Sarcoma

The term sarcoma is derived from the Greek word sarkoma and translates to “fleshy growth”. Medically, it refers to a group of malignant tumors that arise from mesenchymal tissue – meaning cells that are originally responsible for forming supporting and connective tissues. These include muscles, fatty tissue, cartilage, bone, blood and lymph vessels, as well as tendons and fasciae.

Sarcomas are among the rare cancers and account for less than one percent of all malignant tumors in adults. In children and adolescents, however, their proportion is significantly higher. Globally, an estimated 50,000 to 60,000 new cases are diagnosed annually. In Switzerland, due to its rarity, treatment in specialized centers is recommended.

It is important to understand that a “sarcoma” is not a uniform tumor, but an umbrella term for over 70 different subtypes, each with very different behaviors, growth rates, and prognoses.

The two terms are occasionally confused in everyday language, but they describe fundamentally different types of tumors. A carcinoma arises from epithelial cells – meaning the tissue that lines or covers organs, such as the skin, intestines, or lungs. Carcinomas are by far the most common form of cancer, accounting for around 80 to 90 percent of all cancer cases.

A sarcoma, on the other hand, develops in connective tissue, meaning in structures that support, connect, and move the body. This distinction is not merely academic: it has a direct impact on growth behavior, pathways of metastasis, and treatment strategy. While carcinomas frequently spread via the lymphatic system, sarcomas tend to spread through the bloodstream, particularly to the lungs.

Sarcomas are classified according to two overriding criteria: the tissue of origin and the grade of malignancy. Based on the tissue of origin, a fundamental distinction is made between soft tissue sarcomas, bone sarcomas, and skin sarcomas. Based on the grade of malignancy, a distinction is made between low-grade sarcomas, which grow slowly and metastasize less frequently, and high-grade sarcomas, which follow a more aggressive course and carry a higher risk of recurrence. This grading is performed through histological examination of the tumor tissue and is crucial for the choice of therapy.

Soft tissue sarcomas represent the largest group and develop in muscles, fatty tissue, vessels, tendons, or connective tissue. They can occur in almost any part of the body, but predominantly manifest in the extremities and the abdominal cavity.

• Liposarcoma: originates in fatty tissue, frequently in the thigh or abdomen, and is one of the most common soft tissue sarcomas in adults.
• Leiomyosarcoma: originates from smooth muscle, such as in the uterus, gastrointestinal tract, or blood vessel walls.
• Rhabdomyosarcoma: affects skeletal muscle and occurs particularly frequently in children and adolescents.
  Angiosarcoma: develops in blood or lymph vessels and can affect organs including the skin, liver, or heart.
• Fibrosarcoma: originates from fibrous tissue and can develop in various body regions, including bone.
• GIST: the gastrointestinal stromal tumor develops in the digestive tract and biologically forms its own category within soft tissue sarcomas.
• Epithelioid sarcoma: a rare subtype that frequently appears on the hands, forearms, or lower legs of young adults and often presents clinically like a benign lesion.
• Synovial sarcoma: despite the name, it does not necessarily originate from joint structures; it frequently occurs in the extremities and predominantly affects young adults.
• Pleomorphic sarcoma: formerly referred to as malignant fibrous histiocytoma, it is a high-grade tumor with a pleomorphic cellular appearance that primarily affects older adults.

Bone sarcomas originate directly from bone tissue and frequently affect the long bones as well as the pelvis. They are generally less common than soft tissue sarcomas, but occur more frequently in children, adolescents, and young adults.

• Osteosarcoma: the most common primary bone tumor, primarily affecting adolescents and young adults, predominantly at the knee or upper arm.
• Chondrosarcoma: originates in cartilaginous tissue and mostly occurs in middle-aged adults, frequently in the pelvis, thigh, or ribs.
• Ewing sarcoma: an aggressive bone tumor that primarily affects children and adolescents, predominantly developing in the long bones and the pelvis. It responds well to chemotherapy.

Skin sarcomas arise within the connective tissue structures of the skin and are rare overall. They often become noticeable through discoloration or nodules and are sometimes initially mistaken for benign skin changes.

• Kaposi Sarcoma: is associated with an infection by the herpesvirus HHV-8 and occurs more frequently in immunocompromised individuals, such as those with HIV disease. It typically manifests as bluish-red spots or nodules on the skin.
• Dermal sarcoma: a rare skin tumor that grows slowly and can be locally aggressive but rarely metastasizes. Pleomorphic dermal sarcoma is considered a more aggressive variant.

In principle, sarcomas can develop anywhere in the body, since connective and supporting tissues are present throughout the organism. Nevertheless, there are preferred locations depending on the respective type of sarcoma.

Soft tissue sarcomas occur most frequently in the extremities, particularly in the thigh. There, they often present as a painless, slowly growing swelling that is initially ignored. Sarcomas of the arm, leg, shoulder, or knee are also known, albeit less common.

In the trunk area, sarcomas frequently develop in the abdominal cavity or behind the peritoneum (retroperitoneal space). These tumors are often detected late because they have plenty of space inside the body before causing symptoms. Sarcomas of the uterus, also called uterine sarcomas, are a separate subgroup and are sometimes differentiated from fibroids—the benign muscle nodules of the uterus—only after surgery.

Bone sarcomas preferentially affect the long bones, i.e., the thigh, tibia, or upper arm, as well as the pelvis and the spine. Sarcomas in the jaw or head region are rare but known.

The symptoms of a sarcoma are often non-specific, making diagnosis difficult. The most common sign is a palpable swelling or nodule that slowly increases in size. In the early stages, this nodule is usually painless, which often leads patients to not take it seriously at first.

Pain typically occurs only when the tumor exerts pressure on neighboring structures such as nerves, blood vessels, or bones. In the case of bone sarcomas, however, pain can also manifest early and without any apparent external cause, especially at night. A sarcoma in the thigh can cause a feeling of pressure, restricted movement, or visible asymmetry.

General symptoms such as fatigue, unintended weight loss, or night sweats are possible but non-specific and tend to occur in advanced stages. Any newly occurred, growing tissue thickening that is larger than five centimeters or located deep within the tissue should be investigated promptly.

The diagnosis of a sarcoma requires several steps and should take place in a specialized center, as the misdiagnosis rate for these rare tumors is comparatively high.

First, the clinical examination and medical history are paramount. Imaging procedures such as ultrasound provide initial indications regarding the size, location, and characteristics of the tumor. For a more precise assessment, MRI and CT are indispensable. MRI is particularly valuable for soft tissue sarcomas as it depicts tissue structures in great detail.

The final diagnosis is established via a biopsy, i.e., the removal of a tissue sample for histological examination. This should be performed by an experienced surgeon, as an incorrectly placed biopsy can complicate subsequent surgery. In addition, molecular genetic analyses are used to determine the exact subtype, which is crucial for treatment planning.

To evaluate potential metastases, a CT scan of the chest is usually performed, since the lungs are the most common site of distant metastasis in sarcomas.

The treatment of a sarcoma depends on the subtype, location, size, grading, and the patient’s general health condition. It should always be discussed in an interdisciplinary team.

Surgical removal of the tumor is the primary treatment measure for most sarcomas. The objective is complete resection with adequate margins in healthy tissue. For large or unfavorably located tumors, preoperative chemotherapy or radiation therapy may be deployed to shrink the tumor and facilitate surgery.

Chemotherapy plays a central role particularly in Ewing sarcoma and rhabdomyosarcoma, whereas other subtypes such as liposarcoma or leiomyosarcoma are less chemosensitive. Radiotherapy is frequently used as an adjunctive treatment, especially when complete surgical removal is not possible. For certain subtypes, targeted therapies that attack specific molecular alterations within the tumor are also utilized.

A prominent role is played by hyperthermia. In particular, local hyperthermia is a scientifically well-founded approach for solid tumors such as high-risk soft tissue sarcomas. Since tumor cells react more sensitively to overheating than healthy tissue, hyperthermia can significantly enhance the efficacy of chemotherapy and radiation therapy locally.

Since the treatment of sarcomas often involves extensive surgical interventions and radiation therapy, frequently on the extremities, physical therapy plays a central role. Lymphatic drainage is used targetedly to reduce postoperative swelling and prevent or treat distressing lymphedema.

To mitigate the sometimes intense side effects of chemotherapy, we rely on evidence-based procedures such as acupuncture. It has proven effective in integrative oncology, particularly for treating therapy-induced nausea, pain, and exhaustion (fatigue). Mistletoe therapy and selected measures of phytotherapy are also used supportively to improve the tolerability of standard therapy.

Restorative measures such as targeted infusion therapy or an intestinal cleanse to stabilize the microbiome require strict individual adjustment in sarcoma cases. In order not to impair the desired effect of chemotherapy with high-dose antioxidants, these regenerative procedures are preferably used during therapy breaks or for holistic recovery after completion of the acute treatment.

The prognosis for a sarcoma depends on several factors and cannot be generalized. Crucial factors include the subtype, grading, size of the tumor at the time of diagnosis, location, and the presence of metastases.

Localized sarcomas without metastases that can be completely removed surgically have significantly better chances of recovery than advanced tumors. For low-grade soft tissue sarcomas, five-year survival rates sometimes exceed 80 percent. High-grade sarcomas or those with lung metastases carry a less favorable prognosis, although individual outcomes can vary widely here as well.

The sarcoma life expectancy is usually expressed in five-year survival rates, which, however, only reflect statistical averages. Individual patients can deviate significantly from these figures. Early diagnosis, treatment in a specialized sarcoma center, and consistent follow-up care are the most critical factors for a favorable outcome.

Sarcomas raise many questions – here you will find answers to the most common ones.

The information listed contains relevant topics and serves to improve understanding.