Nielsen O S, Cummings B, O'Sullivan B, Catton C, Bell R S, Fornasier V L
Department of Radiation Oncology, Princess Margaret Hospital, Toronto, Canada.
Int J Radiat Oncol Biol Phys. 1991 Nov;21(6):1595-9. doi: 10.1016/0360-3016(91)90337-4.
For the treatment of soft tissue sarcomas it has frequently been staged but not quantitatively demonstrated, that the volume irradiated is smaller when irradiation is given preoperatively as compared to postoperatively. In this study the field size used for preoperative irradiation was compared with that necessary in the same patient had the radiation been given postoperatively. Twenty-six patients with soft tissue sarcomas of the extremity, groin, and shoulder girdle who had received preoperative irradiation were resimulated following surgery to determine the size of the postoperative field. The simulation was performed by a physician not involved in the preoperative treatment planning. Preoperatively a radial margin of 5 cm around the tumor was used for low and intermediate grade and 7 cm for high grade sarcomas. Postoperatively the same margins were used but around the surgical field. Twelve patients underwent a wide resection and 14 patients a resection followed by vascularized tissue transfer to the surgical bed. The median follow-up was 22 months (range 13-46). No local recurrences and two cases of distant metastasis were observed. Independently of surgical procedure and tumor grade, the size of the preoperative radiation field and number of joints included in the field were significantly smaller than that of postoperative radiation (p less than 0.001). In two patients preoperatively and four patients postoperatively, the radiation field involved the whole circumference of the limb. Provided that equivalent radiation time-dose-fraction parameters are used and that the complication rate is proportional to the radiation field size, late complications may be less after preoperative irradiation than after post-operative irradiation.
对于软组织肉瘤的治疗，虽然经常进行分期，但术前放疗与术后放疗相比，照射体积较小这一点尚未得到定量证实。在本研究中，将术前放疗所用的照射野大小与同一患者若接受术后放疗所需的照射野大小进行了比较。对26例接受术前放疗的四肢、腹股沟和肩胛带软组织肉瘤患者在术后进行了重新模拟，以确定术后照射野的大小。模拟由未参与术前治疗计划的医生进行。术前，低级别和中级别的肉瘤在肿瘤周围采用5 cm的径向边界，高级别肉瘤采用7 cm。术后在手术野周围采用相同的边界。12例患者接受了广泛切除，14例患者切除后进行了带血管组织转移至手术床。中位随访时间为22个月（范围13 - 46个月）。未观察到局部复发，有2例远处转移。与手术方式和肿瘤级别无关，术前放疗野的大小和野内包含的关节数量均显著小于术后放疗（p < 0.001）。术前有2例患者、术后有4例患者的放疗野累及肢体全周。如果使用等效的放疗时间 - 剂量 - 分割参数，且并发症发生率与放疗野大小成正比，那么术前放疗后的晚期并发症可能比术后放疗少。
