In the Mayo Clinic/NCCTG 86-47-51 study, patients with stage II or III rectal cancer were treated with adjuvant 5-fluorouracil-based chemotherapy and radiation therapy (50.4 Gy) rand omized to receive either PVI (225 mg/m2 continuously throughout radiation) or bolus 5-fluorouracil (500 mg/m2 on the first 3, and last 3 days of radiation). What difference in disease outcomes was seen?