Stages of cancer
If you have cancer, the doctors will want to know how much the growth can grow. Stages of cancer is a ranking the doctors offer based on tests to assess the severity of the cancer. Laboratory tests are also used to determine how much cancer has spread out of the body inside the tissue extracted. Imaging techniques can also be used to stage cancer. Imaging tests do pictures of the body’s inside. The images help your doctors to see where the cancer is developing and spreading.
More recently, knowledge is being used to stage other cancers other than where and how much cancer is found in your body. These details may include results of blood tests, results of histological (cell) tests and risk factors. A risk factor is something that raises the likelihood of a health occurrence, such as the rapid growth of cancer. Where and how much cancer is still key to cancer stages in your body, though.
Staging cancer is critical for many reasons. Often your doctors will determine if you need further cancer-based tests. The stage of cancer is also one of the criteria used by doctors to determine a prognosis. Prognosis is a scientific term for the pattern and outcome predicted of a disease. Most importantly, the stages of cancer is a consideration the doctors use to determine which therapies are best for you. The cancer stage is used in research to evaluate treatment outcomes across patient groups, to compare results between treatment centres and to plan study studies.
Cancer is often staged twice. Before treatment, the first assessment is performed and is called the clinical level. After diagnosis, the second level is performed after treatments such as surgery and is called the pathologic stage. The pathologic stage of the cancer is more specific.
Tests used to find a cancer’s stage
- Physical examinations. For certain cancers, seeing or feeling the involved body part will give doctors details about how far a cancer has progressed.
- Imaging tests. Tests that help doctors look inside the body to find tumours include:
- CT scan.
- PET scan.
TNM staging system
Most often, doctors use the TNM staging system to stage cancer. It is managed by AJCC (American Joint Cancer Committee) and UICC (Union for International Cancer Control). The letters T, N, and M in this scheme represent a different field of cancer development. Based on the test results, each letter is assigned to a score by the physicians. But not all cancers, such as Hodgkin’s lymphoma, are classified according to TNM scores.
T = Tumour
The T score is a mark of primary tumour magnitude. The first mass of cancer cells in the body is the main tumour. The primary tumour will grow big if untreated. It can also expand through the tissue layers it started out in. This is called the expansion of the tumour. If the tumour has developed through a structure’s outer edge, it may develop into other nearby structures. That is known as an invasion. The T scores are based on primary tumour presence, size, and scale. A TX score means that one can not determine the primary tumour. A T0 score indicates the primary tumour is not present. Cancer may occur but does not have a primary tumour. A Tis score indicates that there are irregular or cancer cells but the cells have no risk of spreading to distant locations. Scores of T1, T2, and so on are dependent on the size, extent or both of the primary tumour. Higher values mean greater cancer coverage.
N = Nodes
Class N represents the degree of cancer within lymph nodes nearby. Lymph nodes are small organs that contain lymph, which battle the disease. Lymph is a clear fluid that provides water and food to the cells inside the tissue. It also collects cell waste and has white blood cells which combat germs. Lymph drains from the tissue into lymph vessels which carry it to the lymph node. Cancer cells may migrate to lymph nodes and invade lymph vessels. The cancer cells will multiply once in the lymph nodes and form new tumours.
N ratings are dependent on whether cancer is present in neighbouring lymph nodes, and the number or area of cancer nodes. An NX score means that one can not determine the lymph nodes. A score of N0 means there was no cancer in the lymph nodes. N1, N2, and N3 ratings are dependent on the number of cancer nodes, or nodal cancer classes. Higher values mean greater cancer coverage.
M = Metastasis
Class M asks you if the cancer has spread to remote locations. Such sites have remote lymph nodes that spread beyond local lymph nodes. Cancer cells can break the primary tumour and spread to remote sites. This is called metastasis. Cancer cells may spread through the lymph or blood to distant locations. M0 means the cancer is not present in remote areas. M1 means cancer in distant areas.
TNM staging labels
|T (tumour)||N (lymph nodes)||M (metastasis)|
How many stages of cancer are there?
- Stage 0 or carcinoma in situ. In situ carcinoma is known to be pre-malignant, or pre-cancer. Abnormal cells can only be identified in the first layer of cells at the location where the changes first began. Deeper tissues are not infiltrated by cells. Over time, these cells may become cancer, so it is important to find them and treat them before this happens. This stage is not used in most forms of cancer.
- Stage I. Cancer only exists in the cells where it began first, and the region is small. This is deemed to be early and most curable
- Stage II. Cancer is inside the organ where it began first. It may be slightly larger than stage I, and/or spread to neighbouring lymph nodes.
- Stage III. Cancer is in the organ where it initially began. It may be larger than stage II and may have spread to neighbouring lymph nodes and/or other tissues, organs, or structures close by.
- Stage IV. Cancer has spread (metastasised) to organs in other areas of the body. There may be cancer-indifferent organs, but it is still the same form of cancer as it started at first. For example, colon cancer that spreads to the liver is not liver cancer, it is cancer of the stage IV colon with liver metastases. The cancer cells in the liver look like colon cancer cells and are classified as colon cancer.
- Recurrent. Recurrent cancer has (recurred) returned since it was treated. It that return to the same place, or to another part of the body.
Typically, higher numbers mean more widespread disease, greater tumour size and/or cancer spread beyond the organ where it first grew. Higher grade and stage cancers tend to be more difficult to cure and also need heavy treatments.
When assigned a stage and provided care, the stage is never changed. A stage I cancer of the cervix, for example, is treated. The same cancer has spread two years later and is now contained in the heart. It is not stage IV now but stage I, with recurrence to the lung.
The main thing about staging is that it decides the correct treatment, lets health care professionals make a prognosis and enables the outcomes of the procedure to be compared.
Grade and stage of cancer can be extremely complex and confusing. Be sure to ask your health care professional to explain this cancer information to you in a manner you would understand.