Ⅱ/Ⅲ期直肠癌术后辅助放疗

Postoperative radiotherapy for stage Ⅱ/Ⅲ rectal cancer

背景与目的：直肠癌是常见的肿瘤，手术是其主要的治疗方法，辅助放疗能提高Ⅱ／Ⅲ期直肠癌的局控率。但放疗剂量的增加是否能进一步提高局控率并对生存率有所改善尚不明确。本研究观察Ⅱ／Ⅲ期直肠癌根治术后辅助放疗的疗效，探讨是否存在肿瘤局控与剂量效应关系。方法：回顾性分析1993年7月至2001年12月间Ⅱ／Ⅲ期直肠癌接受术后放射治疗的病例74例。Ⅱ期32例，Ⅲ期42例。放射治疗常规分割1．8～2．0Gy／次，总剂量40—70Gy，中位剂量54Gy。全组中有62例患者接受了以氟尿嘧啶为基础的辅助化疗1～10疗程。应用SPSS11．5统计软件，Kaplan—Meier法进行生存分析。结果：全组中位随访时间44．6个月（7．3～119．9个月），全组5年生存率和无瘤生存率分别为58％和60％。局部复发14例，远处转移17例。将全组按剂量分为≤50Gy，51-60Gy，〉60Gy3组，5年局控率分别为92％，71％和87％（P=0．9194）；5年生存率分别为68％，62％和53％（P=0．4194），3组间未显示有统计学差异。共有5例因并发症而死亡，接受的放疗剂量均大于50Gy。结论：Ⅱ、Ⅲ直肠癌根治术后辅助放疗未显示有剂量效应，剂量增加未提高局控率和生存率。常规分割放疔时以50Gy为宜，过高的剂量有增加并发症发牛的危险。

Background and Purpose： Rectal cancer is a common malignancy in China. Surgery is the first option for the treatment. Adjuvant radiotherapy can improve local control after surgery for stage Ⅱ/Ⅲ patients. However, whether escalation of radiation dose can further improve the local control and even the survival are unknown. This study analyzed the efficacy of adjuvant radiotherapy and its dose-response relationship. Methods： Seventy-four patients with stage Ⅱ and stage m rectal cancer who received postoperative adjuvant radiotherapy were retrospectively analyzed. All the patients received conventional irradiation with 1.8-2.0Gy per fraction daily. The total dose was 40-70Gy （ median： 54Gy）. Sixty-two patients received 1-10 cycles of sequential or concurrent 5-FU based chemotherapy. SPSS 11. 5 is used for statistics, the survival rate is calculated by the actuarial method of Kaplan and Meier. Results： The median follow-up was 44.6months（ ranges 7.3- 119.9 mo）. The 5-year overall survival rate and disease-free survival rate are 58% and 60% respectively. Fourteen patients had local recurrence, and 17 patients experienced distant metastasis. All patients were subdivided into three dose groups with the dosage of ≤50 Gy, 50-60 Gy and 〉60 Gy. The 5-year local control rates are 92%, 71% and 87% respectively （P = 0. 9194）, and 5-year overall survival rate are 68%, 62% and 53% respectively（P = 0. 4194）. There is no significant difference of overall survival and local control rate between these three dose groups. Five patients with dose of more than 50Gy died of late toxicities. Conclusions： Adjuvant radiotherapy for Stage ⅡandⅢ patients with rectal cancer dose not show dose response. There is no improvement of local control and survival due to the escalation of dose. The dose of conventional radiotherapy is better at less than 50Gy. Overdosage may lead to severe toxicitics.