Soft tissue sarcomas are rare. Their annual incidence is around 2-3/100,000. The peak age incidence is around 50 years. Overall, soft tissue sarcomas comprise .7of all malignant tumors, while they give rise to 2of the total cancer-related mortality.
1.2 Etiologic and risk factors
Clinical evidence of a genetic predisposition is rare, even if genetic factors are increasingly recognized as of importance in oncogenesis as well as growth and progression of tumours including sarcomas (e.g. the ras gene in rhabdomyosarcoma and fibrosarcoma and the myc expression in rhabdomyosarcoma; the p53 gene, which seems altered in at least one third of sarcoma patients, while in another third of patients the MDM2 gene is amplified, with inhibition of the p53 as a result; the evidence of distinct chromosomal abnormalities in some histotypes). Clinically, however, genetic predisposition is associated within some rare syndromes. Von Recklinghausen's disease carries a 15lifetime probability of giving rise to a neurofibrosarcoma. Other genetic diseases which can increase the risk of soft tissue sarcomas are Li Fraumeni syndrome, basal cell nevus syndrome, tuberous sclerosis, Werner's syndrome, intestinal polyposis, and Gardner's syndrome.
Some chemical carcinogens have been linked to the occurrence of soft tissue sarcomas, such as phenoxy herbicides and chlorinated phenols. Also chemotherapeutic drugs are likewise associated with the risk of developing sarcomas.
Ionizing radiations are able to increase the risk of soft tissue sarcomas. In fact, sarcomas may rarely arise in previously irradiated fields, with a median time from radiotherapy around 10 years, but time to the second primary may be much less. The frequency increases with dose and is only rarely seen after low doses.
1.3 Screening and case finding
Soft tissue sarcomas are rare and no screening program has been evaluated. Screening is therefore not recommended. Preclinical case finding has not been evaluated and is not recommended either. On the contrary, a diagnostic goal may reasonably be to avoid any medical delay in the presence of suspicious symptoms.
A soft tissue sarcoma should be suspected whenever a soft tissue mass becomes palpable. Swellings of soft tissues, in the absence of evident signs of infection, should be evaluated carefully, since soft tissue sarcomas are often deeply seated and may not be easily palpable. Deepness, firmness and fixity are suspicious signs. Deep sarcomas, especially those arising in the trunk, are generally very large at diagnosis. In such cases the first symptoms of disease may stem from compression of adjacent nerves or visceral structures (e.g. ureter or bowel). Unexplained deep pain should prompt the physician to consider a possible soft tissue origin in addition to a skeletal one, and skeletal X-ray is therefore insufficient to exclude a neoplastic cause for pain.
Treatment of soft tissue sarcomas is complex, virtually in all stages of disease, and is often multidisciplinary. Therefore, it is recommended that sarcoma patients be referred to experienced institutions, which often participate in national as well as international clinical trials. Clinical research in soft tissue sarcomas is needed, but is always difficult due to insufficient patient accrual. Even when treatment looks technically easy (e.g. a small soft tissue lesion easily amenable to surgical shelling out) a referral to these institutions is recommended. In particular, biopsy and surgery of the primary lesion, pathological diagnosis, surgery of lung metastases, consolidation radiotherapy are critical, and require experience in the disease. In principle, a multidisciplinary approach to clinical decision making is essential in all stages of disease. Even when surgery, radiotherapy, and chemotherapy are standard treatment, their combination may need to be individualized. The treatment of soft tissue sarcomas has changed from ablative to more conservative treatment by increasing use of combined treatment modalities. In addition, investigational and/or new treatment modalities may be resorted to on an individual basis in specialized institutions.
1.5 Selected reviews
Dirix et al and Robinson on all clinical aspects of the disease, with updated references (1994)
Leyvraz et al on pathology (1988)
Eilber et al on surgery (1984)
Santoro et al on chemotherapy (1993).
1.I 1.II 1.III 1.IV
Dirix LY, van Oosterom AT. Diagnosis and treatment of soft tissue sarcomas in adults. Curr Opin Oncol 1994;6:372-383.
Eilber FR, Eckardt J, Morton DL. Advances in the treatment of sarcomas of the extremities. Current status of limb salvage. Cancer 1984; 54: 2695-2701.
Leyvraz S, Costa J. Histological diagnosis and grading of soft-tissue sarcomas. Sem Surg Oncol 1988; 4: 3-6.
Robinson MH. The management of adult soft tissue sarcomas. Clin Oncol 1994; 6:183-192.
Santoro A, Bonadonna G. Soft tissue and bone sarcomas. In: Cancer Chemotherapy and Biological Response Modifiers Annual 14. HM Pinedo, DL Longo, BA Chabner (eds). Amsterdam, London, New York, Tokyo, Elsevier, 1993; pp 594-605.
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