Carcinoid Lung Tumor Exams and Tests

Blood tests

There are no biochemical tests to determine the presence of a carcinoid lung tumor or to diagnose a known lung tumor as a carcinoid lung tumor.

If your health care practitioner suspects that a patient has a carcinoid lung tumor, he or she may be advised to undergo some blood and urine tests. Sometimes the hormone-like substances can affect the chemistry of the blood by altering kidney and/or intestinal function and therefore alter the results of certain blood tests. Some tests would detect some of the hormone-like substances or their by-products produced by the carcinoid tumor.

Chest X-ray

• An abnormal finding on chest X-ray is present in about 75% of patients with a carcinoid lung tumor.
  
  
• Findings on X-ray include either the presence of the tumor itself or indirect evidence of its presence (for example, indication of obstruction caused by the tumor).

CT scan

• Some carcinoid lung tumors that are small or in locations where they are covered by other organs in the chest may not be seen on a chest X-ray. If a patient's health care practitioner is in doubt or there is a vague abnormality on the chest X-ray, the patient may be advised to get a CT scan done.
  
  
• CT scna can demonstrate more details about the nodules, masses, or suspicious changes found on chest X-ray.
  
  
• A CT scan using intravenous contrast dye also can be useful. Because carcinoid tumors are highly vascular, they may show greater enhancement on CT scan.
  
  
• It is useful for characterizing and staging of the tumors.

Magnetic resonance imaging (MRI)

• MRI generally provides information similar to that of CT scan.
  
  
• MRI may be useful for differentiating small tumors from adjacent blood vessels.

Radionuclide studies

• Octreotide scintigraphy or OctreoScan: A small amount of octreotide (a radioactive hormone-like drug) is injected into a vein. The drug is taken up by the cells of the carcinoid tumor. The health care practitioner uses a special radioactivity-detecting camera to see where the drug accumulates. This exam helps in the diagnosis of a carcinoid lung tumor and determining whether the tumor has spread to other areas of the body.
  
  
• Iodine-131 meta-iodo-benzyl guanidine (MIBG) scintigraphy: MIBG is a chemical that is taken up by the cells of the carcinoid tumor. In this exam, radioactive iodine attached to MIBG is injected into the bloodstream. If a carcinoid tumor is present, the scanner will detect the radioactivity and thus help in diagnosing the tumor.

Biopsy

Even if a chest X-ray and/or CT scan shows a tumor, these exams cannot confirm whether the mass is a carcinoid lung tumor, a lung carcinoma, or a localized infection. The only way to verify the diagnosis of a carcinoid tumor is to remove cells from the tumor and examine them under a microscope. This procedure is called biopsy.

A lung biopsy can be done in several ways:

• Bronchoscopy
  
  
  • This procedure involves inserting a fiber optic viewing tube called a bronchoscope into the windpipe and the airways of your lungs through the throat.
    
    
  • It allows the health care practitioner to visualize the airways of the lungs, and in case a tumor is found, to do a biopsy.
    
    
  • In most cases, the physician makes the diagnosis of carcinoid lung tumor based on the findings from bronchoscopy and a combination of radiologic (for example, X-ray, CT scan) studies.
    
  
  
  
• Transbronchial fine-needle biopsy: If the tumor is small, a fine-needle biopsy of a carcinoid tumor may be performed through the bronchoscope. This procedure is called transbronchial fine-needle biopsy
  
  
• Transthoracic needle biopsy: Tumors that are not accessible through bronchoscopy and are located in the periphery of the lung are accessed using a long needle inserted between the ribs. CT scan images are used to guide the needle into the tumor for taking a biopsy. This procedure is called transthoracic needle biopsy.
  
  
• Thoracotomy (surgically opening the chest cavity): In some persons, neither a bronchoscopic biopsy nor a transthoracic needle biopsy can provide enough tissue to identify the type of tumor, and a thoracotomy may be necessary to obtain a biopsy. Usually, the tumor is completely removed during thoracotomy.

Staging

Staging is a process of finding out how localized or widespread a tumor is.

• Typical carcinoid tumors, considered the least aggressive form, most commonly are found to be stage I tumors (localized to one area) at the time of diagnosis.
  
  
• More than 50% of the less common atypical carcinoid tumors show evidence of further spread to adjacent areas or lymph nodes at the time of diagnosis.
  
  
• The outlook for a carcinoid lung tumor depends, to a large extent, on its stage.