未接受过治疗的Koos III-IV级囊性前庭神经鞘瘤立体定向放射外科治疗后的早期体积反应

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中文摘要

背景： 立体定向放射外科（SRS）在大型前庭神经鞘瘤（VS）中的作用仍存在争议，尤其是对于囊性VS患者，这类肿瘤可能快速生长，通常采用显微外科切除术治疗。
目的： 本研究旨在评估未接受过治疗的Koos III-IV级肿瘤患者中，囊性VS与实性VS在SRS后的体积反应。
方法： 这项回顾性研究纳入了新诊断的Koos III-IV级VS并接受SRS治疗、且有>6个月影像学随访的患者。根据治疗前MRI将肿瘤分类为囊性或实性。应用逆概率治疗加权（IPTW）以调整基线差异，多变量加权线性回归确定了末次随访MRI时体积反应的预测因素。还在早期（3-6个月）、中期（12-18个月）和晚期（>24个月）随访时评估了肿瘤体积变化。局部控制（LC）定义为无需额外治疗（手术切除或再次SRS）。
结果： 在261例接受SRS治疗的VS患者中，76例（15例囊性，61例实性）符合纳入标准。平均影像学随访时间为34.0个月。IPTW调整后，基线肿瘤体积是体积缩小的显著预测因素（p<0.01）。囊性VS在早期和中期随访期间显示的肿瘤体积缩小显著大于实性VS（Mann-Whitney U检验：p=0.029和p=0.031；IPTW调整后：分别为p<0.01和p=0.024）。这种差异在晚期随访时未观察到（Mann-Whitney U检验：p=0.064；IPTW调整后：p=0.780）。囊性VS的LC率为100%，实性VS为98.4%。
结论： 大型囊性VS在SRS后表现出显著更大的早期肿瘤缩小，且局部控制极佳，与实性VS相当。这些发现表明，对于选定的大型囊性VS患者，SRS是一种可行、侵入性较小的治疗选择。

英文摘要

BACKGROUND: The role of stereotactic radiosurgery (SRS) for large vestibular schwannomas (VS) remains controversial, particularly for patients with cystic VS, which can grow rapidly and are often managed by microsurgical resection.
OBJECTIVE: This study aimed to evaluate the volumetric response of cystic VS compared with solid VS following SRS in patients with treatment-naïve Koos grade III-IV tumors.
METHODS: This retrospective study included patients with newly diagnosed Koos grade III-IV VS treated with SRS, with > 6 months of radiological follow-up. Tumors were classified as cystic or solid based on pretreatment MRI. Inverse probability of treatment weighting (IPTW) was applied to adjust for baseline differences, and multivariable weighted linear regression identified predictors of volumetric response at the last follow-up MRI. Tumor volumetric changes were also assessed at early (3-6 months), intermediate (12-18 months), and late (>24 months) follow-up. Local control (LC) was defined as no need for additional treatment (surgical resection or repeat SRS).
RESULTS: Among 261 SRS-treated VS patients, 76 (15 cystic, 61 solid) met inclusion criteria. The mean radiological follow-up was 34.0 months. After IPTW adjustment, baseline tumor volume was a significant predictor of volume reduction (p <0.01). Cystic VS demonstrated significantly greater tumor volume reduction during early and intermediate follow-up than solid VS (Mann-Whitney U: p = 0.029 and p = 0.031; IPTW-adjusted: p < 0.01 and p = 0.024, respectively). This difference was not observed at late follow-up (Mann-Whitney U: p = 0.064; IPTW-adjusted: p = 0.780). The LC rate was 100% in cystic and 98.4% in solid VS.
CONCLUSION: Large cystic VS exhibit significantly greater early tumor shrinkage following SRS, with excellent local control comparable to solid VS. These findings suggest that SRS is a viable, less invasive treatment option for selected patients with large cystic VS.