Background and objective: Controversies exists with regard to target volumes as far as thoracic radiotherapy (TRT) is concerned in the multimodality treatment for limited-stage small cell lung cancer (LSCLC). The aim of this study is to prospectively compare the local control rate, toxicity profiles, and overall survival (OS) between patients received different target volumes irradiation after induction chemotherapy.
Methods: LSCLC patients received 2 cycles of etoposide and cisplatin (EP) induction chemotherapy and were randomly assigned to receive TRT to either the post- or pre-chemotherapy tumor extent (GTV-T) as study arm and control arm, CTV-N included the positive nodal drainage area for both arms. One to 2 weeks after induction chemotherapy, 45 Gy/30 Fx/19 d TRT was administered concurrently with the third cycle of EP regimen. After that, additional 3 cycles of EP consolidation were administered. Prophylactic cranial irradiation (PCI) was administered to patients with a complete response.
Results: Thirty-seven and 40 patients were randomly assigned to study arm and control arm. The local recurrence rates were 32.4% and 28.2% respectively (P = 0.80); the isolated nodal failure (INF) rates were 3.0% and 2.6% respectively (P = 0.91); all INF sites were in the ipsilateral supraclavicular fossa. Medastinal N3 disease was the risk factor for INF (P = 0.02, OR = 14.13, 95% CI: 1.47-136.13). During radiotherapy, grade I, II weight loss was observed in 29.4%, 5.9% and 56.4%, 7.7% patients respectively (P = 0.04). Grade 0-I and II-III late pulmonary injury was developed in 97.1%, 2.9% and 86.4%, 15.4% patients respectively (P = 0.07). Median survival time was 22.1 months and 26.9 months respectively. The 1 to 3-year OS were 77.9%, 44.4%, 37.3% and 75.8%, 56.3%, 41.7% respectively (P = 0.79).
Conclusions: The preliminary results of this study indicate that irradiant the post-chemotherapy tumor extent (GTV-T) and positive nodal drainage area did not decrease local control and overall survival while radiation toxicity was reduced. But the current sample size has not met designed requirements, and further investigation is warranted before final conclusions could be drawn.
背景与目的: 在局限期小细胞肺癌（limited-stage small cell lung cancer, LSCLC）的放化疗综合治疗中，放疗靶区等方面尚存争议。本研究旨在前瞻性比较LSCLC经诱导化疗后按不同靶区范围进行放疗的局部控制率和毒副反应的差异及对生存的影响。
方法: LSCLC患者，经EP方案诱导化疗2周期后，随机分为研究组和对照组，分别按照化疗后和化疗前原发灶范围勾画放疗靶区（gross tumor volume-tumor, GTV-T），区域淋巴结靶区（gross tumor volume-nodal, CTV-N）两组均包括达到诊断标准的淋巴结所在的结区。放疗45 Gy/30次/19天，开始于化疗后1周-2周，放疗中按期进行第3周期化疗。放疗后再行3周期化疗。完全缓解者行预防性全脑照射（prophylactic cranial irradiation, PCI）。
结果: 研究组与对照组分别入组37例、40例患者。局部复发率分别为32.4%、28.2%（P=0.80），其中单独照射野外复发率分别为3.0%、2.6%（P=0.91），且均位于原发病灶同侧锁骨上区。纵隔型N3是照射野外复发危险因素（P=0.02, OR=14.13, 95%CI: 1.47-136.13）；放疗期间发生Ⅰ度、Ⅱ度体重减轻分别为29.4%、5.9%和56.4%、7.7%（P=0.04）；0度-Ⅰ度和Ⅱ度-Ⅲ度后期放射性肺损伤发生率分别为97.1%、2.9%和84.6%、15.4%（P=0.07）。研究组和对照组中位生存时间分别为22.1个月和26.9个月；1、2、3年总生存率分别为77.9%、44.4%、37.3%及75.8%、56.3%、41.7%（P=0.79）。
结论: 本研究结果显示仅照射化疗后原发灶范围及阳性淋巴结区未降低局部控制率和总生存率，而放疗毒性降低。但目前样本量尚未达到设计要求，最终结论需继续扩大样本数后得出。