1. ¹Medical Department, Division of Oncology, Graz Medical School, A-8036 Graz, Austria
2. ²St Veit Hospital, A-9300 St Veit/Glan, Austria
3. ³Department of Surgery, Vienna Medical School, A-1090 Vienna, Austria
4. ⁴First Medical Department, Division of Oncology, Vienna Medical School, A-1090 Vienna, Austria
5. ⁵Third Medical Department of the Private Medical Paracelsus University Salzburg, A-5020 Salzburg, Austria
6. ⁶Department of Surgery, Graz Medical School, A-8036 Graz, Austria
7. ⁷Department of Surgery, Oberpullendorf Hospital, A-7350 Oberpullendorf, Austria
8. ⁸Department of Surgery, Innsbruck Medical School, A-6020 Innsbruck, Austria
9. ⁹Core Unit for Medical Statistics and Informatics, Vienna Medical School, A-1090 Vienna, Austria

Correspondence: Dr W Schippinger, Klinische Abteilung für Onkologie, Medizinische Universitätsklinik Graz, Auenbruggerplatz 15, A-8036 Graz, Austria. E-mail: walter.schippinger@klinikum-graz.at

Received 29 November 2004; Revised 3 March 2005; Accepted 4 March 2005; Published online 26 April 2005.

Abstract

The purpose of this trial was to examine the efficacy of the addition of levamisole (LEV) or interferon alfa (IFN) to an adjuvant chemotherapy with 5-fluorouracil (5-FU) in patients with stage III colon cancer. According to a 2 2 factorial study design, 598 patients were randomly assigned to one of four adjuvant treatment arms. Patients in arm one received 5-FU weekly for 1 year, patients in arm two 5-FU plus LEV, in arm three 5-FU plus IFN and patients in arm four 5-FU, LEV and IFN. The relative risk of relapse and the relative risk of death were significantly higher for patients treated with LEV compared with those without LEV treatment (HR 1.452, 95% CI 1.135–1.856, P=0.0028; HR 1.506, 95% CI 1.150–1.973, P=0.0027, respectively). No significant impact on survival was observed for therapy with IFN in the univariate analysis. The addition of LEV to adjuvant 5-FU significantly worsened the prognosis of patients with stage III colon cancer. Interferon alfa had no significant influence on survival when combined with adjuvant 5-FU, but increased the toxicity of therapy substantially.