前列腺癌新辅助内分泌治疗对精囊靶区勾画范围的影响

Reduction of seminal vesicle after androgen deprivation therapy： effects of neo-adjuvant or monal therapy to the target volume of seminal vesicles in prostate cancer radiotherapy

目的研究新辅助内分泌治疗对前列腺癌放疗时精囊靶区范尉的影响。方法31例cT2-4N0M期 捐前列腺癌患者放疗前接受内分泌治疗，中位时间5个月，疗前、后均行盆腔MR，三维方向测量内分泌治疗前后精囊体积、前后径、左右径和长度，评估对精囊照射范围的影响。配对t检验差异。结果内分泌治疗前、后精囊体积分别为（12．5±4．5）、（7．3±2．1）cm3，长度分别为（34．1±5．7）、（29．7±5．2）mm；体积、长度、前后径、左右径缩小率分别为（39.3±13．6）％、（12．9±5．2）％、（26．2±9．8）％、（17．4±11．0）％。精囊受侵与元受侵的长度缩小率分别为（16．7±4．8）％与（11．1±4．4）％（P=0．000）。经内分泌治疗后40％（8／20）受侵病灶消失或精囊整体表现为低信号。结论内分泌治疗后精囊体积明显缩小，有利于减小高剂量区靶区体积和保护周围正常器官。相比前后径和左右径．精囊在长轴方向缩短最少，且个体差异大，提示勾画内分泌治疗后的精囊靶区时需谨慎缩小精囊的照射范围，可继续参考前列腺癌术后标本病理研究中有关精囊亚临床灶的范围来决定勾画范围。

Objective To clarify the morphological reduction of seminal vesicle （SV） after neoadjuvant androgen deprivation （NHT）, and determine the optimal SV target volume for prostate cancer radiotherapy. Methods MR images both before and after NHT （median 5 months） were collected from thirty-one patients with cT2-4 N0M0 prostate cancer. SV volume was measured in axial T1WI,while SV length was obtained in a reconstructed oblique coronary plane through its long axial fi＇om a 3D sequence. The difference was analyzed with paired t-test method. Results SV significantly decreased after NHT （volume： （ 12.5±4. 5） cm2 to （7.3±2. 1） cm2 ,length： （34.1±5.7） mm to （29.7±5.2） mm）.The reduction rate of volume,length, anterior-posterior diameter and left-right diameter was （ 39.3± 13.6） %, （ 12.9± 5.2 ） %, （26.2±9. 8）%, （17.4± 11.0）%, respectively. For SV with and without MR detected involvement, length shortening were （ 16.7＋4. 8） % and （11.1＋4.4） %（P=0. 000） ;for involved SV and lesions within,volume reduction were （41.0±16. 0）% and （66.3±14. 4）%（P=0. 000） ,both indicating a more sensitive response to NHT of the involved portion than normal SV.40% （8/20） SV showed diffuse lower signal but no residual lesion after NHT. Conclusions After NHT the SV volume shrinkage was obviously, which may reduce the SV target volume and enable sparing of the surrounding normal tissues. Compare with the anterior-posterior diameter and left-right diameter,the reduction rate of the length is smaller,which suggests that it may be not reasonable to reduce the extent of SV included into CTV for the patients who have received NHT. [ Key words ] Prostate neoplasms/neo-adjuvant androgen deprivation; Prostate neoplasms/ radiotherapy; Seminal vesicle ; Target delineation