Pineal region tumors (PTs) represent extremely rare pathologies, characterized by highly heterogeneous histological patterns. Most of the available evidence for Gamma Knife radiosurgical (GKSR) treatment of PTs arises from multimodal regimens, including GKSR as an adjuvant modality or as a salvage treatment at recurrence. We aimed to gather existing evidence on the topic and analyze single-patient-level data to address the efficacy and safety of primary GKSR. This is a systematic review of the literature (PubMed, Embase, Cochrane, Science Direct) and pooled analysis of single-patient-level data. A total of 1054 original works were retrieved. After excluding duplicates and irrelevant works, we included 13 papers (n = 64 patients). An additional 12 patients were included from the authors' original series. A total of 76 patients reached the final analysis; 56.5% (n = 43) received a histological diagnosis. Confirmed lesions included pineocytoma WHO grade I (60.5%), pineocytoma WHO grade II (14%), pineoblastoma WHO IV (7%), pineal tumor with intermediate differentiation WHO II/III (4.7%), papillary tumor of pineal region WHO II/III (4.7%), germ cell tumor (2.3%), neurocytoma WHO I (2.3%), astrocytoma WHO II (2.3%) and WHO III (2.3%). Presumptive diagnoses were achieved in the remaining 43.5% (n = 33) of cases and comprised of pineocytoma (9%), germ cell tumor (6%), low-grade glioma (6%), high-grade glioma (3%), meningioma (3%) and undefined in 73%. The mean age at the time of GKSR was 38.7 years and the mean lesional volume was 4.2 ± 4 cc. All patients received GKSR with a mean marginal dose of 14.7 ± 2.1 Gy (50% isodose). At a median 36-month follow-up, local control was achieved in 80.3% of cases. Thirteen patients showed progression after a median time of 14 months. Overall mortality was 13.2%. The median OS was not reached for all included lesions, except high-grade gliomas (8mo). The 3-year OS was 100% for LGG and pineal tumors with intermediate differentiation, 91% for low-grade pineal lesions, 66% for high-grade pineal lesions, 60% for germ cell tumors (GCTs), 50% for HGG, and 82% for undetermined tumors. The 3-year progression-free survival (PFS) was 100% for LGG and pineal intermediate tumors, 86% for low-grade pineal, 66% for high-grade pineal, 33.3% for GCTs, and 0% for HGG. Median PFS was 5 months for HGG and 34 months for GCTs. The radionecrosis rate was 6%, and cystic degeneration was observed in 2%. Ataxia as a presenting symptom strongly predicted mortality (odds ratio [OR] 104, p = .02), while GCTs and HGG histology well predicted PD (OR: 13, p = .04). These results support the efficacy and safety of primary GKSR treatment of PTs. Further studies are needed to validate these results, which highlight the importance of the initial presumptive diagnosis for choosing the best therapeutic strategy.

中文翻译：

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松果体区肿瘤的初级伽玛刀放射外科治疗：对现有文献进行组织学分层的系统回顾和汇总分析

松果体区肿瘤（PT）代表着极其罕见的病理，其特征是高度异质的组织学模式。伽玛刀放射外科 (GKSR) 治疗 PT 的大多数现有证据都来自多模式治疗方案，包括 GKSR 作为辅助治疗方式或作为复发时的挽救治疗。我们的目的是收集有关该主题的现有证据并分析单个患者水平的数据，以解决主要 GKSR 的有效性和安全性。这是对文献（PubMed、Embase、Cochrane、Science Direct）的系统回顾以及单个患者水平数据的汇总分析。共检索到原创作品1054件。排除重复和不相关的作品后，我们纳入了 13 篇论文（n  = 64 名患者）。另外 12 名患者也来自作者的原始系列。共有76名患者进入最终分析；56.5% ( n  = 43) 获得了组织学诊断。确诊病灶包括松果体细胞瘤WHO I级（60.5%）、松果体细胞瘤WHO II级（14%）、松果体母细胞瘤WHO IV级（7%）、中分化松果体肿瘤WHO II/III级（4.7%）、松果体区乳头状肿瘤WHO II /III (4.7%)、生殖细胞瘤 (2.3%)、神经细胞瘤 WHO I (2.3%)、星形细胞瘤 WHO II (2.3%) 和 WHO III (2.3%)。其余 43.5% ( n  = 33) 的病例获得推定诊断，包括松果体细胞瘤 (9%)、生殖细胞瘤 (6%)、低级别胶质瘤 (6%)、高级别胶质瘤 (3%) 、脑膜瘤 (3%) 和未定义的 73%。GKSR 时的平均年龄为 38.7 岁，平均病变体积为 4.2 ± 4 cc。所有患者均接受平均边缘剂量为 14.7 ± 2.1 Gy（50% 等剂量）的 GKSR。在中位 36 个月的随访中，80.3% 的病例实现了局部控制。13 名患者在中位时间 14 个月后出现进展。总死亡率为13.2%。除高级别胶质瘤（8 个月）外，所有纳入的病变均未达到中位 OS。LGG 和中分化松果体肿瘤的 3 年 OS 为 100%，低级别松果体病变为 91%，高级别松果体病变为 66%，生殖细胞肿瘤 (GCT) 为 60%，HGG 为 50%，未确定的肿瘤为 82%。LGG 和松果体中间肿瘤的 3 年无进展生存率 (PFS) 为 100%，低级别松果体肿瘤为 86%，高级别松果体肿瘤为 66%，GCT 为 33.3%，HGG 为 0%。HGG 的中位 PFS 为 5 个月，GCT 的中位 PFS 为 34 个月。放射性坏死率为6%，囊性变为2%。共济失调作为一种主诉症状可以强烈预测死亡率（比值比 [OR] 104，p  = .02），而 GCT 和 HGG 组织学可以很好地预测 PD（OR：13，p  = .04）。这些结果支持了 PT 主要 GKSR 治疗的有效性和安全性。需要进一步的研究来验证这些结果，这凸显了初步推定诊断对于选择最佳治疗策略的重要性。