Mahmoud Omar, Reis Isildinha M, Samuels Michael M, Elsayyad Nagy, Bossart Elizabeth, Both Joseph, ELGhoneimy Ehsan, Moustafa Magda, AbdAllah Mohamed, Takita Cristiane
Kasr El-Aini Center of Radiation Oncology and Nuclear Medicine (NEMROCK), Cairo, Egypt.
Department of Radiation Oncology, Rutgers, The State University of New Jersey, New Brunswick, NJ, USA.
Technol Cancer Res Treat. 2017 Dec;16(6):1014-1021. doi: 10.1177/1533034617717624. Epub 2017 Jul 3.
Adaptive radiotherapy is being used in few institutions in patients with head and neck cancer having bulky disease using periodic computed tomography imaging accounting for volumetric changes in tumor volume and/or weight loss. Limited data are available on ART in the postoperative setting. We aim to identify parameters that would predict the need for ART in patients with head and neck cancer and whether ART should be applied in postoperative setting.
Twenty patients with stage III-IV head and neck cancer were prospectively accrued. A computed tomography simulation was done prior to treatment and repeated at weeks 3 and 6 of concurrent intensity-modulated radiotherapy and chemotherapy. The final plan was coregistered with the subsequent computed tomography images, and dosimetric/volumetric changes at weeks 1 (baseline), 3, and 6 were quantified in high-risk clinical target volumes, low-risk clinical target volumes , right parotid , left parotid , and spinal cord . An event to trigger ART was defined as spinal cord maximum dose >45 Gy, parotid mean dose >26 Gy, and clinical target volume coverage <95%.
Comparing the 2 groups, the proportion of patients with at least 1 event triggering ART was higher in bulky disease than in postoperative group: 72.7% versus 18.2% ( = .03) overall; 54.6% versus 1.8% ( = .064) at week 3; and 63.6% versus 18.2% ( = .081) at week 6. In the bulky disease group, 8 of 11 patients had events at week 3 and/or 6 as follows: overdose in spinal cord (n = 2), right parotid (n = 3), left parotid (n = 5), coverage < 95% seen in low-risk clinical target volumes (n = 3), and high-risk clinical target volumes (n = 5). In the postoperative group, 2 of 11 patients had events: spinal cord (n = 1) and low-risk clinical target volume (n = 1).
Our study confirmed the need for ART in patients with head and neck cancer having bulky disease due to target under dosing and/or spinal cord/parotids overdosing in weeks 3 and 6. In contrast, the benefit of ART in postoperative patients is less clear.
自适应放疗目前仅在少数机构应用于患有体积较大疾病的头颈癌患者，通过定期计算机断层扫描成像来考虑肿瘤体积的变化和/或体重减轻情况。关于术后应用自适应放疗（ART）的数据有限。我们旨在确定能够预测头颈癌患者是否需要进行自适应放疗的参数，以及术后是否应采用自适应放疗。
前瞻性纳入20例III-IV期头颈癌患者。在治疗前进行一次计算机断层扫描模拟，并在同步调强放疗和化疗的第3周和第6周重复进行。将最终计划与后续的计算机断层扫描图像进行配准，并对高危临床靶区、低危临床靶区、右侧腮腺、左侧腮腺和脊髓在第1周（基线）、第3周和第6周的剂量学/体积变化进行量化。触发自适应放疗的事件定义为脊髓最大剂量>45 Gy、腮腺平均剂量>26 Gy以及临床靶区覆盖率<95%。
比较两组患者，体积较大疾病组中至少有1个事件触发自适应放疗的患者比例高于术后组：总体上分别为72.7%和18.2%（P = 0.03）；第3周时分别为54.6%和1.8%（P = 0.064）；第6周时分别为63.6%和18.2%（P = 0.081）。在体积较大疾病组中，11例患者中有8例在第3周和/或第6周出现事件，情况如下：脊髓剂量过量（2例）、右侧腮腺（3例）、左侧腮腺（5例）、低危临床靶区覆盖率<95%（3例）以及高危临床靶区覆盖率<95%（5例）。在术后组中，11例患者中有2例出现事件：脊髓（1例）和低危临床靶区（1例）。
我们的研究证实，由于在第3周和第6周存在靶区剂量不足和/或脊髓/腮腺剂量过量的情况，体积较大疾病的头颈癌患者需要进行自适应放疗。相比之下，术后患者进行自适应放疗的获益尚不清楚。
