imaging of ovarian malignant germ cell tumors - sichig of ovarian malignant germ cell tumors mri, ct...
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Imaging of ovarian
malignant germ cell
tumorsMRI, CT and PET/CT
Luca Guerra – Dolci Carlotta
Nuclear Medicine – Molecular Bioimaging Centre
San Gerardo Hospital – University of Milan Bicocca
Malignant Ovarian Germ Cell
TumorsConsolidated applications of radiological
Imaging
• CT and MRI
– Differential diagnosis
– Staging (T-N-M)
– Restaging
– Evaluation of Therapy Response
– Suspected relapse
Immature teratoma- MRI
T1 - A T2 - B FS_T1 -C
Immature teratoma- CT
Radiological features for differential diagnosisRadiological features for differential diagnosis
Dysgerminoma - MRI
T1 T2Dysgerminoma - CT
Radiological features for differential diagnosisRadiological features for differential diagnosis
Endodermal sinus tumor - MRI
Endodermal sinus tumor - CT
T2
T1
Radiological features for differential diagnosisRadiological features for differential diagnosis
Radiological imaging useful for the differential
diagnosis of the OGCT and the definition of the
local extension of the disease.
N staging in ovarian germ cell
tumor
Radiological Imaging
• Morphologic criteria
– size: > 8 mm in the pelvis and >10 mm in the
abdomen
– shape: round or irregular
– internal architecture: signal intensity heterogeneity
on T2-weighted MRI images or central necrosis on
CT images
McMahon et al., Radiology 2010, 254: 31
Detection of metastases (M)
Radiological Imaging
• CT and MRI in assessment of distant
metastases
– Peritoneal mts (nodule, peritoneal fat
infiltration, free fluid)
– Hematogenous mts (liver, lung, and rarely
brain) more frequently than epithelial tumors
The Tracer (not the only one) – [18F]-FDG
Many tumors base their metabolism on glucose consumption
[18F]-FDG is taken up by the tumor but it is not metabolized
Basics of PET/CT
glucose fluorodeoxiglucose
CT PET
Basics of PET/CTThe scanner
CT PET
Basics of PET/CTThe scanner
PET/CT limitations
• Diabetes (cut-off 170 mg/dL; optimal below 140 mg/dL)
• Inflammations (False Positive)
• PET/CT Scanner resolution ~ 5 mm
• False Negative
• Low grade, borderline, mucinous type
• False Positive
• Ovarian Cysts, Ovarian mature teratoma, Mioma
PET/CT limitations
• False Positive: Mioma
PET/CT limitations
• False Negative: epithelial ovarian ca. – mucinous type
Malignant Ovarian Germ Cell
Tumors
What Role for PET ?
Role of PET & PET/CT in ovarian germ cell
tumors in scientific literature
No data regarding PET & PET/CTNo data regarding PET & PET/CT
May 2010
Is there a role for PET/CT in T
staging?
303717 Endodermal Sinus Tumor – staging PET
Limited resolution (5-6
mm) not adequate to
define neither
anatomical
characteristic of the
lesion nor the
involvement of pelvic
organs.
Possible role for
metabolic
characterization of
pelvic mass
N staging in ovarian germ cell
tumor
Role of PET/CT
• Radiological Morphologic Criteria
– size: > 8 mm in the pelvis and >10 mm in the
abdomen
– shape: round or irregular
– internal architecture: signal intensity heterogeneity
on T2-weighted MRI images or central necrosis on
CT images McMahon et al., Radiology 2010, 254: 31
Is morphology sufficient ?Is morphology sufficient ?
Is morphology a sufficient
criteria
for N definition ?424507 Endometrial ca.
staging
Anatomical and
metabolic abnormalities
on PET/CT scan in
paraortic LN
Is morphology a sufficient
criteria for N definition ?
424507 Endometrial ca.
staging
Metabolic abnormality in
anatomically normal (9
mm diam.) cervical LN
• Five year survival was 95.7% in pts with LN- compared to 82.8% in pts with
LN+ (p < 0.001).
• Lymph node involvement was an independent predictor of poor survival
with a hazards ratio of 2.87 (95% CI 1.439–5.725; p < 0.05)
Detection on nodal involvement (N)
Presence of lymph node metastasis in ovarian
malignant germ cell tumors is a predictor of
poor survival
Kumar et al. Gynecol Oncol 2008;110:125
• 613 pts from the Surveillance, Epidemiology, and End Results Program (SEER) from
1988 to 2004 with a histologic diagnosis of OGCT after surgical resection +
lymphadenectomy
• Prevalence of lymphnode metastasis 18.1% (111/613)
- dysgerminoma 28%
- malignant teratoma 8%
- mixed germ cell tumors/pure non-dysgerminoma 16%
Nodal involvement and
survival Lymphadenectomy
and survival
Detection on nodal involvement (N)
Presence of lymph node metastasis in ovarian
malignant germ cell tumors is a predictor of
poor survival
Prevalence of lymphnode metastasis in OGCT 18.1%
Lymphadenectomy performed in more than 80% of Lymphadenectomy performed in more than 80% of
patients without LN metastases.patients without LN metastases.
Possible role of 18 F-FDG PET/CT
in staging nodal stagingCould be PET/CT indicated in OGCT for excluding
patients from unnecessary lymphadenectomy?
PurposePurpose: to determine prospectively the diagnostic accuracy of 18F-FDG
PET/CT in the detection of nodal metastases in patients with high risk
endometrial cancer.
• 37 pts with high risk endometrial cancer
• 18 F-FDG PET/CT for N staging and submitted to total hysterectomy, bilateral salpingo-
oophorectomy and systematic pelvic lymphadenectomy
• PECT/CT findings compared with histologic result for nodal involvement
Signorelli M, Guerra L, Buda A et al. Gynecol Oncol 2009
PET/CT resultsPET/CT results (pts based) Sensitivity 77,8%; Specificity 100%; PPV
100%; NPV 93,1%;NPV 93,1%; Accuracy 94,4%
ConclusionConclusion: 18F-FDG PET/CT is an accurate method for the
presurgical evaluation of pelvic nodes metastases. The high negative
predictive value may be useful in selecting patients who might avoid
lymphadenectomy, minimizing operative and surgical complications.
Detection of metastases (M)
by 18F FDG PET/CT• 18F-FDG PET/CT in assessment of
distant metastases
– Peritoneal mts
• nodules > 5 mm (limitation thin layers spread;
aspecific bowel activity)
– Hematogenous mts
• Liver (limitation high bkg; movement)
• Brain not indicated
• Lung
4D PET/CT
Liver mts
420504 male 49 yr - CRC
restaging for metastases
Equivocal finding: a third metastasis?
4D PET/CT
Improving Quantification
420504 male 49 yr - CRC
restaging for metastases
Detection of metastases (M)
Lung
18F-FDG PET/CT in malignant
ovarian germ cell tumors -
experience in HSG• 46 PET/CT studies in 29 pts treated in
Gynecological Dept. from 2000 to 2009.– 18 pts 1 PET/CT study;
– 11 pts more than 1 PET/CT study
Histology N° pts %
Dysgerminoma 17 59%
Immature teratoma 6 21%
Yolk sac tumor 3 10%
Mixed tumors 3 10%
55% stage I
45% stage III-IV
stage (n° pt & %)
9; 32%
7; 24%
9; 31%
1; 3%
2; 7% 1; 3%
IA
IC
IIIC
III
IV
Clinical Indicationsn° of PET/CT studies and %
PET/CT experience in HSG
48%28%
11%
9% 4%
18F-FDG PET/CT and pathologic results
pts-based analysis
• 19 PET/CT studies (19 pts)
– 2 staging
– 9 post surgical restaging
– 5 chemotp. response
– 1 evaluation after surgery & adjuvant
chemotp.
– 2 suspected relapse
18F-FDG PET/CT and pathologic
results
pts-based analysis
• 11 PET/CT negative studies
– confirmation by surveillance LPS
• 2 < 1 month
• 7 1 - 2 months
• 2 5 - 8 months
NO false negative
8 restaging after
surgery
• 8 PET/CT positive studies (1 suspicious)
– Surgical intervention 1-2 months after PET/CT
– 4 TP results
– 4 FP results50% false positive!
1 restaging after surgery
Accuracy in 9 post surgical restaging pts =
88,8%
19 PET/CT studies
Case 1: 18F-FDG PET/CT insuspect of relapse of a mixed
germ cell tumor
Histology: nodule withHistology: nodule with
foam cells infiltrationfoam cells infiltration
Mixed germinal tumor;
suspected disease relapse
18F-FDG PET/CT findings and
correlation with clinical course
• 27 PET/CT studies (17 pts)
– 13 post surgical restaging
– 7 chemotp. response evaluation
– 4 followup
– 3 suspected relapse
18F-FDG PET/CT findings and
correlation with clinical course
• 11 PET/CT negative– 7/11 PET/CT confirmed as TN at followup (FU range 12 – 42
months)
– 3/11 PET/CT before (1) or during chemotp (2)
– 1/11 followup ongoing
• 12 PET/CT positive + 1 suspicious– 3/12 confirmed by other imaging
– 9/12 submitted to chemotp
• 4 PET/CT equivocal– All negative at the followup (FU range 12 – 36 months)
27 PET/CT studies
Conclusions
• Few data available for drawing conclusion
• Possible role of PET/CT in restaging after
surgery (high NPV to be confirmed)
• Possible role of PET/CT in nodal
presurgical staging in tumor
macroscopically limited to pelvis (high
NPV expected)
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