Transcript Document

MULTI-MODALITY IMAGING
OF PREOPERATIVELY
IRRADIATED SARCOMA PATIENTS
DOES NOT PREDICT
PATHOLOGICAL OUTCOME.
Rick Haas
Luc Dewit, Frits van Coevorden,
Hans Peterse, Claudette Loo, Renato Valdés Olmos
NKI – AVL Amsterdam
MULTI-MODALITY IMAGING
OF PREOPERATIVELY
IRRADIATED SARCOMA PATIENTS
DOES NOT PREDICT
PATHOLOGICAL OUTCOME.
…..or does it…..????
Objectives & Purpose
Statement:
• Often treatment outcome can be predicted by specific imaging modalities.
• Sometimes very early after treatment initiation.
(FDG-PET in imatinib treated GIST patients)
Objectives & Purpose
Statement:
• Often treatment outcome can be predicted by specific imaging modalities.
• Sometimes very early after treatment initiation.
(FDG-PET in imatinib treated GIST patients)
Questions:
• Are imaging modalities able to predict radiation outcome in preoperatively
irradiated sarcoma patients.
• And if so; which modality performs best.
Patients & Methods
15 patients received preoperative irradiation (50 Gy in 5 weeks) in various
sarcoma subtypes.
Baseline investigations:
Pathology
MRI
CT
FDG-PET
Reevaluation: 4 weeks after radiotherapy
Patients & Methods; scoring
Pathology:
necrosis on biopsy material and the surgical specimen.
MRI:
necrosis on a 5 step scale
tumor measurements
CT:
Houncefield Units (HU; average number over tumor volume)
FDG-PET:
SUVmax
SUVmean
Note:
pathology is “the golden standard”
Results
(I)
Necrosis is adequately predicted by
modality
% of cases
SUVmax
57%
SUVmean
43%
MRI
50%
HU
9%
Results
(II)
In 30% of cases volume after irradiation increased (140-236% relative to
baseline).
Performance of these tests was not significantly better in good responding
myxoid liposarcomas patients as compared to other sarcoma subtypes.
Pathology
Pathology
100
percentage
80
60
40
20
0
vitality pre-RT
vitality post-RT
The “perfect radiosensitive tumor”
"perfect patient"
120
normalized values
100
80
pathology
SUV-max
60
MRI necrosis
size
CT-HU
40
20
0
pre-RT
post-RT
The “perfect radioresistent tumor”
"perfect patient"
120
normalized values
100
80
pathology
SUV-max
MRI necrosis
size
CT-HU
60
40
20
0
pre-RT
post-RT
Patients in this study
patient 2
patient 1
80
pathology
SUV-max
60
MRI necrosis
size
CT-HU
40
normalized values
250
200
200
pathology
150
SUV-max
MRI necrosis
size
100
CT-HU
50
20
0
0
120
120
100
100
80
80
pathology
SUV-max
60
MRI necrosis
size
CT-HU
40
20
post-RT
CT-HU
250
200
pathology
SUV-max
60
MRI necrosis
size
CT-HU
40
post-RT
pathology
150
SUV-max
MRI necrosis
size
100
CT-HU
50
0
pre-RT
patient 7
post-RT
pre-RT
patient 8
160
160
140
140
140
SUV-max
80
MRI necrosis
size
60
CT-HU
normalized values
120
pathology
100
120
pathology
100
SUV-max
80
MRI necrosis
size
60
CT-HU
SUV-max
80
size
40
20
20
20
0
MRI necrosis
60
40
post-RT
pathology
100
40
0
post-RT
patient 9
160
120
post-RT
patient 6
0
pre-RT
size
pre-RT
20
0
normalized values
MRI necrosis
100
patient 5
normalized values
normalized values
patient 4
pre-RT
SUV-max
0
pre-RT
post-RT
normalized values
pre-RT
pathology
150
50
normalized values
normalized values
100
patient 3
250
normalized values
120
CT-HU
0
pre-RT
post-RT
pre-RT
post-RT
First Conclusions
Multi-modality imaging in preoperatively irradiated sarcoma patients in this
population did not adequately predict pathology outcome.
Induction of necrosis and increase in volume is a common phenomenon.
More patients and longer follow-up on local control is needed to fully
appreciate the most appropriate imaging modality.
However……
Suppose you would consider a boost of 10Gy if 50Gy would not induce necrosis.
Prerequisites:
adequately define necrotic tumors after 50Gy
enough is enough => no need of boost
adequately define vital tumors after 50Gy
don’t deny these patients a boost
However……
Suppose you would consider a boost of 10Gy if 50Gy would not induce necrosis.
By ROC-curve analysis using a SUV max-preRT of 4.5 as a cut-off value
Than:
In 100% of cases necrosis correctly identified:
50Gy = enough; no boost
However……
Suppose you would consider a boost of 10Gy if 50Gy would not induce necrosis.
By ROC-curve analysis using a SUV max-preRT of 4.5 as a cut-off value
Than:
In 100% of cases necrosis correctly identified:
50Gy = enough; no boost
In 75% of cases vital tumor correctly identified:
you "win" 75% of your patients who might need a boost
at no loss of patients who get more RT, while not necessary
Final conclusions
More patients and longer follow-up on local control is needed to fully
appreciate the most appropriate imaging modality.
Probably SUV max-preRT
Final conclusions
More patients and longer follow-up on local control is needed to fully
appreciate the most appropriate imaging modality.
Probably SUV max-preRT
This will be part of a new EORTC STBSG / ROG phase III trial.
EORTC 6207NN / 2207NN