Lung Cancer Diagnosis

Diagnosis

Chest x-rays may not show a tumor but may show other clues that indicate a problem related to lung cancer. An x-ray may show spots or images suggestive of fluid accumulation, masses, enlarged lymph nodes or pneumonia.

A chest CT (Computerized Axial Tomography) is a more precise way of studying chest anatomy. Both chest CT and MRI (magnetic resonance imaging) scans use computers to produce highly detailed cross-sectional (slices) images of the body. They can show 3-dimensional images that help determine the size, shape, and location of a tumor. A CT scanner uses fine streams of X-rays taken from many angles to produce picture of anatomical details within a "slice" through the person. Magnetic Resonance Imaging (MRI) does much the same thing, but using magnetic and radiowave fields.

PET (Positron Emission Tomography) scanning is different from CT and MRI scanning. A CT or MRI scan shows only structural details of the tissue, whereas the PET scan provides a color-coded image of the tissue’s function.

Simple sugars, labeled with radioactive tracers, are injected into the body intravenously (or inhaled as a gas). All cells pick up the sugar, but since tumor cells are metabolically more active than normal cells, a larger concentration of the radioactive sugar will accumulate in them. The PET scanner picks up the radiation given off by the sugar as it journeys through the body and collects in the targeted tissue (the tissue ‘lights up’ called a ‘hot spot’). A computer reassembles the signals into actual images and shows in fine detail the metabolism of the sugar in the tumor cells. PET can tell you whether a tumor is benign or malignant, the extent of the disease, and if the tumor has spread or has recurred.

PET/CT is a new technique that fuses PET and CT technologies into a single device. The PET scan picks up the metabolic activity in the body, and the CT scan provides a detailed picture of the body’s structure. By taking the pictures simultaneously, the two images are overlaid so that the tumor "hot spot" on the PET scan corresponds directly to the physical mass on the CT scan, thus eliminating the visual side-by-side comparison. This new technology has the potential to substantially impact treatment plans for many patients.

A sputum (mucus coughed up from the lungs) sample can be used to look for the presence of cancerous cells. If there are cancer cells in the bronchi, some of these cells are likely to be shed and carried up the throat in the sputum.

A Bronchoscopy involves the use of a bronchoscope to directly view the airways into the lungs. A bronchoscope is a small tube that is inserted through the nose or mouth, down the throat, and into the bronchi (the small tubes that go into each lung). During the procedure, the surgeon may remove some tissue for analysis. Local anesthesia and mild sedation are generally used to make the patient comfortable during the procedure

A biopsy involves obtaining a small piece of tissue and examining it under a microscope. A biopsy is necessary to confirm a cancer diagnosis and to identify the specific type of cancer and its stage. To examine areas of the lungs that are not accessible during a bronchoscopy, physicians may perform a needle biopsy (called "fine needle aspiration" or FNA) to remove a small sample of tissue for analysis. Sometimes, surgical biopsies of the lung may be performed. If a surgical biopsy is needed, the surgeon will perform the surgery through an incision in the chest so that all or part of a tumor and/or lymph nodes can be removed.