Evaluation of a sequential 5-FU and hydroxyurea combination in advanced bowel cancer

Twenty-nine patients (two with small bowel cancer and 27 with colorectal cancer) were treated with a sequential 5-FU-hydroxyurea combination following the suggestion of schedule-dependent synergism in experimental systems. No enhanced toxicity was observed, but the response rate was only 4%. Seven additional patients manifested greater than or equal to 50% declines in CEA, but caution must be used in interpreting such changes as antitumor activity.