Sarcoma

# Overview
A sarcoma (from the Greek 'sarx' meaning "flesh") is a cancer of the connective or supportive tissue (bone, cartilage, fat, muscle, blood vessels) and soft tissue.  This is in contrast to carcinomas, which are of epithelial origin (breast, colon, pancreas, and others). It can be classified based on the tissue involved and the histology of the lesion. Soft tissue sarcoma needs to differentiated from soft tissue benign tumors such as Adenoma, lipoma, and fibroma. The estimated incidence of soft tissue sarcoma worldwide is 1.8 to 5 per 100,000 per year. Soft tissue sarcomas are more commonly found in older patients (>50 years old). Risk factors include radiation exposure, damaged lymphatic system, and inherited conditions. There is insufficient evidence to recommend routine screening for sarcoma. If left untreated, sarcoma can lead to complications of local tissue erosion, compression and invasion. Complications can also include side effects of chemotherapy and radiation therapy. Prognosis depends upon the size and stage of the tumor, age and general health of the patient, and benign/malignant nature of the tumor. Sarcoma can be diagnosed by combination of imaging and biopsy. Symptoms include painless swelling or lump, menstrual irregularities, constipation, and indigestion. Chemotherapy may be used with radiation therapy either before or after surgery to try to shrink the tumor or kill any remaining cancer cells. Surgery is the most common treatment for soft tissue sarcomas. It is important to obtain a margin free of tumor to decrease the likelihood of local recurrence and give the best chance for eradication of the tumor. Radiation therapy (treatment with x-rays or radioactive implants) may be used either before surgery to shrink tumors or after surgery to kill any cancer cells that may have been left behind. There are no established measures for the primary and secondary prevention of sarcoma.

# Classification
- Sarcomas are given a number of different names, based on the type of tissue from which they arise.  For example, osteosarcoma arises from bone, chondrosarcoma arises from cartilage, and leiomyosarcoma arises from smooth muscle.
- Sarcomas strike people in all age ranges, but they are very rare, accounting for only 1% of all cases of cancer.
- Soft tissue sarcomas, such as leiomyosarcoma, chondrosarcoma, and gastrointestinal stromal tumor (GIST), are more common in adults than in children.
- GIST is the most common form of sarcoma, with approximately 3000 - 3500 cases per year in the United States.
- Bone sarcomas, such as osteosarcoma and Ewing's sarcoma, are more common in children than in adults.  These tumors most commonly strike adolescents and young adults between the ages of 12 and 25.
- In addition to being named based on the tissue of origin, sarcomas are also assigned a grade, such as low grade or high grade.
- Low grade sarcomas are usually treated surgically, although sometimes radiation therapy or chemotherapy are used.
- High grade sarcomas are more frequently treated with chemotherapy.  Since these tumors are more likely to undergo metastasis (spreading to distant sites), these tumors are treated more aggressively.
- Childhood sarcomas are almost always treated with a combination of surgery and chemotherapy, and radiation is frequently used as well.
- The recognition that childhood sarcomas are sensitive to chemotherapy has dramatically improved the survival of patients.  For example, in the era before chemotherapy, long term survival for patients with localized osteosarcoma was only approximately 20%, but now, it has risen to 60 - 70%.

## Tables

## Types of sarcoma
(ICD-O codes are provided where available.)
- Askin's tumor (8803/3)
- Chondrosarcoma (9220/3-9240/3)
- Ewing's (9260/3) - PNET (9473/3)
- Malignant Hemangioendothelioma (9130/3)
- Malignant Schwannoma (9560/3-9561/3)
- Osteosarcoma (9180/3-9190/3)
- Soft tissue sarcomas, including:
Alveolar soft part sarcoma (9581/3)
Angiosarcoma (9120/3)
Cystosarcoma Phylloides
Dermatofibrosarcoma (8832/3-8833/3)
Desmoid Tumor (8821/1-8822/1)
Desmoplastic small round cell tumor (8806/3)
Epithelioid Sarcoma (8804/3)
Extraskeletal chondrosarcoma (9220/3)
Extraskeletal osteosarcoma (9180/3)
Fibrosarcoma (8810/3)
Hemangiopericytoma (9150)
Hemangiosarcoma (9120/3)
Kaposi's sarcoma (9140/3)
Leiomyosarcoma (8890/3-8896/3)
Liposarcoma (8850/3-8858/3)
Lymphangiosarcoma (9170-9175)
Lymphosarcoma
Malignant fibrous histiocytoma (8830/3)
Neurofibrosarcoma (9540/3)
Rhabdomyosarcoma (8900-8920)
Synovial sarcoma (9040/3-9043/3)
- Alveolar soft part sarcoma (9581/3)
- Angiosarcoma (9120/3)
- Cystosarcoma Phylloides
- Dermatofibrosarcoma (8832/3-8833/3)
- Desmoid Tumor (8821/1-8822/1)
- Desmoplastic small round cell tumor (8806/3)
- Epithelioid Sarcoma (8804/3)
- Extraskeletal chondrosarcoma (9220/3)
- Extraskeletal osteosarcoma (9180/3)
- Fibrosarcoma (8810/3)
- Hemangiopericytoma (9150)
- Hemangiosarcoma (9120/3)
- Kaposi's sarcoma (9140/3)
- Leiomyosarcoma (8890/3-8896/3)
- Liposarcoma (8850/3-8858/3)
- Lymphangiosarcoma (9170-9175)
- Lymphosarcoma
- Malignant fibrous histiocytoma (8830/3)
- Neurofibrosarcoma (9540/3)
- Rhabdomyosarcoma (8900-8920)
- Synovial sarcoma (9040/3-9043/3)

# Differentiating Sarcoma from Other Diseases
Soft tissue sarcoma needs to differentiated from soft tissue benign tumors such as:
- Adenoma
- Lipoma
- Fibroma

# Epidemiology and Demographics

## Incidence
- The estimated number of new cases of soft tissue sarcoma in the United States is approximately 12,000.
- The estimated incidence of soft tissue sarcoma worldwide is 1.8 to 5 per 100,000 per year.

## Age
- Soft tissue sarcomas are more commonly found in older patients (>50 years old).
- Certain histological sub-types are more common in children and adolescents under age 20 (rhabdomyosarcoma).

## Percent Distribution of Soft Tissue Sarcoma by Histology
- Fibrosarcoma: 6.9%
- Infantile fibrosarcoma: 0.2%
- Fibrous histiocytoma, malignant: 9.2%
- Dermatofibrosarcoma: 3.6%
- Liposarcoma: 17.1%
- Leiomyosarcoma: 13.2%
- Rhabdomyosarcoma: 3.1%
- Embryonal rhabdomyosarcoma: 1.3%
- Hemangiosarcoma: 3.7%
- Hemangiopericytoma, malignant: 0.5%
- Kaposi's sarcoma: 0.8%
- Malignant peripheral nerve sheath tumor: 1.6%
- Malignant neurilemmoma: 0.2%
- Neuroblastoma: 0.6%
- Synovial sarcoma: 4.8%

# Risk Factors
- Radiation exposure: Clinical studies suggest that patients with other kind of cancers such as lymphoma and breast cancer may develop sarcomas from radiation therapy. The sarcoma often develops in the area of the body that had been treated with radiation.
- Damaged lymphatic system: Clinical observations demonstrate that lymphangiosarcoma is a very rare complication of chronic lymphedema that is the result of damaged lymphatic system.
- Inherited conditions: Some inherited conditions may increase the risk of developing soft tissue sarcomas, such as neurofibromatosis, Gardner syndrome, Li-Fraumeni syndrome, Retinoblastoma, and Werner syndrome.

# Screening
- There is insufficient evidence to recommend routine screening for sarcoma.

# Natural History, Complications, and Prognosis
- If left untreated, sarcoma can lead to complications of local tissue erosion, compression and invasion.
- It can also lead to metastasis to distant sites.
- Complications can also include side effects of chemotherapy and radiation therapy.
- Surgical wound after resection can also complicate a sarcoma.
- The prognosis of soft tissue sarcoma is poor and it depends on the following:
- Whether or not the tumor can be removed by surgery
- The stage of the sarcoma:
The size of the tumor.
Benign or malignant nature.
- The size of the tumor.
- Benign or malignant nature.
- The patients general health.
- Whether the sarcoma has just been diagnosed or has recurred.

# Diagnosis

## Diagnostic Study of Choice
- Sarcoma can be diagnosed by combination of imaging and biopsy.

## History and Symptoms
- Painless lump or swelling
- Pain or soreness
- Menstrual cramps
- Indigestion
- Constipation

## Physical Examination
- Patients with sarcoma usually appear normal.
- Common physical examination findings include painless lump or swelling.

## Laboratory Findings
- There are no diagnostic laboratory findings associated with sarcoma.

## Electrocardiogram
- There are no ECG findings associated with sarcoma.

## X-ray
- X-ray can be the first investigation ordered to evaluate a suspected sarcoma.
- Chest x-ray can help rule in/out metastasis to the lungs.

## Echocardiography or Ultrasound
- Ultrasound can help determine if a suspected sarcoma is fluid filled.
- Ultrasound is usually performed before biopsy.

## CT scan
- CT scan can be used as a guiding tool in taking biopsy.
- It can also help in making a diagnosis of the lesion itself.

## MRI
- MRI determines the extent of tumor invasion.
- It provides a detailed picture of the lesion.
- It can also help in determining the tissue of origin.

## Other Imaging Findings
- PET (positron emission tomography) scan can be used to determine the spread of sarcoma.

## Other Diagnostic Studies
- There are no other diagnostic studies associated with sarcoma.

# Treatment

## Medical Therapy
- Chemotherapy may be used with radiation therapy either before or after surgery to try to shrink the tumor or kill any remaining cancer cells.
- In general, the effects of chemotherapy on soft tissue sarcoma have had little impact as opposed to other cancers.
- If the cancer has spread to other areas of the body, chemotherapy may be used to shrink tumors and reduce the pain and discomfort.
- The use of chemotherapy to prevent the spread of soft tissue sarcomas has not been proven to be effective.
- Patients with soft tissue sarcomas usually receive chemotherapy intravenously.

## Surgery
- Surgery is the most common treatment for soft tissue sarcomas.
- Depending on the size and location of the sarcoma, it may occasionally be necessary to remove all or part of an arm or leg (amputation).
- In most cases, limb-sparing surgery is an option to avoid amputating the arm or leg.
- It is important to obtain a margin free of tumor to decrease the likelihood of local recurrence and give the best chance for eradication of the tumor.

## Radiation Therapy
- Radiation therapy (treatment with x-rays or radioactive implants) may be used either before surgery to shrink tumors or after surgery to kill any cancer cells that may have been left behind.
- In some cases, it can be used to treat tumors that cannot be surgically removed.
- In multiple studies, radiation therapy has been found to improve the rate of local control, but has not had any influence on overall survival.

## Primary Prevention
- There are no established measures for the primary prevention of sarcoma.

## Secondary Prevention
- There are no established measures for the secondary prevention of sarcoma.