Soft Tissue Sarcoma Presley Regional Trauma Center Department of Surgery University of Tennessee Health Science Center Memphis, Tennessee
Soft Tissue Sarcoma • Collective term for an unusual and diverse group of malignancies that arise from cells of the embryonic mesoderm • Account for 1% of adult and 15% of pediatric tumors • Comprise more than 50 distinct histologic subtypes
Soft Tissue Sarcoma • May occur anywhere in the body • 43% - extremities • 15% - RP • 10% - trunk • 19% - viscera • 13% - other
Etiology • Unclear and controversial • Genetic factors • Chemical exposure • Lymphedema
Etiology • Chromosomal abnormalities - Translocations - Point mutations - Deletions • Regulatory genes - p53 - RB1
Etiology • Ionizing radiation - Often do not become clinically apparent until long after inciting exposure - Osteosarcoma - Malignant fibrous histiocytoma • Chemical carcinogenesis - Thorotrast - Vinyl chloride - Arsenic
Pathologic Classification
STS • Categorized on the basis of the tissue type from which it is believed to originate • Subtypes may be defined by histochemistry, flow cytometry, EM, tissue culture and cytogenetic analysis • Useful in determining which therapy is best – not part of staging system
Grade • Best indicator of biologic aggressiveness and metastatic potential • Defined by tumor’s cellularity, nuclear atypia, degree of necrosis and mitotic activity • AJCC staging system integrates tumor grade, size, depth of tissue invasion, degree of nodal involvement and mets
Clinical Evaluation
Presentation • Asymptomatic mass • Painless and large • Often noticed because of h/o recent trauma to the area • 38% are > 10 cm
Presentation • Distant mets vary with tumor histology and site of primary • Extremity lung • Abdominal and RP liver • Few go to regional LN (2.6%)
Management
Surgical Therapy • Foundation of treatment • Amputation was once considered the only option for cure • Rosenberg et al (1982) • Amputation is usually reserved for extremity sarcomas that involve major vessels, nerves or bones
NCI • Rosenberg et al (1982) - 43 patients with extremity sarcoma - Amputation – (n = 16) - Limb-sparing surgery + radiation – (n = 27) - All received adjuvant chemotherapy - 5-year local recurrence slightly higher in LSS - 5-year survival nearly identical
Surgical Therapy • Adequate resection involves excising a margin of normal tissue along with any areas through which biopsies have been performed • Compartmental resection or resection of entire muscle groups provides no benefit over WLE • 1 to 2 cm margin should be the goal
Surgical Therapy • Regional lymphadenectomy is not usually indicated • Tumor is in proximity to a LN basin • Tumor is one of the following subtypes - Rhabdomyosarcoma - Epithelioid sarcoma - Clear cell sarcoma - Synovial sarcoma - Vascular sarcoma
Sarcoma Type Incidence of Nodal Metastases (%) Rhabdosarcoma 11 - 36 Epithelioid Sarcoma 17 - 80 Clear Cell Sarcoma 25 - 50 Synovial Sarcoma 2 - 17 Vascular Sarcoma 11 - 40
Radiation Therapy • Dramatically changed the surgical treatment of sarcomas • Provides local control • Brachytherapy • Post-, pre-operative external beam
Brachytherapy • MSKCC - 164 pts with extremity or superficial trunk sarcoma - Resection ± brachytherapy - 76 month median f/u - Local control rate better in BT group - No difference in 5-year disease-specific survival
External Beam • NCI - 91 pts with high-grade STS - Resection ± radiation - All pts received adjuvant chemotherapy - One local recurrence with radiation vs 8 with no radiation - No difference in overall survival
Pre- vs Post-op External Beam • Canada - 190 pts - Closed because of wound complications - Pre-op = 35% vs 17% with post-op - No difference in local control - Significant difference in overall survival that slightly favored the pre-op group
Chemotherapy • Post-op chemo has been studied in multiple prospective, randomized trials but small sample sizes and differences among them have made it difficult to interpret the data • Sarcoma Meta-analysis Collaboration • Post-op adjuvant chemotherapy is best employed in the context of appropriate clinical trials
Pre-op Chemotherapy • Allows delivery of agents through native vasculature • Permits assessment of effectiveness of tx by pathologic analysis • May facilitate tx of micromets • May downstage tumors – making them more amenable to resection
Conflicting Data • MD Anderson - Retrospective, 46 pts extremity sarcomas - Overall tumor response rate was 40% - Significant improvement in both disease-free and overall survival • MSKCC - Prospective, 29 pts - Large, high-grade extremity sarcomas - No benefit
Conclusion • Given the lack of sufficient evidence for any survival benefit, pre-op chemotherapy may be considered in attempting to preserve limb function but otherwise its use should be limited to clinical trials
Targeted Therapeutics • Most interesting and exciting advances • The characterization and targeting of the tyrosine kinase receptor = c-kit • GIST
Isolated Limb Perfusion • Reserved for patients in whom LSS is not possible • Cannulate the arterial and venous supply and apply a proximal tourniquet • Bypass machine maintains mild hyperthermia, oxygenation and circulates chemotherapeutic agents in the limb
Recurrent STS • Extremity - local recurrence = 8 to 20% • RP - local recurrence = 38 to 50% • Salvage surgery is an option • Radiation for those who did not receive it previously
Metastatic Disease
Resectable • Lung mets present in 20% of pts with trunk or extremity • Resection may be attempted if pt is medically fit, no extrathoracic disease is present and the primary tumor is controlled • 3-year survival ranges from 23 to 54%
Unresectable • Distant mets may develop in as many as 50% of cases • For the vast majority, only available treatment option is systemic chemotherapy • Doxorubicin
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