Fischer-Valuck Benjamin W, Gay Hiram A, Patel Sagar, Baumann Brian C, Michalski Jeff M
Department of Radiation Oncology, Winship Cancer Institute, Emory University, Atlanta, GA, United States.
Department of Radiation Oncology, Washington University School of Medicine in St. Louis, St. Louis, MO, United States.
Front Oncol. 2019 Dec 10;9:1378. doi: 10.3389/fonc.2019.01378. eCollection 2019.
For patients with unfavorable or high-risk prostate cancer, dose escalated radiation therapy leads to improved progression free survival but attempts to deliver increased dose by external beam radiation therapy (EBRT) alone can be limited by late toxicities to nearby genitourinary and gastrointestinal organs at risk. Brachytherapy is a method to deliver dose escalation in conjunction with EBRT with a potentially improved late toxicity profile and improved prostate cancer related outcomes. At least three randomized controlled trials have demonstrated improved biochemical control with the addition of either low-dose rate (LDR) or high-dose rate (HDR) brachytherapy to EBRT, although only ASCENDE-RT compared brachytherapy to dose-escalated EBRT but did report an over 50% improvement in biochemical failure with a LDR boost. Multiple single institution and comparative research series also support the use of a brachytherapy boost in the DE-EBRT era and demonstrate excellent prostate cancer specific outcomes. Despite improved oncologic outcomes with a brachytherapy boost in the high-risk setting, the utilization of both LDR, and HDR brachytherapy use is declining. The acute genitourinary toxicities when brachytherapy boost is combined with EBRT, particularly a LDR boost, are of concern in comparison to EBRT alone. HDR brachytherapy boost has many physical properties inherent to its rapid delivery of a large dose which may reduce acute toxicities and also appeal to the radiobiology of prostate cancer. We herein review the evidence for use of either LDR or HDR brachytherapy boost for high-risk prostate cancer and summarize comparisons between the two treatment modalities.
对于预后不良或高危前列腺癌患者，剂量递增放射治疗可改善无进展生存期，但仅通过外照射放疗（EBRT）来增加剂量会受到附近泌尿生殖系统和胃肠道危险器官迟发性毒性的限制。近距离放射治疗是一种与EBRT联合使用以增加剂量的方法，其潜在地改善了迟发性毒性特征并改善了前列腺癌相关结局。至少三项随机对照试验表明，在EBRT基础上加用低剂量率（LDR）或高剂量率（HDR）近距离放射治疗可改善生化控制，尽管只有ASCENDE-RT将近距离放射治疗与剂量递增的EBRT进行了比较，但确实报告了LDR增敏后生化失败率改善超过50%。多个单机构和比较研究系列也支持在剂量递增EBRT时代使用近距离放射治疗增敏，并显示出优异的前列腺癌特异性结局。尽管在高危情况下近距离放射治疗增敏可改善肿瘤学结局，但LDR和HDR近距离放射治疗的应用率都在下降。与单独的EBRT相比，近距离放射治疗增敏与EBRT联合使用时的急性泌尿生殖系统毒性，尤其是LDR增敏，令人担忧。HDR近距离放射治疗增敏具有快速给予大剂量所固有的许多物理特性，这可能会降低急性毒性，并且也符合前列腺癌的放射生物学特性。我们在此回顾了使用LDR或HDR近距离放射治疗增敏高危前列腺癌的证据，并总结了两种治疗方式之间的比较。
