Outcomes of Neoadjuvant Chemoradiation Therapy for Locally Advanced Rectal Cancer: The Effect of Preoperative Chemoradiotherapy Followed by Additional Chemotherapy on Advanced Rectal Cancer

Background. In most cases of locally advanced rectal cancer, neoadjuvant chemoradiation therapy (CCRT) reduces tumor size and results in histopathologic downstaging. This results in improved long-term oncologic outcomes. Pathologic complete remission ranges from 8% to 19%, depending on the regimen and dose of chemotherapy and/or radiotherapy.Patients and Methods. We retrospectively reviewed the medical records of patients diagnosed with rectal adenocarcinoma who were receiving neoadjuvant CCRT and curative surgery in our hospital from January 2005 to December 2008. The regimen of neoadjuvant CCRT included a high weekly dose of 5-fluorouracil (5-FU) (2000 mg/m^2 5-FU for 24 hours plus 500 mg/m^2 leucovorin intravenously for 2 hours), concurrent with radiotherapy at a total dose of 4500 cGy. Chemotherapy was continued until 2 weeks before surgery, and patient underwent surgery within 6 to 8 weeks of completing CCRT.Result. In total, 61 patients, including 31 males and 30 females with an average age of 67.6 years were examined. Most patients had a good response to neoadjuvant CCRT and experienced tumor downstaging. Only 15 patients did not experience a change in disease stage after neoadjuvant CCRT. The non-responding group had a significantly lower curative resection rate (R0 resection rate) (p=0.04) and higher local recurrence rate (p=0.03) than the responding group.Conclusion. Neoadjuvant CCRT for locally advanced rectal cancer can result in tumor downstaging and shrinkage. The regimen, dosage, and duration of chemotherapy were variable. Our results demonstrate that the administration of chemotherapy until 2 weeks before curative surgery was safe, however, the effect on the pathological complete response rate requires additional study.