SCOT: short course oncology therapy — a comparison of 12 and 24 weeks of adjuvant chemotherapy in colorectal cancer

Colorectal cancer is one of the leading causes of cancer mortality worldwide. Many large randomized clinical trials have established a benefit for adjuvant 5-fluorouracil (5-FU) based chemotherapy in this disease. More recently the NSABP C-07 and MOSAIC trials have shown a benefit for the addition of oxaliplatin to adjuvant treatment, but this has also led to increased toxicity (Kuebler JP, Wieand HS, O'Connell MJ, et al. J Clin Oncol. 2007;25:2198-2204; Andre T, Boni C, Mounedji-Boudiaf L, et al. N Engl J Med. 2004;350:2343-2351.). This is an important issue for a population of patients in whom a proportion will be cured of their disease by surgery alone. Currently the standard treatment duration for adjuvant chemotherapy for colorectal cancer is 24 weeks. One way to address the important issues of increasing toxicity and cost would be to shorten treatment. The SCOT study aims to ascertain whether 12 weeks of treatment is as efficacious as 24 weeks. Methods: SCOT is a randomised non-inferiority study comparing 12 and 24 weeks of adjuvant treatment. The primary end-point is disease free survival (DFS) and the study is designed to exclude a maximum 2.5% fall in 3-year DFS on the 12 week arm with 90% power at the 2.5% 1-sided level of statistical significance. This requires 9,500 patients recruited over 5 years with minimum subsequent follow-up of 2 years. Secondary end-points are cost-effectiveness, survival, quality of life and toxicity. Patients with fully resected fully resected stage III/high risk stage II colorectal cancer are eligible for SCOT. Participating sites can select either oxaliplatin/capecitabine (q3/52) or oxaliplatin/5FU (q2/52) for each individual patient prior to randomization. Results: UK enrollment began in May 2008 and currently 1,917 patients are on study. Australasia is participating, shortly to be joined by Denmark and Spain. Conclusions: The study will contribute to the IDEA collaboration (International Duration Evaluation of Adjuvant Chemotherapy – secretariat Daniel Sargent/Axel Grothey) which is a planned prospective analysis of several studies (currently from USA, France and Italy) looking at the question of treatment duration in stage III colon cancer