[Three dimensional conformal radiotherapy (3D-CRT) for localized prostate cancer under field adjustment with implanted gold markers: early clinical outcome].

: Three dimensional conformal radiotherapy (3D-CRT) for localized prostate cancer under field adjustment with gold marker implantation was performed according to the treatment strategy based on the clinical risk factors to the patients who chose external beam radiotherapy. The treatment strategy contains indications for laparoscopic staging lymphadenectomy and neoadjuvant combined androgen blockade (CAB). This protocol was applied to 19 patients at Kagawa University Hospital from July 2001 to December 2003. The patients were divided into high-risk group (n=14): T3-4N0M0 or PSA > or = 20 ng/ml or Gleason sum > or = 8 or suspicious node, and low-risk group (n=5): T1c-2bN0M0 and PSA < 20 ng/ml and Gleason sum < or = 7 and no suspicious nodes. Basically, high-risk patients underwent laparoscopic staging lymphadenectomy prior to radiotherapy. One of the 14 patients had a positive node and underwent endocrine therapy. The high-risk group received neoadjuvant CAB for 3 to 4 months, followed by gold marker implantation. One patient chose endocrine therapy at this point. Low-risk patients underwent marker implantation without endocrine therapy. Every patient successfully completed planned irradiation. The changes of prostate volume and serum PSA after neoadjuvant CAB were significant [28.7 ml to 15.7 ml (p=0.004) and 53.9 ng/ml to 1.4 ng/ml (p=0.023), respectively]. Only one patient in the high-risk group had biochemical failure. No grade 3 or 4 adverse events occurred in NCI-CTC grading. The analysis of gravity center migration of the implanted gold markers in the first 8 patients showed that the planned safety margin might not be wide enough to avoid neighboring organ irradiation. These results suggested that 3D-CRT under field adjustment with implanted gold markers contributes to both higher efficacy and lower morbidity.