PURPOSE: The purpose of this study was to evaluate the impact of intraoperative MRI/TRUS fusion procedure in cT3a prostate cancer patients treated with high-dose-rate (HDR) real-time brachytherapy.
MATERIAL AND METHODS: Prostate gland, dominant intraprostatic lesions (DILs), and extracapsular extension (ECE) were delineated in the pre-brachytherapy magnetic resonance images (MRI) of 9 consecutive patients. The pre-implant P-CTVUS (prostate clinical target volume) was defined as the prostate seen in the transrectal ultrasound (TRUS) images. The CTVMR includedthe prostate with the ECE image (ECE-CTV) as defined on the MRI. Two virtual treatment plans were performed based on the MRI/TRUS fusion images, the first one prescribing 100% of the dose to the P-PTVUS, and the second prescribing to the PTVMR. The implant parameters and dose-volume histogram (DVH) related parameters of the prostate, OARs, and ECE were compared between both plans.
RESULTS: Mean radial distance of ECE was 3.6 mm (SD: 1.1). No significant differences were found between prostate V100, V150, V200, and OARs DVH-related parameters between the plans. Mean values of ECE V100, V150, and V200 were 85.9% (SD: 15.1), 18.2% (SD: 17.3), and 5.85% (SD: 7) when the doses were prescribed to the PTVUS, whereas ECE V100, V150, and V200 were 99.3% (SD: 1.2), 45.8% (SD: 22.4), and 19.6% (SD: 12.6) when doses were prescribed to PTVMR (p = 0.028, p = 0.002 and p = 0.004, respectively).
CONCLUSIONS: TRUS/MRI fusion provides important information for prostate brachytherapy, allowing for better coverage and higher doses to extracapsular disease in patients with clinical stage T3a.
Gomez-Iturriaga A, Crook J, Casquero F, Carvajal C, Urresola A, Canteli B, Ezquerro A, Hortelano E, Cacicedo J, Espinosa JM, Perez F, Minguez P, Bilbao P. Are you the author?
Department of Radiation Oncology, Cruces University Hospital, Barakaldo, Spain; Department of Radiation Oncology, British Columbia Cancer Agency, Cancer Center for the Southern Interior, Kelowna, BC, Canada; Department of Radiology, Cruces University Hospital, Barakaldo, Spain; Department of Radiation Physics, Cruces University Hospital, Barakaldo, Spain.
Reference: J Contemp Brachytherapy. 2014 Jun;6(2):154-60.