Ramsey Shelileah, Tepper Joel E
Department of Radiation Oncology, University of North Carolina School of Medicine, UNC/Lineberger Clinical Cancer Center, Chapel Hill, NC 27599-7512, USA.
Cancer J. 2007 May-Jun;13(3):204-9. doi: 10.1097/PPO.0b013e318074def2.
Adjuvant therapy for rectal cancer has undergone significant modifications over the past 30 years, including the addition of radiation therapy, significant improvements in surgical technique, and the administration of systemic therapy. Historically, curative resection commonly required an abdominoperineal resection and permanent colostomy. Adjuvant radiation therapy not only improved local control and overall survival, but allowed the opportunity for sphincter-preserving resections in patients with adequate sphincter function and tumors located approximately 1-2 cm from the dentate line. Local recurrence, a primary mode of failure in rectal cancer, has been improved by the development of the total mesorectal excision, with en-bloc resection of the rectum and its lymphovascular mesentery, the mesorectum. Removing micrometastatic disease within the mesorectum has also enhanced sphincter preservation without compromising local control or survival. Locoregional recurrence has remained a significant issue for patients with locally advanced disease (node positive or high T stage). Multiple studies have shown that the addition of chemotherapy further improves outcomes versus surgery alone or combined surgery and radiation, due both to the radiosensitizing properties of certain systemic agents as well as to the direct cytotoxic effect of the chemotherapy on micrometastatic disease. Adjuvant concurrent chemoirradiation in locally advanced rectal cancer confers a significant improvement in local control and overall survival compared with either modality alone. The future direction of treatment for rectal cancer will certainly consist of improved imaging and other diagnostic techniques to determine more accurately the need for adjuvant therapy. Multimodality therapy with radiotherapy administered in combination with systemic and biologic agents as radiation sensitizers is currently under investigation and may allow for improved local control and perhaps allow for minimizing the extent of surgery in selected situations.
在过去30年里，直肠癌的辅助治疗发生了重大变革，包括增加放射治疗、手术技术显著改进以及全身治疗的应用。从历史上看，根治性切除通常需要腹会阴联合切除术和永久性结肠造口术。辅助放射治疗不仅提高了局部控制率和总生存率，还为括约肌功能良好且肿瘤距齿状线约1-2厘米的患者提供了保留括约肌切除术的机会。局部复发是直肠癌的主要失败模式之一，全直肠系膜切除术的发展改善了这一情况，该手术整块切除直肠及其淋巴血管系膜即直肠系膜。清除直肠系膜内的微转移病灶也提高了括约肌保留率，同时不影响局部控制或生存率。对于局部晚期疾病（淋巴结阳性或高T分期）患者，局部区域复发仍然是一个重大问题。多项研究表明，与单纯手术或手术联合放疗相比，添加化疗可进一步改善预后，这既归因于某些全身药物的放射增敏特性，也归因于化疗对微转移病灶的直接细胞毒性作用。与单独使用任何一种治疗方式相比，局部晚期直肠癌的辅助同步放化疗在局部控制和总生存率方面都有显著改善。直肠癌治疗的未来方向肯定包括改进成像和其他诊断技术，以更准确地确定辅助治疗的必要性。目前正在研究将放疗与全身和生物制剂联合作为放射增敏剂的多模式治疗，这可能会改善局部控制，或许还能在某些情况下尽量减少手术范围。
