Phase III Randomized Study of Adjuvant Chemotherapy With L-leucovorin and Fluorouracil Versus Observation in Patients With Resected Colorectal Cancer. Note: The information about this trial has not been updated by the sponsor/principal investigator/lead organization. cannot verify the accuracy of the information.

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First Published: 5/1/2000     Last Modified: 5/13/2008  

Alternate Title

Leucovorin and Fluorouracil Compared With Observation in Treating Patients With Colorectal Cancer That Has Been Surgically Removed. Note: The information about this trial has not been updated by the sponsor/principal investigator/lead organization. cannot verify the accuracy of the information.

Basic Trial Information

PhaseTypeStatusAgeSponsorProtocol IDs
Phase IIITreatmentClosed18 and overOtherNCRI-QUASAR1
EU-99053, UKCCCR-QUASAR1, NCT00005586, ISRCTN82375386


  1. Compare all-cause mortality in patients with resected colorectal cancer treated with adjuvant chemotherapy with L-leucovorin and fluorouracil vs observation.
  2. Compare the recurrence rates in patients treated with this regimen vs observation.
  3. Compare the effectiveness of a monthly 5-day schedule vs a once weekly schedule of L-leucovorin and fluorouracil in this patient population.

Entry Criteria

Disease Characteristics:

  • Completely resected stage II or III colorectal cancer
  • No distant metastases
  • No positive resection margins
  • No positive peritoneal washings

Prior/Concurrent Therapy:

    Biologic therapy:

  • Not specified


  • No concurrent chemotherapy in observation only arm

    Endocrine therapy:

  • Not specified


  • Concurrent radiotherapy allowed in adjuvant chemotherapy arm provided chemotherapy administered on the once weekly schedule


  • See Disease Characteristics

Patient Characteristics:


  • 18 and over

    Performance status:

  • Not specified

    Life expectancy:

  • Not specified


  • Not specified


  • Not specified


  • Not specified


  • No clear definite indication for, or contraindication against, systemic chemotherapy with L-leucovorin and fluorouracil

Expected Enrollment


A total of 2,500 patients (1,250 per arm) will be accrued for this study.


Primary Outcome(s)

All-cause mortality

Secondary Outcome(s)

Death from colorectal cancer
Disease recurrence


This is a randomized, open-label, multicenter study. Patients are randomized to receive adjuvant chemotherapy (arm I) or undergo observation only (arm II).

  • Arm I: Within 12 weeks of surgery, patients receive L-leucovorin IV followed by fluorouracil IV on days 1-5 every 4 weeks for 6 courses. Alternatively, patients may receive L-leucovorin IV followed by fluorouracil IV on day 1 weekly for 30 weeks.
  • Arm II: Patients undergo observation.

Patients are followed annually.

Published Results

Quasar Collaborative Group, Gray R, Barnwell J, et al.: Adjuvant chemotherapy versus observation in patients with colorectal cancer: a randomised study. Lancet 370 (9604): 2020-9, 2007.[PUBMED Abstract]

Trial Contact Information

Trial Lead Organizations

National Cancer Research Institute

Norman Williams, MD, Protocol chair
Ph: 44-20-7377-7079

Registry Information

Official TitleA UKCCCR Study of Adjuvant Chemotherapy for Colorectal Cancer
Trial Start Date1997-10-26
Registered in ClinicalTrials.govNCT00005586
Date Submitted to PDQ2000-01-13
Information Last Verified2007-03-26

Note: The purpose of most clinical trials listed in this database is to test new cancer treatments, or new methods of diagnosing, screening, or preventing cancer. Because all potentially harmful side effects are not known before a trial is conducted, dose and schedule modifications may be required for participants if they develop side effects from the treatment or test. The therapy or test described in this clinical trial is intended for use by clinical oncologists in carefully structured settings, and may not prove to be more effective than standard treatment. A responsible investigator associated with this clinical trial should be consulted before using this protocol.