Sarcomas

Sarcomas are rare, malignant tumors that originate from cells of the soft tissue or bone. They can occur anywhere in the body, for example, in connective or fatty tissue, muscles, nerves, blood vessels, cartilage, or bone. This distinguishes them from cancers that arise in the epithelium (skin and mucosal cells) or in the glandular tissue of certain organs. 

The term “sarcomas” applies to more than 100 different tumor types, which differ in their growth behavior and prognosis. The exact distinction is important for treatment.

Sarcomas are much rarer than other types of cancer. Every year, around 5,000 people in Germany develop sarcoma. That is about 1% of new cancer cases. Among malignant sarcomas, about 85% occur in soft tissue and about 15% in bone.  

Soft tissue tumors 

There are three types of soft tissue tumors: 

• Benign and non-aggressive soft tissue tumors: these tumors grow locally and do not grow into other tissues. Examples include lipomas, fibromas, or hemangiomas. 
• Intermediate soft tissue tumors: they grow directly into neighboring tissues. However, for all intents and purposes, they do not spread to other sites in the body, meaning they do not or very rarely metastasize. Examples include aggressive fibromatoses such as desmoid tumors. 
• Malignant soft tissue tumors (sarcomas): they grow directly into adjacent tissues and may spread to other organs. Examples include liposarcomas or leiomyosarcomas.  

Soft tissue sarcomas usually occur on the arms or legs. However, they can also affect the abdomen and pelvis, or the shoulder and head and neck. 

Bone tumors 

Bone tumors can also be benign or malignant. Bone sarcomas are malignant bone tumors. 

They originate in bone or cartilage tissue. This distinguishes them from bone metastases where the causative tumor is not located in the bones, but in other organs and has spread tumor cells to the bones.  

The most common bone sarcomas are osteosarcoma, chondrosarcoma, and Ewing sarcoma. Osteosarcomas and Ewing sarcomas occur mainly in children and adolescents or young adults. They are rare in adults over 40 years of age. Chondrosarcoma usually affects people over the age of 50.

There are no typical symptoms for sarcomas. Therefore, sarcomas are often detected late. Most sarcomas initially cause a painless swelling or lump. As they grow, a feeling of tightness may develop in the affected area. If the sarcoma suppresses nerves or grows into nerve tissue, pain is present.

Superficial sarcomas are usually discovered earlier than tumors deeper in the tissue or sarcomas in the chest or abdomen. Bone sarcomas may cause joint pain, joint stiffness, or a broken bone from the tumor. 

If the swelling persists for more than 4 weeks, the affected person should go to the doctor and have this clarified. This can be the family doctor or, depending on the location of the tumor, a specialist.  

Swollen areas should be clarified if they: 

• have a diameter of 5 cm.
• increase in size.
• cause pain. 
• are located deeper in the body. 

The probability of malignant disease is high if all these characteristics are present. 

In most cases, the exact cause of a sarcoma is unknown. A few risk factors for sarcomas in a general sense are known:

• For example, sarcomas may occur as clusters in rare genetic syndromes.
• In isolated cases, a sarcoma may also develop at the irradiated site after radiation therapy.
• Sarcomas can also develop after chemotherapy. This particularly applies in the event of children who receive a combination of chemotherapy and radiation therapy.

Experts have also identified several other possible risk factors:

• Viral diseases, which are associated with a heightened risk of sarcomas, occur more commonly in the event of immunodeficiency. A certain type of human herpes virus (type 8) plays a role in the development of Kaposi’s sarcoma. The Epstein-Barr virus (EBV) is also commonly associated with soft tissue sarcomas in patients with immunodeficiency.
• There is a link between vinyl chloride and sarcomas in the liver.
• Environmental toxins and chemicals may contribute to the development of a sarcoma.
• Chronic inflammation is also thought to increase the risk of a soft tissue sarcoma.

Diet or lifestyle factors, such as smoking or alcohol, have no known influence on the development of a sarcoma.

The course of a sarcoma varies greatly from individual to individual. It depends on: 

• what subtype of sarcoma it is. 
• how malignant the tumor cells are.
• how large the sarcoma already is at the time of diagnosis.
• where the tumor is located. 
• whether and to what extent the sarcoma has already formed metastases.
• whether the doctors can remove the tumor completely.

Soft tissue sarcomas spread tumor cells primarily through the bloodstream. Metastases often form in the lungs. Metastases rarely occur in the lymph nodes. 

Sarcomas are rare tumors that can have many different forms. Detecting a sarcoma with certainty can therefore be difficult. However, a correct diagnosis is necessary for optimal treatment.  

Physicians use various and complementary methods to diagnose sarcomas:  

• They first question the patient about underlying medical conditions and symptoms (anamnesis). A thorough physical examination is also performed.
• Doctors use imaging techniques such as magnetic resonance imaging (MRI), ultrasound and/or computed tomography (CT) to check how far the tumor has already spread. This allows them to plan the next steps.
• A tissue sample (biopsy) is removed and a histological examination of the tissue sample is performed to confirm the diagnosis of sarcoma. The exact description of the tumor cells is important in order to assign the tumor to a sarcoma subgroup.

Experts recommend that, if necessary, the tissue sample should also be evaluated by specialists who have extensive experience in determining the types of sarcomas (reference histology).

Centers specializing in the treatment of sarcomas can be found on the website of the German Cancer Research Center’s Cancer Information Service (in German). 

Caring for patients with a sarcoma requires the cooperation of different specialties. Diagnosis and therapy should therefore, if possible, take place in a center with extensive experience in the treatment of sarcomas (sarcoma center) or in close consultation with such a center.

One of the most important factors for treatment is determining the exact type of sarcoma. Doctors also need to know whether:

• the tumor is growing locally.
• the tumor has invaded neighboring tissues.
• it has already spread to other organs of the body, i.e., formed metastases.

However, patient factors are also important in deciding on treatment, for example, the age or co-morbidities of a patient.

Soft tissue sarcomas

Physicians use various treatment methods to treat soft tissue sarcomas. These are primarily surgery, radiation therapy, and chemotherapy. Targeted drugs may also be considered to treat some sarcomas.

For localized soft tissue sarcoma, surgeons surgically remove the tumor as completely as possible. If this is successful, soft tissue sarcoma may be permanently cured.

In some cases, the patient may receive radiation therapy and/or chemotherapy before surgery. This can improve the chance of complete tumor removal. Experts call this neoadjuvant treatment.

If patients receive additional treatment after surgery, experts refer to this as adjuvant treatment. In most cases, this refers to postoperative radiation. It is intended to reduce the risk of the tumor coming back in the same place.

Sometimes doctors treat the tumor locally with hyperthermia, both before and after surgery. However, it is never used alone, but always together with chemotherapy and/or radiation. Whole-body hyperthermia is ineffective in the event of soft tissue sarcomas.

Patients with localized soft tissue sarcoma who cannot be operated on are treated like patients with advanced soft tissue sarcoma. In this case, a cure is no longer possible, but sometimes the disease can be managed by slowing tumor growth.

In the case of an advanced, metastasized soft tissue sarcoma, it must be clarified whether surgery is possible. Sometimes only individual organs are affected in a patient with advanced soft tissue sarcoma: the sarcoma and metastases appear operable on principle. In such cases, doctors first aim for a complete operation of the tumor and the metastasis(es). In most cases, additional chemotherapy, radiation therapy, and/or further local therapy options are then also considered.

If the sarcoma is already quite advanced, and/or if there are many metastases, the goal of treatment is mainly:

• to alleviate symptoms of the tumor disease.
• to avoid possible complications caused by the tumor growth.
• to ensure the best possible quality of life.

Experts call this palliative treatment. In this situation, doctors mainly use chemotherapy.

Bone sarcomas

Physicians also use various treatment methods to treat bone sarcomas. These are primarily surgery, radiation therapy, and chemotherapy. Targeted drugs may also be considered for individual bone sarcomas.

The type of treatment depends on several factors:

• the type of sarcoma
• the location of the tumor
• whether the sarcoma is growing aggressively, i.e., invading neighboring tissue
• how large the tumor is
• whether it has already spread and formed metastases

When treating bone sarcomas, doctors also take into account individual patient factors such as age or possible co-morbidities.

What do you need to know about cancer treatment?
How do operations, chemotherapy, radiotherapy, and targeted therapies work and what side effects do they have? Detailed additional information about treatment methods can be found on the website of the German Cancer Research Center’s Cancer Information Service (in German).

The treating physicians design aftercare for each patient individually. Patients with an aggressive and fast-growing sarcoma generally require closer monitoring than those with a slow-growing sarcoma.  

Aftercare after sarcoma treatment focuses in particular on the following: 

• Detecting relapse: in the event of a relapse, the tumor can grow again in the same spot. Experts call this a local recurrence. Sometimes the tumor also grows in other parts of the body during a relapse, in which case it forms remote metastases.
• Recognizing and treating the side effects of therapy: in addition to side effects from the treatment, long-term side effects can occur. They may only become noticeable long after the treatment is complete. Secondary tumors are a rare long-term side effect.

Rehabilitation (rehab) or follow-up treatment is an important component of sarcoma therapy: 

• General oncological rehab helps patients regain their strength.
• A rehab plan is individually tailored to the needs of the patient and can have specific objectives depending whether the condition has resulted in orthopedic, gynecological or urological impairments, for example.  
• Rehab clinics also inform patients about what they themselves can do to contribute to the success of their therapy. This can be, for example, diet, exercise, psychological treatment, or complementary treatment methods. 

What is meant by medical, occupational, and social rehabilitation? Who is entitled to it and is it compulsory? You can find facts and information about oncological rehab on the website of the German Cancer Research Center’s Cancer Information Service (in German).

Cancer changes the life of a person affected and raises numerous questions. Speaking with a psychooncologist can be helpful in coping with the psychological stresses caused by cancer.  

If affected individuals are unable to return to their jobs after treatment, obtaining information about social services is important.  

Some sarcoma surgeries result in disability or functional limitations. In such cases, affected individuals receive help and support from physiotherapists, occupational therapists, or orthopedists. 

Information on how to find a psycho-oncologist, cancer counseling centers, or points of contact for socio-legal questions can be found on the website of the German Cancer Research Center’s Cancer Information Service (in German).

Hospitals with physicians specialized in treating patients with sarcomas can have this confirmed with certification as an oncological center with the sarcoma module. The German Cancer Society (DKG) regularly checks their compliance with certain professional requirements.

An overview of centers certified with the sarcoma module can be found on the OncoMap website. Select “sarcomas” under “Centre” in the search box.

Information about finding a sarcoma center can also be found on the homepage of the German Sarcoma Foundation (Deutsche Sarkomstiftung) (in German). 

Do you have further questions about dealing with the condition in everyday life and additional support options? You can find information about this on the website of the Cancer Information Service of the German Cancer Research Center (in German).

If you have any questions about sarcomas you can also make personal contact with the Cancer Information Service by dialing the freephone number 0800 - 420 30 40 or writing an email to krebsinformationsdienst@dkfz.de.