Comparison of outcomes for MR-guided versus CT-guided high-dose-rate interstitial brachytherapy in women with locally advanced carcinoma of the cervix.
The purpose was to compare local control (LC), overall survival (OS) and dose to the organs at risk (OAR) in women with locally advanced cervical cancer treated with MR-guided versus CT-guided interstitial brachytherapy (BT).



56 patients (29 MR, 27 CT) were treated with high-dose-rate (HDR) interstitial BT between 2005-2015. The MR patients had been prospectively enrolled on a Phase II clinical trial. Data were analyzed using Kaplan-Meier (K-M) and Cox proportional hazards statistical modeling in JMP® & R®.



Median follow-up time was 19.7months (MR group) and 18.4months (CT group). There were no statistically significant differences in patient age at diagnosis, histology, percent with tumor size >4cm, grade, FIGO stage or lymph node involvement between the groups. Patients in the MR group had more lymphovascular involvement compared to patients in the CT group (p<0.01). When evaluating plans generated, there were no statistically significant differences in median cumulative dose to the high-risk clinical target volume or the OAR. 2-year K-M LC rates for MR-based and CT-based treatments were 96% and 87%, respectively (log-rank p=0.65). At 2years, OS was significantly better in the MR-guided cohort (84% vs. 56%, p=0.036). On multivariate analysis, squamous histology was associated with longer OS (HR 0.23, 95% CI 0.07-0.72) in a model with MR BT (HR 0.35, 95% CI 0.08-1.18). There was no difference in toxicities between CT and MR BT.



In this population of locally advanced cervical-cancer patients, MR-guided HDR BT resulted in estimated 96% 2-year local control and excellent survival and toxicity rates.
Harvard Radiation Oncology Program, Boston, MA, United States. Electronic address: sophia_kamran@post.harvard.edu.
Sophia C
SC
Kamran
Department of Radiation Oncology, Brigham and Women's Hospital, Boston, MA, United States; Department of Radiation Oncology, Dana-Farber Cancer Institute, Boston, MA, United States; Bronx-Lebanon Hospital Center, Bronx, NY, United States.
Matthias M
MM
Manuel
Department of Radiation Oncology, Brigham and Women's Hospital, Boston, MA, United States; Department of Radiation Oncology, Dana-Farber Cancer Institute, Boston, MA, United States; Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States.
Linda P
LP
Cho
Department of Radiation Oncology, Brigham and Women's Hospital, Boston, MA, United States; Department of Radiation Oncology, Dana-Farber Cancer Institute, Boston, MA, United States; Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, United States.
Antonio L
AL
Damato
Department of Radiology, Brigham and Women's Hospital, Boston, Boston, MA, United States.
Ehud J
EJ
Schmidt
Department of Radiology, Brigham and Women's Hospital, Boston, Boston, MA, United States.
Clare
C
Tempany
Department of Radiation Oncology, Brigham and Women's Hospital, Boston, MA, United States; Department of Radiation Oncology, Dana-Farber Cancer Institute, Boston, MA, United States.
Robert A
RA
Cormack
Department of Radiation Oncology, Brigham and Women's Hospital, Boston, MA, United States; Department of Radiation Oncology, Dana-Farber Cancer Institute, Boston, MA, United States; Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins Sidney Kimmel Comprehensive Cancer Center, Baltimore, MD, United States. Electronic address: anv@jhu.edu.
Akila N
AN
Viswanathan
D000328:Adult; D000368:Aged; D001918:Brachytherapy / Q000379:methods*; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged; D016016:Proportional Hazards Models; D011446:Prospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*; D016896:Treatment Outcome; D002583:Uterine Cervical Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000532:radiotherapy*
Cervical carcinoma; Interstitial brachytherapy; MR-guidance; Radiation oncology