Cancer Staging is used to define the growth of the cancer mass based on the size and/or extent (reach) of the primary tumor. It also help to evaluate amount of spread to surrounding (local) tissues and check whether or not the cancer has spread to the lymph nodes and other parts of the body
All type of cancers is staged when they are diagnosed. This stage typically defined before treatment, is called the clinical stage. A cancer may be further staged after surgery or biopsy. Thus the extent of the cancer is better known. This stage defined as pathologic stage which combines the outcome of the clinical staging with the surgical results. There are several important reasons for staging:
- Staging will help doctor to plan the effective treatment for the patients.
- Evaluate treatment for a particular stage of cancer
- Estimate a person’s chance for recovery or person’s prognosis
- Choose an appropriate clinical trial that may be a suitable treatment option for a patient
- Staging helps health care providers and researchers exchange information about patients; it also gives them a common terminology for evaluating the results of clinical trials and comparing the results of different trials.
What is the TNM system?
The TNM system is the one of most widely used to define the cancer staging. Most medical facilities use the TNM system as their main method for cancer reporting.
TNM stands for Tumor (T), Node (N), and Metastasis (M). Here is briefly explained on the TNM staging system as per following:
T (Tumor): indicates the size of the primary tumor and the degree of spread into nearby tissues.
N (Node): indicates whether or not the cancer has spread to nearby lymph nodes, the size of the nodes that contain cancer.
M (Metastasis): indicates whether or not cancer has spread (metastasized) to distant organs or secondary tumors formed by the spread of cancer cells to other parts of the body.
For most of the cancers, TNM combinations correspond to one of five stages (0-4 or 0 to IV). These numbers help doctor to identify whether the cancer is at an early stage or advanced stage. The higher number of stage, it means the more severity of the cancer. The stages can be grouping as following:
- Stage 0 (also known as carcinoma in situ)- The cancer is in very early stage which the tumor cells have not yet damaged the surrounding tissues.
- stages 1 and 2 – the cancer is limited to the organ or localized location where it began or it may have spread to a nearby structure
- stage 3 – the cancer has spread further into a surrounding structure or to the regional lymph nodes (regional spread)
- stage 4 – the cancer has spread to a distant tissues in the body or organs (metastatic spread)
In addition to the TNM staging system, your doctor may use other information to help determine the chance of recovery and decide on the best available treatment. This may include:
- Grade. The grade identifies the health of the cancer cells under a microscope. It can help doctor to predict how quickly the cancer will spread. A tumor with cells that look more like healthy cells is called well-differentiated or low-grade. A tumor with cells that look less like healthy cells is described as undifferentiated or high-grade. Different types of cancer have different methods to assign a cancer grade.
- Tumor markers. Tumor markers are substances found at higher than normal levels in the blood, urine, or body tissues of the person who have cancer. Doctors and researchers found that tumor markers for many types of cancer that can help determine the effective treatment for the patient. For certain cancers, certain tumor markers show helpful than stage in predicting how well a specific treatment will work.
- Tumor genetics. The genes in cancer cells may help predict if the cancer will spread or what treatment will work. Recent research studies have discovered the ways to determine the genes involved in many types of cancer. This information is valuable for doctors target treatment to each person’s cancer.
Other Staging Systems
Are all cancers can classisify with TNM system? Actually the TNM system is mainly used to describe cancers that form solid tumors, such as breast, colon, and lung cancers. Doctors and Health care provider also use other type of the staging systems to classify other types of cancer, such as:
- Brain tumors – the cancerous brain tumors do not normally spread outside the brain and spinal cord, only the “T” description of the TNM system applies. Currently, no single staging system exists for this types of tumors.
- Childhood cancers. The American Joint Committee on Cancer’s (AJCC’s) does not include childhood cancers in its staging system. Doctors stage most childhood cancers separately according to other staging systems that are often specific to the cancer type.
- Cancers origin from blood. The TNM system does not describe leukemia, lymphoma, or multiple myeloma because they usually do not form solid tumors. Each blood cancer has a unique staging system.
What is restaging?
Restaging is the doctors reassess a person’s cancer after completed the treatment. Simultaneously, it also determines how the cancer responded to treatment. Such a reassessment, or restaging, may be done when a cancer has recurred and may require more treatments or others method treatment to cure the cancer. This restage involves the same tests that were done when the cancer was first diagnosed. After these tests, the doctor may assign a new stage to the cancer. The new stage will be preceded by an “r” to indicate that it reflects the restaging. The original stage at diagnosis does not change.