Chief Investigator: 
Tim Iveson

In collaboration with the CRUK Clinical Trials Unit, Glasgow

Short Course Oncology Treatment - A study of adjuvant chemotherapy in colorectal cancer by the  CACTUS and OCTO groups.

The primary aim of the trial is to assess the difference in disease-free survival for patients receiving either 12 weeks or 24 weeks of chemotherapy for colorectal cancer.

Study Status

Closed: Total recruitment: 6144 patients (30 Nov 2013)
Number of active sites: 243 (01 Nov 2013)

Study Schema

Scot study arms

Inclusion Criteria

  • Fully resected stage III colorectal cancer*


  • Fully resected high-risk stage II colorectal cancer* (defined as having one or more of the following - T4 disease, tumour obstruction and/or perforation of the primary tumour during the pre-operative period, inadequate nodal harvest as indicated by <10 nodes examined, poorly differentiated histology, perineural invasion, peritoneal involvement or extramural venous/lymphatic invasion).
    See tumour staging guideline in Appendix 11 for clarification on SCOT eligibility.
  • No evidence of residual or metastatic disease.
  • Ideally patients should be randomised within 11 weeks of surgery and treatment should start within 2 weeks of randomisation. However as long as the surgery to cycle 1 treatment start date is ≤ 13 weeks the patient will be considered eligible.
  • WHO PS = 0 or 1.
  • Age >18 years.
  • Life expectancy >5 years with reference to non-cancer related diseases.
  • Written informed consent.
  • CEA ≤ 1.2 X ULN (as per local values) (see Schedule of Assessments section 4.1 Baseline Evaluations for details).
  • Patients with rectal cancer will be eligible unless they have had pre-operative combined chemotherapy and radiotherapy, or are scheduled for post-operative combined chemotherapy and radiotherapy.
  • All rectal cancer patients included in the trial must have had TME type surgery with negative (R0) resection margins (R0 defined as greater than 1mm clearance).
    * All patients must have negative (R0) resection margins defined as greater than 1mm clearance.

Exclusion Criteria

  • Previous chemotherapy*.
  • Previous long course chemoradiotherapy (pre-operative short course radiotherapy is allowed).
  • Moderate/severe renal impairment (GFR/Creatinine Clearance <30 ml/min), as calculated by the Cockcroft-Gault equation (Appendix 2).
  • Absolute neutrophil count<1.5x109/L.
  • Platelet count <100x109/L.
  • Haemoglobin <9 g/dL.
  • Aspartate aminotransferase/Alanine aminotransferase >2.5 x upper limit of normal (at least one of AST or ALT must be performed).
  • Clinically significant cardiovascular disease. [i.e. active; or <12 months since e.g. cerebrovascular accident, myocardial infarction, unstable angina, New York Heart Association (NYHA – Appendix 4) grade II or greater congestive heart failure, serious cardiac arrhythmia requiring medication, uncontrolled hypertension].
  • Pregnancy/lactation or of child bearing potential and not using, or willing to use medically approved contraception. (Postmenopausal women must have been amenorrheic for at least 12 months to be considered of non-childbearing potential.)
  • Previous malignancy other than adequately treated in situ carcinoma of the uterine cervix or basal or squamous cell carcinoma of the skin, unless there has been a disease-free interval of at least 5 years.
  • Known or suspected dihydropyrimidine dehydrogenase (DPD) deficiency.

* No previous chemotherapy except chemotherapy administered with curative intent completed more than 5 years ago and from which there are no residual complications.

Study Objectives


  • 3 year disease free survival


  • Overall Survival
  • Cost-effectiveness
  • Toxicity
  • Quality of Life

Key Dates

Planned recruitment start: March 2008
Accrual completion: end Nov 2013

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