Neoadjuvent androgen deprivation for seminal vesicle reduction:The optimal portion of seminal vesicle included in the high-dose CTV in localized prostate cancer radiotherapy

Objective:To clarify the length and volume reduction of seminal vesicles(SVs)after neo-adjuvant hormonal therapy(NHT),in order to help contour the optimal SV included into high-dose clinical target volume(CTV)for radiotherapy in intermediate-and high-risk patients.Methods:MR images both before and after NHT(5.3±2.2 months)were collected from thirty-one patients with cT2-4N0M0 prostate cancer.SV volume was measured in axial T1WI,while SV length was obtained in a reconstructed oblique coronary plane through its long axial from a 3D sequence.Results:SVs showed evident reduction both in length and volume(length:median 12.1%,range 4.0%–28.0%;volume:median 39.9%,range 9.4%–66.2%).For SVs with and without MR detected involvement,length shortening were(16.7±4.8)%and(11.1±4.4)%(P<0.001);for involved SVs and lesions,volume reduction were(41.0±16.0)%and(66.3±14.4)%,respectively(P<0.001),both indicating a more sensitive response to NHT of the involved portion than normal SV.Conclusions:Both volume and length of the SV will be reduced after receiving NHT.Besides,the invaded segments shrink more than normal SV tissue,indicating that SV portion included within the CTV can be reduced.

巨块型NSCLC质子部分立体定向消融推量放疗的剂量学优势

目的探索肿瘤长径>8 cm的巨块非小细胞肺癌(NSCLC)放疗中质子部分立体定向消融推量放疗(P-SABR)的剂量学优势。方法收集既往应用光子P-SABR治疗的9例巨块NSCLC的定位影像。在光子肿瘤推量靶区(光子GTVb)基础上逐步外扩,直到重要危及器官受量达3.0 Gy/次时停止,形成质子肿瘤推量靶区(质子GTVb),质子GTV、CTV范围同光子,分别制订光子固定野调强放疗(光子FF-IMRT)、光子容积调强弧形治疗(光子VMAT)、质子调强放疗(IMPT)计划。对比不同治疗技术的剂量学参数。结果光子GTVb和质子GTVb占GTV体积比分别为25.4%±13.4%和69.7%±30.0%(P<0.001)。光子IMRT、光子VMAT、IMPT的CTV平均剂量分别为(76.1±4.9)Gy、(78.2±3.6)Gy、(84.7±4.9)Gy,生物有效剂量(BED)≥90 Gy所包含肿瘤占GTV体积的百分比分别为70.7%±21.7%、76.8%±22.1%、97.9%±4.0%,质子较光子P-SABR计划显著提高了靶区剂量及BED(P<0.05)。质子较光子计划还降低了危及器官受量,其中光子FF-IMRT、光子VMAT和IMPT的双肺V5 Gy分别为49.2%±22.0%、56.8%±19.0%和16.1%±6.3%(P<0.001)。结论质子P-SABR较光子可在降低危及器官受量情况下,扩大肿瘤推量靶区范围并提高肿瘤内BED,有望进一步提高巨块NSCLC的局部控制率。