SummaryThe records of 110 patients with recurrent and metastatic cancer of the colon and rectum are reviewed. Most patients had evidence of recurrence within two years of initial treatment. The abdomen was the most common site of recurrence. The “pelvic syndrome,” an expression of local recurrence in the lower abdomen, was the most frequent clinical indication for treatment.The effect of radiation therapy was assessed by assigning definite criteria of success or failure. Treatment prescriptions were expressed in Nominal Single Dose Equivalent (NSDE) units, relating the total dose given to the number of fractions in which it was given and the time of the whole treatment course. There was a significant correlation between the effective dose, expressed in NSDE Rets, and improvement noted. It is concluded that a moderately aggressive course of radiation therapy often ameliorates symptoms and improves the quality of survival of these patients.