Cancer is a disease that can affect any body organs and produce serious health problems. According to the National Cancer Institute (NCI), abnormal cancerous cells replicate, or multiply, uncontrollably, forming a tumor that can invade surrounding healthy tissue. The cancerous cells can also break up and spread, or metastasize, to other areas of the body. The NCI states that the stages of cancer indicate the degree and severity of cancer and other factors such as the primary tumor location, its size and extent, whether it has spread to lymph nodes, how closely cancer cells resemble healthy cells and whether or not they have metastasized.
TNM Staging
According to the American Joint Committee on Cancer (AJCC), TNM staging is a commonly used system to describe cancer. "T" describes the extent of the tumor's size, location and whether the primary location of the tumor can be evaluated. "N" represents whether surrounding lymph nodes have been involved by the cancerous cells and to what extent. The "M" category provides explanation for whether the cancer has spread, or metastasized, from the original site. The AJCC also says that following determination of TNM, the information is combined to produce an overall cancer stage numbering from 0 to IV.
Stage Grouping
Stage 0 denotes a very early stage of cancer when the cancerous cells are still confined within the tissue they originated in.
Stage I describes cancer with localized tumor growth but still limited to the site of origin.
Stage II cancer means the cancer cells have spread but within a limited local area of the primary site.
Stage III indicates more widespread cancer that is extensive within the local or in the regional area of the original tumor site.
Stage IV identifies cancer that has spread to distant organs. Metastasis occurs when cancerous cells break off from a tumor in the original location and travel via the bloodstream or the lymphatic system, causing tumor growth in other organs.
Staging and Prognosis
According to the AJCC, the information acquired from cancer staging helps an oncologist, or cancer specialist, determine the prognosis of the disease. The prognosis describes the likely outcome of the disease. Stages 0 and I present a good prognosis, according to the American Cancer Society (ACS). As cancer advances, stage number increases and treatment appropriate for a lesser stage may not work. The ACS says many cases of advanced stage cancers can be treated, but the outcomes are uncertain.
