适形放疗局部晚期非小细胞肺癌缩小纵隔淋巴结区的对照研究

Treatment of Non-Small Cell Lung Cancer(NSCLC) Using CT in Combination with a PET Examination to Minimize the Clinical Target Volume of the Mediastinum

目的:CT结合PET肿瘤显像,缩小局部晚期非小细胞肺癌放疗的临床靶区,不做淋巴引流区预防性照射,减少食管和肺的放射损伤。方法:76例局部晚期非小细胞肺癌患者,放疗前32人接受了PET检查,对于CT和PET都认为没有淋巴结转移的纵隔区域不作预防性照射;另44例患者给予常规淋巴引流区预防性照射,PET检查组患者的临床靶体积平均缩小了近1/3。两组患者放疗方法相同,加速分割照射,3Gy/次,5次/周,预防剂量42～45Gy/14～15次/3周,治疗剂量60～63Gy/20～21次/4～5周。结果:PET检查组和非PET检查组照射野外淋巴结失控分别为6.3%和4.5%(P=0.831);急性放射性食管炎的发生率分别为15.6%、和45.5%(P=0.006);两组患者的急性放射性肺炎和远期肺纤维化发生率分别为6.3%、9.1%和68.8%、75.0%(P=0.982和P=0.547)。结论:缩小临床靶体积后,靶区外淋巴结复发率无增加,而放射性肺和食管损伤减轻,尤其是急性放射性食管炎的发生率下降明显。CT结合PET缩小纵隔临床靶体积优于传统的纵隔预防性照射。

Objective： To decrease radiation injury of the esophagus and lungs by utilizing a CT scan in combination with PET tumor imaging in order to minimize the clinical target area of locally advanced non-small cell lung cancer, without preventive radiation on the lymphatic drainage area. Methods： Of 76 patients with locally advanced non-small cell lung cancer （NSCLC）, 32 received a PET examination before radiotherapy. Preventive radiation was not conducted in the mediastinum area without lymphatic metastasis, which was confirmed by CT and PET. For the other 44 patients, preventive radiation was performed in the lymphatic drainage area. PET examinations showed that the clinical target volume of the patients was decreased on average to about one third. The radiation therapy for patients of the two groups was the same, i.e. the dose for accelerate fractionated irradiation was 3 Gy/time and 5 time/week. The preventive dose was 42 to 45 Gy/time, 14 to 15 time/week, with 3-week treatment, and the therapeutic dose was 60 to 63 Gy/time, 20 to 21 time/week, with a period of 4 to 5 weeks. Results： The rate of missed lymph nodes beyond the irradiation field was 6.3% and 4.5% respectively in the group with and without PET examination （P=0.831）. The incidence of acute radioactive esophagitis was 15.6% and 45.5% in the two groups respectively （P=0.006）. The incidence of acute radiation pneumonia and long-term pulmonary fibrosis in the two groups was 6.3% and 9.1%, and 68.8% and 75.0%, respectively （P=0.982 and P=0.547）. Conclusion： The recurrence rate in the lymph nodes beyond the target area was not increased after minimizing the clinical target volume （CTV）, whereas radioactive injury to the lungs and esophageal injury was reduced, and especially with a significant decrease in the rate of acute radioactive esophagitis. The method of CT in combination with PET for minimizing the mediastinal CTV is superior to the conventional preventive radiation of the mediastinum.