Jani Ashesh B, Schreibmann Eduard, Rossi Peter J, Shelton Joseph, Godette Karen, Nieh Peter, Master Viraj A, Kucuk Omer, Goodman Mark, Halkar Raghuveer, Cooper Sherrie, Chen Zhengjia, Schuster David M
Department of Radiation Oncology, Winship Cancer Institute of Emory University, Atlanta, Georgia
Department of Radiation Oncology, Winship Cancer Institute of Emory University, Atlanta, Georgia.
J Nucl Med. 2017 Mar;58(3):412-418. doi: 10.2967/jnumed.116.176057. Epub 2016 Sep 8.
The purpose of this study was to evaluate the role of the synthetic amino acid PET radiotracer F-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. 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-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-fluciclovine PET/CT. For each patient, the clinical and treatment-planning target volumes that would have been treated before F-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 test. Acute genitourinary and gastrointestinal toxicity as defined by the Radiation Therapy Oncology Group was compared between the control and experimental arms using the χ test. 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 postregistration 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. Including information from F-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-fluciclovine PET on cancer control and late toxicity endpoints.
本研究的目的是评估合成氨基酸PET放射性示踪剂F-氟代氯膦酸在修改前列腺切除术后接受挽救性放疗患者的既定临床和治疗计划靶体积方面的作用，并评估对周围危及器官产生的剂量学后果。96例患者参加了一项随机、前瞻性意向性治疗临床试验，用于前列腺切除术后复发性前列腺癌的潜在挽救性放疗。初始治疗计划基于传统腹部盆腔CT和MRI的结果。试验组的45例患者还接受了腹部盆腔F-氟代氯膦酸PET/CT检查，并将图像与传统图像配准，以确定结果是否会修改初始治疗计划。对照组的51例患者未接受F-氟代氯膦酸PET/CT检查。对于每例患者，比较F-氟代氯膦酸配准前和配准后拟治疗的临床和治疗计划靶体积。对于危及器官（直肠、膀胱和阴茎球部），比较配准前和配准后接受40 Gy和65 Gy剂量的体积。采用配对t检验进行统计学比较。使用χ检验比较对照组和试验组之间由放射肿瘤学组定义的急性泌尿生殖系统和胃肠道毒性。24例患者的放疗计划针对仅由前列腺床组成的临床靶体积（CTV）（64.8 - 66.6 Gy）。21例患者的放疗计划针对由盆腔组成的临床靶体积（CTV1）（45.0 Gy），随后对前列腺床进行加量照射（CTV2）（19.8 - 25.2 Gy）。在每种情况下，各自的治疗计划靶体积扩展（PTV、PTV1或PTV2）为0.8 cm（后部0.6 cm）。除PTV2外，所有配准后的体积均显著大于相应的配准前体积。对接受40 Gy和60 Gy剂量的直肠、膀胱和阴茎球部体积分析表明，仅阴茎球部体积在配准后显著增大。未观察到急性泌尿生殖系统或胃肠道毒性的显著差异。在治疗计划过程中纳入F-氟代氯膦酸PET的信息导致既定靶体积有显著差异，阴茎球部接受的剂量更高，但直肠或膀胱剂量以及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-氟代氯膦酸PET对癌症控制和晚期毒性终点的影响。
