PET scan plays an important role in gynecological malignancies by identifying malignant cells with high sensitivity. It has applications in initial staging of cancers of the cervix, ovary, and endometrium by detecting lymph node and distant metastases. PET scan is also useful for detecting recurrence through increased glucose uptake in cancer cells and can change treatment plans in up to 30% of cases. Overall, PET-CT provides benefits as a single imaging test for accurate staging and response assessment in gynecological cancers.

1. Role of PET Scan in
Gynecological malignancies
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2. Metabolic imaging
• Metabolic imaging studies the physiological
processes without affecting the normal
metabolism in the body
• Metabolic pathways are altered at the onset
of disease process
• Structural changes occur only later
• Identification of pathology using alteration in
metabolism provides a “lead time”
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3. Metabolic imaging
• Metabolic imaging using radio-labeled glucose
identifies malignant cells with very high
sensitivity
• PET presently has the highest sensitivity
among all imaging modalities in identifying
malignant cells (108 – 109 cells)
• The specificity is higher than routine
conventional imaging like CT and MRI
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4. FDG – The molecule of the century
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5. Physiology of glucose uptake
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• Cancer cells have ischemia / hypoxia
• Switches to anaerobic metabolism using
glucose as its substrate
• Warburg effect
• Hence rapidly growing cancer cells show
increase uptake of radiolabelled glucose
• Once intra-cellular FDG is trapped inside the
cell
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6. CT PET PET-CT
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7. PET-CT role in Oncology
• Diagnosis – Limited role
• Staging
– Excellent role in Nodal and distant metastases
• Response evaluation
– Best modality to identify response to chemo / RT
• End of treatment assessment
• Evaluation of disease recurrence
• Surveillance
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8. • Brain
• Brown Fat
• Cardiac activity
• Liver, Spleen
• Renal pelvis
• Intestines
• Urinary bladder
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9. ROLE OF FDG PET IN GYNEC
MALIGNANCIES
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10. Vaginal and vulval cancers
• Limited published data is available on the role
of FDG PET in these cancers
• FDG PET has high sensitivity in identifying
lymph nodal metastases and distant
metastases
• Definitive role in malignant melanoma
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12. Melanoma Vagina
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13. CANCER CERVIX
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14. FDG PET initial staging
• FDG PET detects primary tumor with
sensitivity of >95%
• Sensitivity of FDG PET for identifying para
aortic lymph node involvement is approx 90%
• Biggest advantage of PET is in identification of
lymph nodal and distant mets
• PET is better than conventional modalities in
initial staging
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15. Initial staging
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16. Ca Cervix – Primary staging
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18. FDG PET in initial staging
• PET is not advocated in patients with Stage IB or
less
• Especially useful in locally advanced Ca cervix
• PET/CT leads to
– to major alterations in treatment plans in 23% of
patients with widespread disease
• The presence of PET-positive LNs has prognostic
significance in patients with cervical carcinoma
– Nucl Med Commun. 2012 Oct
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20. Ca Cervix – Residual disease
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21. PET CT in recurrence
• A recent meta-analysis showed
– the pooled sensitivity and specificity to detect
distant metastasis in recurrent cervical
cancer were 87% and 97%
– the pooled sensitivity and specificity for local
regional recurrence were 82% and 98 %
respectively
– Diagnostic value of 18F-FDG-PET or PET-CT in
recurrent cervical cancer: a systematic review and meta-
analysis.
– Nuclear medicine communications 2013
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22. Ca Cervix – Recurrent LN disease
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23. Ca Cervix – Abdominal wall
recurrence
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24. Impact of PET in recurrence
• More sites of metastases detected with FDG-PET - 56%
of the patients compared to conventional imaging.
• Change in treatment modality - 33% of the patients;
• Change in dose or deliverance of treatment 22%
• Treatment intention was changed in 30%
• Initially planned treatment was reduced regarding dose
or extent, or was withheld in 48% of the patients
• Clinical Impact of 2-Deoxy-2-[18F]fluoro-D-Glucose (FDG)-
Positron Emission Tomography (PET) on Treatment Choice
in Recurrent Cancer of the Cervix Uteri.
• Int J Gynecol Cancer. 2013 Nov;23(9):1642-6
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25. Incidental finding of invasive Ca cervix
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26. NCCN guidelines 2016 - Surveillance
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29. CANCER OVARY
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30. Equivocal ovarian masses
• FDG PET has been tried in characterising
equivocal ovarian masses
• PET showed a 93% sensitivity in a prospective
study
• Specificity was approx 80%
• PET identified more retro-peritoneal disease
compared to CT
– Gynecol Oncol. 2013 Aug 27
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33. Ca Ovary Rising tumor markers
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34. Ca Ovary Rising CA 125
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35. Rising Ca 125
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36. • PET CT identifies more lesions than detected
in CT in up to 60% of these patients
• Additional findings potentially alter the
treatment plan
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37. CA OVARY SURVEILLANCE
• In surveillance of Ca ovary patients
– CA 125 has the highest pooled specificity 93%
– PET-CT has highest pooled sensitivity, 91%
– Sensitivity of CT and MRI are 88% and 79%
• Hence, PET-CT seems the next valid
investigation in a patient with rising CA 125
levels
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38. CANCER ENDOMETRIUM
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39. Ca Endometrium – Primary staging
• Detection of the primary lesions
– Sensitivity 81.8% (77.9%-85.3%)
– specificity 89.8% (79.2%-96.2%)
• Lymph node staging
– Sensitivity 72.3% (63.8%-79.8%)
– Specificity 92.9% (90.6%-94.8%)
• Distant metastasis detection
– Sensitivity 95.7% (85.5%-99.5%)
– specificity 95.4% (92.7%-97.3%)
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41. Ca Endometrium – Primary staging
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42. Ca Endometrium – Back pain on follow up
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43. Ca Endometrium – Back pain
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44. Ca Endometrium metastatic
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46. PET in carcino-sarcoma
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47. PET in response assessment
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48. Summary
• PET-CT scan has an established role in
gynecological malignancies
• PET-CT offers unparalled benefit in being a
“one stop shop imaging” for complete
evaluation of the extent of disease
• PET-CT is probably the best available modality
for response assessment
• PET-CT causes major change in the
management in up to 30% of the patients
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