MRI guided nodular salvage Brachytherapy after Prostatectomy and EBRT. 3 years outcome
Patricia Willisch Santamaria,
Spain
PO-2198
Abstract
MRI guided nodular salvage Brachytherapy after Prostatectomy and EBRT. 3 years outcome
Authors: Patricia Willisch Santamaria1, Benito Andrade Alvarez2, Enrique Cespon Outeda3, Laura Rojas Bua4, Maria luisa Vazquez de la Torre Gonzalez1, Antonio Lopez Medina5, Sara Montemuiño Muñiz1, Marta Martínez Agra6, Esteban Castelao7, Victor Manuel Muñoz Garzon1
1Galaria, Radiation Oncology, Vigo, Spain; 2Galaria, Radiophysis , Vigo, Spain; 3Sergas, Urology, Vigo, Spain; 4Fundación biomédica Galicia Sur, Radiation Oncology, Vigo, Spain; 5Galaria, radiophysics, Vigo, Spain; 6Povisa, Radiation Oncology, Vigo, Spain; 7Fundación biomedica galicia sur, Fundación biomedica galicia sur, Vigo, Spain
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Purpose or Objective
Patients who relapse locally after radical prostatectomy and external radiation therapy, treated with local brachytherapy are presented to delay treatment with hormonal blockade and new therapeutic target.
Material and Methods
From April 2016 to December 2020, 16 patients have been treated with an average age of 67,64 years (52-77).
Inclusion criteria is: Progressive increase of PSA after Prostatectomy and EBRT, local recurrence positive in perfusion- diffusion MRI and Coline PET in prostatectomy bed, treatment with RP and EBRT almost one year before and IPSS <15.
The prescribed dose and fractionation was (17-25,5 Gy) in 2-3 fractions.
Prior to the procedure, a volumetric T2-weighted MR with slice thickness and spacing of 3mm is done.
The MR to US image registration is manually done using the TPS translation and rotation tools at the moment of the procedure so the fused image set is used for contouring the target, with a median volume: 2,43cc (0,32-11,27).
In order to reduce the dose to rectum, High density Hyaluronic Acid is injected between rectum and target volume.
A preplanning before insertion is done. After insertion, needles (Average: 5(3-13) are reconstructed, live plan is re-optimized and treatment is delivered.
Results
With a medium follow-up of 37,7 months, 43,75% (7 patients) have been able to delay treatment with hormone blockade for 2 years, and 18,75% (3 patients) up to 3 years.
In the subanalysis of this data we have obtained a complete response maintained in 18.75%. Of the 25% (4 patients) who relapsed after 2 years, 3 were done locally, 2 at the treatment site and 1 remotely.
The longest response time has been observed in patients with a single poor prognostic factor (T3b and/or R1) and with BED greater than 220 Gy.
Treatment toxicity was acceptable with a grade 3 percentage of 18.75%.
Conclusion
Patients with good prognostic factors and who receive a BED dose greater than 220 Gy are good candidates for Re-salvage for nodular locally recurrent prostate cancer by focal HDR-BT guided by MRI-US
Further studies are needed.