Causes and stages of soft tissue sarcoma
The condition of soft tissue sarcoma is a form of cancer that grows in the connective tissues and other soft tissues. Soft tissues perform the function of supporting, connecting and surrounds other structures and organs of the body. Soft tissues include ligaments, tendons, fascia, etc. The substances inside the matrix that the soft tissue is made up of are collagen, elastin and ground substance. Usually, this tissue has a good amount of water content due to the presence of the ground substance. Fibroblasts are the most common cells which are credited with the production of fibers and ground substance of the soft tissue.
The risk factors or the causes of soft tissue sarcoma have not been medically identified yet. In general, soft tissue sarcoma occurs when cells undergo mutations in their DNA, usually the genes, because of which cells grow incessantly and divide without any stoppage. These accumulating unwanted cells together are called a tumor that can grow to invade nearby structures and spread to other parts of the body. Below are some of the known cases that have formed a basis for its causes for soft tissue sarcoma:
People who are exposed to chlorophenols and phenoxy herbicides have found to be at an increased risk of catching soft tissue sarcoma. This might occur in wood furnaces where they might be working. People working in plastic manufacturing firms are exposed to vinyl chloride which is another cause of the development of soft tissue sarcoma.
Exposure to radiation is a leading cause of soft tissue sarcoma. This can happen if a person is working closely with radiation-related stuff or if he has gone through radiation therapy before for some other disease. The radiation reacts with the connective tissue material and mutates it unusually which has not till date been medically established.
If a person has AIDS (Acquired Immunodeficiency Syndrome) then he has a higher chance of developing soft tissue sarcoma because both of these diseases are precursors to a third one named Kaposi’s sarcoma. It is a rare cancer of the cells that line blood vessels in the skin and mucous membranes.
Li-Fraumeni syndrome occurs when sarcoma is associated with the mutation of a genetic problem related to p53 gene. Some other inherited diseases are associated with an increased risk of developing soft-tissue sarcomas.
After a medical professional has detected soft tissue sarcoma, then the next step of the diagnosis is to find out how far and at what stage it has reached. This process is called staging. The stage of cancer describes the percentage of cancer in the body. It helps in determining how serious the cancer is and what is the best way to treat it. Doctors also use cancer’s stage when talking about survival statistics. There are four stages. As according to usual notation, the higher the stage, the more cancer has spread in the body, and hence it is more difficult to treat it. Although the experience of each patient is different during each stage, still there are underlying similarities in every stage.
The staging system is most often used for soft tissue sarcoma or for any cancer diagnosis which has been recommended by American Joint Committee on Cancer (AJCC) and is called the TNM staging, which is based on four important cues of information:
- The area reached by a tumor (T): How large is the lump?
- The spreading to nearby lymph nodes (N): Has cancer spread to nearby lymph nodes or is it limited to its origin?
- The spread to other far-off sites (M): Has cancer spread to distant organs such as the intestines?
- The grade (G) of cancer: How much resemblance is there between the normal cells and the cancer cells?
The grade of sarcoma is determined using the French originated system and has three key factors for its determination, which are:
- Differentiation: Cancer cells are scored from 1 to 3. 1 is assigned when they show similarity to normal cells and 3 is assigned when the cancer cells look extremely abnormal, totally unlike the normal cells. Certain types of sarcoma represent a higher score without calculation.
- Mitotic count: How many cancer cells are showing division when observed under a microscope? Hence given a score ranging from 1 till 3, with 1 meaning that they show the least division and 3 meaning the most.
- Tumour necrosis: What part of a tumor is made up of dying tissue? This is assigned by a score from 0 till 2 (0 means there was less dying tissue present, and 2 means the opposite).
The individual scores for each of the above factors are then calculated together to determine the grade of cancer. A higher grade cancer represents a higher stage, and hence it spreads faster, whereas the opposite holds true in the case of a lower or no grade.
Grade X: The grade cannot be calculated (because of lack of information).
Grade 1: Score of 2 or 3
Grade 2: Score of 4 or 5
Grade 3: Score of 6, 7 or 8.
Thus, the grade G obtained is the actual stage of cancer. G3 is the highest whereas GX is the lowest.