Prabhu Roshan S, Ward Matthew C, Heinzerling John H, Corso Christopher D, Buchwald Zachary S, Dhakal Reshika, Asher Anthony L, Sumrall Ashley L, Burri Stuart H
Levine Cancer Institute, Atrium Health, Charlotte, North Carolina.
Southeast Radiation Oncology Group, Charlotte, North Carolina.
Adv Radiat Oncol. 2020 Oct 26;6(1):100577. doi: 10.1016/j.adro.2020.09.017. eCollection 2021 Jan-Feb.
Previous trials have shown no benefit for radiation therapy (RT) dose escalation when RT is given as adjuvant monotherapy for infiltrative low-grade glioma (LGG). However, the current standard of care for high-risk LGG is RT with concurrent and/or adjuvant chemotherapy. The effect of RT dose escalation on overall survival (OS) in the setting of concurrent and/or adjuvant chemotherapy is not well established.
We used the National Cancer Database to select records for adult patients with intracranial grade 2 LGG diagnosed between 2004 and 2015. Patients must have received adjuvant external beam RT with concurrent and/or adjuvant chemotherapy. RT dose level was categorized as standard (45-54 Gy) or high (>54-65 Gy). Multivariable and propensity score matched analyses were used.
The study cohort consisted of 1043 patients, of whom 644 (62%) received standard dose (median, 54 Gy) and 399 (38%) received high-dose RT (median, 60 Gy). RT dose level was not associated with OS (hazard ratio, 1.2; = .1) in multivariable analysis. Propensity score matching yielded 380 matched pairs (n = 760). There was no difference in OS for high-dose versus standard-dose RT in the matched cohort (5-year OS 64% vs 69%; = .14) or in the 2 prespecified subgroups of astrocytoma histology and 1p/19q noncodeleted.
Adjuvant RT dose escalation above 54 Gy in the setting of concurrent and/or adjuvant chemotherapy was not associated with improved OS for patients with infiltrative LGG in this National Cancer Database retrospective study. This was also true for the subgroups with less chemotherapy-sensitive disease, including astrocytoma histology and 1p/19q noncodeleted, although these analyses were limited by small size. Methods to improve OS other than RT dose escalation in the setting of concurrent and/or adjuvant chemotherapy should be considered for patients with poor-prognosis LGG.
既往试验表明，对于浸润性低级别胶质瘤（LGG），辅助性单一放疗时增加放疗（RT）剂量并无益处。然而，目前高危LGG的标准治疗方案是同步和/或辅助化疗联合RT。RT剂量增加在同步和/或辅助化疗情况下对总生存期（OS）的影响尚未明确。
我们利用国家癌症数据库选择2004年至2015年间诊断为颅内2级LGG的成年患者记录。患者必须接受过同步和/或辅助化疗的辅助性外照射RT。RT剂量水平分为标准剂量（45 - 54 Gy）或高剂量（>54 - 65 Gy）。采用多变量和倾向评分匹配分析。
研究队列包括1043例患者，其中644例（62%）接受标准剂量（中位剂量，54 Gy），399例（38%）接受高剂量RT（中位剂量，60 Gy）。多变量分析中，RT剂量水平与OS无关（风险比，1.2；P = 0.1）。倾向评分匹配产生380对匹配病例（n = 760）。在匹配队列中，高剂量与标准剂量RT的OS无差异（5年OS分别为64%和69%；P = 0.14），在星形细胞瘤组织学和1p/19q未缺失的2个预先指定亚组中也是如此。
在本国家癌症数据库回顾性研究中，对于浸润性LGG患者，同步和/或辅助化疗情况下辅助RT剂量增加至54 Gy以上与OS改善无关。对于化疗敏感性较低的亚组，包括星形细胞瘤组织学和1p/19q未缺失的情况也是如此，尽管这些分析因样本量小而受到限制。对于预后不良的LGG患者，应考虑在同步和/或辅助化疗情况下采用除增加RT剂量之外的改善OS的方法。
