A computed tomography (CT) scan is a non-invasive medical imaging procedure that uses specialized X-ray equipment and computer processing to create detailed, cross-sectional images of the body. For suspected throat cancer, which includes cancers of the larynx (voice box) and pharynx (throat), this technology provides a comprehensive view of the internal structures of the head and neck. The scan allows clinicians to visualize abnormal growths or masses in the tissues of the throat, offering an initial indication of a potential problem. While a CT scan is not a standalone diagnostic tool, it serves as an informative first step in understanding the nature and extent of a possible malignancy.
Understanding the CT Scan’s Purpose in Diagnosis
The CT scan is used for assessment following the detection of symptoms, not for screening asymptomatic individuals. Once a patient presents with persistent hoarseness, difficulty swallowing, or a palpable neck mass, the imaging test is ordered to localize the abnormality. The scan helps medical professionals determine the exact location of the mass within the throat, whether it originates in the larynx, the pharynx, or an adjacent structure.
The CT scan is a standard tool used for cancer staging. Staging is the process of determining the extent of the disease, which guides treatment decisions by assessing whether the suspected tumor is confined to its original site or if it has spread to other areas. A CT scan of the chest and abdomen may be performed in addition to the neck scan to check for distant metastasis to organs like the lungs. This initial visualization helps define the scope of the problem and is helpful in planning subsequent diagnostic and therapeutic steps.
Specific Information CT Scans Provide
Radiologists analyze the scan to measure the dimensions and volume of the primary tumor. Knowing the tumor size is a component of the staging system and impacts treatment planning.
The scan also provides detailed information on local invasion, which refers to whether the mass has grown into surrounding tissues. For laryngeal cancer, this is particularly relevant for structures like the thyroid cartilage. Visualization of subtle changes, such as erosion or sclerosis in the cartilage, helps determine the depth of penetration.
Another element is the status of the lymph nodes in the neck. The CT scan helps identify enlarged or irregularly shaped lymph nodes, which can be a sign that cancer cells have traveled from the primary tumor. Radiologists look for specific characteristics, such as central low-density areas within the nodes, which may suggest necrosis and a higher likelihood of malignancy. This assessment of regional lymph node involvement is necessary for determining the overall stage of the cancer.
Confirmatory Testing and Next Steps
Although a CT scan can reveal a suspicious mass and provide information about its size and spread, it cannot confirm a cancer diagnosis. Imaging tests only show structural abnormalities; they cannot determine the specific type of cells present. Therefore, a biopsy is required to confirm malignancy.
A biopsy involves removing a small tissue sample from the suspected area, which a pathologist then examines under a microscope for cancer cells. The CT scan data is used to guide the physician in planning the safest and most effective way to obtain this tissue sample.
Following the CT scan, other imaging modalities may be used to complement the data. A positron emission tomography (PET) scan, often combined with a CT scan (PET-CT), is frequently used to detect cancer that may have spread to distant parts of the body. An MRI scan may also be ordered, as it offers superior visualization of soft tissues, which is useful for assessing the extent of local invasion in certain areas of the throat.