Definitive 3D-CRT for clinically localized prostate cancer: modifications of the clinical target volume following a prostate MRI and the clinical benefits

Definitive 3D-CRT for clinically localized prostate cancer: modifications of the clinical target volume following a prostate MRI and the clinical benefits

SpringerPlus, July 2015

26191474

Shinsaku Yamaguchi, Takayuki Ohguri, Masami Fujii, Katsuya Yahara, Yoshiko Hayashida, Naohiro Fujimoto, Yukunori Korogi

To evaluate the modifications of the tumor stage and clinical target volume following a prostate magnetic resonance imaging (MRI) to evaluate the tumor (T) staging, and the clinical benefits for prostate cancer. A total of 410 patients with newly diagnosed and clinically localized prostate cancer were retrospectively analyzed. The patients were treated with definitive three-dimensional conformal radiotherapy (3D-CRT). In all of the patients, digital rectal examination, transrectal ultrasound, prostate biopsy and computed tomography were performed to evaluate the clinical stage. Of the 410 patients, 189 patients had undergone a prostate MRI study to evaluate the T staging, and 221 patients had not. Modification of the T stage after the prostate MRI was seen in 39 (25%) of the 157 evaluable patients, and a modification of the risk group was made in 14 (9%) patients. Eventually, a modification of the CTV in 3D-CRT planning was made in 13 (8%) patients, and 10 of these had extracapsular disease. Most of the other modifications of the T staging were associated with intracapsular lesions of prostate cancer which did not change the CTV. There were no significant differences in the biological relapse-free survival between the patients with and without a prostate MRI study. Modification of the CTV were recognized in only 8% of the patients, most of whom had extracapsular disease, although that of the T stage was seen in approximately one-quarter of the patients. Prostate MRI should only be selected for patients with a high probability of extracapsular involvement.