Sarcoma Flashcards
Sarcoma higher risk of nodes
higher risk of nodes: SCARE- synovial clear cell angio rhabdo epitheliod (10-30%)
Genetic/Environmental conditions more likely to develop sarcoma
Genetic factors
- NF1 (MPNST)
- Li-Fraumeni (TP53 gene)
- FAP (abdominal desmoids)
- Retinoblastoma (RB1 gene; osteosarcoma)
Environmental factors
- RT (breast angiosarcoma)
- Lymphedema (arm angiosarcoma in PMRT arm)
- Immunosuppression
- Trauma not associated
Sarcoma Workup
H&P: extremity fxn, neuro status, blood flow; LN; lungs
Labs: CBC, chem 7, LDH
Imaging (before bx!):
- CT/MRI primary (hyperintense on T2)
- CT chest
- CT abd and MRI spine if myxoid
- MRI brain if alveolar
Biopsy: (in order of pref)
- core needle: preferred
- longitudinal incisional
- excisional (worst → nononcologic, need WLE)
- consider SLNBx for CARE histologies
- expert pathology review!
MRI:
T1 – fat hyperintense
T2 – fat intermediate intensity, fluid/edema bright
Sarcoma Staging TNM
T1 – up to 5cm
T2 – >5-10cm
T3 – >10-15cm
T4 – >15 cm
N1 regional nodes
Sarcoma Group Stage
Stage Groups
IA: G1, T1
IB: G1, T2-4
II: G2-3, T1
IIIA: G2-3, T2
IIIB: G2-3, T3-4
IV: N1 or M1
- if G1, always Stage I
- if N1, then Stage IV
T1 – up to 5cm
T2 – >5-10cm
T3 – >10-15cm
T4 – >15 cm
N1 regional nodes
Sarcoma Stage I treatment
I: surgery alone (LC 90-100% as long as margin >1 cm) (if close margin, re-excise)
- Consider RT if: +margins, mult LRs, location not amenable to subsequent salvage surgery
Sarcoma Stage II-III treatment
II – III: surgery with preop vs postop EBRT
- Consider neoadjuvant or adjuvant chemo for deep, large, high grade tumors
Pre v Post RT Sarcoma
Pre-op xRT:
- smaller fields, lower doses, treats O2 tumor, increases resectability, less fibrosis/joint stiffness/edema, BUT more post-op wound healing issues, and delays surgery
- no diff in OS or LC
- surgery 3 weeks after RT
Sarcoma when chemo
do NOT bring up chemo
Chemo:
- consider for high grade (5% OS survival benefit), extremity, or large (> 8 cm)
- AIM (adria, ifos, mesna)
- do NOT bring up chemo
Sarcoma preop volumes
50/2
GTV=defined by MRI T1 post
CTV=GTV + T2 edema (just make sure it is covered with 1cm margin– don’t expand off of it) + 4 cm sup/inf + 1.5 cm radial cropped at fascial/ compartment barrier, joint, bone and subcutaneous tissue (controversial – maybe 5mm), skin
PTV=CTV + 0.5 cm
If R1/R2 after surgery, boost area of margin + 1 cm to (start 4 wks after surg): 60 Gy if close margins 66 Gy if R1 (positive microscopic) 70 Gy if R2 -no consensus on boosting pre-op
Sarcoma post op dose volumes
Post-op xRT:
Starts 4-6 wks after surgery
Make sure to wire scar and consider bolus to full dose
-If close margin – ask to speak to surgeon if re-excision w wider margins is possible (want > 1 mm) – if yes, could do pre-op RT and then re-excise
CTV_50=tumor bed + scar + drain sites + pre-op tumor + 4 cm sup/inf + 1.5 cm radial cropped at fascial/compartment barrier, joint, bone, skin
PTV_50=CTV + 0.5-1 cm
CTV_boost=pre-op GTV + surg bed + 2 cm sup/inf and 1.5 cm radial
PTV_boost=CTV + 0.5-1 cm
60 Gy if R0
66 Gy if R1 (conedown margin + 2 cm)
70 Gy if R2 (conedown margin + 2 cm)
Sarcoma treatment goals
Spare 1.5 – 2 cm strip of skin/limb (dose < 20 Gy), spare bone as much as possible, especially anterior tibia due to poor vascularity
Exclude joint space after 45-50 Gy to avoid joint fibrosis (i.e. knee)
Gonadal shield, sperm banking prn
Positioning:
upper inner thigh - frog
post thigh – prone
From RTOG 0630: Anus/vulva: V30 < 50% Testis: V3 < 50% Femoral neck: V60 < 5% Skin strip (1-2 cm depth from surface): V20 < 0% Bone: V50 <50% Bone mean <37 Gy Bone V60<5% Bone V40 <65% Joint V30 <50% Bone=2 cm sup/inf off PTV
Plan eval:
>99% of PTV should get >97% of dose
< 20% of PTV getting > 110% of dose
RT benefit
RT brings LR from 25-30% to <10%
5 yr OS
5 yr OS: I – 90% II – 80% III – 60% M1 – 20%
Follow-up
Follow-up:
PT/OT to maximize functional outcome
Chest imaging q 3-6 months for 2-3 yrs, then q 6 months thru year 5, then annually
Imaging of primary depending on physical exam accesibility
Risk Factors for Recurrence
LR: +margins, > 50 years old, HN/RP/deep location, fibrosarcoma type (including desmoid)
DM: high grade, large size, deep location, +LN, leiomyosarcoma, high Ki-67
