Soft tissue sarcoma
| Classification according to ICD-10 | |
|---|---|
| C49.- | Malignant neoplasm of other connective tissue and other soft tissue The fourth digit indicates the location |
| ICD-10 online (WHO version 2019) | |
Soft tissue sarcomas are malignant ( malignant ) tumors ( sarcomas ), which the soft tissue arise from the body. They are a relatively rare form of cancer, but their proportion is relatively high in children and adolescents. The therapy depends on the type and classification of the respective tumor and ranges from surgical removal to radiation and chemotherapy .
Epidemiology
Soft tissue sarcomas are relatively rare neoplasms . They are of mesenchymal origin. In the USA they represent 0.7% of all new cancer cases. They are found across all age groups with a disproportionate incidence in childhood. In childhood, they represent 5–7% of all cancers. About every seventh sarcoma is diagnosed in children under 15 years of age. Soft tissue sarcomas are the second large group of solid tumors in paediatrics , along with CNS malignancies, and are among the fifth most common causes of cancer death. 40% of all new cancer cases occur after the age of 55. The incidence is currently around 2–3 / 100,000 per year.
localization
The tissues of origin of soft tissue sarcomas are muscles , tendons , adipose tissue , connective tissue , synovial tissue of the joint capsule , vascular muscles and nerves.
A typical localization of a soft tissue sarcoma is the lower extremities. About 60% of all tumors are found on the arms or legs. One third of sarcomas develop on the trunk , with weighting in the retroperitoneum . Occasionally they can also be found in the neck and face area.
etiology
Most soft tissue sarcomas arise primarily as malignant neoplasms . A malignant transformation of a benign soft tissue tumor into a sarcoma is an outspoken rarity. The exception is fibrosarcoma in the context of Recklinghausen's disease , which typically develops from a neurofibroma . In the case of the enchondroma , too , degeneration to a chondrosarcoma is occasionally observed.
Numerous risk factors for developing soft tissue sarcoma have been described, but they only explain a fraction of sarcomas. Chemical carcinogens can play a role in the development; for example, exposure to individual (phenoxy) herbicides , dioxins and chlorophenols has been observed to be an increased risk. Soft tissue sarcomas are also often found in the context of genetic diseases , such as Li-Fraumeni syndrome or neurofibromatosis type 1 (NF-1, Recklinghausen's disease). A family disposition also seems to exist, even if only to a minor extent.
For the development of Kaposi's sarcoma is human herpes virus 8 held responsible. This develops its effect exclusively in a T-cell immunodeficient organism (for example patients with HIV- 1). Kaposi's sarcoma is the only sarcoma in which a virus could be detected during genesis.
A more than random occurrence in parts of the body with a previous violation of tissue integrity can be observed. Sarcomas are often found near surgical or burn scars ( keloids ) and in places of previous tissue transplants.
There is also a clear association with radiation exposure , e.g. B. after radiation therapy or radioactive exposure. In a cohort study over more than forty years of over 80,000 survivors of the atomic bombs in Hiroshima and Nagasaki , there was a linearly increasing risk of developing soft tissue sarcomas with a relative risk of 1.01 per Gray irradiation and an absolute risk of 4.3 soft tissue sarcomas per Gray and per 100,000 person-years. This could be observed regardless of gender and age. The division of soft tissue sarcomas into histological types did not differ from other studies; the most common were leiomyosarcomas and malignant fibrous histiocytomas . However, as was generally the case for radiation-induced soft tissue sarcomas, the prognosis was significantly poorer with a five-year survival rate of 39% (compared to 71% for non-radiation-induced sarcomas).
classification
There are currently around 20 different groups of sarcomas:
- Rhabdomyosarcomas arise from immature mesenchymal cells. Components of striated muscles can be found histologically . In children and adolescents, they usually develop in the head, neck or genital tract. In adults, the urinary bladder is often the starting organ. "Rhabdo" is a relatively common tumor in adolescence.
- Leiomyosarcomas histologically have smooth muscle components . A typical original structure is the uterus .
- The liposarcoma is a malignant Fettgewebstumor. It mostly occurs in deep soft tissues and in the retroperitoneum.
- Fibrosarcoma
- Malignant fibrous histiocytoma
- Synovial sarcoma
- malignant vascular tumors ( angiosarcoma , malignant hemangiopericytoma, etc.)
- rare forms ( alveolar soft tissue sarcoma ; cystosarcoma phylloides of the breast )
Symptoms
Initially, there is usually an asymptomatic mass, which in the course of the often considerable growth exerts mechanical symptoms on the environment. This includes a local feeling of pressure or tension. But neurological complaints due to pinching of nerves or circulatory disorders due to vascular compression also occur.
In principle, a biopsy should be carried out of every newly formed tissue mass, unless it can be clearly classified as benign, which can also be done as an excisional biopsy for smaller tumors.
Further complaints can result from the metastasis . Metastasis occurs mainly through the bloodstream (hematogenic dissemination). The typical settlement site for most soft tissue sarcomas is the lungs . Lymph nodes metastases are less common . Some sarcomas have very specific metastatic routes. Sarcomas of the gastrointestinal tract often metastasize to the liver , myxoid liposarcoma is one of the rare types of cancer that metastasize in adipose tissue. The clear cell sarcoma , however, tends to infiltrate the bone .
diagnosis
In addition to a biopsy, radiological imaging is used for diagnosis. The methods of choice are computed tomography (CT) and magnetic resonance imaging (MRI), the latter being particularly preferred for peripheral tumors. Central tumors are often better recognized with computed tomography.
The most important prognostic factors are the degree of histological differentiation , the size of the primary tumor and the extent to which the fascia is involved. Sarcomas in the non-metastatic stage have a good chance of lasting healing. Occasionally, however, curation is also possible in the already metastatic stage. The prognosis essentially depends on the staging (tumor spread).
AJCC (American joint Commission on Cancer) staging system for sarcomas
|
Histology (G) |
Tumor size (T) |
Lymph node (N) |
Metastases (M) |
|---|---|---|---|
|
well differentiated (G1) |
≤ 5 cm (T1) |
no participation (N0) |
not available (M0) |
|
moderately differentiated (G2) |
> 5 cm (T2) |
involved (N1) |
available (M1) |
|
poorly |
superficial |
||
|
undifferentiated (G4) |
deep |
|
stage |
5 year survival rate |
|---|---|
|
Stage I |
99% |
|
Stage II |
82% |
|
Stage III |
52% |
|
Stage IV of |
<20% |
therapy
The therapeutic approach depends on the stage of the disease. Patients who are in stage I according to the AJCC staging system can usually be treated with surgery alone. Stage II patients are typically given concomitant radiation therapy . From stage III the therapy is supplemented with chemotherapy . Stage IV patients are primarily treated with palliative chemotherapy.
surgery
Soft tissue sarcomas tend to grow along the fascia around them . The compression that the sarcoma exerts on the surrounding tissue and the resulting pressure atrophy of the surrounding structures creates a pseudocapsule. This suggests a good delimitation of the sarcoma. However, since the malignant tissue usually propagates via this pseudocapsule via satellite foci, the surgeon will endeavor to choose a correspondingly generous excision margin to avoid the development of a local recurrence , which otherwise occurs with a probability of 50 to 90% to prevent. A large-scale excision with tumor-free tissue margins including the biopsy site is the standard procedure for local disease. In more advanced stages, adjuvant radio or chemotherapy can often prevent amputations .
Radiotherapy
Radiation therapy is often carried out as an adjuvant to structure-preserving surgery. Operations with subsequent radiation have a prognosis comparable to that of an amputation in extremity sarcomas. The neoadjuvant therapy is used. The preoperative radiation therapy has the advantage that both the dose and the radiation field can be selected to be smaller than with postoperative radiation. Another established therapy method is brachytherapy .
chemotherapy
Rhabdomyosarcoma and PNET ( primitive neuroectodermal tumor ) in particular are very sensitive to chemotherapy. These are mostly anthracycline-based. Preferred chemotherapeutic agents are doxorubicin and alkylating agents such as ifosfamide . A special type of chemotherapy is isolated hyperthermal limb perfusion (ILP) for locally advanced sarcoma. For this purpose, the blood supply is surgically separated from the body's circulation by exposing arteries and veins . An extracorporeal circuit is then established with a heart-lung machine via catheters and medication is administered intra-arterially .
With larotrectinib , the first specific therapy was approved in 2019 that can be used independently of the tumor in the rare TRK fusion tumors and shows a high and long-lasting response.
Advanced disease
There is generally no cure for metastatic soft tissue sarcoma. However, there are long-term survivors even among Stage IV patients. The 5-year survival rate in stage IV is still 20%. The therapeutic approach in palliation lies in the attempt to achieve the greatest possible remission of the tumor. Both chemotherapy and repeated operations (including the removal of metastases) significantly improve the prognosis.
literature
- Patient information from Heidelberg University Hospital on soft tissue sarcoma , accessed on March 11, 2019
- Harrison's Principles of Internal Medicine 16th Edition, Part V Hematology and Oncology
- Soft tissue sarcomas: diagnosis
- Soft tissue sarcomas: therapy and prognosis
- Soft tissue sarcomas - an overview of current evidence-based treatment concepts, Scheidt S. et al., Zeitschrift für Orthopädie und Unfallchirurgie, Thieme Verlag, edition 01/2019, accessed on March 11, 2019
Individual evidence
- ↑ Dino Samartzis, Nobuo Nishi, John Cologne, Sachiyo Funamoto, Mikiko Hayashi, Kazunori Kodama, Edward F. Miles, Akihiko Suyama, Midori Soda, Fumiyoshi Kasagi: Ionizing Radiation Exposure and the Development of Soft-Tissue Sarcomas in Atomic-Bomb Survivors . Journal of Bone and Joint Surgery 2013, Volume 95-A, Issue 3, Feb. 6, 2013, pages 222-229.
- ↑ Isolated hyperthermic extremity perfusion with TNF-α and melphalan , Peter M. Schlag ; Per-Ulf Tunn, Deutsches Ärzteblatt, Issue 33, August 17, 2007, accessed on March 11, 2019.
- ↑ Klaus Fleck: TRK Fusion Cancer: A Remedy for Many Tumors , Deutsches Ärzteblatt 2019, Volume 116, Issue 44 of November 1, 2019, Page A2026, Link
