Lung Cancer Diagnosis & Staging

 Patients usually present to their primary care provider with symptoms of lung cancer.  While all of these symptoms are not specific to lung cancer, having a collection of these symptoms in a patient who has a history of smoking tobacco typically is a cause for further evaluation.  These include:

  • Cough
  • Hemoptysis (coughing up blood)
  • Shortness of Breath
  • Repeat Pneumonias
  • Chest Pain
  • Bone Pain

As screening programs become more common, we hope that more lung cancer will be found before they are large enough to give patients symptoms.  Dr. Nurani will provide a full discussion of lung cancer screening in a blog post  on the website.

Tests used to Diagnose Lung Cancer

Radiology Studies

When one suspects lung cancer in a patient with no prior history of lung cancer a radiographic study is ordered.  These include:

Chest X-Ray 

This is an x-ray imaging test that projects the area being imaged in two dimensions only.  It is a very useful first test as most of the symptoms described above are from a simple cause such as pneumonia and not cancer.  It is also limited as objects that are behind each other in three dimensional space may get obscured in the two dimensional rendering of the x-ray film.    

Lung Cancer CT Rizwan Nurani

CT Scan showing a Lung Cancer Mass

Chest Computed Tomography Scan (Chest CT Scan)

This is an x-ray imaging test that uses sophisticated computers to reconstruct in 3 dimensions the spatial anatomy of the area being imaged.  A detailed evaluation of the shape, size, orientation and relation of all objects in the chest can be obtained.  Structures that appear as a solid mass in the lung, are associated with jagged margins and are present in areas where only lung tissue should be present raise the suspicion of cancer.

Positron Emission Tomography (PET Scans) 

PET Lung Cancer Rizwan Nurani

PET/CT Scan showing Lung Cancer

 A PET scan requires a two-step process.  First, a sugar solution labeled with a radioactive molecule call 18-fluoro-2-deoxyglucose (FDG) is injected into the patient’s blood stream. Next, a Special camera (SPECT gamma camera) is used to detect areas in the body that are actively absorbing this radioactive labeled sugar.  Organs that are active such as the brain and heart normally take up large amounts of signal.  Accumulation of sugar in these organs is expected and not indicative of cancer.  However, cancer masses are also very active and use a large amount of sugar.  Thus, cancer also actively accumulates the radioactive sugar and is detected with the gamma cameras.  PET scans are often combined with CT scans so that one can use the advantages of both methods of scanning to get a detailed picture.

Magnetic Resonance Imaging (MRI)

MRIs use magnets to change the spin direction of protons in the atoms making up tissue.   An additional energy is then applied, radiofrequency energy, and the characteristic changes in the spin of the various atoms reveal to the imaging cameras their makeup.  This is then used to reconstruct a very detailed image of the area being evaluated. MRIs are typically not used to image the chest.  In the setting of Lung Cancer, MRIs are used to detect for any areas of spread (metastases) to the brain.


Direct Visualization and Cancer Tissue Sampling

Bronchoscopy:  

Bronchoscopy Rizwan Nurani

A bronchoscope allows the physician to directly look for any evidence of cancer in the windpipe and major airway branches (Bronchi) in the lung.  

This is an outpatient procedure performed under light anesthesia (conscious sedation).  A thin tube with a camera at the end is passed through the mouth and into the windpipe.  Fiber optic wires from the camera transmit images to the physician at the other end of the tube. There are also wires that allow the tip of the tube to be moved and thus steered into different positions.   Small instruments can be passed through the tube and used to retrieve small pieces of tissue at the end of the tube.  

 Bronchoscopic Biopsy:

endobronchial tumor rizwan nurani

While using a bronchoscope to look at any suspicious areas in the airways of the lung, a small tool can be passed through the bronchoscope and small pieces of tissue can be cut off and removed from the airways.  These pieces of tissue are then examined under a microscope to determine if they are cancerous.  

Endobronchial Ultrasound and biopsy:

Sometimes a cancerous lymph node or mass may be just outside the airway and so cannot be seen with a simple light camera.  A small ultrasound at the end of the bronchoscope can be used to look across the wall of the airway.  If the mass appears to be abnormal a needle can be passed into the mass and cells removed for analysis for cancer. 

Radiographic imaging guided percutaneous biopsy

Lung cancer frequently occurs in the parts of the lung that are far away from the large airways.  The small airways in these areas do not allow for the passage of a traditional bronchoscope.  In this situation, A CT scan is used to determine the positioning of the suspicious mass.  While the physician is looking at the tumor mass under CT imaging, a needle can be passed across the skin and into the lung.  Once the CT confirms that the tip of the needle is in the lung mass, cells can be removed for pathological analysis for lung cancer.


© Rizwan Nurani 2012