Gérard J P, Rocher F P, Fric D, Coquard R, Romestaing P
Service de Radiothérapie, Centre Hospitalier Lyon Sud, Pierre Bénite.
J Chir (Paris). 1993 May;130(5):218-25.
The response of adenocarcinoma of rectum to radiotherapy is dependent on the use of irradiation techniques that ensure a sufficient dose be applied to the tumor without exceeding tolerance limits of pelvic tissues. This has been clearly demonstrated by results of contact radiotherapy over the last 30 years or so. Doses of about 100 Gy provide local control in 90% of cases and a 5 year survival rate of 80% in patients with highly selected tumors. For several years now, contact radiotherapy has been associated with external irradiation and iridium therapy with resulting sterilization of T2 and even T3 or N1 tumors in inoperable cases. Endorectal ultrasound imaging is essential for selecting those patients requiring radiotherapy alone and for evaluating the results, but in more than 90% of patients, surgery remains basic treatment for cancer of rectum. The incidence of local recurrence, very difficult to treat, is non negligible, however, but combining radiotherapy with surgery has been shown to reduce the rate of by 50%. Opinions differ on the relative efficacy of pre- or post-operative radiotherapy, but tolerance to this treatment is good in both cases if the technique used limits radiation to the posterior pelvis. Results of a Swedish randomized trial demonstrated greater efficacy for pre-operative radiotherapy for controlling local spread. Meta analysis showed that irradiation produces a definite gain in local control with a resulting gain in survival of about 5 to 10%. In the USA, chemotherapy based on 5 FU combined with post-operative radiotherapy was equally favorable in terms of survival. Pre-operative radiotherapy may also increase the chance of conservation of the sphincter. Although numerous points concerning chronology and mode of treatment remain open to discussion, a combination of radiotherapy and surgery now appears as standard treatment for rectal cancer.
直肠癌对放疗的反应取决于所采用的照射技术，该技术要确保在不超过盆腔组织耐受限度的情况下，给予肿瘤足够的剂量。过去30年左右的接触放疗结果已清楚地证明了这一点。约100戈瑞的剂量可使90%的病例实现局部控制，对于经过高度筛选的肿瘤患者，5年生存率为80%。多年来，接触放疗一直与外照射及铱治疗联合使用，在无法手术的病例中可使T2甚至T3或N1期肿瘤灭活。直肠内超声成像对于选择仅需放疗的患者以及评估疗效至关重要，但在90%以上的患者中，手术仍是直肠癌的基本治疗方法。局部复发的发生率虽很难治疗，但却不容忽视，不过，放疗与手术联合已被证明可使复发率降低50%。对于术前或术后放疗的相对疗效，意见不一，但如果所采用的技术将辐射限制在盆腔后部，两种情况下对这种治疗的耐受性都较好。一项瑞典随机试验的结果表明，术前放疗在控制局部扩散方面疗效更佳。荟萃分析显示，放疗在局部控制方面有明确获益，生存率因此提高约5%至10%。在美国，基于5-氟尿嘧啶的化疗联合术后放疗在生存率方面同样良好。术前放疗还可能增加保留括约肌的机会。尽管关于治疗时间和方式的许多问题仍有待讨论，但放疗与手术联合目前似乎已成为直肠癌的标准治疗方法。
