Endorectal MRI assessment of local relapse after surgery for prostate cancer: A model to define treatment field guidelines for adjuvant radiotherapy in patients at high risk for local failure
- Division de Radio-oncologie, Hopitaux Universitares, Geneva (Switzerland) and Servei de Radio-oncologia, Instituto Oncologico Teknon, Barcelona (Spain)
- Division de Radio-oncologie, Hopitaux Universitares, Geneva (Switzerland)
- Servei de Radio-oncologia, Instituto Oncologico Teknon, Barcelona (Spain)
- Institut de Radiologie Jean Violette, Geneva (Switzerland)
- Servei de Radiodiagnostic, Centro Medico Teknon, Barcelona (Spain)
Purpose: To assess the role of endorectal magnetic resonance imaging (MRI) in defining local relapse after radical prostatectomy for prostate cancer to help to reassess the clinical target volume (CTV) for adjuvant postprostatectomy radiotherapy. Methods and Materials: Sixty patients undergoing an endorectal MRI before salvage radiotherapy were selected. Spatial coordinates of the relapses were assessed using two reference points: the inferior border of the pubic symphysis (point 1) and the urethro-vesical anastomosis (point 2). Every lesion on MRI was delineated on the planning computed tomography and center of mass coordinates were plotted in two separate diagrams (along the x, y, and z axes) with the urethro-vesical anastomosis as the coordinate origin. An 'ideal' CTV was constructed, centered at a point defined by the mathematical means of each of the three coordinates with dimensions defined as twice 2 standard deviations in each of the three axes. The dosimetric impact of the new CTV definition was evaluated in six adjuvantly treated patients. Results: The ideal CTV center of mass was located at coordinates 0 (x), -5 (y), and -3 (z) mm with SDs of 6 (x), 6 (y), and 9 (z) mm, respectively. The CTV size was 24 (x) x 24 (y) x 36 (z) mm. Significant rectal sparing was observed with the new CTV. Conclusions: A CTV with an approximately cylindrical shape ({approx}4 x 3 cm) centered 5 mm posterior and 3 mm inferior to the urethro-vesical anastomosis was defined. Such CTV may reduce the irradiation of normal nontarget tissue in the pelvis potentially improving treatment tolerance.
- OSTI ID:
- 20944673
- Journal Information:
- International Journal of Radiation Oncology, Biology and Physics, Vol. 67, Issue 2; Other Information: DOI: 10.1016/j.ijrobp.2006.08.079; PII: S0360-3016(06)02965-8; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0360-3016
- Country of Publication:
- United States
- Language:
- English
Similar Records
Magnetic Resonance Imaging in Postprostatectomy Radiotherapy Planning
Pretreatment Endorectal Coil Magnetic Resonance Imaging Findings Predict Biochemical Tumor Control in Prostate Cancer Patients Treated With Combination Brachytherapy and External-Beam Radiotherapy