Multiparametric magnetic resonance imaging (mpMRI) has demonstrated the ability to localize intraprostatic lesions. It is our goal to determine how to optimally target the underlying histopathological cancer within the setting of high-dose-rate brachytherapy (HDR-BT).
Ten prostatectomy patients had pathologist-annotated mid-gland histology registered to pre-procedural mpMRI, which were interpreted by four different observers. Simulated HDR-BT plans with realistic catheter placements were generated by registering the mpMRI lesions and corresponding histology annotations to previously performed clinical HDR-BT implants. Inverse treatment planning was used to generate treatment plans that treated the entire gland to a single dose of 15 Gy, as well as focally targeted plans that aimed to escalate dose to the mpMRI lesions to 20.25 Gy. Three margins to the lesion were explored: 0 mm, 1 mm, and 2 mm. The analysis compared the dose that would have been delivered to the corresponding histologically-defined cancer with the different treatment planning techniques.
mpMRI-targeted plans delivered a significantly higher dose to the histologically-defined cancer (p < 0.001), in comparison to the standard treatment plans. Additionally, adding a 1 mm margin resulted in significantly higher D98, and D90 to the histologically-defined cancer in comparison to the 0 mm margin targeted plans (p = 0.019 & p = 0.0026). There was no significant difference between plans using 1 mm and 2 mm margins.
Adding a 1 mm margin to intraprostatic mpMRI lesions significantly increased the dose to histologically-defined cancer, in comparison applying no margin. No significant effect was observed by further expanding the margins.
Brachytherapy. 2022 Mar 22 [Epub ahead of print]
Christopher W Smith, Taylor Marcus, Douglas Hoover, Kathleen Surry, David D'Souza, Derek Cool, Zahra Kassam, Matthew Bastian-Jordan, José A Gómez, Madeleine Moussa, Joseph L Chin, Stephen Pautler, Glenn S Bauman, Aaron D Ward
Baines Imaging Research Laboratory, London, Ontario, Canada; Lawson Health Research Institute, London, Ontario, Canada; Department of Medical Biophysics, Western University, London, Ontario, Canada; London Regional Cancer Program, London, Ontario, Canada., Department of Medical Biophysics, Western University, London, Ontario, Canada., Lawson Health Research Institute, London, Ontario, Canada; Department of Medical Biophysics, Western University, London, Ontario, Canada; Department of Oncology, Western University, London, Ontario, Canada; London Regional Cancer Program, London, Ontario, Canada., Lawson Health Research Institute, London, Ontario, Canada; Department of Oncology, Western University, London, Ontario, Canada; London Regional Cancer Program, London, Ontario, Canada., Lawson Health Research Institute, London, Ontario, Canada; Department of Medical Imaging, Western University, London, Ontario, Canada., University of Queensland, Queensland, Australia., Department of Pathology and Laboratory Medicine, Western University, London, Ontario, Canada., Department of Surgery, Western University, London, Ontario, Canada; Department of Oncology, Western University, London, Ontario, Canada., Baines Imaging Research Laboratory, London, Ontario, Canada; Lawson Health Research Institute, London, Ontario, Canada; Department of Medical Biophysics, Western University, London, Ontario, Canada; Department of Oncology, Western University, London, Ontario, Canada; London Regional Cancer Program, London, Ontario, Canada. Electronic address: .