Department of Radiation Oncology, University of California Davis Cancer Center, 4501 X Street, Suite G140 Sacramento, CA, USA.
Technol Cancer Res Treat. 2011 Apr;10(2):171-7. doi: 10.7785/tcrt.2012.500192.
Currently, the most common method of delivering intensity-modulated radiotherapy (IMRT) is through step-and-shoot, segmental multi-leaf collimator (SMLC)-based techniques. Although rotational delivery methods such as helical tomotherapy (HT) have been proposed as offering advantages in the treatment of head and neck cancer, a lack of clinical data exists on its potential utility. This study compared dosimetric, clinical, and quality-of-life endpoints among 149 patients treated by HT and SMLC-IMRT for head and neck cancer. Dosimetric analysis revealed that the use of HT resulted in significant improvements with respect to mean dose (23.5 versus 27.9 Gy, p = 0.03) and V30 (30.1 versus 43.9 Gy, p = 0.01) to the contralateral (spared) parotid gland. However, the incidence of grade 3+ xerostomia in the late setting was 10% and 8% among patients treated by HT and SMLC-IMRT, respectively (p = 0.46). There were no significant differences in any of the quality of life endpoints among patients treated by HT and SMLC-IMRT (p > 0.05, for all). Acknowledging the biases inherent in this retrospective analysis, we found that the dosimetric advantages observed with HT compared to SMLC-IMRT failed to translate into significant improvements in clinical outcome. Prospective studies are needed to further evaluate how HT may affect the therapeutic ratio.
目前，传递强度调制放疗（IMRT）最常用的方法是通过步进式、分段多叶准直器（SMLC）技术。虽然旋转传递方法，如螺旋断层放疗（HT）已被提出作为治疗头颈部癌症的优势，但在其潜在应用方面缺乏临床数据。本研究比较了 149 例头颈部癌症患者接受 HT 和 SMLC-IMRT 治疗的剂量学、临床和生活质量终点。剂量学分析表明，与 SMLC-IMRT 相比，HT 治疗显著提高了双侧（未受照射的）腮腺的平均剂量（23.5 与 27.9Gy，p=0.03）和 V30（30.1 与 43.9Gy，p=0.01）。然而，HT 和 SMLC-IMRT 治疗的患者在晚期发生 3 级以上口干症的发生率分别为 10%和 8%（p=0.46）。HT 和 SMLC-IMRT 治疗的患者在任何生活质量终点方面均无显著差异（p＞0.05，均）。尽管承认本回顾性分析中存在的偏见，但我们发现与 SMLC-IMRT 相比，HT 观察到的剂量学优势未能转化为临床结局的显著改善。需要前瞻性研究进一步评估 HT 如何影响治疗比。
