensional picture that can help to locate a tumor. Once a tumor can be seen on x-ray, however, it may have already spread into the lymph nodes or elsewhere in the body. A negative chest x-ray does not always mean that there is no lung cancer present. If the tumor is small it may not be visible on an x-ray.

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Computed tomography imaging (CT scan) or, on occasion, magnetic resonance imaging (MRI): These tests may help your doctor confirm a diagnosis based on a chest x-ray. CT scans and MRIs are tests that use computerized pictures to show very detailed three-dimensional images of the body. They can show the size, shape, and location of a tumor. These tools are also useful in finding out if the tumor has spread from the lung to lymph nodes or other organs in the chest or to other parts of the body.

Positron emission tomography: In this procedure, the patient is injected intravenously with a small amount of radioactive sugar that is highly absorbed by cancer cells and detected by a special camera. The technique is very sensitive and even very small malignant tumors can show up easily on the PET scan. The test can determine if the cancer has spread to lymph nodes or other distant places because PET scans the entire body and can be used in place of several x-rays. It is also helpful in telling whether a shadow on your chest x-ray is cancer. Most insurance companies cover expenses for PET imaging and in Dec. 2000 the Health Care Financing Administration (HCFA) expanded Medicare coverage for diagnosis, staging, treatment and for monitoring recurrences.

Bone scans: A small amount of radioactive tracer is injected into a vein and accumulates in areas of bone that may be cancerous. Then a gamma camera is used to scan the body to detect where bone formation is occurring faster than the surrounding bone in response to injury of the bone by cancer. Bone scans are commonly done in patients with lung cancer when symptoms or other test results suggest that the cancer has spread to the bones.

Lung biopsy: A biopsy is a test in which tissue is removed from the suspected tumor and examined under a microscope to see if cancer cells are present. A biopsy is necessary for the doctor to confirm a cancer diagnosis, and to identify the specific type of cancer and its stage. There are two types of biopsy. Needle biopsy is just like it sounds: a needle is inserted through the chest wall to take a sample of tissue from a known tumor after it has been located by chest x-ray, CT scan or fluoroscopy (fluoroscopy is like an x-ray, but the image is viewed on a screen in real time rather than on film). The other kind is surgical biopsy. In this test, the chest wall is opened to remove a part or all of the tumor. Tissue samples are examined by a pathologist, who will be able to provide information about the type of cancer, if any, that is present and the stage of the cancer.

Bronchoscopy: A procedure in which a flexible lighted tube (bronchoscope) is inserted through the nose or mouth, and into the airways to collect bronchial and/or lung secretions or to biopsy for tissue specimens. Sedation is required because the procedure can be uncomfortable.

Mediastinoscopy: Under general anesthesia, a small cut is made in your neck to allow a hollow lighted tube to be inserted behind the sternum (breast bone). Through this hollow tube specialized instruments can be placed to sample tissue from the mediastinal lymph nodes (along the windpipe and the major bronchial tube areas). Microscopic examination can reveal if cancer cells are present.

Mediastinotomy: A surgical procedure that opens the chest cavity to remove samples of mediastinal lymph nodes while the patient is under general anesthesia. More lymph nodes can be sampled in this way than with the mediastinoscopy procedure.

Thoracentesis: A needle is placed between the ribs to drain accumulated fluid around the lungs (called pleural effusion) and examined microscopically for the presence of cancer cells. Malignant pleural fluid can indicate that cancer has spread to the delicates membranes that cover the lungs (called pleural membranes) Fluid accumulation can also prevent the lungs from filling with air, so thoracentesis can also help improve the patient's breathing.

Thoracoscopy: A procedure that views the space between the lungs and the chest wall using a thin, lighted tube connected to a video camera and monitor. Like thoracentesis, this examination checks whether a pleural effusion is the result of cancer mestastasis to the pleural membranes or to some other, benign condition such as heart failure or an infection.

Bone marrow biopsy: A sample of bone about 1/16 inch across and 1 inch long (usually from the back of your hip bone) is removed after the area has been numbed with local anesthesia. The sample is checked for cancer cells under the microscope.

The stages of non-small cell cancer are:

  • Occult stage: Cancer cells are found in sputum, but no tumor can be found on x-rays.
  • Stage 0: Cancer is only found in a local area and only in a few layers of cells. It has not grown through the top lining of the lung. Another term for this type of lung cancer is carcinoma in situ.
  • Stage I: The cancer is only in the lung, and normal tissue is around it.
  • Stage II: Cancer has spread to nearby lymph nodes within the lung or to the surrounding chest wall.
  • Stage III: The cancer has spread to the lymph nodes in the area that separates the two lungs (mediastinum); or to the lymph nodes on the other side of the chest or in the neck. Stage III is further divided into stage IIIA (occasionally can be operated on) and stage IIIB (usually cannot be operated on).
  • Stage IV: Cancer has spread to other parts of the body.
  • Recurrent: Cancer has come back (recurred) after previous treatment.

The following stages are used for small-cell lung cancer:

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  • Limited stage: Cancer is found only in one lung and in nearby lymph nodes. (Lymph nodes are small, bean-shaped structures that are found throughout the body. They produce and store infection-fighting cells.)
  • Extensive stage: Cancer has spread outside of the lung where it began to other tissues in the chest or to other parts of the body.
  • Recurrent stage: Recurrent disease means that the cancer has come back (recurred) after it has been treated. It may come back in the lungs or in another part of the body.

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