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MUSCLE and FAT TUMORS
(Sarcomas)
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MUSCLE and FAT TUMORS
(Sarcomas)
While cancers of the body's soft tissues are fairly rare, those stricken have to make important choices about the care they are to recieve. While total amputation was most common in the past for large tumors of the limbs, recent research has demonstrated just as good survival for most patients if the limb is kept with newer treatments.
It is crucial to be well educated when dealing with a soft tissue cancer, or "sarcoma". This can make the difference between keeping or loosing a limb, or even life and death.
What is Soft Tissue Cancer?
The "mesenchymal" or "soft tissues", like all tissues, are made up of individual cells. Normally, cells within the forming body divide and grow very rapidly in the womb, in early childhood, and through puberty. In adulthood, new cells are only formed to replace those which have died from injury, old age or disease. The division of cells to produce new ones is under tight control by the "genes" within each cell. These genes are made up of DNA, and if it becomes damaged, that cell may start dividing out of control.Soft Tissue Cancer starts in a single cell which has become abnormal. This cells produces millions, and eventually billions, of copies of itself. The copies are called"clones" . These clones fail to function as normal body tissue, but instead divert resources from healthy cells to fuel their own growth. When there are about 1 billion cells, they form a clump, or "tumor" 1/2 inch across. A "tumor" merely means a swelling, it can be caused by infection, inflammation, cancer or whatever. If a tumor can only grow in it's local area (even very large) but does not have the capacity to spread to distant body areas, it is called"benign" and isnot cancer. If, however, the tumor has the ability to spread to distant body areas, it is called "malignant" andthis is cancer. The actual process of spread is called"metastasis", and can occur to any area of the body.
For benign Soft Tissue tumors, they are commonly given the suffix "oma" . The most common types of benign tumor are "Lipoma " (from fat), "Leiomyoma " (from smooth muscle) and "Fibroma " (from fibrous tissue). These benign tumors may grow very large, but they will never"metastasize" (spread distantly) and so are not considered "cancer". Simply removing them surgically should be curative, and if surgery is not practical then radiation therapy will often shrink them. Unless they are disturbing body function or cosmetic appearance, they often require NO THERAPY.
For malignant Soft Tissue tumors, they are commonly given the suffix"sarcoma" .This means a cancer that has arisen from the mesenchymal tissue, as opposed to "carcinomas", which develop from the body's lining tissues and organs. Any tumor that is called a "sarcoma" is cancerous, but not all cancerous mesenchymal tumors end with "sarcoma" . However, the common ones do, and include "Liposarcoma" (from fat cells), "Rhabdomyosarcoma" (from skeletal muscle cells), "Leiomyosarcoma" (from smooth muscle cells), "Fibrosarcoma" (from fibrous cells) and "Chondrosarcoma" (from cartilage cells). "Osteosarcoma" is the most common bone cancer, but is not considered a"Soft Tissue Sarcoma" and is discussed as a "Primary Bone Tumor".
Other, rarer types of Soft Tissue Sarcoma (which may or may not have the word "sarcoma" in them) include "Angiosarcoma" (divided into Hemangiosarcoma and Lymphangiosarcoma-- from blood or lymph vessels),"Hemangiopericytoma" (also from a blood vessel cell), "Mesothelioma " (from abdominal or lung linings),"Synovial Sarcoma" (from joint linings), "Neurofibrosarcoma" (from nerve sheaths),"Kaposi's Sarcoma (origin uncertain) and "Malignant Fibrous Histioctyoma" (from fibrous tissue). Some of the above are more aggressive than others, but they are all cancer!
How Common is Soft Tissue Sarcoma?
Each year in there about 8,000 new cases of "Soft Tissue Sarcoma" in the United States, which cause approximately 2,500 deaths per year. Thus, they represent ~1% of all new cancers. Soft Tissue Sarcoma is about 3 times more common than Bone Sarcoma. There are two "peaks" of most common patient age, one in childhood at 10 years old and the other in 40 year old adults. Thus Sarcomas are unlike the other major type of cancer, "Carcinomas" (e.g. breast, lung, prostate, colo-rectal) which all tend to get more likely as we age. Males and Females are overall equally affected by Sarcomas. In children, the most common type of Soft Tissue Sarcoma is "Rhabdomyosarcoma" (from skeletal muscle cells), which occur mostly in the Head and Neck areas. In adults, the most common type is now"Fibrosarcoma" or"Malignant Fibrous Histiocytoma", which tends to occur in the trunk or extremities. In contrast to childhood cases, the least common area for adult sarcomas is in the Head and Neck area. Overall, the number of new cases of Soft Tissue Sarcoma has remained stable for the past 3 decades.
What Causes, or Increases the Risk for Getting Sarcoma?
As with every cancer, the precise reason why one person gets a Sarcoma and another does not remains unknown . However, depending upon the particular subtype, various things have been noted (by studying groups of patients) which seem to increase the risk:
1) Carcinogens (Chemical Exposure)-- Some chemicals have the ability to get into cells and damage their DNA, leading to disease. The chemical may kill cells, leading to an increase in production of new ones, but some cells may not be killed only injured. These cells often try hard to repair themselves, but may try to divide before succeeding with complete repair. The more often damaged cells try to divide, the higher the chance for a cancer to arise. Some chemicals shown to raise the risk for cancer in general, and sarcomas in particular, include Dioxin, Polyvinyl Chloride, Arsenic, Benzene, and Thorium.
2) Radiation Exposure-- Ionizing radiationpasses through cells and damages their DNA. This may lead to malfunction of genes which would normally prevent the damaged cell from dividing ("suppressor gene"), or turn on a potential cancer gene ("oncogene") . The most common type of cancers arising from prior radiation treatment are sarcomas. Early watch makers licked their radium-tipped brushed (used to pain luminous dials), getting bone sarcomas. While the risk is extremely low with occasional diagnostic X-rays, getting X-ray therapy (especially for a cancer caused by a genetic disease {e.g. retinoblastoma} may result in a 20% risk of later sarcomas ("radiation carcinogenesis") .
3) Viruses -- These actually get into cells, insinuate themselves into the DNA, and start giving their own instructions to the cell! In the process, they can do damage to the "host" DNA, leading to cancer. Kaposi's sarcoma linked with the HIV (AIDS) virus is the best known example.
4) Genetic Diseases (Family Syndromes)-- These include disease where the genes are damaged from birth, and thus susceptible to turning cancerous (such as Neurofibromatosis, Beckwith Weidemann and Retinoblastoma). Also, there are inborn diseases where DNA repair is impaired, or the "stop" signal that prevents damaged cells from dividing is broken ("Li-Fraumeni").
5) Chronic Irritation-- This can stimulate cells to divide, and the more often division occurs (especially in cells that don't normally divide often) the more likely a cancerous one is to arise. Examples include the lymphangiosarcomas seen in limbs with chronic swelling ("edema") called the "Stewart-Treves" syndrome in women with arm swelling after treatment for breast cancer. Also, there is more risk for sarcomas around permanent stabilization pins placed into bones and joints after traumatic injuries.
The common underlying factor is damage to "DNA" which causes the affected cell to become "transformed" -- that is lose control over it's division. Cancer is ultimately a disease of the DNA! The DNA is packed into thousands of "genes", which are themselves located upon the 48 "chromosomes" (46 general plus 2 sex chromosomes) that all healthy humans have in every cell. The chromosomes become visible under an ordinary light microscope when cells divide, and nearly every case of Sarcoma shows chromosome damage. This damage usually includes pieces missing from chromosomes ("deletions"), or even parts of one chromosome getting stuck onto another ("translocations"). Overall, anything which can damage DNA, the fundamental genetic material, will increase the risk of a cell turning cancerous. This damage may be"latent", meaning a cancer may arise many years or decades after the damage occurs.
Can Sarcomas Be Prevented?
There is no sure way to prevent sarcomas. It is always a good idea to avoid unnecessary exposure to potential carcinogens and avoid unwarranted X-rays. This is especially true for patients with family susceptibility to cancers, or who actually have genetic diseases. If a worrisome sign or symptom arises (see below) it should be evaluated promptly, and not ascribed to some benign process without proof. Eating a diet with enough vitamin C ("Ascorbic Acid") is important for proper maintainance and healing of soft tissues. Vitamin C deficiency results in a breakdown of the soft tissues ("scurvy"), since it is essential for crosslinking their crucial collagen proteins. However, taking too much can also be harmful by causing the blood to become too acidic ("ascorbic acidemia"). A standard supplement multi-vitamin is well advised.
What are the Common Signs and Symptoms of Sarcoma?
"Signs" are what can be measured, such as fever or a tissue mass, while "symptoms" are what the patient feels. Very early sarcoma will have no signs or symptoms, since the disease is too small to cause cosmetic changes or organ malfunction. A growing tumor will cause changes in it's area of origin:
1) Painless Swelling is the hallmark of a Soft-Tissue sarcoma, the swelling is progessive over months. Adult sarcomas in the extremities (arms and legs) are often mistaken for an injury, or an injury may point them out. Any steadily increasing local swelling ("mass") in the body is suspicious for cancer. Also, a change in a long standing mass is concerning. Even though most new sarcomas start in previously normal tissue, some start by "malignant degeneration" of a previously benign tumor.
2) Pain is seen later with malignant tumors, as they invade into nerves. Also, growing tumors can cause pain by streching nearby normal structures and the nerves supplying them. Back pain is seen from "retroperitoneal" sarcoma as a first symptom, since the tumor can grow to large sizes in the area in front of the spinal column without being noticed.
3) Nerve Symptoms are especially seen for Head and Neck area sarcomas, and may include facial droop, crossed eyes, double vision, bulging eyes or tongue deviation to the one side. The tumor may press upon nerves and cause numbness and tingling ("paresthesias").
4) Bone Fractures -- In the area of the cancer, local invasion into bone can cause it to break ("pathologic fracture"). These fractures heal poorly unless the cancer is properly treated.
5) Paraneoplastic Syndromes are rare conditions caused by either the tumor itself, or some chemical put out by it. These include High and Low blood calcium (hyper and hypocalcemia), bone softening ("osteomalacia") and low blood sugar ("hypoglycemia")-- but are seen in only 2% of so of cases.
6) Signs of Spread include swelling in glands (lymph nodes) closeby the tumor, most commonly seen with synovial, rhabdomyosarcoma, and "undifferentiatted" sarcoma. These have about a 25% chance of going to local glands in the groin (inguinal) or armpit (axillary) area, if the "primary tumor" is in the lower or upper extremities respectively. Other types have much less chance for lymph node spread (unlike carcinomas). Distant spread-- sarcomas will most commonly go to the lungs, where they can grow into large tumors and cause shortness of breath or block bronchioles causing pneumonia. The cancer can also spread to the liver with painful stretching of it's capsule. Unlike carcinomas, spread to the brain is exceedingly rare.
What are the Features of the Common Sarcomas?
Overall, 2/3 of patients have a painless "mass" when they first come to medical attention, and 1/3 have pain, tingling, or limb swelling ("edema"). The lower limbs are involved in 45% of adult patients, the upper limbs in 15%, the trunk area in 30% and the head and neck in 10%. Thus, lower limb tumors are 3 times more common than upper limb tumors . With regard to the limbs, over 80% of cases are above the knee or elbow (that is in the upper limb region). In childhood, 40% of the tumors are rhabdomyosarcomas in the Head in Neck area. The location of the sarcoma gives a clue to it's type.
Typically, a Head and Neck tumor is Rhabdomyosarcoma in a child, but Angiosarcoma in an elderly person. Tumor within the trunk or organs are Rhabdomyosarcoma, Leiomyosarcoma, or Liposarcoma. This is due to the skeltal muscle, smooth muscle at fat their. Tumors of the "Retroperitoneum" (in front of the spinal column), uterus or bowels are Leiomyosarcoma. Tumors of the pelvis or extremities are Rhabdomyosarcoma, Malignanant Fibrous Histiocytoma (a form of Fibrosarcoma), or Synovial sarcoma. Tumors of the skin are Kaposi's sarcoma, Angiosarcoma or Lymphangiosarcoma. It must be recognized that there are over 100 forms of soft tissue sarcoma, but the above are most frequent.
Commonly, the disease starts from a single abnormal cell, which multiplies until a"mass" is formed. The tumor then spreads along muscle compartments, and starts invading into nearby muscle, fat, skin, nerves and bone. Tumors in the Head and Neck tend to invade these nearby normal areas sooner. The tumor may show "skip metastasis", meaning that a cell breaks off and implants ("seeds") a short distance away, eventually forming a new tumor there. When the "primary tumor" (original site) is larger than 5 cm (about 2 inches) across, the chance for distant spread increases markedly. The lungs are the first site of distant spread in over 50% of patients.
The likelihood of any soft tissue sarcoma to spread is based upon it's "GRADE" . This means how aggressive it appears under the microscope. A "pathologist" (physician who specializes in diagnosing disease from tissue sample) looks at a "biopsy" (sample piece of the tumor) to assign the "grade". A "high grade" tumor means that there are frequent cell divisions ("mitoses"), the cells nuclear centers look dark, some cells are dying within the tumor ("necrosis") and in general the cells poorly resemble there normal "tissue of origin". A "high grade" tumor will tend to grow quickly, spread early, and in general act aggressively. In contrast, a "low grade" tumor has infrequent cell divisions, the nuclei look pretty normal, all the cells within the tumor a alive, and the cells very much look like their normal cell counterparts. The more "low grade" the tumor is, the more it will act a benign tumor, stay in it's own area, and grow slowly. There is actually a "spectrum" of "grades" between low and high grade, with many tumors being of "intermediate" grade. Their behavior is harder to predict, since they may spread or not. There may be a mixture of "grades" within the tumor, and it will then behave as the highest grade present. Grades are now given "G1" (lowest) through "G4" (highest). In general, Rhabdomyosarcomas, Angiosarcomas and Synovial sarcomas are "high grade", while Fibrosarcoma and Liposarcoma are often (but not always!) "low grade". Pathologists disagree about the "grading" in about 25% of cases, and often ask other pathologists for their opinion. They all agree, however, that higher grade tumors are more malignant and act worse!
You deserve the peace-of-mind of knowing that you have done everything you could to fight a soft-tissue cancer successfully.
The Cancer Group Institute's materials explain, in plain English, the definition, types, frequency, symptoms, evaluation, historic and latest treatment for soft tissue sarcoma. We describe surgery, radiation and chemotherapy and their results. We tell you everything you need to know to help you make the right decisions today for a soft-tissue sarcoma problem.
