Soft tissue sarcomas are uncommon malignant tumours arising from
mesoderm-derived tissue (fat, muscle, c.t., vessels).
Cf bone and cartilage sarcoma.
Peripheral nerve sheath tumours are usually included as STS despite
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Any; median 50y
Vast majority are simply sporadic
- risk increases with dose and time
- angiosarcoma most common post-breast radioRx
- but rare; actuarial rate 0.2% in 15-20y after any full dose cancer
- higher in children
Chemotherapy also increases risk
Trauma is rarely a factor except desmoid tumours
- but recent trauma may bring attention to underlying mass
NF1 (15% risk of malignant peripheral nerve sheath tumour)
- and increase risk of GIST
Gardner syndrome (APC gene defect); increased risk of
intra-abdominal / mesenteric desmoid tumours.
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Mesodermal-derived malignant tumour
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Heterogeneous with respect to anatomical distribution, histologic
subtype and clinical behavior.
- 50% on extremities
- 1/3 in abdo / pelvis
--> includes visceral sarcomes (leiomyosarcoma and gist) vs
50 subtypes exist
- malignant fibrous histiocytoma (MFH)
--> myxofibrosarcoma and undifferentiated pleomorphic sarcoma.
- dermatofibrosarcoma protuberans
- synovial sarcoma
Retroperitoneal 2/3 liposarcomas or leiomyosarcomas; rest v. mixed
Unique properties depend on subtype
But generally considered low-grade, intermediate-grade and
- Low grade --> grow slowly, may recur locally, and have low risk
of distant mets (<5%)
- High grade --> grow rapidly, recur locally, and added risk of
distant mets (50% if large ie 8-10cm)
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Given histological variability / many subtypes of 'sarcomas',
workup and treatment can be confusing and quite challenging.
painless mass felt for weeks to months
Pain or tenderness can precede detection.
Later oedema, neuropathy due to infiltration or pressure
Note status of overlying skin
Neurovascular limb status
Presence of distal oedema
Frequently asymptomatic until large
Often picked up incidentally.
May develop a mass or symptoms from compression or invasion of gut,
Primary germ cell tumours
Malignant testicular tumours
Second most common sarcoma
SLow growing red plaque on trunk in pts 30-40y old usually
- histology shows low-grade spindle cell tumour that stains for CD34
and unbalanced gene translocation on c22
Image with CXR; distant mets uncommon
Classifally there is subcliinical disease extending beyond visibly
--> treat with WLE and frozen section; typically to 3cm margins
Mohs reduces local recurrence substantially
Involved margins --> reecision
Radiotherapy if close or involved margins cannot be re-excised
Most local recurrences occur in first 5y; 25% beyond that
--> long term f/up.
Most common skin sarcoma
HHV-8 (human herpes virus) infection; slow growing painless vascular
appearing lesion on skin
- often face or groin
- often HIV or immunosuppressed
Biopsy the area
- confirm diagnosis and exclude bacillary angiomatosis
Solid organ disease excluded with FOB and CXR
Treatment is to optimise HIV with antiretrovirals
- then intralesional vinblastine or radiotherapy if local
- add doxorubicin if advanced
Rare skin tumour; rapidly growing vascular lesion
- ulcerates and shows satellite nodules
- head and neck in the elderly and male.
Operate to wide margins (2cm), with reconstruction
Post op radiotherapy required
Prognosis is still poor; 20% 5y survival
Significant proportion already unresectable at presentation
- then do induction chemo (paclitaxel or doxorubicin) followed by
surgery and radiorx
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Routine FBC and biochem panel
There are no specific tumour markers for STS.
CT and / or MRI
MRI most useful for extremities
- characteristically may have large areas of abnormal fat (well
- sometimes with higher density nodules (de-differentiated
Chest CT for high-grade lesions
CXR probably ok alone for low-grade tumours
PET role as-yet undefined
- but most do show increased fluorodeoxyglucose uptake
Essential to establish a histologic
diagnosis and to determine the definitive treatment strategy.
Core needle biopsy usually
- palpable lesions can be biopsied in clinic under local anaesthetic
- deep tumours require image-directed core-biopsy; can guide toward
solid regions in heterogeneous tumour mass.
- CT guided biopsy for retroperitoneal tumours
Open biopsy reserved for unusual cases when core-biopsy inadequate.
- orient these biopsies longitudinally so can incorporate in final
- minimize bleeding and surrounding tissue contamination.
FNA can confirm metastatic or recurrent tumour when primary
diagnosis already established
- but FNA inadequate for primary
experienced in these tumours; 1-% are not STS, 20% assigned
- 10% may be misdiagnosed and 20% assigned wrong type
Task force of AJCC
Extension of TNM system to include G for histologic grade.
Determined on grade, size, depth, nodal or distant mets.
Cellularity, differentiation, pleomorphism, necrosis, mitotic
Common to assign as grades 1-3.
- low, intermediate and high.
TX = cannot assess
T0 = no tumour
T1 = <= 5cm in greatest dimension
T1a = superficial tumour
T1b = deep tumour
T2 = >5cm in greatest dimension
T2a = superficial tumour
T2b = deep tumour
NX = cannot assess nodes
N1 = no regional nodes
N2 = regional nodes
MX = cannot assess distant mets
M1 = no distant mets
M2 = distant mets
IA = G1, T1, N0, M0
IB = G1, T2, N0, M0
IIA = G2-3, T1, N0 M0
IIB G2, T2, N0-1, M0
III G3, T2, N0, M0
IV Any G, Any T, Any N, M1
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1. MDT management
Multi-modal therapy typically essential, so surgeons, rad and med
onc involved from outset.
2. Rx specific to anatomic
- extremity and trunk tumours can generally be considered together
- retroperitoneal tumours separately
- GIST also separately
1. Commonly surrounded by a pesudocapsule
- if they are shelled out
recurrent rate is 90%.
Need more radical resection with a margin of normal tissue
- reduces recurrence rate to 10-30%.
2. Grow close to nerves, vessels and bones.
- used to be that amputation was the norm.
Revolutionized in 1982 by RCT showing equal outcome with limb
- now limb sparing in >90%;
overall local recurrence rate <10% with adjuvant
3. Preoperative imaging is
- extent of tumour penetration
- relationship to vital structures
- need for vascular, reconstructive involvement.
4. Incisions should be longitudinal
- should extend beyond the beginning and end of the tumour.
- must take overlying subcut fascia
and skin if reqd to achieve the margin
5. Can raise subcut flaps at Scarpa level
- then track past tumour, going deeper into fascia.
- it can be difficult to know where the tumour border is
6. Obtain a 2cm margin.
- if achievable without severe morbidity.
- work with non-dominant hand at edge of tumour.
- nb that some normal tissues like fascia probide better quality
margin than fat and muscle.
--> thus a 1 mm margin to fascia may be ok, but be concerned if a
close margin is next to fat or muscle.
- know that STS does not usually
invade peri-adventitial tissue of arteries, peri-neurium or periosteum.
--> can dissect to these barriers to obtain negative margins.
7. Work to Histology
- e.g. an atypical lipoma has a relatively low recurrence with a
positive microscopic margin
--> so don't need to be aggressive.
- but cutaneous angiosarcomas are highly irregular and infiltrative
so aggressive surgical resection (and radioRx) essential)
8. Careful wound closure lowers complication rates
- handle skin and subcut tissue with care to avoid trauma.
- used closed-suction drains liberally
- wraps, extremity elevation, limited activity all decrease oedema
and fluid accumulation.
For large defects, rotational and free flaps and skin grafts may be
RadioRx doubles wound complication rates.
- reduces ability of tissues to absorb fluid and delays wound
Vast majority treated with adjuvant radiation; this allows limb-sparing surgery.
Several RCTs support this.
Obviously doesn't affect distant disease, but can dramatically
reduce local recurrence rates
Generally external beam, but brachytherapy via catheters post-op or
- generally brachy reserved for patients with recurrence.
T1a tumours well circumscribed and resected with clear 1 cm margins
may not require radio
Timing of radio with regard to
resection is a matter of debate
Trials suggest no clear difference wrt to local recurrence.
Wound complications 2x with pre-op
But tissue fibrosis more frequent in post-op.
Difficult problem of T2b tumours.
High recurrence, high met rates.
?Aggressive chemo (MAID - doxorubicin, mesna, ifosfamide,
Inter-digitated with pre-op radio
?Then post-op MAID.
May achieve overall survival of 70-80%.
Hyperthermic isolated limb
Vascular catheters inserted and limb isolated by a tourniquet.
- TNF-alpha and melphalan infusion at 38.5-40oC
Role of chemo
High risk metastasis patients
- surgery and radio ok in most; 25-50% with large, high grade STS
will benefit from chemo
Doxorubicin and ifosfamid are most active.
- past trials suggested response rates 20-40%
- and that improves survival rates by maybe 10%
But mixed evidence.
--> recent large RCT of adjuvant doxofubicin and ifosfamide vs no
chemo showed no impact on survival
Thus chemo often reserved for young high risk patients
Whereas in other centers, chemo is not used.
Consider that side effects are substantial
- doxorubiin - cardiotoxic
- ifosfamid - haemorrhagic cystitis
Complete R0 resection
- quite difficult to achieve; e.g. only in ~60%.
Negative microscopic margins is frequently not achieved and local
recurrence rates are high; 40%+
= primary cause of death.
1. Carefully evaluate imaging; as above.
2. Prep colon, and confirm contralateral kidney function.
3. Consider optimal patient positioning and incision
- often modified lateral decubitus
- may need thoraco-abdominal incisions
4. Dissect circumferentially;
anterior to posterior.
- can help exposure with judicious bed tilts to move organs.
- don't work into deep holes as vessel injury can have serious
- general goal is to aggressively dissect to clear margins, taking
involved organs en-bloc
- posterior margin taken under direct vision, sharp dissection to
deep margin under direct vision.
5. Accurately orient lesion
- e.g. take lesion to pathologist and discuss.
It is difficult to deliver high dose radiation to the abdomen,
unlike the limb.
Usually preferred pre-op when given.
- margin around tumour at risk of local recurrence more clearly
defined, and effective dose lower.
Post-op positive margins treated with a boost radio dose.
The future is intensity-modulated radiation therapy (IMRT), ie.
3D-guidance of rays to image-planning of tumour position.
- can also retract organs out the way and deliver high doses to the
Mix of targeted approaches tailored to individual patient context
may be most effective.
Median survival is 12m with mets
Extremity --> lung
Abdominal --> lung and liver.
Lymph nodes = rare; 5% except for certain subtypes including
epithelioid sarcoma and synovial sarcoma
Response rates are poor <15% with combo therapy, duration 8m on
Multi-agent approach = no proven benefit over sequential single
Surgical resection can be attempted in highly selected cases.
- isolated lesions; 5-yr survival can approach 20%.
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