Soft Tissue Sarcoma

Soft Tissue Sarcoma is a very rare form of cancer. It comprises approximately one half of one percent of all cancers diagnosed. There are approximately 7,800 new cases of soft tissue sarcoma in the United States each year and approximately 4,400 people die of the disease each year. Slightly more men than women develop soft tissue sarcoma and the race distribution mirrors that of the U.S. population. Due to it's rarity, it is crucial for patients to seek a cancer specialist in the treatment of their disease.

Soft tissue sarcoma can occur in the muscles, fat, blood vessels, tendons, fibrous tissues and synovial tissues (tissues around joints). About 40 percent occur in the legs usually at or above the knee. Fifteen percent develop in the hands and arms, another 15 percent in the head and neck and 30 percent in the shoulders, chest, abdomen, or hips. Soft tissue sarcomas can invade surrounding tissue and can metastasize (spread) to other organs of the body, forming a secondary tumor. Secondary tumors are referred to as metastatic soft tissue sarcoma because they are part of the original cancer and are not a new disease. Some tumors of the soft tissue are benign (non-cancerous) and are rarely life threatening.

It is not clear why some people develop sarcoma; however, researchers have been able to identify some common characteristics in groups with high rates of soft tissue sarcoma. Some studies have shown that people exposed to phenoxyacetic acid in herbicides and clorphenols in wood preservative have increased risk of soft tissue sarcoma. Researchers also know that people exposed to high doses of radiation are at a greater risk for developing soft tissue sarcoma. Researchers are also studying genetic abnormalities and chromosome mutations as possible causes for soft tissue sarcoma. People with certain inherited diseases such as neurofibromatosis have been shown to have higher risks of soft tissue sarcoma.

Early on, soft tissue sarcoma rarely causes any symptoms. Because soft tissue is very elastic, the tumors can grow quite large before they are felt. The first symptom is usually a painless lump. As the tumor grows and begins to press against nearby nerves and muscles, pain or soreness can occur.

Soft tissue sarcomas can only be diagnosed by a surgical biopsy. A biopsy is a procedure which removes tissue from the tumor and is analyzed under a microscope.

Soft tissue sarcomas are treated using surgery, radiation therapy and chemotherapy. Depending on the size, location, extent and grade (severity) of the tumor, a combination of all or some of these treatments may be used. Biological therapy (treatment to stimulate the body's immune system to fight cancer) is being used in clinical trials.

Liposarcoma

Liposarcoma is the most commonly diagnosed soft tissue tumor. They are also among the largest category of sarcomas reported. These tumors usually develop in the deep fatty tissue. They most commonly occur in the thigh, behind the knee, the groin, the gluteal area or behind the abdominal cavity (retroperitoneum). Liposarcomas are usually malignant (cancerous) and rarely are from a pre-existing lipoma. They are most commonly found in adults between 30 and 60 years old and are slightly more common in men than women.

Tumors are usually firm and bumpy and invade surrounding tissue aggressively. Metastases (spreading) to the lymph nodes occur in approximately 10% of patients with liposarcoma. They are very different than lipomas (non-cancerous tumors), which are superficial and typically soft and smooth and are mobile.

Fibrosarcoma (Fibrous Tissue)

Fibrosarcomas usually occur in the arms or legs or on the trunk but can occur in any of the soft tissues. They can occur around scars, muscles, nerves, tendons, and around the lining of the bone (periosteum). Local recurrence after surgery is common.

Fibrosarcomas typically invade local tissues and can metastasize through the bloodstream to the lungs. Less than 5% of patients will experience metastases to the lymph nodes.

Dermatofibrosarcoma Protuberans
This lesion develops as a tumor sticking out of the skin usually found on the back or abdomen. In the early stages the tumor remains under the skin and the skin surface appears dark red-violet. If untreated the tumor can break through the skin forming an open wound. It has a tendency to recur but rarely metastasizes. Treatment consists of wide surgical excision.

Malignant Fibrous Histiocytoma (MFH)
Malignant fibrous histiocytomas are the most commonly diagnosed soft tissue sarcoma in patients between the ages of 50 and 70. It is twice as common in men than women.

There are four variations of MFH: storiform pleomorphic, myxoid malignant fibrous histiocytoma, malignant giant cell tumor of soft parts, and inflammatory malignant fibrous histiocytoma. Storiform and Myxoid MFH types are typically high grade (fast growing and invasive) tumors, whereas, malignant giant cell MFH and inflammatory MFH tend to be lower grade (slower growing and less invasive) tumors. While the Myxoid type is lower grade they tend to have local recurrence rate and therefore treatment usually consists of radical resection or amputation. Storiform pleomorphic MFH is typically a deep-seated large tumor of the thigh. The deeper and larger tumors found in MFH have a higher rate of metastases than the more superficial smaller tumors.

Synovial Cell Sarcoma

Synovial Cell sarcoma usually occurs in young adults. They are most commonly found in the arms or legs next to a joint. They are usually found around the joint capsule but rarely invade the joint itself. The most common site is adjacent to the knee. They are also commonly found near the foot, ankle and hand.

Unlike other soft tissue sarcomas, synovial cell sarcomas are often painful. Treatment usually consists of radical excision with radiation and chemotherapy or amputation combined with chemotherapy.

Epithelioid Sarcomas

Epithelioid sarcomas typically occur in the hand or foot of young adults. They appear like small nodules, which sometimes merge together. Spreading to lymph nodes occurs in approximately 20% of patients. Because of their proximity to the joints, surgical excision can be difficult and often amputation is the surgery of choice for long-term survival.

Rhabdomyosarcomas (Striated muscle tumor)

Cancerous tumors in the skeletal muscle are one of the most common types of soft tissue sarcoma. There are four different types: pleomorphic, alveolar, embryonal and botryoid .

Pleomorphic Rhabdomyosarcoma

This tumor occurs in people over 30 years of age. It commonly affects males on their extremities but not exclusively. Because it grows in the skeletal muscle, it usually is deep in the limb. Tumors can arise at many sites within the same muscle group and grow very rapidly. The tumor spreads through the bloodstream although in approximately 15% of cases the tumor spreads through the lymphatic system. Rhabdomyosarcoma is often widely spread at the time of diagnosis. Treatment generally consists of surgery and combination chemotherapy (multiple drugs used).

Alveolar Rhabdomyosarcoma

This tumor is extremely aggressive and typically occurs in adolescents and young adults. Tumors metastasize widely at an early stage.

Embryonal Rhabdomyosarcoma

This tumor usually occurs in children under the age of 10. It most often occurs in the head and neck especially around the eye. Chemotherapy is very effective in these tumors. There is a high cure rate in these tumors when combination therapy is used (i.e. surgery and chemotherapy).

Botryoid Rhabdomyosarcoma

These lesions usually occur in children at the average age of 7. They generally occur in the genital region and urinary tract. They appear as a swollen lumpy mass.

Leiomyosarcoma (Smooth Muscle Tumor) Uterine Sarcoma & Gastrointestinal Sarcoma

Leiomyosarcomas are cancerous tumors of the smooth muscle. They most commonly occur in the organs (e.g., gastrointestinal tract and the uterus). The average age of patients is 60 years. Of the tumors occurring in the GI tract 61% occur in the stomach, 29% in the small bowel, and 10% in the colon. Symptoms of GI or uterine leiomyosarcomas are significant bleeding and pain. Metastases occur in more than half of patients.

Leiomyosarcomas of the retroperitoneum and the vena cava are found mostly in women. The growth of the tumors can accelerate during pregnancy. Metastases usually occur in the lungs except in GI tumors, which often metastasize in the liver. Treatment for uterine leiomyosarcoma is total abdominal hysterectomy.

Extraosseous Tumors

There are three types of Extraosseous tumors. They are giant cell tumors, osteosarcomas, and Ewing's sarcoma. These are bone sarcomas, which are found in the soft tissue. They have very similar characteristics as their bone sarcoma variation, Extraosseous Ewing's sarcomas respond well to radiation therapy.

Myxoma

Myxomas occur in men and women averaging the age of 50. They are most often found in the arms and legs. Tumors can be small nodules or very large tumors. They do not metastasize; however, they do spread locally. Treatment is usually wide local excision.

Mesenchymomas

Mesenchymomas can be distributed throughout the body and approximately 75% are malignant. The tumors are invasive especially when they are located in the skeletal muscle. Treatment is wide excision sometimes combined with radiation and or chemotherapy.

Vascular Sarcomas (containing many blood vessels)

Hemangioendothelioma

Hemangioendotheliomas are a very rare vascular (containing many blood vessels) tumor, which can be malignant. They occur in men and women but rarely in children. One variety of this tumor occurs in younger males and typically arises on the hand and tends to recur locally.

Angiosarcomas

Angiosarcomas represent 1% of all sarcomas. One-third of the cases occur on the skin, one-fourth of the cases occur in the soft tissue or organs such as breast, liver, heart and lungs. Tumors arising in the liver are seen in adults exposed to angiography, insecticides or plastics. Angiosarcomas of the breast typically occur in young or middle aged women. Additionally some angiosarcomas occur at the site of previous radiation therapy. Tumors metastasize widely. The most common form of treatment is radical amputation.

Hemangiopericytoma

Hemangiopericytomas are typically found in the thigh, retroperitoneum or near the kidneys. Intracranial hemangiopericytoma grow along the sinuses, tend to locally recur and can metastasize.

Malignant Neurilemoma (Malignant Schwannoma & Neurosarcoma)

Malignant Neurilemomas usually develop in young to middle aged adults, most commonly in males. They occur in the peripheral nerves (not brain or spinal cord nerves). Half of these tumors occur in people with Von Recklinghausen's disease or multiple neurofibromatosis. The spreading of these tumors occurs in the surrounding soft tissue forming a nodular tumor. Metastases can occur through the bloodstream. Tumors can be painful, tender and sometimes nerve function is affected. Treatment is generally wide resection of the nerve in either direction. Radiation therapy and chemotherapy can be used as well.

Alveolar Soft-Parts Sarcoma

This is a very rare tumor that typically occurs in female adolescents and young adults. It is usually a slow growing tumor found in the extremities and commonly metastasizes to the lung. The typical form of treatment is wide resection of the lesion.

Kaposi's Sarcoma

Kaposi's Sarcoma is a disease in which cancerous cells are found in the tissues under the skin or mucous membranes that line the mouth, nose and anus.

There are three groups of patients for Kaposi's sarcoma. The first group typically includes older men of Jewish, Italian or Mediterranean heritage. This type of Kaposi's usually progresses slowly over 10-15 years. Patients commonly develop a bluish lesion on the front of the lower leg, which typically spreads to multiple lesions. After some time the disease can spread to other organs.

The second group of Kaposi's sarcoma occurs in patients who have received organ transplant. Due to the Immunosuppressive treatment following a transplant, patients immune systems are weakened thus are more susceptible to infection.

The third group of Kaposi's sarcoma is found in AIDS patients. This group is referred to as epidemic Kaposi's sarcoma. Due to the weakened immune system cause by the HIV virus, Infections and other diseases such as Kaposi's can invade the body. Kaposi's sarcoma in people with AIDS usually spreads more quickly and can be found in many parts of the body.

Radiation therapy is usually the treatment for Kaposi's; however, when lesions have spread to the organs, chemotherapy is often used as well.

Bone Cancer

The second group of sarcoma is bone cancer. It is very rare with approximately 2,000 new cases diagnosed in the United States each year. The incidence is slightly higher in males than females and no race has a higher incidence than another, although, Ewings sarcoma is even more rare among African and American blacks. Due to the rarity and severity of bone cancer, a bone cancer specialist such as an Orthopedic Oncologist should be consulted in the treatment of the disease.

Bones consist of three types of tissue: compact tissue (the hard outer portion of the bone), cancellous tissue (spongy tissue inside the bone containing the bone marrow), and subchondral tissue (the smooth bone tissue of the joints). Cartilage surrounds the subchondral tissue to form a cushion around the joints.

Bone tumors can be benign (non-cancerous) or malignant (cancerous). Benign bone tumors are rarely life threatening and do not spread within the body; however, they can grow and compress healthy bone tissue. Cancer that develops in the bone is called primary bone cancer. It is differentiated by secondary bone cancer which spreads to the bone from another part of the body. Primary bone cancer is rare with approximately 2,500 new cases diagnosed each year in the United States (this figure includes bone cancer which is not sarcoma).

The most common type of primary bone cancer is osteosarcoma. Because it occurs in growing bones, it is most often found in children. Another type of primary bone cancer is chondrosarcoma which is found in the cartilage. This cancer occurs more often in adults.

Scientists are uncertain what causes bone cancer however they have been able to identify some factors which may put a person at risk. Children and young adults who have had undergone radiation therapy or chemotherapy for other diseases are at increased risk for bone cancer. Additionally, adults with Paget's disease which is a disease characterized by abnormal growth of new bone cells have an increased risk of osteosarcoma. There are also some hereditary conditions which can increase the risk of bone cancer.

Symptoms of bone cancer can vary depending on the size and location of the tumor. Pain is the most common symptom. Tumors arising in or around the joints often cause swelling and tenderness. Tumors can also weaken the bones thus causing fractures. Some other symptoms can be weight loss, fatigue and or anemia.

The first step in diagnosing primary bone cancer is a complete medical history and physical examination performed by a physician. The doctor may order a blood test to determine the level of an enzyme called alkaline phosphatase. Approximately 55% of patients with primary bone cancer will have elevated levels of alkaline phosphatase. However, it isn't a completely reliable indicator for bone cancer since growing bones in children will cause the enzyme to be elevated.

X-rays are also used to locate a tumor. If an x-ray suggests a tumor is present than a doctor may require further testing such as a CT scan, Magnetic Resonance Imaging (MRI), or an angiogram. Finally, a biopsy must be performed to determine if cancer is present. A biopsy is a procedure used to remove sample tissue from the tumor. A surgeon, usually an orthopedic oncologist, performs the procedure using a needle or making an incision. During a needle biopsy the surgeon makes a small hole in the bone and removes sample tissue with a small instrument. During an incisional biopsy, the surgeon cuts into the tumor and removes sample tissue. A Pathologist (a doctor specializing in identifying disease) then studies the cells and tissues under a microscope to determine whether the tumor is cancerous.

The treatment of bone cancer depends on the size, location, type and stage of the cancer. Surgery is often the primary treatment. While amputation of a limb is sometimes necessary, using chemotherapy either before or after surgery has allowed physicians to save the limb in many cases. Radiation may also be used alone or in combination with the other treatments.

New and more effective treatments are being developed in clinical trials at many hospitals and cancer centers in the United States.

Osteogenic Sarcoma (Osteosarcoma)

Osteogenic sarcoma is a malignant (cancerous) bone tumor that occurs predominantly in adolescents and young adults. It accounts for approximately 5% of the tumors in childhood. the bones most frequently involved are the large bones of the upper arm (humerus) and the leg (femur and tibia). In children and adolescents, 80% of these tumors arise from the bones around the knee. It is slightly more common in males than females. It is the most common primary malignant bone tumor with the exception of myeloma. Although osteosarcoma is a common malignant bone tumor, it is still rare with less than 1,000 new cases each year in the United States. Due to its rarity, it is imperative that patients with proven or suspected osteosarcoma have an initial evaluation by an orthopedic oncologist familiar with the management of this disease. This evaluation should be done prior to the initial biopsy, since an inappropriately performed biopsy may jeopardize a limb-sparing procedure.

Osteogenic sarcoma occurs in adolescents at the time they are most rapidly growing in their most rapidly growing bones; therefore, it is suspected that rapid bone growth may play a role in the development of osteosarcoma. Additionally, some evidence suggests that chronic bone injury can increase the risk for osteosarcoma. When Osteosarcoma occurs in adults over age 40 it is usually associated with a pre-existing condition such as Paget's disease.

The initial symptoms include pain, often in and around the knee, especially in tumors on the tibia or femur. The pain typically worsens over time and is not related to the time of day. Swelling and tenderness typically occur late in the course of osteogenic sarcoma, followed by a large soft tissue mass appearing.

A screening of serum alkaline phosphatase levels may be done. These levels are high in approximately 45-50% of patients with osteosarcoma; therefore it cannot be used alone to diagnose the disease.

Osteogenic sarcoma must be diagnosed by biopsy. Because the disease commonly spreads (metastasizes) to other parts of the body, especially the lungs, chest x-rays, lung tomograms, CT scans of the chest , and an x-ray skeletal survey or bone scan may be done before treatment. This process is called staging. There are three groups used to describe the extent of the disease: Localized - the cancer cells have not spread beyond the bone or nearby tissue. Metastatic - the cancer cells have spread from the bone where the cancer began to other parts of the body (commonly the lungs, however it can spread to other bone). Recurrent - the cancer has come back after it has been treated. It may come back to the original site of the tumor or another part of the body.

Surgery is the primary method of treatment. This can be either an amputation or limb-sparing procedure. A limb-sparing procedure is when a surgeon removes the tumor and a block of surrounding tissues to ensure clean (cancer free) margins around the tumor. The surgeon then reconstructs the limb using prosthetic devices, bone grafts or other reconstructive techniques. These procedures are highly specialized and are usually performed by an orthopedic oncologist. In general 70-90% of osteosarcomas of the limb can be treated by a limb-sparing procedure and do not require amputation; therefore, before undergoing an amputation, it is recommended that the patient seek the advice of an orthopedic oncologist.

Surgery is usually followed by a course of chemotherapy using one or more anti-cancer drugs. Some clinical trials have shown that adjuvant chemotherapy ( chemotherapy given when no clear evidence of cancer can be found i.e. after the tumor is removed) may be helpful in preventing the relapse or recurrence of the disease. Other trials suggest that there is no difference in outcome between pre-operative chemotherapy or adjuvant chemotherapy.

Parosteal osteogenic sarcoma

Parosteal ostegenic sarcoma is a low grade tumor that arises on the surface of the bone. It rarely penetrates the center of the bone and rarely becomes a highly malignant osteogenic sarcoma. It accounts for approximately 4% of all osteosarcomas and is slightly more common in females than males. It is different than classic osteogenic sarcoma in that it typically arises in adults between the ages of 20 and 40. It has a better prognosis than classic osteogenic sarcoma with an overall survival rate of 75% to 85%. It has a very slow rate of metastases (spreading).

Parosteal osteogenic sarcoma is most commonly found on the femur, behind the knee (72% of all cases). It usually presents itself with minimal pain and tenderness and in it's typical location behind the knee there may be some restriction in movement of the knee joint.

Surgery with wide margins is the standard treatment for parosteal osteosarcoma, either by amputation or limb-sparing surgery. Because they are located at the end of the bone, are typically low grade, and lack local invasiveness, they are often amenable to limb-sparing procedures. Grade III parosteal lesions usually require chemotherapy because of the risk of metastases.

Periosteal osteosarcoma

Like parosteal osteosarcoma, periosteal osteosarcoma is an uncommon tumor arising on the surface of the bone, most commonly the tibia. It is a high grade tumor composed of malignant cartilage. It occurs in a younger age group and is even more common among females than males than parosteal osteosarcoma.

Because periosteal osteosarcoma is more likely to metastasize than the parosteal, some oncologists treat this tumor more aggressively with combination therapy such as surgery and chemotherapy.

Multifocal Sclerosing osteogenic sarcoma

Multifocal sclerosing osteogenic sarcoma is an extremely rare form of osteogenic sarcoma. It tends to occur in children less than 10 years old and represents less than 3% of all primary osteogenic sarcomas. It is an aggressive tumor which presents as a single painful tumor, much like other types of osteogenic sarcoma. However further tests looking for metastases reveal tumor in virtually all of the skeleton.

Since all the bones of the body are involved surgery is usually not an option, except to relieve pain. Aggressive chemotherapy can lead to a remission; however, multiple tumors eventually progress and mortality approaches 100%.

Osteogenic Sarcoma of the Jaw and Skull

Osteogenic sarcoma of the craniofacial bones are relatively rare and represent less than 10% of all osteosarcomas. They typically occur in patients between the ages of 20 and 40 and have the same occurrence rate between males and females. The bones most commonly affected are the mandible (jaw bone) and the maxilla (cheek bone). Because they are located in the head and neck, they tend to be diagnosed earlier and can remain localized for longer periods of time; however, they are more difficult to remove surgically and therefore local recurrence is common.

Treatment of malignant osteogenic sarcoma in the skull bones is similar of classic osteogenic sarcoma. It should include preoperative chemotherapy. This is extremely important due to the limited margins available for surgical excision.

Osteogenic Sarcoma in Paget's Disease

Paget's disease affects approximately 3% of the population over the age of 60. It is characterized by abnormal growth of new bone cells leading to multiple bone deformities. Approximately 1% of patients with Paget's disease develop primary bone sarcoma. The tumors usually arise in the pelvis, femur, or humerus. They typically are large and very destructive making surgery difficult. At the time of diagnosis, the cancer has often metastasized to the lungs. Amputation is sometimes necessary.

Patients with suspected osteogenic sarcoma arising in Paget's disease should receive a bone scan and x-ray of all identified tumors. Additionally, a CT scan of the chest should be done to rule out metastases to the lungs. Treatment is the same as fully malignant osteogenic sarcoma arising in a younger population. Patients with preoperative chemotherapy, radical surgery of the tumor, followed by post-operative chemotherapy have the best prognosis. Tumors arising in the skull and spine are sometimes inoperable. In this instance patients are typically given chemotherapy and radiation therapy to control and shrink the tumor. Great care must be taken during chemotherapy treatments since many older patients have impaired kidney function.

Postirradiation Osteogenic Sarcoma (Radiation Induced)

Radiation Induced Osteosarcoma is a rare form of osteogenic sarcoma which occurs in people who have undergone radiation therapy treatments for other diseases. The average length of time before these tumors appear is 10 years following radiation. The younger the patient is at the time of radiation, the higher the risk of osteogenic sarcoma. Additionally, evidence suggest that patients who receive higher doses of radiation are at a higher risk of developing osteogenic sarcoma than patients who receive lower doses of radiation.

Postirradiation osteogenic sarcomas are most commonly located in the spine, pelvis, hips and shoulders. People with retinoblastoma, a malignant tumor of the eye , are at a higher risk of developing postirradiation osteogenic sarcoma due to a defect in the RB gene.

Symptoms of postirradiation osteogenic sarcoma are painful swelling in and around the area of radiation. A biopsy must be performed in order to diagnose the disease. Once the diagnosis is made, staging of the tumor is done using bone scan, CT scan or MRI. Additionally a CT scan of the lungs should be done to rule out metastases to the lungs.

The treatment of postirradaition sarcoma is similar to classic osteogenic sarcoma. It usually included preoperative chemotherapy, surgery and followed by postoperative chemotherapy. Surgery can be difficult when tumors are in and around the spine and therefore preoperative chemotherapy to shrink the tumor is crucial. Due to this challenge, the prognosis for postirradiation osteogenic sarcoma is worse than that for classic osteogenic sarcoma.

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