By Consultant Surgeon Prof G. Sivakumar
The human adult grows from the three-layered tiny embryo. The outer covering layer is called the Ectoderm and the inner lining layer is the endoderm. The middle layer between them is called the mesoderm which develops into future supportive structures. Cancerous growths from connective tissue are called as sarcoma. Connective tissue makes up a variety of physical structures including, tendons, blood, cartilage, bone, adipose tissue, and lymphatic tissue.
Etymologically the word sarcoma is derived from sarkoma meaning “fleshy substance” (Galen), “harmful tumor of the connective tissue” and was first recorded in 1804. Connective Tissue (CT) is found throughout the body. It has 3 main components; cells, fibers, and extracellular matrix.
Where do you find sarcomas?
A large variety of soft tissue sarcomas can occur in these areas. Soft tissue sarcomas can occur anywhere in your body. Soft tissue sarcomas go by a variety of names, depending on the tissue in which they originate. Sarcomas are extremely rare with only 15,000 new cases per year in the United States. Sarcomas represent about one per cent of the new cancer diagnoses in our country each year.
Two thirds of sarcomas are located in the extremities. These tumors occur in the arms, legs, hands or feet. Another 20 percent occur in the chest and abdomen. Gastrointestinal stromal tumor (GIST) occur in the abdomen and is the most common form of sarcoma. About 10 percent are found in the head and neck.
Sarcomas affect people of all ages. Approximately 50% of bone sarcomas and 20% of soft tissue sarcomas are diagnosed in people under the age of 35.
A soft tissue sarcoma usually produces no signs and symptoms in its early stages. As the tumor grows, it may cause any of the following symptoms.
- A noticeable lump or swelling
- Pain, if it presses on nerves or muscles
- A blockage in the stomach or intestines or gastrointestinal bleeding if the tumor is located in the abdomen or digestive tract.
Generally, anyone who has a persistent mass or lump that is getting bigger or is causing pain or other symptoms should consider a biopsy. A biopsy is a procedure in which some tissue from the tumor is removed in order to examine it under a microscope. Read all about biopsy and how it helps to understand the nature of the tissue.
A biopsy is the only way to determine whether a soft-tissue tumor is benign or malignant and, for sarcomas, what type of sarcoma it is. Pathologists evaluate the aggressiveness of the tumor. This is called GRADE of the tumor which is very important in therapy and prognosis.
Radiation exposure is known to trigger sarcomatous development and was reported from Chernobyl victims. Radiation was used to treat a variety of noncancerous medical problems including enlargement of the tonsils, adenoids, and thymus gland in yester years. Later, researchers found that high doses of radiation caused soft tissue sarcomas in some patients. Because of this risk, radiation treatment for cancer is now planned to ensure that the maximum dosage of radiation is delivered to diseased tissue while surrounding normal healthy tissue is protected as much as possible
Genetic defect and mutations can lead to familial and sporadic sarcomas. Chemical exposure especially the emissions from incinerators and industrial plants contain various substances classed as certain or suspected carcinogens: metals, heavy metals, polyaromatic hydrocarbons (PAHs), polycyclic aromatics (PCA), dioxins (PCDDs and PCDFs).
Polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF), commonly known as dioxins, are pollutants that are mostly generated by human activity. The main sources are combustion, metal smelting, refining, and processing, and chemical manufacturing and processing. The results of many research studies clearly show a significant increase in the risk of sarcoma, correlated both with the level and the length of exposure to dioxin-like substances. The risk excess is also evident in females.
As with other cancers, treatment for sarcomas depends on the size, type, location and stage of the sarcoma. The tumor usually skips lymph nodes and reaches Lung, Brain and Liver through blood stream. When the tumor spreads to lung and liver it is in an advanced stage (Stage IV). The investigations like CT scan, USG abdomen, MRI and angiogram are done to assess the spread of sarcoma.
Surgery is the most common treatment for soft tissue sarcomas, especially if malignant cells haven’t spread to other parts of the body. The type of operation you have will depend on where in your body the sarcoma is. Many sarcomas are in the arm or leg. But they can occur anywhere in the body. Surgery for sarcomas is very specialised treatment. The aim of most surgery is to completely remove the tumor. The most common operation is a ‘wide local excision’. This means removing cancer with a border of healthy tissue around it. If the sarcoma has spread, surgical removal of the primary and secondary tumors may be possible but limits survival.
Multimodality therapies like Radiotherapy, chemotherapy and targeted therapy are required in advanced sarcoma. The first successful targeted treatment, the drug imatinib (Gleevec), was approved for use in people with a rare type of sarcoma in the upper digestive tract called gastrointestinal stromal tumor (GIST).
Previously, amputation was a common treatment for soft tissue sarcomas in an arm or leg. Today, advances in surgical techniques and chemotherapy before surgery (neoadjuvant chemotherapy) or after surgery (adjuvant chemotherapy) and radiation therapy make limb-sparing surgery possible in most cases. Sometimes the only possible treatment is to remove the limb or part of the limb in which the sarcoma is growing.
Amputation may be necessary to remove all of the malignant cells from soft tissue sarcoma in an arm or leg that has invaded nerves, arteries or muscles and rehabilitation afterwards. Sometimes the surgeon has to remove quite a lot of tissue. So you may need some plastic surgery to repair the area. This is done at the same time as your sarcoma operation. The aim will be to give you as natural looking a result as possible and as much normal function as possible.
Any painless lump increasing in size needs to be evaluated to rule out the sarcoma or the dangerous flesh.