Sarcoma Flashcards
Site of metastatic disease
- For extremity: lung, bone, soft tissue
- For retroperitoneal: liver
Histologies with higher risk of nodal metastases
CARE
- Clear cell
- Angiosarcoma
- Rhabdomyosarcoma
- Epithelioid
Physical exam features for sarcoma
- ROM
- Pain
- Swelling
- Neurologic dysfunction
- Pulses
Necessary workup
Try to obtain imaging prior to biopsy –CT/MRI –+/-PET –Plain film of chest or CT chest –Special imaging
What other imaging does myxoid sarcoma require
MRI spine
What other imaging does alveolar soft part sarcoma or angiosarcoma require
MRI brain
After imaging of sarcoma –> next step
Biopsy
- Core is preferred
- Incisional
- Excision is lowest priority given risk of non-oncologic surgery
When would an RP sarcoma get biopsied
If preop RT is planned
What dictates sarcoma grade
- Mitoses
- Atypia
- Necrosis
Sarcoma T1
<5 cm
Sarcoma T2
5-10 cm
Sarcoma T3
10-15 cm
Sarcoma T4
>15 cm
Stage IA sarcoma
T1 G1
Stage IB sarcoma
T2-T4 G1
Stage II sarcoma
T1 G2 or G3
Stage III
T2-T4 G2-3
Management of stage I tumors
- Several options
- Surgery alone with observation (preferred for T1)
- Surgery plus adjuvant RT if close or positive margins (more if IB)
- Pre-op RT –> surgery
Principles of sarcoma surgery
- Limb sparing
- Wide local excision with 1-2 cm of margins
- Place clips at any area of concerning margin
- Resect biopsy and scar
- Closer or positive margins are acceptable at major nerves/vessel/bone or areas that cause functional deficits
Indications for neoadjuvant RT
- Amputation would be necessary with surgery
- Poor functional outcomes anticipated
- Concerns about margin +
Indications for postop RT
- Close or positive margins (<1 cm) and reresection not possible
- Larger size (T2+)
- Higher grade (G2-G3)
What is the benefit of RT for sarcomas
Improves local control (70% –> 90%)
No difference in OS
Management of stage II tumors
- Surgery +/- Adjuvant RT
- Pre-op RT –> surgery
- Brachytherapy
What is the management of stage III sarcomas?
- Preop RT –> surgery
- Surgery –> RT + chemo
- Brachytherapy
What chemo regimen is recommended for sarcomas?
doxorubicin containing regimen, single or multi-agent
What is the preop dose for sarcomas?
50 Gy in 25 daily fractions of 2 Gy
What is the postop dose for extremity sarcomas?
- Negative margins: 60 Gy
- Microscopic margins: 66 Gy
- Gross positive margins: 70 Gy
What is the benefit/tradeoff of preop RT
- Benefits
- More defined targets
- Smaller targets
- Lower dose
- Less fibrosis/joint stiffness and edema
- Less hypoxia
- Downside
- More wound complications post op, especially LE
- Delays surgery
What is anticipated rate of wound complications preop vs. postop
- Preop: 35%
- Postop: 17%
What are the 5 year OS rates for stage I-III tumors
- stage I: 85-90%
- stage II: 70-80%
- stage III: 70-80%
Downside of postop RT
More fibrosis, joint stiffness, edema
Management of N1 or M1 sarcoma
Doxorubicin containing chemo
SBRT or surgery for up to 4 spine or lung mets
General principles of STS RT treatment
- CT and MRI sim if possible or fuse T1 post contrast and T2 sequences
- Spare >1 cm of limb cross section to reduce edema risk
- Treat < 50% of bone circumference if possible
- Avoid joint space or exclude after 40-45 Gy
What RT approach should be used for STS
IMRT with faily KV/CBCT
CTV margins for preop RT
- If GTV >8 cm
- CTV = gross disease + T2 edema + 3cm longitudinal, 1.5 cm radial
- If GTV <8 cm
- CTV = gross disease + T2 edema + 2cm longitudinal, 1 cm radial
CTV margins from GTV for large sarcomas
3 cm longitudinal
1.5 cm radial
When should postop RT start?
10-20 days postop for healing
What is the contouring strategy for postop RT for STS?
- CTV50: tumor bed, scar, drain sites + 4 cm longitudinal, 1.5 cm radial
- CTVboost: tumor bed + 2 cm longitudinal, 1.5 cm radial
Boost doses for postop RT
If R0: 60 Gy
If R1: 66 Gy
If R2: 70 Gy
Strategy if preop given and then margin positive
Give boost dose post op
srugical margin + 1 cm
Anus/vulva constraint
V30 <50%
Testis constraint
V3 < 50%
Femoral neck
V60 < 5%
Joint constraint
V50 < 50%
Skin strip constraint
V20 < 50%
PTV coverage goal for sarcomas
- V97% = 99%
- V110% <20%
Follow-up recs for sarcomas
MRI primary and CT chest q3m x 2years –> q6m x 2-5 years –> annual
Complications for STS
Wound complictions
Fibrosis and decreased ROM
Weakening of bone/fracture
Limb length discrepancies
Lymphedema
Dermatitis, hyperpig, telangiectasia
5% risk of second malig
Compartment syndrome (dex and fasciotomy)
Staging of RP sarcomas
same as extremity
Management of RP sarcomas
In general, if resectable should go to surgery straight
If concern about margin–> core needle biopsy –> neoadjuvant RT (45-50 Gy) –> maximal safe surgery
What is the rate of local failure for RP sarcoma
50-80%
What is 5 year OS for RP sarcoma
30-60%
What histology for RP sarcoma has poorest outcomes
leiomyosarcoma (highest rate of DM)
What is the controversey of preop RT
Recent trial demonstrated no difference in abdominal RFS but this was a controversial primary otucome.
The LF was significant reduced (50%) with RT
When should postop RT be done for RP sarcoma
Maybe +margin but very discouraged due to high GI toxicity
Simulation for RP sarcoma
Supine, alpha cradle, 4dCT, PO/IV contrast, fuse with diagnostic CT and MRI
Contouring for RP sarcoma
- GTV = gross disease
- ITV = accounting for motion
- CTV = 1.5 cm expansion (edit of organs, bones), with only 5 mm extension into bowel
- PTV = 5 mm expansion, daily CBCT
Management of desmoid tumors
Surgery is best with wide margins (2cm+)
If R1: 50 Gy if re-resection not possible
If R2: re-resect or RT (50 Gy)
What if desmoid is unresectable?
56 Gy or systemic therapy
Use wide margins
