STS Temp

== Sarcoma Studies ==

Incidence

  • ~9000 new cases/year
  • 1% of non-skin cancers
  • Male:Female 1.2:1.0
  • Can occur anywhere in the body

Natural History

Presents usually as a painless lump
Latency to diagnosis is ~4 months
Pain, numbness, edema are caused by neurovascular compromise

Biopsy any lesion persisting >6 weeks, >5 cm, or symptomatic

Patterns of Spread

  • Pseudencapsulation occurs by surrounding fibrous and reactive connective tissues.
  • Perforation of capsule occurs and microscopic spread beyond capsule is seen as it locally invades
  • Longitudinal extension occurs along muscular fascial planes, skip metastases occur
  • Rarely crosses intermuscular septa
  • Hematogenously metastasize to lung primarily
  • 10% incidence of distant metastasis at diagnosis
  • Grade is the most important factor in distant metastasis followed by tumor size

Lymph node

  • Lymph node involvement uncommon ~6%
  • Exception to the above statement include the following table.
Histologic Subtype Lymph node risk
Rhabdomyosarcoma
- Embryonal 13.6%
- Other 2.9%-14.8%
Angiosarcoma 13.5%
Clear cell 27.5%
Epitheliod 16.7%-20.0%
Synovial cell 13.7%

Clinical Evaluation

  • History/Physical – evaluate size, fixation, functional status of involved part, nodes
  • Radiographs – Define anatomic site, extent; include MRI, CT, plain film

PET Scanning – may have preop treatment eval. role
Arteriography – may have use in retroperitoneal sarcomas
Bone scan – Usually shows periosteal reaction well

  • Biopsy – This critical first step must be done correctly to not complicate treatment and eliminate options of treatment

Excisional bx

  • Only done for superficial small lesions (<5cm)
  • May leave gross or microscopic tumor
  • Can contaminate tissue planes 2º to hematoma

FNA/Core needle

  • Small tissue sample makes determination of grade and type very difficult
  • Good for sampling deep seated tumors or recurrent lesions

Incisional – Technique of choice

  • Must orient along long axis of extremity
  • Situate so that incision site can be excised with tumor
  • Place over tumor at point where lesion is closest to surface
  • If drain used, should exit through or near incision

Prognostic Factors

  • Single most important independent factor is Grade
  • 5-DM increases with grade(1) and size of lesion(2)
  • 5-DM ~5% grade 1, 40% grade 3

Treatment

UF Treatment Philosophy
Preoperative radiation is preferred for previously untreated high grade lesions
Dose 50.4Gy / 42Fx BID with surgery 2-3 weeks later
Volume

  • Entire cross section of compartment with 2-3cm margin
  • Longitudinal borders 7-12cm on tumor depending on size, grade, extracompartmentality, and involvement of NVB
  • Spare post strip of tissue
  • Frequently uses extended SSD, CT planning custom immobilization

Post-Operative Radiotherapy

  • Preferred if pt referred from outside institution with inadequate margins (re-resected at STH)
  • Low grade lesion with less than wide margin
  • High grade lesion, less than radical margin
  • Residual disease in re-excised specimen, cut through, or recurrent tumor after surgery

Treatment employs shrinking field

  • ~50Gy to initial field (scar, drain sites, clips)
  • 1st reduction field to 55Gy
  • Tumor bed boost

negative margin 60Gy
Close or positive ~66Gy
Desmoid and Aggressive Fibromastosis Tumors
When postop used for positive margins dos is 45-55Gy
RT alone – 54-55Gy – 90% LC
BRT
Used for recurrent lesions
tx scheme 24Gy EBRT then resection
40Gy with implant to * cm depth, 2cm margin on resection cavity
Catheters loaded 4-5 days postop
Chemotherapy
Rarely used as trials show no survival benefit
New Horizons
As of 1/1/99 – Patients with high grade tumors ≥8cm will receive:
1 Preop XRT – 5040cGy
2 Postop 24Gy/10FX (120cGy Bid) to the whole lung, density corrected

Separate Mangement Issues

Retroperitoneal Tumors

  • Abdomnial pain is the most common presenting symptom
  • Histologic type and invasiveness are major prognostic factos.

Retroperitoneal Sarcomas

  • OS-5 is 50%
  • Histologic grade is the most important factor for retroperitoneal sarcomas (ie. histologic type loses some significance once we have the diagnosis of sarcoma).
  • Rectability and size have been correlated with prognosis.

Aggressive Fibromatosis (desmoid tumor)

  • Also termed, extra-abdominal desmoid tumor

Pathology

  • Appear like low-grade fibrosarcoma.
  • The rare reports of metastasis of desmoid must be interpreted as misdiagnosis of fibrosarcoma.

Adjuvant RT

  • Controversial - May delay local relapse but not prevent it.
  • 33% Local recurrence at 10-year with complete resection alone (MDA)
  • Margin does influence local control, however, failure does not invariably occur if residual microscopic tumor from a primary lesion is left in situ as long as local progression would not cause significant morbidity50%+ local recurrence with positive margins (MDA), but with RT the local recurrence was reduced to 31%.
  • RT alone 24% local relapse rate
  • Adjuvant RT is controversial as other surgeons have reported lower local recurrence rate with surgery alone.

Other Treatment modalities

  • Hormonal manipulation, EBRT and chemotherapy can be used for unresectable disease; but a trial of surveillance to evaluate the presence or pace of presence, or both, may be considered.

Definitive Radiation Dose

  • Dose of 56 Gy in 2 Gy fx to 59.4/ 1.8 Gy per day for definitive RT alone is recommended.
Bibliography
1. O'Sullivan B, Davis AM, Turcotte R, Bell R, Catton C, Chabot P, Wunder J, Kandel R, Goddard K, Sadura A, Pater J, Zee B. Preoperative versus postoperative radiotherapy in soft-tissue sarcoma of the limbs: a randomised trial. Lancet. 2002 Jun 29;359(9325):2235-41. PMID: 12103287
2. Pisters PW, Harrison LB, Leung DH, Woodruff JM, Casper ES, Brennan MF. Long-term results of a prospective randomized trial of adjuvant brachytherapy in soft tissue sarcoma. J Clin Oncol. 1996 Mar;14(3):859-68. PMID: 8622034
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