The role of radiation therapy in the adjuvant treatment of rectal cancer

There have been several advances in the treatment of rectal cancer in the past 20 years. The recognition that surgical therapy alone leads to a local failure rate of 15 to 50% in stages II and III has led to the use of adjuvant radiation therapy. Multiple prospective, randomized trials conducted by multi-institutional cooperative groups have resulted in the use of adjuvant combined modality therapy using radiation therapy and 5-fluorouracil chemotherapy. Some of the trials fine-tuned the sequencing and dose of radiation and chemotherapy to maximize efficacy and minimize toxicity. The advent of accurate endorectal ultrasound and MRI staging has allowed the use of preoperative therapy without the unnecessary treatment of patients with early stage. This has resulted in greater sphincter preservation and fewer complications. The optimal sequencing of adjuvant therapy has yet to be found.