Pancoast tumors form at the very top of either lung. Pancoast tumors are a subset of non-small cell lung cancers that invade the top of the chest wall. Because of their location, they invade adjoining tissue.
Pancoast tumors form an abnormal patch of tissue over the lung apex and principally involve the chest wall structures rather than the underlying lung tissue. They may invade areas such as lymph nodes, nerves, ribs, and spine.
The risk factors for almost all lung cancers are similar. These include the following:
Secondary smoke exposure
Prolonged asbestos exposure
Exposure to industrial elements (such as gold or nickel)
Pancoast Tumor Symptoms
Although a Pancoast tumor is a lung tumor, it rarely causes symptoms that are typically related to the lungs (like cough or chest pain).
The initial symptom is pain in the shoulder, the inner part of the shoulder blades, or both.
The pain may later extend to the inner side of the arm, the elbow, and the pinky and ring fingers.
The associated pain is severe and constant, often requiring narcotic pain medications for relief. The affected person usually needs to support the elbow of the affected arm in the opposite hand to ease the tension on the shoulder and upper arm.
The hand, arm, and forearm may weaken, muscles degenerate or shrink from disuse, or develop a sensation of pricking, tingling, or creeping on the skin.
If the tumor extends to the certain nerves, Horner syndrome may develop on the face and hand of one side of the body. Horner syndrome is characterized by drooping eyelids, absence of sweating, and sinking of the eyeball.
In as many as 10%-25% of persons with Pancoast tumor, compression of the spinal cord and paralysis of the lower half of the body develop when the tumor extends into the opening between two vertebrae.
Pancoast Tumor Exams and Tests
The blood exam for persons with Pancoast tumor is not specific, and the results cannot diagnose the condition.
In the early stages, Pancoast tumors are difficult to detect on chest X-rays because the top of the lung is located in an area of the body that is difficult to visualize clearly on an X-ray. Shadows that lie over the lungs make the image on the X-ray film unclear. Many patients end up consulting orthopedic surgeons and/or neurologists before a definitive diagnosis is made.
A chest X-ray may reveal anything from asymmetry of the top of the lungs in the form of a small, uniform patch of tissue on the apex of one lung to a large mass, depending on the stage when the tumor is first diagnosed.
The plain chest X-ray may show that the tumor has invaded one or more ribs or parts of the vertebrae. Bone destruction of the back ribs may be visible on the X-ray.
CT scan of the chest: A CT scan helps determine if the tumor has invaded areas, such as the trachea (windpipe), or esophagus (food pipe). Contrast CT scanning, with the help of an injected, radioactive dye that is visible on the scan, is useful for assessing if the tumor has involved the blood vessels under the collarbone.
MRI of the chest: MRI findings are more accurate than CT scans in identifying the extent of the tumor's growth. An MRI can also better assess the tumor's invasion of nearby areas.
Arteriogram or venogram: For this test, a liquid is injected into nearby blood vessels so they will show up on an X-ray. Rarely, the Pancoast tumor involves the artery or the vein under the collarbone.
Bronchoscopy (using a tubular, illuminated instrument for inspecting the airways of the lung) helps evaluate the tracheal and bronchial cavities. However, because most Pancoast tumors form on the periphery of the lung, bronchoscopy does not usually help the doctor make a diagnosis.
Biopsy: This is the removal of a sample of tissue for examination under a microscope. Following a biopsy, the doctor can make a diagnosis in 95% of persons based on results from a needle biopsy through the skin, either with the help of an X-ray or CT scan to help guide the doctor.
Although more than 90% of patients can be correctly diagnosed based on clinical and radiological findings (chest X-ray, CT, MRI) alone, open biopsy of the tumor for confirmation may need to be performed through an incision above the collarbone. A definite diagnosis is important before proceeding with treatment of a Pancoast tumor. Results from a needle biopsy are also useful in determining the cell type prior to treatment. Even though getting a diagnosis is relatively simple, performing a tissue biopsy is always necessary.
Tests to Determine Spread
Among other considerations, a CT or MRI scan of the brain is recommended in the initial evaluation because distant spread to the brain is common, and diagnosis of these is necessary to determine treatment.
Mediastinoscopy: This procedure is performed to determine the extent the tumor has spread into nearby areas. It is a procedure in which a tube is inserted behind the breastbone through a small cut at the lowest part of the neck. Samples of lymph nodes are taken from this area to look for cancer cells.
Positron emission tomography (PET) scans (a nuclear imaging technique used to view body functions) may help identify involved lymph nodes and the distant spread of cancer.
Bone scans may be used to see if the cancer has spread to the bones.