The treatment of soft tissue sarcomas and osteosarcomas at EMC is carried out by an interdisciplinary team of specialists, including medical oncologists, radiologists, orthopedic surgeons specializing in oncology, pathologists and rehabilitologists. A treatment plan for a patient diagnosed with sarcoma is developed at an oncological consultation. Doctors of the EMC Institute of Oncology specialize in the treatment of rare types of oncological diseases using modern methods of surgical treatment, radiation and chemotherapy.
Sarcomas are a rare and diverse group of malignant tumors: less than 1% of all malignancies in adults and about 12% of cancers in children. Approximately 80% of sarcomas are formed from soft tissues, the rest from bone tissue.
The most common subtypes of soft tissue sarcomas in adults:
gastrointestinal stromal tumors (GISO, GIST).
liposarcoma
leiomyosarcoma
undifferentiated pleomorphic sarcoma
It is important to distinguish between the types of sarcomas, both in terms of prognosis and differences in treatment. This is especially important for pediatric tumors that develop in adults, such as rhabdomyosarcoma (RMS). Both embryonic and alveolar RMS are more susceptible to chemotherapy and have a better prognosis than many types of soft tissue sarcomas in adults. However, pleomorphic RMS have a relatively unfavorable prognosis compared to other subtypes of RMS. Such tumors predominate in adults, and the outcomes of this type of sarcoma are worse than in children.
In almost all cases, sarcomas occur primarily, rather than developing from benign lesions. In most cases, the exact etiology is unclear, but several concomitant or predisposing factors have been identified.
These include:
genetic predisposition (for example, Lee Fraumeni syndrome, type I neurofibromatosis, retinoblastoma)
effects of radiation therapy or chemotherapy
chemical carcinogens
lymphedema (swelling of the soft tissues of the affected area)
human immunodeficiency virus (HIV) and herpes virus type 8 (in Kaposi's sarcoma)
The most common complaint in soft tissue sarcomas is a gradually increasing in size, painless bulky formation. Tumors can reach quite large sizes, especially in the hip and retroperitoneal space. Some patients complain of pain or symptoms associated with compression of the bulky formation, including paresthesia or swelling of the limb. In rare cases, patients have common symptoms: fever or weight loss.
Soft tissue sarcomas can develop in any part of the body, but most often on the extremities.
According to the American College of Surgeons, the localization of soft tissue sarcomas is distributed as follows:
Thigh, buttocks and groin area – 46%
Upper extremities – 13%
Body – 18%
Retroperitoneal space – 13%
Head and neck – 9%
The presence of distant metastases at the time of initial diagnosis is infrequent, but it is more likely with large, deep sarcomas of high malignancy.
The spread to regional lymph nodes in soft tissue sarcomas is rare.
The highest risk of lymph node metastasis is typical for rhabdomyosarcoma, synovial sarcoma, epithelioid sarcoma, clear cell sarcoma, and vascular sarcomas (including angiosarcomas).
Recurrence after treatment of soft tissue sarcoma can be either local or in the form of metastasis. In 70-80%, metastasis occurs in the lungs.
The most important prognostic factors are histological assessment, tumor size and stage at the time of diagnosis.
In a study conducted by Memorial Sloan Kettering Cancer Center (MSKCC) using the TNM classification of malignant neoplasms, the 5-year disease-free survival rates for stage I, II, and III diseases were 86, 72, and 52%, respectively.
The initial assessment of a patient with suspected soft tissue sarcoma begins with anamnesis collection. The rate of tumor growth and the presence of symptoms suggesting a neurovascular disorder are established. During physical examination, special attention is paid to the size and depth of the tumor, its connection with surrounding structures, the presence of concomitant edema or signs of nerve involvement.
The diagnosis of soft tissue sarcoma is often made late. Patients often postpone seeking medical help because the tumor is painless.
Partial excision of the tumor before referral to a specialist may lead to the appearance of distant metastases and the need for extended resection. A diagnostic biopsy performed in an inappropriate manner may interfere with subsequent surgical resection, cosmetic repair, or lead to the need for more extensive surgical intervention. Therefore, it is recommended to contact a specialized medical institution as early as possible.
Diagnostic examination of soft tissue tumors includes:
Magnetic resonance topography (MRI) for tumors of the extremities, trunk, head and neck, or computer topography (CT) for tumors of the abdominal cavity and retroperitoneal space
A thick-needle biopsy followed by morphological examination, if technically feasible. If an open (incision) biopsy is required, it must be carefully planned and performed by the surgeon who will perform the total resection.
Morphological examination of samples suspected of soft tissue sarcomas is carried out in EMC's own histological laboratory. If necessary, the biopsy materials can be reviewed in the laboratories of EMC partner clinics in Israel, Germany or the USA.
As soon as the diagnosis of soft tissue sarcoma is confirmed, a chest examination is performed in all patients to check for lung metastases. CT is used in patients with a high risk of lung metastasis (tumors >5 cm, deeply located or having a moderate or high degree of malignancy). CT scans of the abdominal cavity and pelvis are also recommended for round-cell/myxoid lipomas, as extrapulmonary metastases in the abdominal cavity and retroperitoneal space are common.
Brain imaging is offered to patients with angiosarcoma and alveolar soft tissue sarcoma, since these tumors are characterized by a high tendency to metastasis to the central nervous system.
In everyday practice, positron emission topography (PET) or PET/CT is not performed for the initial assessment of the stage of a newly diagnosed soft tissue sarcoma. PET or gallium scanning may be significant in patients with neurofibromatosis as an auxiliary method of differential diagnosis.
In most cases, sarcoma treatment is combined. The choice of treatment method is influenced by the size and location of the tumor, the degree of malignancy, as well as the prevalence of the process.
Surgery as the only treatment method can be used only if the tumor is highly differentiated and its radical removal is possible.
Surgical resection of the primary tumor is the main component of the treatment of almost all patients with soft tissue sarcomas of the extremities. In most patients, tumor resection with adequate resection boundaries is possible, and this method preserves limb function; a small subset of patients may require primary amputation.
Resection should be performed with the capture of tissues extending beyond the pseudocapsule of the tumor, if any, until a visually healthy tissue is reached that is not involved in the process. Tumor damage (i.e. dissection of the tumor or resection, after which a macroscopic or microscopic residual fragment of the tumor remains) is associated with a higher incidence of local recurrence, even if performed radiation therapy (LT). The boundaries of resection are the most important indicator that affects the local control of the tumor.
The use of radiation therapy in combination with resection reduces the need for amputation and increases the likelihood of sarcoma removal while maintaining limb function. In most cases, the combination of surgery with limb preservation and radiation therapy provides better local control.
Postoperative radiation therapy significantly affected the frequency of limb preservation in soft tissue sarcomas of the extremities. In the 1970s, about half of the patients with CMT had their limbs amputated. With the development of radiation therapy, the amputation rate decreased to almost 1% without a noticeable decrease in overall survival.
Surgical resection during the metastatic process provides long-term disease-free survival and, possibly, cure in individual patients, most of whom have isolated lung metastases. However, for most patients with metastatic soft tissue sarcomas, chemotherapy is prescribed as a palliative treatment in order to reduce the overall tumor volume, reduce symptoms, improve quality of life, and increase survival.
The natural course of the disease in patients with unresectable metastatic disease can be different and depends more on the biological characteristics of the tumor than on treatment. In some patients with asymptomatic, unresectable, low-grade malignancy, it may be rational to monitor the patient without active chemotherapy. Conversely, in patients with a high-grade tumor that is sensitive to chemotherapy, such as synovial sarcoma or liposarcoma, early initiation of combined chemotherapy may be preferable.
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