Department of Radiation Oncology, St. Jude Children's Research Hospital, Memphis, Tennessee.
Department of Oncology, St. Jude Children's Research Hospital, Memphis, Tennessee.
Int J Radiat Oncol Biol Phys. 2020 May 1;107(1):172-180. doi: 10.1016/j.ijrobp.2020.01.011. Epub 2020 Jan 25.
Our purpose was to assess disease outcomes and late toxicities in pediatric patients with rhabdomyosarcoma treated with conformal photon radiation therapy (RT).
Sixty-eight patients (median age, 6.9 years) were treated with conformal photon RT to the primary site on a prospective clinical trial. Target volumes included a 1-cm expansion encompassing microscopic disease. Prescribed doses were 36 Gy to this target volume and 50.4 Gy to gross residual disease. Chemotherapy consisted of vincristine/dactinomycin (n = 6), vincristine/dactinomycin/cyclophosphamide (n = 37), or vincristine/dactinomycin/cyclophosphamide-based combinations (n = 25). Patients were evaluated with primary-site magnetic resonance imaging, whole-body [F]fluorodeoxyglucose positron emission tomography, and chest computed tomography for 5 years after treatment.
Five-year disease-free survival was 88% for low-risk (n = 8), 76% for intermediate-risk (n = 37), and 36% for high-risk (n = 23) patients (P ≤ .01 for low risk/intermediate risk vs high risk). The cumulative incidence of local failure (LF) at 5 years for the entire cohort was 10.4%. Tumor size at diagnosis was a significant predictor of LF (P < .01). Patients with head and neck primary tumors (n = 31) had a 35% cumulative incidence of cataracts; the risk correlated with lens dose (P = .0025). Jaw dysfunction was more severe when the pterygoid and masseter muscles received a mean dose of >20 Gy (P = .013). Orbital hypoplasia developed more frequently after a mean bony orbit dose of >30 Gy (P = .041). Late toxicity in patients with genitourinary tumors included microscopic hematuria (9 of 14), bladder-wall thickening (10 of 14), and vaginal stenosis (2 of 5).
Long-term LF rates were low, and higher rates correlated with larger tumors. Treatment-related toxicities resulting in measurable functional deficits were not infrequent, despite the conformal RT approach.
我们旨在评估接受适形光子放射治疗（RT）的横纹肌肉瘤患儿的疾病结局和晚期毒性。
68 名患者（中位年龄 6.9 岁）在一项前瞻性临床试验中接受了适形光子 RT 治疗。靶区包括 1cm 范围的显微镜下疾病。该靶区的处方剂量为 36Gy，大体残留病灶的剂量为 50.4Gy。化疗包括长春新碱/放线菌素 D（n=6）、长春新碱/放线菌素 D/环磷酰胺（n=37）或长春新碱/放线菌素 D/基于环磷酰胺的联合治疗（n=25）。治疗后 5 年内，患者接受原发部位磁共振成像、全身[F]氟脱氧葡萄糖正电子发射断层扫描和胸部计算机断层扫描评估。
低危（n=8）、中危（n=37）和高危（n=23）患者的 5 年无病生存率分别为 88%、76%和 36%（低危/中危与高危相比，P≤.01）。整个队列的 5 年局部失败（LF）累积发生率为 10.4%。诊断时肿瘤大小是 LF 的显著预测因素（P<.01）。头颈部原发肿瘤患者（n=31）有 35%的累积白内障发生率；风险与晶状体剂量相关（P=.0025）。当翼内肌和嚼肌的平均剂量>20Gy 时，咀嚼肌功能障碍更为严重（P=.013）。眼眶平均骨剂量>30Gy 时，更常发生眼眶发育不全（P=.041）。生殖泌尿系统肿瘤患者的晚期毒性包括镜下血尿（14 例中有 9 例）、膀胱壁增厚（14 例中有 10 例）和阴道狭窄（5 例中有 2 例）。
长期 LF 发生率较低，且较高的发生率与较大的肿瘤相关。尽管采用了适形 RT 方法，但仍会出现导致可测量的功能缺陷的治疗相关毒性。
