Head & Neck
Diagnosing & Staging
Determining the type of cancer you have and the extent of it will be the first goal of your physician. A variety of tests may be used, including a physical exam, imaging studies, blood tests and a biopsy. Your doctor will be looking for where the tumor is, how large it is, whether it has spread to lymph nodes or other organs, any biomarkers and the type or subtype of the cancer.
Once a diagnosis is made, your doctor will classify and stage the cancer according to the TNM system developed by the American Joint Committee on Cancer (AJCC). This system classifies the cancer by tumor (T), node (N) and metastasis (M). The T category describes the size and location of the primary tumor. The N category indicates whether the lymph nodes show evidence of cancer cells. The number and location of these lymph nodes are important because they show how far the disease has spread. The M category describes metastasis (spread of cancer to another part of the body), if any.
Staging also allows doctors to group patients who have a similar prognosis (outlook), and it is not the same for all types of head and neck cancer. By grouping patients this way, doctors are able to more accurately predict outcomes for patients depending on the type of treatment they receive. In certain cancers, the stage is also determined by other factors. For throat cancer, the presence of human papillomavirus (HPV) and the location of the cancer cells are considered. For thyroid cancer, the subtype of cancer and age of the patient influence the stage. This information helps your doctor determine the best treatment options for you.
If your cancer returns after treatment, your doctor may repeat the diagnostic tests used originally to reassess your stage. This is known as restaging. If a new stage is assigned, it is often preceded by an “r” to denote that it has been restaged and is different from the original stage given at diagnosis.
The Use of Biomarkers in Head and Neck Cancers
Biomarkers are substances, such as genes and molecules, that are produced by cancer cells or other cells of the body in response to cancer. They can be measured in the blood, plasma, urine, cerebrospinal fluid or other body fluids or tissues. They are also known as tumor markers or biological markers. Testing for biomarkers is also known as molecular testing.
Some biomarkers have been found that are associated with certain head and neck cancers. Testing for these biomarkers helps your doctor better diagnose and treat the cancer. With head and neck cancers, biomarkers are most often tested during staging, and the results help determine treatment.
Some of the biomarkers that may be tested if you have a head and neck cancer include the following.
Epstein-Barr virus (EBV) is associated with some nasopharyngeal cancers and may be tested to help make a diagnosis as well as assess the response of therapy and monitor for recurrence.
Human papillomavirus (HPV) is primarily tested with throat cancers as a part of the staging process. It has strains that are linked to throat cancer, specifically oropharyngeal (see HPV and Cancer, page 11). Research is still determining whether HPV is a biomarker for any of the other types of head and neck cancer.
Genes may be tested to determine a patient’s eligibility to receive certain types of targeted therapy. Currently, therapies are approved for people with abnormalities in the BRAF, RET, p53 and NTRK genes.
Programmed cell death-ligand 1 (PD-L1) helps determine whether a patient will respond to immunotherapy. At this time, it is the only biomarker to test for a response to immunotherapy in head and neck cancer.
Proteins and growth factors affect how tumor cells develop and survive. They are tested to determine whether a person has abnormalities in the vascular endothelial growth factor (VEGF), epidermal growth factor receptor (EGFR) and the MEK protein. Some types of targeted therapy known as tyrosine kinase inhibitors (TKIs) are available to treat these abnormalities.
Thyroid hormone levels, such as thyroglobulin, thyroid-stimulating hormone and medullary type-specific tests, which include calcitonin and carcinoembryonic antigen levels, are biomarkers for thyroid cancer.
Research in clinical trials is ongoing to identify more biomarkers.