This document discusses soft tissue sarcomas (STS), a rare type of cancer that arises in connective tissues like muscles or fat. It notes that STS account for about 1% of adult cancers in the US, with most occurring in extremities or trunk. Risk factors include radiation exposure, certain chemicals, and genetic conditions. STS are classified and graded based on cell type and differentiation. Treatment typically involves surgical resection with clear margins, sometimes combined with radiation or chemotherapy depending on stage, grade, and location. Prognosis depends on stage and grade, with 5-year survival rates ranging from 54-65% after complete resection of primary retroperitoneal sarcomas.
2. Introduction
Group of anatomically and histologically diverse
tumors of extraskeletal mesenchymal origin.
Rare: Account for about 1% of adult malignancies and
approximately 9,000 to 12,000 cases reported every
year in the United States
3,000 to 4,000 deaths annually from STS in the
United Stated
7. Biopsy
Most present as painless mass leading to delayed diagnosis
– Mistaken for lipoma, hematoma, muscle injury
Core needle biopsy guided by palpation or by image
guidance if not palpable
Few cases of tumor seeding with closed biopsy so some recommend
tattooing site for later excision with specimen
Excisional biopsy for superficial small lesions if needle
biopsy non-diagnostic
Incision biopsy
Longitudinal incision without tissue flaps with meticulous hemostasis
to prevent tumor seeding in hematomas
Send biopsy fresh and orientated
8. Imaging
MRI
For extremity masses
Gives good delineation between muscle, tumor and blood
vessels
CT for abdominal and retroperitoneal
PET
May help determine high vs. low grade
May be helpful in recurrences
9. Staging
AJCC/UICC Staging System for Soft Tissue Sarcomas
T1: <5cm
T1a: superficial to muscular fascia
T1b: Deep to muscular fascia
T2: >5cm
T2a: superficial to muscular fascia
T2b: Deep to muscular fascia
N1: Regional nodal involvement
Grading
G1: Well-differentiated
G2: Moderately differentiated
G3: Poorly differentiated
G4: Undifferentiated
10. Staging
Stage IA G1,2 T1a,b N0 M0
Stage IB G2,2 T2a,b N0 M0
Stage IIA G3,4 T1a,b N0 M0
Stage IIB G3,4 T2a N0 M0
Stage III G3,4 T2b N0 M0
Stage IV Any G Any T N1 M1
**Does not take into account extremity vs. visceral
Staging system predicts survival and risk of metastasis, but not local recurrence
12. Relative risk for recurrence and survival
Age >50 years 1.6
Local recurrence at presentation 2.0
Microscopically positive margin 1.8
Size 5.0–10.0 cm 1.9
Size > 10.0 cm 1.5
High-grade 4.3
Deep location 2.5
Local recurrence 1.5
13. Surgery
Limb-sparing vs amputation
Comparison study with post-op radiation in limb sparing
showed no difference in survival
Amputation still may be indicated for neurovascular
or bone involvement
14. Resection
Arbitrary 2 cm margin if no plan for post-op
radiotherapy
Negative margins may be adequate for post-op
radiation therapy
Presence of positive margins increases local recurrence by 10-
15%
No need for lymph node dissection as only 2-3% have
nodal metastasis
15. Adjuvant radiotherapy
Small, low grade tumors resected with 2 cm margins
may not require radiation
Improves local control but not survival
Whether improved local control leads to improved
survival is controversial
17. Pre-op or post-op radiation?
Some avoid pre-op use because of increased wound
complications (although this is debatable)
RCT looking at wound complication rate pre-op vs post-op
radiation showed 35% vs 17%
Risk confined to lower extremity
Conclusions: pre-op may be better for upper extremity and
head & neck because of equal wound complication risk and
benefit of lower radiation doses to more vital tissues
19. Chemotherapy
Can improve local control, but not survival
Doxorubicin and ibosfamide have response rates of
20%
Use only in advanced disease
Combination with radiation or neoadjuvant therapy
are controversial
Hypothermic isolated limb perfusion may be used for
palliation
20. Treatment of Recurrence
20-30% of STS patients will recur
More common in retroperitoneal and head & neck
high grade tumors because hard to get clear margins
38% for retroperitoneal
42% for head and neck
5-25% for extremity
After re-resection recurrence is 32% for extremity and
much higher for visceral
21. Metastatic disease
Lung most common site of mets, but visceral often go
to liver
Median survival from development of metastatic
disease is 8-12 months
Resection of pulmonary mets can give 5 year survival
of 32% if all mets can be removed
>3 mets is poor prognosticator
23. Retroperitoneal Sarcomas
15% of all sarcomas
Liposarcoma 42% and leiomyosarcoma 26%
CT scan can show cystic/solid/necrotic components and relation to
surroundings
CXR to r/o mets, chest CT if CXR abnormal
Biopsy not necessary unless suspect a lymphoma or germ cell tumor
or plan preop chemo or radiation
En bloc resection is standard treatment
bowel prep
assess bilateral kidney function
50-80% need organ resection
78% of primary lesions can be completely resected
26. Prognosis for retroperitoneal sarcomas
5 year survival after complete resection of 54-65%
Drops to 10-36% if incompletely resected
Recurrence occurs in 46-59% of completely resected
tumors
27. Radiation or chemotherapy for retroperitoneal
sarcomas
Radiation
GI and neurotoxicities limit delivery of sufficient doses
May improve local control
Recommended for use only in clinical trials given lack
of data either way
Chemotherapy
Use for recurrent, unresectable or metastatic disease
28. Case #2
• 49 y/o female with GERD undergoing EGD
29. GIST
Separate subtype of sarcoma defined by expression of c-
Kit (CD117)
Surgery: complete resection without local or regional
lymphadenectomy
Very resistant to traditional chemotherapy
Gleevec (imantinib mesylate)
c-Kit is constitutively active tyrosine kinase receptor
Drug is tyrosine kinase inhibitor used in CML
Initial studies showed 54% response rates
Two RCTs currently looking at adjuvant treatment