Prediction of radiotherapy outcome using dynamic contrast enhanced MRI of carcinoma of the cervix.
OBJECTIVE
To investigate whether analysis of MRI enhancement data using a pharmacokinetic model improved a previously found correlation between contrast enhancement and tumor oxygenation measured using PO2 histograph. To evaluate the prognostic value of gadolinium enhancement data for radiotherapy outcome, and to study the efficacy of combined enhancement and MRI volume data.


METHODS
Fifty patients underwent dynamic gadolinium-enhanced MRI as part of their initial staging investigations before treatment. Gadolinium enhancement was analyzed using the Brix pharmacokinetic model to obtain the parameters amplitude and rate of contrast enhancement. Pretreatment tumor oxygen measurements (Eppendorf PO2 histograph) were available for 35 patients.


RESULTS
Both standard and pharmacokinetic-derived enhancement data correlated with tumor oxygenation measurements, and poorly enhancing tumors had low tumor oxygen levels. However, only the pharmacokinetic-analyzed data correlated with patient outcome and patients with poorly (amplitude less than median) vs. well-enhancing tumors had significantly worse disease-specific survival (p = 0.024). For the 50 patients studied, no relationship was found between enhancement and volume data. Combining MRI volume and enhancement information highlighted large differences in outcome (p = 0.0054). At the time of analysis, only 55% of patients with large, poorly enhanced tumors were alive compared with 92% of patients with small, well-enhanced tumors.


CONCLUSIONS
These preliminary results suggest that pharmacokinetic modeling of dynamic contrast-enhanced MRI provides data that reflect tumor oxygenation and yields useful prognostic information in patients with locally advanced carcinoma of the cervix. Combining MRI-derived enhancement and volume data delineates large differences in radiotherapy outcome.
Loncaster
Juliette A
JA
Academic Department of Radiation Oncology, Christie Hospital NHS Trust, Manchester, UK.
Carrington
Bernadette M
BM
Sykes
Johnathan R
JR
Jones
Andrew P
AP
Todd
Susan M
SM
Cooper
Rachel
R
Buckley
David L
DL
Davidson
Susan E
SE
Logue
John P
JP
Hunter
Robin D
RD
West
Catharine M L
CM
D000230:Adenocarcinoma / Q000378:metabolism* / Q000473:pathology / Q000532:radiotherapy; D000704:Analysis of Variance; D018196:Carcinoma, Adenosquamous / Q000378:metabolism* / Q000473:pathology / Q000532:radiotherapy; D015687:Cell Hypoxia; D005260:Female; D005682:Gadolinium / Q000493:pharmacokinetics*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged; D010100:Oxygen / Q000032:analysis*; D011868:Radioisotopes / Q000493:pharmacokinetics*; D016896:Treatment Outcome; D002583:Uterine Cervical Neoplasms / Q000378:metabolism* / Q000473:pathology / Q000532:radiotherapy
D011868:Radioisotopes; D005682:Gadolinium; D010100:Oxygen