METASTASIS – secondary growth, related in cell type to the primary growth, near or far, with normal tissue intervening

• If cancer metastasizes the secondary growth is of the same type as the cells in the primary growth site (ex. Cells that metastisize are basically of the same kind as those in the original tumor. So, if the cancer arose in the lung and metastasized to the liver, the cancer cells growing in the liver are lung cancer cells .)
• Primary site – is the original site of the cancer

Main pathway for the spread of a tumor :

1. lymphatic spread – usually start at the local nodes (nodes that are closest to the tumor)
• then spreads throught the lymphatic system
2. blood borne metastasis – travels through the circulatory system till “suitable soil” is found
3. seeding (implantation) – mechanical transference of cells from one tumor site to another
• primary tumor site must be in a cavity (such as ovarian cancer)
• tumor spill – cancer cells break off (occurs during surgery)
• (cancers have a tendency to lack cohesiveness therefore cell shedding is possible)

* presence of organ metastasis means the patient will be treated palliatively. (except in children)

STAGING –   a method of describing the extent of disease.   A means of defining the tumor size and extension at the time of diagnosis.  Tumor staging provides a means of communication about tumors, helps in determining the best treatment aids in predicting prognosis, and provides a means for continuing research.

              Reasons for staging :

•  to determine the best treatment (Tx)

•  to create statistic about the tumor leading to a prognosis

•  to facilitate research

•  to provide a framework for communication (language for comparison)

AJCCS (American Joint Commission on Cancer Staging)

•  proposes and modifies staging systems

AJCC Staging System: American Joint Committee on Cancer staging system (also called the TNM system), which describes the extent of a cancer's spread in Roman numerals from 0 through IV.

The TNM system, described below, is one used often. The TNM system for staging gives three key pieces of information: T refers to the size of the Tumor, N describes how far the cancer has spread to nearby Nodes, M shows whether the cancer has spread or Metastasized to other organs of the body. Letters or numbers after the T, N, and M give more details about each of these factors. To make this information somewhat clearer, the TNM descriptions can be grouped together into Stages, labeled with Roman numerals. In general, the lower the number, the less the cancer has spread. A higher number means a more serious cancer .