If a person is suspected to have HNC due to the presence of signs and symptoms or based on the physical examination of the head and neck region, head and neck investigations are required to confirm the diagnosis of the disease. Further, these investigations can help in determining the extent of invasion and spread of disease to other body parts, which in turn help in selecting an appropriate treatment option. Following are some commonly used diagnostic tools for HNCs:
1.Endoscopy: Endoscopy is a diagnostic technique which uses an endoscope – a long, flexible, slender tube usually equipped with a camera, a light source, and some special instruments for biopsy or surgery. A variant of the endoscope, like the nasal endoscope, laryngoscope, bronchoscope, or nasopharyngoscope may be utilized depending upon the specific site involved. These techniques enable the doctors to examine the surface layer of the specific structures and to determine the presence of any cancerous changes. The biopsy samples can also be collected with the help of special instruments if an abnormal area is observed during the procedure. The endoscopy and related procedures are considered safe and do not have any side-effects; however, if biopsy samples are collected during the procedure local bleeding and pain may occur.
2.Biopsy: Biopsy sample(s) from the site involved or the affected lymph nodes are generally collected in case an abnormal area(s) is observed during the endoscopy procedure or during the physical examination indicating swollen lymph nodes. It is very important because the biopsy sample can provide very useful information about the cancer cells such as the type of cancer, the severity of cancerous changes involved (grade of cancer), and the presence of specific defective genes or virus proteins (for example HPV or EBV). The detected defect(s) can be targeted with the help of an appropriate treatment approach. Following are common techniques used for collecting the biopsy samples from the affected region/lymph nodes:
- Fine needle aspiration (FNA) biopsy: In this technique, a fine, hollow needle attached to a syringe is used to collect the biopsy sample from the affected lymph node in the neck region (most common site of disease spread in case of HNCs). This technique is most commonly used and very easy to perform with minimum side effects. A very small sample of tissue or cells is usually obtained with this technique that can be tested to establish the diagnosis of any cancer. This technique can help in ruling out any infectious cause of lymph node swelling and can be utilized for estimating the extent of disease when HNC has already been diagnosed. This technique can also be utilized to diagnose disease progression or recurrence in patients who have received treatment for HNC.
- Incisional/Excisional biopsy: In this technique, the affected site is removed surgically. When only a part of the tumor is removed, it is called an incisional biopsy and when the whole tumor is removed, it is called an excisional biopsy. The magnitude of the procedure depends upon the location of the disease. The incisional biopsy is generally recommended to be performed for oral cavity cancers while the excisional biopsy is usually performed in case of the salivary glands cancers.
3.Imaging Tests: These tests help in scanning a larger body area to find out the exact location of the disease and the spread of disease to the distant body parts. These tests are generally employed after the establishment of the pathological diagnosis. The extent of invasion can also be assessed with the help of these techniques. Alternatively, these tests are employed after treatment to evaluate the treatment efficacy and to detect any signs of disease progression/recurrence.
- Computed tomography (CT) scan: In this technique, detailed cross-sectional images of body organs are generated using x-rays, with or without a contrast medium. It can help diagnose the spread of disease to nearby/distant lymph nodes and other organs. This is very helpful for planning the treatment in case radiation therapy is indicated for the treatment. This technique can sometimes be used to guide a biopsy needle to collect biopsy samples from the affected site or lymph nodes.
- Magnetic resonance imaging (MRI) scan: This technique provides detailed images of soft tissues in the body using radio waves, strong magnetic field, and gadolinium – the contrast material, which is used via intravenous injection to improve the clarity of the MRI images. Similar to CT, this technique can accurately diagnose the size, location, extent of invasion, and spread of disease to distant body parts, especially soft tissues like the muscles, eyeballs, blood vessels, brain, and spinal cord. This technique is better than CT for the examination of soft tissues in the head and neck region, but inferior to CT for examining the bones. Additionally, similar to CT, this technique can be used in planning radiation treatment for HNCs.
- Positron emission tomography (PET) scan: This technique uses a radioactive substance (fluorodeoxyglucose [FDG], etc) that is given via intravenous injection prior to the procedure. Cancer cells absorb larger amounts of the radioactive substance than normal cells. The areas of higher radioactivity indicate cancerous tissue on the PET scan. Thus, this technique can diagnose unsuspected spread of disease to distant body parts. It is usually combined with CT scan (PET/CT).
Certain blood tests may also be employed in the HNC patients for the estimation of overall health, nutritional status, liver and kidney functions, and blood cells counts. These tests help in assessing whether the standard treatment like surgery, chemotherapy, or radiotherapy can be safely employed for the patient.
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