Impact of 18F-Fluciclovine PET on Target Volume Definition for Postprostatectomy Salvage Radiotherapy: Initial Findings from a Randomized Trial
Impact of 18F-Fluciclovine PET on Target Volume Definition for Postprostatectomy Salvage Radiotherapy: Initial Findings from a Randomized Trial
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DOI：
10.2967/jnumed.116.176057
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发表时间：
2017-03-01
影响因子：
9.3
通讯作者：
Schuster, David M.
中科院分区：
文献类型：
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作者：
Jani, Ashesh B.;Schreibmann, Eduard;Schuster, David M.
本研究的目的是评价合成氨基酸PET放射性示踪剂F-18-fluciclovine在修改接受挽救性放疗的直肠切除术后患者的临床和治疗计划靶体积中的作用，并评价对周围危险器官的剂量测定结果。研究方法：96例患者入组了一项随机、前瞻性意向治疗临床试验，旨在对前列腺切除术后复发性前列腺癌进行潜在的挽救性放疗。最初的治疗计划是基于常规腹盆CT和MRI的结果。实验组中的45名患者还接受了腹盆F-18-fluciclovine PET/CT，并将图像与常规图像配准，以确定结果是否会修改初始治疗计划。对照组中的51名患者未接受F-18-fluciclovine PET/CT。对于每例患者，将在F-18-氟鹿草碱注册前治疗的临床和治疗计划靶体积与注册后进行比较。对于危险器官（直肠、膀胱和阴茎球），将登记前和登记后接受40戈伊和65戈伊的体积进行比较。使用配对t检验进行统计学比较。使用卡方检验比较对照组和实验组的急性泌尿生殖系统和胃肠道毒性（由放射治疗肿瘤学小组定义）。结果：24例患者计划放疗至仅包括前列腺床（CTV）的临床靶区（64.8-66.6戈伊）。在21例病例中，计划对包括骨盆的临床靶体积（CTV1）（45.0戈伊）进行放疗，然后对前列腺床（CTV2）（19.8 - 25.2戈伊）进行增强。在每种情况下，各自的治疗计划靶体积扩张（PTV、PTV1或PTV2）均为0.8 cm（后0.6 cm）。除PTV2外，所有配准后体积均显著大于相应的配准前体积。对接受40戈伊和60戈伊照射的直肠、膀胱和阴茎球体积的分析表明，登记后仅阴茎球体积显著升高。未观察到急性泌尿生殖道或胃肠道毒性的显著差异。结论：在治疗计划过程中纳入来自F-18-氟硝草碱PET的信息导致定义的靶体积存在显著差异，阴茎球的剂量较高，但直肠或膀胱剂量或急性泌尿生殖系统或胃肠道毒性无显著差异。需要更长时间的随访来确定F-18-fluciclovine PET对癌症控制和晚期毒性终点的影响。
The purpose of this study was to evaluate the role of the synthetic amino acid PET radiotracer F-18-fluciclovine in modifying the defined clinical and treatment-planning target volumes in postprostatectomy patients undergoing salvage radiotherapy and to evaluate the resulting dosimetric consequences to surrounding organs at risk. Methods: Ninety-six patients were enrolled in a randomized, prospective intention-to-treat clinical trial for potential salvage radiotherapy for recurrent prostate cancer after prostatectomy. The initial treatment plan was based on the results from conventional abdominopelvic CT and MRI. The 45 patients in the experimental arm also underwent abdominopelvic F-18-fluciclovine PET/CT, and the images were registered with the conventional images to determine whether the results would modify the initial treatment plan. The 51 patients in the control arm did not undergo F-18-fluciclovine PET/CT. For each patient, the clinical and treatment-planning target volumes that would have been treated before F-18-fluciclovine registration were compared with those after registration. For organs at risk (rectum, bladder, and penile bulb), the volumes receiving 40 Gy and 65 Gy before registration were compared with those after registration. Statistical comparisons were made using the paired t test. Acute genitourinary and gastrointestinal toxicity as defined by the Radiation Therapy Oncology Group was compared between the control and experimental arms using the chi(2) test. Results: In 24 cases, radiotherapy was planned to a clinical target volume consisting of the prostate bed alone (CTV) (64.8-66.6 Gy). In 21 cases, radiotherapy was planned to a clinical target volume consisting of the pelvis (CTV1) (45.0 Gy) followed by a boost to the prostate bed (CTV2) (19.8-25.2 Gy). In each case, the respective treatment-planning target volume expansion (PTV, PTV1, or PTV2) was 0.8 cm (0.6 cm posterior). With the exception of PTV2, all post-registration volumes were significantly larger than the corresponding preregistration volumes. Analysis of the rectum, bladder, and penile bulb volumes receiving 40 Gy and 60 Gy demonstrated that only the penile bulb volumes were significantly higher after registration. No significant differences in acute genitourinary or gastrointestinal toxicity were observed. Conclusion: Including information from F-18-fluciclovine PET in the treatment-planning process led to significant differences in the defined target volume, with higher doses to the penile bulb but no significant differences in rectal or bladder dose or in acute genitourinary or gastrointestinal toxicity. Longer follow-up is needed to determine the impact of F-18-fluciclovine PET on cancer control and late toxicity endpoints.