Department of Radiation Oncology, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Germany.
Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, University of Heidelberg, Germany.
Radiother Oncol. 2019 May;134:166-177. doi: 10.1016/j.radonc.2019.02.003. Epub 2019 Feb 18.
BACKGROUND/PURPOSE: To quantify the risk of radiation-induced optic neuropathy (RION) after stereotactic/image-guided positioning and intensity-modulated radiotherapy (IMRT) with ≥50 Gy to the anterior visual pathway (AVP).
Patients irradiated with ≥50 Gy to the AVP using stereotactic/image-guided positioning between 2002 and 2011 in Mannheim were identified. Detailed dosimetric data were collected and patients or family members were retrospectively asked to rate visual acuity and visual disorders.
125 patients fulfilled the eligibility criteria. Average maximum equivalent point dose (D-EQD-2) to the AVP was 53.1 ± 3.9 Gy. 99 patients received ≥50 Gy bilaterally (chiasm or both optic nerves), resulting in 224 (99x2 bilateral plus 26 unilateral) visual-fields-at-risk (VFAR) for RION. Eighty-two patients provided pre/post-IMRT visual status information (n = 151 VFARs). Permanent visual deterioration occurred in 18 (22%) patients. In seven, visual deterioration was possibly related to radiotherapy (two-sided deterioration in one patient) for a crude incidence of 8.5% (7/82 patients) and 5.3% (8/151 VFARs). Two cases were caused by chronic keratitis/conjunctivitis; in five patients RION could not be excluded (one two-sided). In one of 13 patients with D-EQD-2 > 58 Gy, RION could not be excluded. In all affected patients, visual acuity post-IMRT had decreased only mildly (1-2 points on the 5-point-scale). One patient with relevant baseline visual impairment (3/5) developed unilateral blindness (crude incidence of blindness on patient-/VFAR-level: 1.2% and 0.66%; competing risk-adjusted/actuarial 24-month incidence: patient/VFAR-level: 1.8% and 0.95%).
Risk of RION was low in this cohort with accurate positioning and precise dosimetric information. Less conservative tolerance doses may be considered in patients with high risk of recurrence.
背景/目的：定量研究立体定向/图像引导定位和调强放疗（IMRT）后，在前视觉通路（AVP）接受≥50Gy 照射的放射性视神经病变（RION）风险。
在曼海姆，2002 年至 2011 年间，确定了使用立体定向/图像引导定位接受≥50GyAVP 照射的患者。收集了详细的剂量学数据，并回顾性地询问患者或家属视力和视力障碍的情况。
125 名患者符合入选标准。AVP 的平均最大等效点剂量（D-EQD-2）为 53.1±3.9Gy。99 名患者双侧（视交叉或双侧视神经）接受了≥50Gy 的照射，导致 224 个（99x2 双侧加上 26 个单侧）放射性视神经病变风险视野（VFAR）。82 名患者提供了 IMRT 前后的视觉状态信息（151 个 VFAR）。18 名（22%）患者出现永久性视力下降。其中 7 例可能与放疗有关（1 例双侧），粗发生率为 8.5%（82 例患者中有 7 例）和 5.3%（151 个 VFAR 中有 8 个）。2 例因慢性角膜炎/结膜炎引起，5 例不能排除放射性视神经病变（1 例双侧）。在 D-EQD-2>58Gy 的 13 名患者中，1 例不能排除放射性视神经病变。所有受影响的患者，IMRT 后的视力仅略有下降（5 分制下降 1-2 分）。1 名基线视力相关受损（3/5）的患者出现单侧失明（患者/视野水平的粗发生率：1.2%和 0.66%；竞争风险调整/24 个月累积发生率：患者/视野水平：1.8%和 0.95%）。
在这组使用准确定位和精确剂量学信息的患者中，RION 的风险较低。对于复发风险高的患者，可以考虑不那么保守的耐受剂量。
