Glimelius Bengt L G
Department of Oncology, Radiology and Clinical Immunology, Section of Oncology, University Hospital, SE-751 85 Uppsala, Sweden.
Clin Colorectal Cancer. 2002 Aug;2(2):82-92. doi: 10.3816/CCC.2002.n.014.
Radiotherapy has an important role to play when used in addition to surgery in primary and recurrent rectal cancer. In primary resectable rectal cancer, a large number of randomized trials have shown that preoperative radiotherapy can slightly improve survival and can decrease local recurrence rates by more than half. Postoperative radiotherapy may also decrease the risk of local failure although with less efficacy. A preoperative schedule of 5 Gy/day for 5 out of 7 days is a convenient and low-toxic treatment, provided it is not given with 2 beams to large volumes, and it appears to be at least as effective as postoperative radiochemotherapy, generally meaning 6 months of therapy with 5 weeks of radiation. The schedule of 5 Gy/day for 5 days also reduces local recurrences with total mesorectal excision. It is unlikely that preoperative radiochemotherapy will substantially increase the chances of a sphincter-preserving procedure in a low-lying rectal cancer and that the long-term function will be adequate even if this is believed by many. In primary nonresectable or locally recurrent rectal cancer, preoperative radiotherapy may downsize or downstage the tumor so that it can be resected. Scientific support that radiochemotherapy is more efficient than radiotherapy alone in this situation is weak.
在原发性和复发性直肠癌中，放疗与手术联合使用时可发挥重要作用。在原发性可切除直肠癌中，大量随机试验表明，术前放疗可略微提高生存率，并可将局部复发率降低一半以上。术后放疗也可能降低局部复发风险，尽管疗效较低。每天5Gy、每周照射5天共7周的术前放疗方案是一种方便且毒性较低的治疗方法，前提是不使用两束射线照射大体积区域，而且它似乎至少与术后放化疗一样有效，通常是指为期6个月、包含5周放疗的治疗。每天5Gy、共5天的放疗方案也可减少全直肠系膜切除术后的局部复发。术前放化疗不太可能大幅增加低位直肠癌保留括约肌手术的机会，而且即使许多人认为长期功能会足够，但实际情况未必如此。在原发性不可切除或局部复发性直肠癌中，术前放疗可缩小肿瘤大小或降低肿瘤分期，从而使其能够被切除。在这种情况下，放化疗比单纯放疗更有效的科学依据并不充分。
