Department of Radiology, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya, 467-8601, Japan.
Department of Radiology, Nagoya City West Medical Center, 1-1-1, Hirate-cho, Kita-ku, Nagoya, 462-8508, Japan.
Radiat Oncol. 2017 Sep 11;12(1):152. doi: 10.1186/s13014-017-0888-7.
Efficacy of stereotactic body radiotherapy (SBRT) in stage I non-small-cell lung cancer (NSCLC) has almost been established. In Japan, the protocol of 48 Gy in 4 fractions over 4 days has been most often employed, but higher doses may be necessary to control large tumors. Previously, we conducted a clinical study using SBRT for stage I NSCLC employing different doses depending on tumor diameter, which was closed in 2008. Thereafter, a new study employing higher doses has been conducted, which is reported here. The purpose of this study was to review the safety and effectiveness of the higher doses.
We escalated the total dose for the improvement of local control for large tumors. In this study, 71 patients underwent SBRT between December 2008 and April 2014. Isocenter doses of 48, 50, and 52 Gy were administered for tumors with a longest diameter of < 1.5 cm, 1.5-3 cm, and > 3 cm, respectively. It was recommended to cover 95% of the PTV with at least 90% of the isocenter dose, and in all but one cases, 95% of the PTV received at least 80% of the prescribed dose. Treatments were delivered in 4 fractions, giving 2 fractions per week. SBRT was performed with 6-MV photons using 4 non-coplanar and 3 coplanar beams.
The median follow-up period was 44 months for all patients and 61 months for living patients. Overall survival (OS) was 65%, progression-free survival (PFS) was 55%, and cumulative incidence of local recurrence (LR) was 15% at 5 years. The 5-year OS was 69% for 57 stage IA patients and 53% for 14 stage IB patients (p = 0.44). The 5-year PFS was 55 and 54%, respectively (p = 0.98). The 5-year cumulative incidence of LR was 11 and 31%, respectively (p = 0.09). The cumulative incidence of Grade ≥ 2 radiation pneumonitis was 25%.
Our newer SBRT study yielded reasonable local control and overall survival and acceptable toxicity, but escalating the total dose did not lead to improved outcomes.
UMIN000027231 , registered on 3 May 2017. Retrospectively registered.
立体定向体部放疗（SBRT）在 I 期非小细胞肺癌（NSCLC）中的疗效已几乎得到证实。在日本，最常采用的方案是 48Gy 分 4 次，4 天完成，但对于大肿瘤，可能需要更高的剂量来控制肿瘤。此前，我们开展了一项根据肿瘤直径采用不同剂量的 I 期 NSCLC SBRT 临床研究，该研究于 2008 年结束。此后，开展了一项采用更高剂量的新研究，现报告如下。本研究的目的是回顾更高剂量的安全性和有效性。
我们提高了总剂量以提高大肿瘤的局部控制率。在这项研究中，2008 年 12 月至 2014 年 4 月期间，71 例患者接受了 SBRT。对于最长直径＜1.5cm、1.5-3cm 和＞3cm 的肿瘤，分别给予等中心点剂量 48、50 和 52Gy。建议覆盖 95%的 PTV 至少 90%的等中心点剂量，除 1 例外，所有患者的 95%的 PTV 均接受至少 80%的处方剂量。每周给予 2 次 4 个分次的 SBRT。使用 6MV 光子，采用 4 个非共面和 3 个共面射线进行治疗。
所有患者的中位随访时间为 44 个月，生存患者的中位随访时间为 61 个月。5 年总生存率（OS）为 65%，无进展生存率（PFS）为 55%，5 年局部复发率（LR）累积发生率为 15%。57 例 IA 期患者 5 年 OS 为 69%，14 例 IB 期患者为 53%（p=0.44）。5 年 PFS 分别为 55%和 54%（p=0.98）。5 年 LR 累积发生率分别为 11%和 31%（p=0.09）。≥2 级放射性肺炎的累积发生率为 25%。
我们的新 SBRT 研究获得了合理的局部控制率和总生存率，且毒性反应可接受，但提高总剂量并未带来更好的结果。
UMIN000027231，2017 年 5 月 3 日注册。回顾性注册。
