Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, California.
Department of Radiology, David Geffen School of Medicine at UCLA, Los Angeles, California.
Int J Radiat Oncol Biol Phys. 2018 Jul 1;101(3):564-573. doi: 10.1016/j.ijrobp.2018.03.011. Epub 2018 Mar 21.
Stereotactic body radiation therapy (SBRT) and heat-based ablation (HBA) are both potentially safe and effective treatments for primary and metastatic lung tumors. Both are suboptimal for centrally located tumors, with SBRT having a higher risk of significant toxicity and HBA having lower efficacy. This study evaluates the safety and efficacy of combination SBRT-HBA to determine whether combined treatment can result in superior outcomes to each treatment alone.
Patients with 1 or 2 primary or metastatic lung tumors ≤ 5 cm in size were enrolled in a prospective phase 2 trial and treated with SBRT in 3 fractions followed by HBA. Tumors < 1 cm from the central bronchial tree received a total of 36 Gy, and tumors 1 to 2 cm away received 42 Gy. HBA was delivered within 10 days after SBRT. The primary endpoints were local control, toxicity, and degree of decline in lung function. The secondary endpoints were progression-free survival and overall survival.
We treated 16 patients with 17 tumors. The median follow-up time was 26 months. Fifteen tumors were evaluable for local control. The 1- and 2-year actuarial local control rates were 93% and 81%, respectively. Three patients had grade ≥ 3 toxicity: bronchial stenosis, pain, and pulmonary hemorrhage. The percent predicted forced expiratory volume in 1 second and functional vital capacity decreased by 8% and 8.5%, respectively, at 3 months after treatment (P < .001 for both).
Combining SBRT and HBA for centrally located lung tumors offers reasonable local control and toxicity despite the anatomic challenges of this location. HBA may be a reasonable supplement to SBRT when trachea and bronchus, large vessel, or esophageal constraints cannot be met with full-dose SBRT and a biologically effective dose < 100 Gy is delivered because of an ultra-central location or large tumor size.
立体定向体部放射治疗（SBRT）和热消融（HBA）都是原发性和转移性肺肿瘤潜在安全有效的治疗方法。两者对于中央型肿瘤均不理想，SBRT 毒性显著风险较高，HBA 疗效较低。本研究评估 SBRT-HBA 联合治疗的安全性和有效性，以确定联合治疗是否能获得优于单独治疗的结果。
纳入了一项前瞻性 2 期临床试验，共入组了 1 或 2 个大小≤5cm 的原发性或转移性肺肿瘤患者，采用 SBRT 分 3 次治疗，随后进行 HBA。距中央支气管树<1cm 的肿瘤接受总剂量 36Gy，距离 1 至 2cm 的肿瘤接受 42Gy。HBA 在 SBRT 后 10 天内进行。主要终点是局部控制、毒性和肺功能下降程度。次要终点是无进展生存期和总生存期。
共治疗了 16 例患者的 17 个肿瘤。中位随访时间为 26 个月。15 个肿瘤可评估局部控制情况。1 年和 2 年的局部控制率分别为 93%和 81%。3 例患者发生≥3 级毒性：支气管狭窄、疼痛和肺出血。治疗后 3 个月，预测用力呼气量 1 秒率和功能肺活量分别下降 8%和 8.5%（均 P<.001）。
对于中央型肺肿瘤，SBRT 和 HBA 联合治疗尽管存在该部位的解剖学挑战，但可提供合理的局部控制和毒性。当气管和支气管、大血管或食管限制不能通过全剂量 SBRT 满足，或由于超中央位置或大肿瘤大小导致生物有效剂量<100Gy 时，HBA 可能是 SBRT 的合理补充。
