Sørensen J B
Dept. Oncology, Finsen Centre, National University Hospital, 9 Blegdamsvej, DK-2100 Copenhagen, Denmark.
Monaldi Arch Chest Dis. 2003 Apr-Jun;59(2):128-33.
To review the effectiveness and safety of prophylactic cranial irradiation (PCI) in patients with small-cell lung cancer (SCLC).
Brain metastases are frequent in SCLC with a cumulative incidence of 25% among 1,202 in 17 trials, and a 3-5 months median survival from first occurrence. The 5-year cumulative rate of brain metastases as isolated first site of relapse was 37% among 260 patients without PCI compared to 20% among 245 with PCI in two randomised trials (p < 0.001). A meta-analysis on seven randomised trials of PCI versus no PCI including 987 patients in complete remission without brain metastases or prior brain irradiation showed statistically significant effect in favour of PCI on survival, disease free survival, and risk of brain metastases (relative risks being 0.84, 0.75, and 0.46, and p-values being 0.01, < 0.001, and < 0.001, respectively). Two randomised trials evaluated neurotoxicity in totally 350 patients before PCI and found abnormalities in 24-60%. Repeated examination during the following years revealed no differences on cerebral CT-scans or neuropsychological testing between PCI patients or controls. A review including 42 PCI trials with 4,749 patients revealed the optimal total radiotherapy dose to be 30-35 Gy given as 2 Gy fractions. Also 24 Gy in 3 Gy fractions appear safe based on data from a large randomised study. Both the former study and the meta-analysis suggested early PCI to be better than late.
PCI improves both overall and disease free survival and decreases the risk for brain relapse in SCLC patients in complete remission. PCI should be applied early, and useful and safe doses may be 30-36 GY in 2-3 Gy fractions, though future studies may further illuminate the optimal dose, fractionation and timing.
回顾预防性颅脑照射（PCI）在小细胞肺癌（SCLC）患者中的有效性和安全性。
脑转移在SCLC中很常见，17项试验中的1202例患者累积发生率为25%，首次发生后中位生存期为3至5个月。在两项随机试验中，260例未接受PCI的患者中，脑转移作为孤立的首个复发部位的5年累积发生率为37%，而245例接受PCI的患者中为20%（p<0.001）。一项对7项PCI与未进行PCI的随机试验的荟萃分析，纳入了987例完全缓解、无脑转移或既往未接受过脑部照射的患者，结果显示PCI在生存、无病生存和脑转移风险方面具有统计学显著效果（相对风险分别为0.84、0.75和0.46，p值分别为0.01、<0.001和<0.001）。两项随机试验在总共350例患者PCI前评估了神经毒性，发现异常率为24%至60%。在随后几年的重复检查中，PCI患者和对照组在脑部CT扫描或神经心理学测试方面没有差异。一项纳入42项PCI试验共4749例患者的综述显示，最佳总放疗剂量为30至35 Gy，分2 Gy分次给予。基于一项大型随机研究的数据，分3 Gy分次给予24 Gy似乎也是安全的。前一项研究和荟萃分析均表明早期PCI优于晚期PCI。
PCI可改善SCLC完全缓解患者的总生存和无病生存，并降低脑复发风险。PCI应尽早应用，有用且安全的剂量可能是分2至3 Gy分次给予30至36 GY，不过未来研究可能会进一步阐明最佳剂量、分割方式和时机。
