Evaluating repetitive 18F-fluoroazomycin-arabinoside (18FAZA) PET in the setting of MRI guided adaptive radiotherapy in cervical cancer.
BACKGROUND
The aim of this pilot study was to assess tumour hypoxia in patients with cervical cancer before, during and after combined radio-chemotherapy and Magnetic Resonance Imaging (MRI) guided brachytherapy (BT) by use of the hypoxia Positron Emission Tomography (PET) tracer (18)F-fluoroazomycin-arabinoside ((18)FAZA ).


METHODS
Fifteen consecutive patients with locally advanced cervical cancer referred for definitive radiotherapy (RT) were included in an approved clinical protocol. Stage distribution was 3 IB1, 1 IB2, 10 IIB, 1 IIIB, tumour volume was 55 cm(3) (+/- 67, SD). Dynamic and static (18)FAZA -PET scans were performed before, during and after external beam therapy (EBRT) and image guided BT +/- concomitant cisplatin. Dose was prescribed to the individual High Risk Clinical Target Volume (HR CTV) taking into account the dose volume constraints for adjacent organs at risk.


RESULTS
Five patients had visually identifiable tumours on (18)FAZA -PET scans performed prior to radio-chemotherapy and four patients before brachytherapy. One of five (18)FAZA PET positive patients had incomplete remission three months after RT, one had regional recurrence. Four of ten (18)FAZA-PET negative patients developed distant metastases. The one patient with incomplete remission received 69 Gy (D90) in the HR CTV, whereas all other patients received mean 99 Gy (+/-12, SD).


CONCLUSIONS
PET imaging with (18)FAZA is feasible in patients with cancer of the uterine cervix. However, its predictive and prognostic value remains to be clarified. This applies in particular for the additional value of (18)FAZA-PET compared to morphologic repetitive MRI within the setting of image guided high dose radiotherapy which may contribute to overcome hypoxia related radioresistance.
Schuetz
Matthias
M
Department of Nuclear Medicine, Medical University of Vienna/AKH Wien, Vienna, Austria.
Schmid
Maximilian P
MP
Pötter
Richard
R
Kommata
Spyridoula
S
Georg
Dietmar
D
Lukic
Dobrica
D
Dudczak
Robert
R
Kletter
Kurt
K
Dimopoulos
Johannes
J
Karanikas
Georgios
G
Bachtiary
Barbara
B
D000220:Adaptation, Biological / Q000502:physiology; D000230:Adenocarcinoma / Q000000981:diagnostic imaging / Q000532:radiotherapy; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged; D009593:Nitroimidazoles; D010507:Periodicity; D010865:Pilot Projects; D049268:Positron-Emission Tomography / Q000379:methods*; D011859:Radiography; D011879:Radiotherapy Dosage; D011881:Radiotherapy, Computer-Assisted / Q000379:methods*; D002583:Uterine Cervical Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy*
D009593:Nitroimidazoles; C498052:fluoroazomycin arabinoside