What is Stage 4 throat cancer?
Stage 4 throat cancer can be used to refer to advanced, local extension or metastatic variations of either hypopharyngeal or oropharyngeal cancer.
They are both scenarios where cancer has begun spreading to the lymph nodes with the possibility of regional or distant metastasis (to organs such as the lungs, liver, bones and the brain).
In stage 4 throat cancer, the tumor size is usually pretty large (more than 6 cms). In some cases of advanced throat cancer, the tumor size may be variable and even smaller than 4 cms, but this is accompanied by extensive lymph node involvement.
Stage 4 throat cancer in terms of TNM staging (T1 – T4 | N1 – N3 | M0 – M1)
Throat cancer is staged according to the TNM system, developed by the American Joint Committee on Cancer (AJCC). TNM staging principles are based on the following three factors:
- T: This represents the size of the main tumor, and indicates how far the tumor has grown inside the throat and in nearby tissue areas.
- N: This represents cancer’s extent of spread into nearby lymph nodes and determines the number and size of the affected lymph nodes.
- M: This represents the status of metastasis (spread) to distant organs in the body (commonly: the lungs, liver or bones)
Once the T, N and M aspects of the disease have been established via the right diagnostic systems, the information is consolidated to form a group stage for the grade of hypopharyngeal cancer that a specific patient exhibits. This is called the clinical stage of the disease.
T1 to T4 (Medium to large sized invasive tumors) explained
In stage 4 throat cancer, the tumors are generally larger than 6 cms in size (except for cases of extremely advanced, local extension or metastatic disease with extensive lymph node involvement, where the original tumor was less than 4 cms in size).
Such tumors have generally invaded deeper tissue layers, nearby tissue areas, and the patient’s vocal cords (at stage 4 of the disease).
The tumors at stage 4 may very well have grown into structures outside the hypopharynx and the oropharynx.
N1 to N3 with M0
In stage 4 throat cancer, lymph node involvement is usually extensive, and cancer has generally spread to more than one lymph node, and on the verge of invading nearby tissues, with the possibility of regional metastasis. M0 in stage 4 indicates that cancer has not metastasized to a distant organ yet.
N1 to N3 with M1
In extremely advanced forms of stage 4 throat cancer, the cancerous growth can metastasize (spread) beyond the lymph nodes and nearby tissue areas, and into distant parts of the body such as the lungs, liver, bones or the brain. This scenario is mapped as M1.
Stage 4 throat cancer is very hard to treat and has more aggressive treatment options and less favourable treatment outcomes when compared to earlier stages of the disease.