PDF(Pubmed)
Abstract：
A deep-seated, locally infiltrative 5.8-cm brain metastasis (BM) involving the ventricular wall and optic radiation is deemed unamenable for a safe total resection, while preventing tumor seeding. Meanwhile, radiotherapeutic management alone for such a BM close to the brainstem is also challenging. We describe such a BM (gross tumor volume [GTV] 40.3 cm3) from lung adenocarcinoma (LAC), located in the left temporo-occipital lobes, with extensive invasion to the tentorium cerebelli and a high potential for dissemination. The BM was treated with 15-fraction(s) (fr) stereotactic radiosurgery (SRS) followed by whole-brain irradiation (WBI) at 27 Gy/15 fr with a 19-day interval. During the SRS, the solid component away from the tentorium showed obvious shrinkage. The cumulative biologically effective doses (BEDs) of the minimum and D99% of the GTV were ≥92.3 Gy and ≥102.6 Gy, respectively, where the BED was based on the linear-quadratic formula at an alpha/beta ratio of 10 (BED10). Despite a maximum response with nearly complete regression at 7.5 months, local tumor regrowth near the tentorial incisura became gradually apparent from 11.2 to 19.3 months. Salvage re-SRS with 53 Gy/10 fr specific to these lesions resulted in obvious regression at 5.8 months. However, radiation injury concomitant with triventriculomegaly progressed from 7.9 to 13.9 months, eventually leading to meningeal dissemination and patient mortality at 34.6 months. This case demonstrates that a BED10 ≥90-100 Gy in 30 fr to the GTV boundary with a more than two-week interval without combined systemic therapy is insufficient for achieving complete local tumor eradication of a 40-cc LAC-BM. Shorter treatment duration with a steeper dose gradient outside and inside the GTV in the SRS or a volumetric modulated arc-based SRS combined with simultaneously integrated WBI may improve efficacy and safety.
摘要：
一个根深蒂固的，涉及心室壁和视神经辐射的局部浸润性5.8厘米脑转移瘤（BM）被认为不适合安全的全切除，同时防止肿瘤种植。同时,对于这种靠近脑干的BM，仅进行放射治疗也具有挑战性。我们描述了来自肺腺癌（LAC）的BM（总肿瘤体积[GTV]40.3cm3），位于左颞枕叶，对小脑幕的广泛入侵和很高的传播潜力。BM用15分（s）（fr）立体定向放射外科（SRS）处理，然后以27Gy/15fr进行全脑照射（WBI），间隔19天。在SRS期间，远离天幕的固体成分表现出明显的收缩。GTV最低和D99%的累积生物有效剂量(BED)≥92.3Gy和≥102.6Gy,分别,其中BED基于线性二次公式，α/β比为10(BED10)。尽管最大反应在7.5个月时几乎完全消退，从11.2到19.3个月，小幕切口附近的局部肿瘤再生长逐渐明显。针对这些病变的53Gy/10fr的救助再SRS在5.8个月时明显消退。然而,伴有三室增宽的辐射损伤从7.9个月进展到13.9个月，最终导致34.6个月时的脑膜播散和患者死亡。此病例表明，在没有联合全身治疗的情况下，BED10≥90-100Gy在30fr到GTV边界的时间间隔超过两周，不足以实现40ccLAC-BM的完全局部肿瘤根除。在SRS中的GTV外部和内部具有更陡的剂量梯度的更短的治疗持续时间或与同时集成的WBI组合的体积调制的基于电弧的SRS可以提高功效和安全性。
