Incorporating Routine Magnetic Resonance Imaging-based Planning for the Delivery of High-dose-rate Brachytherapy for Prostate Cancer: An Evaluation of Clinical Feasibility and Dosimetric Outcomes

Introduction To evaluate the implementation and dosimetric outcomes of magnetic resonance imaging (MRI) planning for improved target and normal tissue definition for the treatment of prostate cancer with high-dose-rate brachytherapy (HDRBT). Methods From August 2015 to October 2017, 137 unique patients with newly diagnosed localized prostate cancer underwent a total of 174 outpatient brachytherapy procedures using MRI-based treatment planning. Patients receiving brachytherapy as monotherapy underwent two separate procedures while those receiving brachytherapy as a boost after external beam radiation therapy underwent a single procedure. The target volume was defined as the prostate +/- seminal vesicles as clinically appropriate without any additional margin. Pre-treatment dose-volume histogram (DVH) goals to the target were: D90≥95%, V90≥95%, V100≥90%, V150≤30%, V200≤15%. DVH goals to organs-at-risk (OARs): urethra D.01cc ≤115%, bladder D1cc ≤75%, rectum D1cc ≤75%, neurovascular bundle D0.1cc ≤100%, penile bulb D1cc ≤100%. Procedure times were recorded at each step of the procedure, from catheter insertion to removal. Results The median target volume was 45.9 cc, the median volume receiving the prescription dose was 53.0 cc, and the median selectivity index was 0.9. The median values for target dosimetry were as follows: D90=99.9%, V90=95.7%, V100=90.1%, V150=28.1%, V200=10.5%. The median values for OAR dosimetry were: urethra D.01cc=114.3%, bladder D1cc=68.3%, rectum D1cc=51.8%, left neurovascular bundle D0.1cc=86.8%, right neurovascular bundle D0.1cc=88.5%, penile bulb D1cc=31.7%. The median time from catheter insertion to end of HDRBT delivery was four hours 14 minutes (range 2:56-9:08); total treatment package time was five hours 32 minutes (range 3:31-9:45). Conclusion Routine MRI-based treatment planning is feasible for the delivery of HDRBT for prostate cancer. We met stringent dosimetric criteria despite more objective target and normal tissue definition with MRI imaging. Treatment package time remains reasonable. We have adopted MRI as our standard imaging modality for HDRBT for prostate cancer.

[1]  P. Wiklund,et al.  Erectile Function and Oncologic Outcomes Following Open Retropubic and Robot-assisted Radical Prostatectomy: Results from the LAParoscopic Prostatectomy Robot Open Trial. , 2017, European urology.

[2]  Alexandra Rink,et al.  Dosimetric impact of intrafraction changes in MR-guided high-dose-rate (HDR) brachytherapy for prostate cancer. , 2017, Brachytherapy.

[3]  J. Cunha,et al.  Improved rectal dosimetry with the use of SpaceOAR during high-dose-rate brachytherapy. , 2017, Brachytherapy.

[4]  R. Stafford,et al.  Prostate magnetic resonance imaging for brachytherapists: Anatomy and technique. , 2017, Brachytherapy.

[5]  C. Ménard,et al.  The utilization of magnetic resonance imaging in the operating room. , 2017, Brachytherapy.

[6]  W. J. Morris,et al.  Androgen Suppression Combined with Elective Nodal and Dose Escalated Radiation Therapy (the ASCENDE-RT Trial): An Analysis of Survival Endpoints for a Randomized Trial Comparing a Low-Dose-Rate Brachytherapy Boost to a Dose-Escalated External Beam Boost for High- and Intermediate-risk Prostate Cance , 2017, International journal of radiation oncology, biology, physics.

[7]  W. J. Morris,et al.  ASCENDE-RT: An Analysis of Treatment-Related Morbidity for a Randomized Trial Comparing a Low-Dose-Rate Brachytherapy Boost with a Dose-Escalated External Beam Boost for High- and Intermediate-Risk Prostate Cancer. , 2017, International journal of radiation oncology, biology, physics.

[8]  Kari Tanderup,et al.  Dosimetric impact of contouring and needle reconstruction uncertainties in US-, CT- and MRI-based high-dose-rate prostate brachytherapy treatment planning. , 2017, Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology.

[9]  J. Crook,et al.  Dose escalation to dominant intraprostatic lesions with MRI-transrectal ultrasound fusion High-Dose-Rate prostate brachytherapy. Prospective phase II trial. , 2016, Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology.

[10]  M. Steinberg,et al.  High-Dose-Rate Monotherapy for Localized Prostate Cancer: 10-Year Results. , 2016, International journal of radiation oncology, biology, physics.

[11]  Alexandra Rink,et al.  Lessons learned using an MRI-only workflow during high-dose-rate brachytherapy for prostate cancer. , 2016, Brachytherapy.

[12]  K. Palmer,et al.  Dehydrated Human Amnion/Chorion Membrane Allograft Nerve Wrap Around the Prostatic Neurovascular Bundle Accelerates Early Return to Continence and Potency Following Robot-assisted Radical Prostatectomy: Propensity Score-matched Analysis. , 2015, European urology.

[13]  G. Morton,et al.  High-dose-rate brachytherapy boost for prostate cancer: rationale and technique , 2014, Journal of contemporary brachytherapy.

[14]  P. Georg,et al.  Dosimetric considerations to determine the optimal technique for localized prostate cancer among external photon, proton, or carbon-ion therapy and high-dose-rate or low-dose-rate brachytherapy. , 2014, International journal of radiation oncology, biology, physics.

[15]  D Andrew Loblaw,et al.  Use of cone-beam imaging to correct for catheter displacement in high dose-rate prostate brachytherapy. , 2011, Brachytherapy.

[16]  R. Stock,et al.  Impact of hormonal therapy on intermediate risk prostate cancer treated with combination brachytherapy and external beam irradiation. , 2010, The Journal of urology.

[17]  Victor E Reuter,et al.  Influence of local tumor control on distant metastases and cancer related mortality after external beam radiotherapy for prostate cancer. , 2008, The Journal of urology.

[18]  Lei Dong,et al.  Long-term results of the M. D. Anderson randomized dose-escalation trial for prostate cancer. , 2008, International journal of radiation oncology, biology, physics.

[19]  Daniel W. Miller,et al.  Comparison of conventional-dose vs high-dose conformal radiation therapy in clinically localized adenocarcinoma of the prostate: a randomized controlled trial. , 2005, JAMA.

[20]  David J Brenner,et al.  What hypofractionated protocols should be tested for prostate cancer? , 2002, International journal of radiation oncology, biology, physics.