Department of Radiation Oncology, Cork University Hospital, Wilton, Cork, Ireland.
iThemba LABS, Faure, Cape Town, South Africa.
Int J Radiat Oncol Biol Phys. 2019 Mar 1;103(3):680-685. doi: 10.1016/j.ijrobp.2018.10.022. Epub 2018 Oct 27.
To investigate the occurrence of second malignancies resulting from the secondary radiation from a passively scattered proton beam.
A cohort of patients with long-term follow-up was defined. All were treated at the same institution with the same proton delivery system, consisting of a 200 MeV fixed, horizontal, passively scattered beam combined with a robotic chair. This setup allows for stereotactic positioning and permits fractionated treatments. The majority of patients underwent cranial or intracranial stereotactic radiation therapy. Patients with previous photon therapy or a follow-up of 24 months or less were excluded. For out-of-field secondary malignancies (SMs), the observed incidence in the study population was compared to the risk of developing a malignancy in the general population, taking patient sex into account.
From September 1993 to May 2016, a total of 524 patients received proton beam therapy, and 322 patients could be evaluated for this study (164 female and 158 male). Age ranged from 2 to 85 years, with a median of 40 years. Follow-up ranged from 25 to 276 months, with a median of 150 months (12.5 years). During the study observation period, 7 patients had out-of-field new malignant disease. Three female patients developed a malignancy, compared with an expected incidence of 4.09 (standardized incidence ratio, 0.73 [95% confidence interval, 0.24-2.27]); 4 male patients developed a malignancy, versus an expected incidence of 3.99 (standardized incidence ratio, 1.00 [95% confidence interval, 0.38-2.67]). New intracranial disease developed in 9 patients: 8 meningiomas and 1 carcinoma.
For out-of-field SMs, no increased risk of developing a variety of malignancies was observed. For in-field SMs, only 1 malignant histology was noted 15 years after the original proton therapy. No SM was observed in children and young adults.
研究被动散射质子束二次辐射导致的第二恶性肿瘤的发生情况。
定义了一个具有长期随访的患者队列。所有患者均在同一机构接受治疗，使用相同的质子输送系统，该系统由 200 MeV 固定水平被动散射束与机器人座椅组成。这种设置允许进行立体定向定位，并允许进行分次治疗。大多数患者接受了颅或颅内立体定向放射治疗。排除了先前接受过光子治疗或随访时间少于 24 个月的患者。对于野外二次恶性肿瘤（SM），将研究人群中的观察发生率与考虑患者性别后一般人群中发生恶性肿瘤的风险进行比较。
从 1993 年 9 月至 2016 年 5 月，共有 524 名患者接受了质子束治疗，其中 322 名患者可进行本研究评估（女性 164 名，男性 158 名）。年龄从 2 岁到 85 岁，中位数为 40 岁。随访时间从 25 个月到 276 个月，中位数为 150 个月（12.5 年）。在研究观察期间，7 名患者出现野外新发恶性疾病。3 名女性患者发生了恶性肿瘤，预期发生率为 4.09（标准化发病比，0.73[95%置信区间，0.24-2.27]）；4 名男性患者发生了恶性肿瘤，预期发生率为 3.99（标准化发病比，1.00[95%置信区间，0.38-2.67]）。9 名患者出现新的颅内疾病：8 例脑膜瘤和 1 例癌。
对于野外 SM，未观察到发生多种恶性肿瘤的风险增加。对于场内 SM，在最初质子治疗 15 年后仅观察到 1 例恶性组织学。在儿童和青少年中未观察到 SM。
