Laparoscopic seminal vesicle and pelvic lymph node resection before high-dose three-dimensional conformal radiation therapy for localized prostate cancer. Results of a dosimetric study.

PURPOSE

To analyze the dosimetric implications of seminal vesicle (SV) resection at the time of laparoscopic pelvic lymph node (PLN) dissection in patients presenting with high-risk prostate cancer regarding PLN and SV involvement.

PATIENTS AND METHODS

Between June and September 2005, twelve patients underwent laparoscopic SV resection and PLN dissection before delivering a total dose of 80 Gy through a three-dimensional conformal radiation therapy (3D-CRT). Dose-volume histograms (DVHs; rectum, bladder, femoral heads) were obtained from G1 (group 1 with SV) and G2 (group 2 without SV) according to either three- dimensional or intensity-modulated treatment planning. All DVH medians were compared using the nonparametric sign test.

RESULTS

SV resection during laparoscopic PLN dissection was performed in all twelve patients without major complications. DVH obtained with three-dimensional and intensity-modulated treatment planning showed that the median doses of RV(25%) (25% of rectal volume), RV(50%), RFHV(5%) (5% of right femoral head volume) and LFHV(5%) (5% of left femoral head volume) in G1 were significantly higher compared to those obtained in G2.

CONCLUSION

For patients presenting with high-risk prostate cancer, SV resection performed at the time of laparoscopic PLN dissection allows to significantly decrease the dose delivered to the rectum, using either three-dimensional or intensity-modulated treatment planning, and to reduce the risk of acute and late rectal toxicity.