A tumor can either be benign or
malignant. When a tumor is benign, it is
not cancerous. The mass of cells is
contained to its original location, and even though it can continue to grow, it
does not spread to other parts of the body.
When a tumor is malignant, it is cancerous. The tumor will grow, however, unlike a benign
tumor; it will spread to other parts of the body. Also, after the removal of a malignant tumor,
it often will recur.
Staging a tumor is often the next
step after a cancer diagnosis. Staging
helps oncologists plan treatments, and assists in evaluating treatment
results. The TNM staging system is the
common method of staging which allows health professionals to communicate about
a tumor. TNM staging is based on the
size of the tumor (T), whether lymph nodes have been affected (N) and if the
tumor has spread to other parts of the body, or metastasis (M) has occurred. The TNM staging system has been around for more
than fifty years. The TNM Committee is
made up of cancer experts from around the world. In general, each part of the
TNM staging system is broken down into multiple parts.
T - Tumor
TX: Primary tumor
cannot be evaluated
T0: No evidence of
primary tumor
Tis: In situ (cells are not spreading and not
cancerous, but can turn into cancer)
T1, T2, T3, T4:
Size of the primary tumor
N - Lymph Nodes
NX: Lymph nodes
cannot be evaluated
N0: No lymph node
involvement
N1, N2, N3: Degree
of regional lymph node involvement
M - Metastasis
MX: Metastasis
cannot be evaluated
M0: No metastasis
M1: Metastasis is
present
Each different type of cancer has
its own method of classification on the TNM system. Because of this, once a doctor determines the
TNM of a cancer, a general stage from 0-4 (0, I, II, III, IV) is assigned. In general, cancers that are in stage 0 are
considered “in situ”, meaning that they have not spread past the initial
location. Stage I cancer is considered “localized”. At this point, the tumor has spread to nearby
tissue but is still in the original mass.
At this point, the cancer or tumor is considered a threat to life. Stages II, and III are considered “regional
spread”. During these stages the lymph
nodes are affected by the cancer and tumors can develop in the lymph node. The cancers has spread to other organs or
tissues in the area, but have not moved to other major body regions. The final stage of cancer, stage IV, is
called “distant spread”. During stage
IV, the cancer has been able to make its way throughout the body and tumors can
begin to develop throughout the body.
The stage of cancer does not change
overtime. Even if a cancer spreads, it
is still referred to as the stage it was in when first diagnosed. Doctors will restage a cancer after
treatments or periods of remission.
Restaging allows doctors to determine the best treatment of cancers that
come back or are resilient to treatment.
Exams, imaging tests, biopsies, and surgery are all methods to stage and
restage cancers and tumors.
http://www.nccn.org/patients/resources/diagnosis/staging.aspx
https://cancerstaging.org/references-tools/Pages/What-is-Cancer-Staging.aspx
http://www.uicc.org/resources/tnm
http://www.cancer.org/treatment/understandingyourdiagnosis/staging
http://www.cancer.gov/cancertopics/factsheet/detection/staging
http://pathology.jhu.edu/pc/BasicTypes1.php
