Study: 3-Week Irinotecan Regimen May Benefit Advanced Colorectal Cancer Patients

Advanced colorectal cancer patients whose disease is progressing despite treatment with the chemotherapy drug fluorouracil (5-FU) may be better off also taking the newer chemotherapy drug irinotecan once every three weeks instead of once weekly, according to researchers.

In a multicenter phase III trial, patients were randomly assigned to take either 125 mg of irinotecan weekly or 350 mg once every three weeks. Randomized trials have demonstrated significant survival advantages for fluorouracil (FU)-refractory colorectal cancer patients receiving irinotecan.

With median follow-up of 15.8 months, Dr. Charles S. Fuchs of the Dana-Farber Cancer Institute reported "there was no significant difference in 1-year survival, median survival, or median time to progression.

But only about 19 percent of those treated once weekly suffered the side effect of severe diarrhea, compared to 36 percent of those patients who took irinotecan weekly, he reported in the Journal of Clinical Oncology.

And treatment-related mortality occurred in 5.3 percent of the patients receiving irinotecan weekly compared to 1.6 percent of the patients given irinotecan once every three weeks, he added.

"Irinotecan schedules of weekly and of once every 3 weeks demonstrated similar efficacy and quality of life in patients with FU-refractory, metastatic colorectal cancer," the researchers concluded. "But the regimen of once every 3 weeks was associated with a significantly lower incidence of severe diarrhea."

Other Sources: Journal of Clinical Oncology