Keywords:
Interventional non-vascular, Oncology, Urinary Tract / Bladder, CT, MR, Dosimetry, Radiation therapy / Oncology, VMAT and Tomotherapy, Dosimetric comparison, Radiotherapy techniques
Authors:
M. Chao1, D. Lim Joon2, Y. Chan2, A. Tan3, M. Cokelek1, H. Ho1, P. Manohar4, M. Tacey2, K. McMillan5, T. Pham4, G. Koufogiannis6, M. Guerrieri1; 1Ringwood East, VIC/AU, 2Heidelberg, VIC/AU, 3Mornington, VIC/AU, 4Clayton, VIC/AU, 5Box Hill, VIC/AU, 6Knox, VIC/AU
DOI:
10.26044/ranzcr2021/R-0436
Methods and materials
One hundred and two patients with clinical stage T1-3N0M0 prostate cancer underwent transrectal ultrasound guided transperineal insertion of gold seed fiducial markers and HA into the perirectal space before image guided prostate volumetric arc radiation therapy (VMAT) between 7/2020 to 6/2021. Post insertion CT and MRI scans were obtained for treatment planning (see Figures 1 and 2 for midline sagittal and transverse MRI images of HA inserted between prostate and rectum). HA insertion feasibility, procedural complications and device related safety was collected. Recto-prostatic separation was also assessed with separation in the sagittal plane, at the prostate base (defined as 5mm below prostate base), at mid gland and at the prostate apex (defined as 5mm above prostate apex). In addition, the symmetry of the insertion at midgland was also assessed (symmetrical defined as recto-prostatic separation 1cm on either side of midline greater than 50% measured in the midline). The prescribed dose to the planning target volume (PTV) ranged from 74-80Gy in 37-40 fractions to 60-62Gy in 20 fractions. The rV70 for patients receiving 74-80Gy and rV53 for patients receiving 60-62Gy was assessed and compared with historical controls. We divided urologists and radiation oncologists into new (performed <20 rectal spacers), competent (20-100 rectal spacers) and experienced users (>100 rectal spacers).