All About Soft Tissue Sarcoma

Carolyn Vachani, RN, MSN, AOCN
Updated by: Christina Bach, MBE, MSW, LCSW, OSW-C
The Abramson Cancer Center of the University of Pennsylvania
Last Modified: April 4, 2016

What is sarcoma?

Sarcoma is a cancer of the soft tissue or bone. Soft tissues include muscles, tendons, fibrous tissues, fat, blood vessels, nerves, and synovial tissues (found in joints). Sarcomas are more specifically named by the tissues they affect. For example, sarcoma that arises from the bone is called osteosarcoma (although there are other types that form in the bone), and a sarcoma of the fat cells is called liposarcoma. (See list below for types of soft tissue sarcomas). Soft tissue sarcomas encompass a group of 50 different types of tumors, with most types considered extremely rare. Sarcomas account for 0.7% of all adult cancer diagnoses, with close to 12,000 new cases annually in the soft tissues and 2,900 new cases annually in the bone. Soft tissue sarcomas can develop from any site in the body, but the majority form in the extremities (about 50%), most commonly in the thigh. The remaining cases are evenly distributed throughout the rest of the body (10-15% in the trunk, <10% in the head & neck and 15% in the retroperitoneum).

Am I at risk for sarcoma?

Soft tissue sarcomas (STS) can develop in people of all ages, with approximately 20% of cases in people under age 40, 30% in people from 40-60 years of age, and 50% in people older than 60. In most cases of sarcoma, no specific cause is known. Sarcomas can develop secondary to radiation therapy for another cancer, but these are most often osteosarcomas. There is thought to be an increased risk with exposure to chemicals used in certain industries, but research of these chemicals has produced mixed results, and a clear-cut association has not been found. The agents in question include: phenoxyacetic acids (forestry workers), TCDD (tetrachlorodibenzo-p-dioxin), Agent Orange (Vietnam veterans), chlorophenols (sawmill workers), thorotrast (formerly used as radiology contrast), vinyl chloride, and arsenic (vineyard workers). There is also thought to be a link between chronic lymphedema (induced by surgery, radiation, or congenital abnormalities) and a type of sarcoma called lymphangiosarcoma. Lastly, there are a few genetic syndromes that are linked to STS; these include Li-Fraumeni syndrome, neurofibromatosis, and familial retinoblastoma.

Given the lack of a clear-cut cause, one cannot really prevent sarcoma from developing, aside from maybe avoiding the chemicals listed above.

What screening tests are available?

Unfortunately, there is no screening test for STS. Screening tests are developed for the early detection of common or very deadly diseases. Given how rare STS are, they would be difficult to screen for in the general population. In addition, the number of different types of STS would make it very difficult to develop one single screening test that could detect all types.

What are the signs of soft tissue sarcoma?

The signs of STS are dependent on where the tumor has formed. As the majority of STS form in the extremities, those patients will most likely present with the complaint of a mass or lump found in the extremity, with or without swelling. Depending on its location and size, the mass may or may not cause pain. If the tumor arises in the abdomen, it may reach considerable size before it is detected or leads to abdominal or back pain. Tumors arising in the gastrointestinal tract may cause diarrhea, constipation, blood in the stool, or abdominal pain. A uterine sarcoma may cause bleeding, swelling, or pain in the pelvic area.

How is soft tissue sarcoma diagnosed?

In general, blood tests are normal in patients with STS. Initial imaging studies depend on the location of the tumor. For STS located in the extremities or in the pelvic region, magnetic resonance imaging (MRI) is the study of choice. For STS located in the abdomen, CT scan is the preferred study.

Given how rare sarcomas are, many physicians have never seen or cared for a patient with sarcoma. When sarcoma is suspected, it is important to seek out a physician team familiar with sarcoma. A biopsy is critical for diagnosis and to determine the exact type of sarcoma. Successful biopsy requires knowledge of sarcomas and their treatment, and is best done by a surgeon familiar with sarcoma, followed by examination of the sample by a pathologist who has experience with sarcoma specimens. Biopsies can be performed as an open (surgical) procedure or a closed (percutaneous) procedure (using a large needle to remove the tissue). The biopsy must be performed properly to collect enough tissue to get a diagnosis, but not so much tissue that it would compromise the ultimate surgical treatment of the tumor. In general, the preferred method is the least invasive technique required that still allows the pathologist to give a definitive diagnosis.

Types of Soft Tissue Sarcoma (and the tissue it arises from)

  • Fibrosarcomas (fibrous tissue)
  • Malignant fibrous histiocytoma (fibrous tissue)
  • Liposarcomas (fat cells)
  • Rhabdomyosarcomas (Types: Embryonal, Embryonal botryoid,, Embryonal alveolar, Adult pleomorphic or anaplastic, form from muscle)
  • Leiomyosarcomas (smooth muscle of blood vessels or uterus)
  • Angiosarcomas (vascular tissue)
  • Lymphangiosarcomas (lymphatic system)
  • Synovial Cell Sarcomas (tissue adjacent to joints)
  • Neurofibrosarcoma (peripheral nerves)
  • Malignant schwannomas (peripheral nerves, malignant peripheral nerve sheath tumor)
  • Alveolar soft-part sarcoma (nerves of the muscle)
  • Kaposi's Sarcoma (skin / blood vessels)
  • Gastrointestinal Stromal Tumor (GIST) (arises from bowel wall)
  • Extraskeletal Ewing 's Sarcoma (cartilage and bone forming tissue)
  • Neuroblastoma (nerve tissue) (Learn more about neuroblastoma)
  • Ganglioneuroblastoma
  • Extraskeletal chondrosarcoma (cartilage and bone forming tissue)
  • Extraskeletal osteosarcoma (cartilage and bone forming tissue)
  • Clear cell sarcoma (malignant melanoma of soft parts)
  • Hemangiopericytoma (blood vessels)
  • Desmoplastic small round cell tumor (unknown origin)

How is soft tissue sarcoma staged?

Most tumor types are staged using a system developed by experts, but this has been difficult to develop for STS given the number of types and the varying locations. The most widely used system has been developed by the American Joint Committee on Cancer (AJCC) (7th edition). It incorporates tumor size, histologic grade (how different the cells look under the microscope when compared to normal cells), and spread to lymph nodes or other body sites in determining the stage. The "T stage" represents the extent of the primary tumor itself. The "N stage" represents the degree of involvement of the lymph nodes. The "M stage" represents whether or not there is spread of the cancer to distant parts of the body. The T, N, and M are combined to assign a stage, from I (one) denoting more limited disease, to IV (four) denoting more advanced disease.

AJCC Staging System for Soft Tissue Sarcoma, 7th edition, 2010

The TNM breakdown is quite technical, but is provided here for your reference.

Primary Tumor (T)

TX

Primary tumor cannot be assessed

T0

No evidence of primary tumor

T1

Tumor of 5 cm of less in greatest dimension*

T1a

Superficial tumor

T1b

Deep tumor*

T2

Tumor more than 5 cm in greatest dimension*

T2a

Superficial tumor

T2b

Deep tumor

* Superficial tumor is located exclusively above the superficial fascia without invasion of the fascia. Deep tumor is located either exclusively beneath the superficial fascia superficial to the fascia with invasion of or through the fascia, or both superficial yet beneath the fascia.

Reginal Lymph Nodes (N)

NX

Regional lymph nodes cannot be assessed

N0

No regional lymph node metastasis

N1

Distant metastasis

Distant Metastases (M)

M0

No distant metastasis

M1

Distant metastasis

Histologic Grade (G)

GX

Grade cannot be assessed

G1

Grade 1

G2

Grade 2

G3

Grade 3

These are then combined to give a stage:

Stage IA

T1a

N0

M0

G1, GX

T1b

N0

M0

G1, GX

Stage IB

T2a

N0

M0

G1, GX

T2b

N0

M0

G1, GX

Stage IIA

T1a

N0

M0

G2,G3

T1b

N0

M0

G2, G3

Stage IIB

T2a

M0

M0

G2

T2b

N0

M0

G2

Stage III

T2a, T2b

N0

M0

G3

Any T

N1

M0

Any G

Stage IV

Any T

Any N

M1

Any G

In addition to the staging, doctors consider a few characteristics that point to a higher likelihood of relapse when deciding on treatment options. Patients with these characteristics are considered "high risk" and may be treated more aggressively. Some high-risk factors include: high grade (appearance under the microscope), deep location, size > 10cm, age > 50, or presenting with a recurrence in the area of the original tumor. CT scan of the lungs may be performed to assess for spread of the tumor to the lungs, as this is the most common place to which STS metastasizes (spreads). If the particular tumor type can spread to bone, a bone scan may also be performed to look for metastasis.

How is Soft Tissue Sarcoma treated?

Given the rarity of STS, these patients are best served at a specialty treatment center. Treatment of STS requires complex multi-modality therapy (surgery, radiation, and chemotherapy). Specific treatment is dependent upon the size and location of the tumor, the grade (aggressiveness) of the tumor, and whether or not it has spread. The following is a general review of current treatments, but specific cases should be discussed with your healthcare team.

Surgery

Surgery is the primary means of treatment in STS, with the goal of complete tumor removal. Unfortunately, given that most tumors arise in the extremities, this can mean amputation of the affected limb. Through great surgical advances and the use of radiation therapy after surgery, only 10% of patients require amputation today, an overwhelming improvement from previous years. In addition to the tumor, the surgeon typically removes a 2-cm area of normal tissue around the tumor whenever possible. There is a low risk of spread to lymph nodes, therefore lymph node dissection is not routinely performed. However, in certain subtypes, lymph node involvement is more common (angiosarcoma, embryonal rhabdomyosarcoma). In these patients, if lymph node involvement is suspected, removal of these nodes can be curative. For patients with small, low risk tumors, surgery can be curative. However, most patients will also require radiation therapy.

Radiation Therapy

Radiation therapy can be performed before or after surgery, or during surgery through the use of brachytherapy. Studies have clearly shown that treatment with radiation prevents recurrence in the area of the original tumor more so than surgery alone. In addition, radiation in conjunction with limb-sparing surgery allows patients with STS in an extremity to avoid amputation.

There is no consensus on when to give radiation to achieve the best outcomes. Pre-operative radiation may allow smaller doses of radiation with smaller, better-defined treatment areas and result in a smaller surgery by shrinking the tumor before surgery. But, preoperative radiation can make precise staging more difficult and can result in poorer wound healing after surgery.

Chemotherapy

Chemotherapy can be given before surgery (called neoadjuvant), in an effort to shrink the tumor enough to allow for a better resection, or after surgery (called adjuvant). Surgery and radiation can only act on a small area around the tumor site, whereas the main goal behind adjuvant chemotherapy is to kill any cancer cells floating undetected elsewhere in the body. It is these cells that can plant themselves and start to grow in other organs, most commonly the lungs.

Seventy five percent of patients will be cured with surgery and radiation alone, so it is important to limit chemotherapy treatment to those patients at highest risk for relapse, as chemotherapy carries with it the downside of significant toxicity. Commonly used chemotherapeutic medications used in the treatment of STS are: doxorubicin, ifosfamide, epirubicin, gemcitabine, mesna, vinorelbine, docetaxel, and dacarbazine. These medications can be used in combination or as single agents. The medications used are dependent on the subtype of soft tissue sarcoma being treated.

Some STS subtypes may be treated with targeted therapies that focus on specific gene mutations or proteins present in that tumor. These medications include pazopanib, imatinib and sorafenib.

Hyperthermic Isolated Limb Perfusion (HILP) is a technique that is used to treat STS in the extremities (legs or arms). The circulation to that limb is basically isolated and chemotherapy is infused directly into it, all while the limb's temperature is heated above normal temperatures. This technique makes the chemotherapy far more potent than administering it through a regular IV. HILP is being studied in patients who would otherwise require amputation or those who have a localized area of recurrence.

Clinical Trials

Clinical trials have played and continue to play an important role in the treatment of sarcomas. In the past 20 years, considerable improvements have been made in sarcoma therapy, particularly surgical treatments, with great improvements in rates of amputations. The treatments we have today were refined through clinical trials, and many new avenues continue to be explored. Talk with your physician about current clinical trials for sarcomas in your area. You can also explore currently open clinical trials using the OncoLink Clinical Trials Matching Service.

Follow Up Care and Survivorship

After initial treatment, patients should be seen and examined every 3-4 months for the first 3 years, every 6 months for the next 2 years, then annually (may be less frequent for stage I cases). Periodic CT scans or MRIs of the original tumor site may allow detection of a recurrence before symptoms arise. Abdominal sarcomas should be scanned every 3-6 months for the first 3 years, then annually, as recurrence is more difficult to detect in the abdomen using physical examination alone. Chest x-ray or CT scan of the chest can be performed every 6-12 months to monitor for lung metastases.

Fear of recurrence, relationships challenges, the financial impact of cancer treatment, employment issues, and coping strategies are common emotional and practical issues experienced by survivors. Your healthcare team can identify resources for support and management of these practical and emotional challenges faced during and after cancer.

Cancer survivorship is a relatively new focus of oncology care. With some 15 million cancer survivors in the US alone, there is a need to help patients transition from active treatment to survivorship. What happens next, how do you get back to normal, what should you know and do to live healthy going forward? A survivorship care plan can be a first step in educating yourself about navigating life after cancer and helping you communicate knowledgeably with your healthcare providers. Create a survivorship care plan today on OncoLink

Resources for More Information

Sarcoma Foundation of America

The SFA raises money for sarcoma research and aims to raise awareness of sarcoma. The site has information for patients as well.

http://www.curesarcoma.org/

Sarcoma Alliance

This website, started by a sarcoma survivor, is based on the mantra "guidance, education, and support". They also maintain a list of specialty centers.

http://www.sarcomaalliance.org

Bone Tumor.org

A site maintained by Dr. Henry DeGroot, an orthopedic oncologist from the University of Massachusetts Medical School. It provides information on a comprehensive list of types of bone tumors in English and Spanish.

http://www.bonetumor.org/

Amschwand Sarcoma Cancer Foundation

Aims to educate the public about sarcoma, support those with the disease, and encourage sarcoma-specific research. Provides a list of sarcoma treatment centers and housing information.

http://www.sarcomacancer.org/

References

SEER Statistics, Soft Tissue Sarcoma, http://seer.cancer.gov/statfacts/html/soft.html

American Cancer Society, Soft Tissue Sarcoma, http://www.cancer.org/cancer/sarcoma-adultsofttissuecancer/index

NCCN Guidelines, Soft Tissue Sarcoma (registration required), www.nccn.org

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