Comparison of outcomes for MR-guided versus CT-guided high-dose-rate interstitial brachytherapy in women with locally advanced carcinoma of the cervix

Gynecol Oncol. 2017 May;145(2):284-290. doi: 10.1016/j.ygyno.2017.03.004. Epub 2017 Mar 18.

Abstract

Objective: 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).

Methods: 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®.

Results: 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.

Conclusion: 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.

Keywords: Cervical carcinoma; Interstitial brachytherapy; MR-guidance; Radiation oncology.

Publication types

  • Clinical Trial, Phase II
  • Comparative Study
  • Research Support, N.I.H., Extramural

MeSH terms

  • Adult
  • Aged
  • Brachytherapy / methods*
  • Dose-Response Relationship, Radiation
  • Female
  • Humans
  • Kaplan-Meier Estimate
  • Magnetic Resonance Imaging / methods*
  • Middle Aged
  • Proportional Hazards Models
  • Prospective Studies
  • Tomography, X-Ray Computed / methods*
  • Treatment Outcome
  • Uterine Cervical Neoplasms / diagnostic imaging*
  • Uterine Cervical Neoplasms / pathology
  • Uterine Cervical Neoplasms / radiotherapy*