3-month versus 6-month adjuvant chemotherapy for patients with high-risk stage II and III colorectal cancer: 3-year follow-up of the SCOT non-inferiority RCT.

BACKGROUND

Oxaliplatin and fluoropyrimidine chemotherapy administered over 6 months is the standard adjuvant regimen for patients with high-risk stage II or III colorectal cancer. However, the regimen is associated with cumulative toxicity, characterised by chronic and often irreversible neuropathy.

OBJECTIVES

To assess the efficacy of 3-month versus 6-month adjuvant chemotherapy for colorectal cancer and to compare the toxicity, health-related quality of life and cost-effectiveness of the durations.

DESIGN

An international, randomised, open-label, non-inferiority, Phase III, parallel-group trial.

SETTING

A total of 244 oncology clinics from six countries: UK (England, Scotland, Wales and Northern Ireland), Denmark, Spain, Sweden, Australia and New Zealand.

PARTICIPANTS

Adults aged ≥ 18 years who had undergone curative resection for high-risk stage II or III adenocarcinoma of the colon or rectum.

INTERVENTIONS

The adjuvant treatment regimen was either oxaliplatin and 5-fluorouracil or oxaliplatin and capecitabine, randomised to be administered over 3 or 6 months.

MAIN OUTCOME MEASURES

The primary outcome was disease-free survival. Overall survival, adverse events, neuropathy and health-related quality of life were also assessed. The main cost categories were chemotherapy treatment and hospitalisation. Cost-effectiveness was assessed through incremental cost comparisons and quality-adjusted life-year gains between the options and was reported as net monetary benefit using a willingness-to-pay threshold of £30,000 per quality-adjusted life-year per patient.

RESULTS

Recruitment is closed. In total, 6088 patients were randomised (3044 per group) between 27 March 2008 and 29 November 2013, with 6065 included in the intention-to-treat analyses (3-month analysis,

CONCLUSIONS

The study achieved its primary end point, showing that 3-month oxaliplatin-containing adjuvant chemotherapy is non-inferior to 6 months of the same regimen; 3-month treatment showed a better safety profile and cost less. For future work, further follow-up will refine long-term estimates of the duration effect on disease-free survival and overall survival. The health economic analysis will be updated to include long-term extrapolation for subgroups. We expect these analyses to be available in 2019-20. The Short Course Oncology Therapy (SCOT) study translational samples may allow the identification of patients who would benefit from longer treatment based on the molecular characteristics of their disease.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN59757862 and EudraCT 2007-003957-10.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in

Patients diagnosed with bowel cancer are likely to have surgery to remove the tumour. Patients diagnosed with a more advanced stage of the disease are then likely to be offered what is known as adjuvant chemotherapy – chemotherapy to kill any cancer cells that have already spread but cannot be seen. Adjuvant chemotherapy is usually given over 6 months using two medicines known as oxaliplatin and fluoropyrimidine. This chemotherapy has side effects of diarrhoea, nausea and vomiting, and it reduces the numbers of cells in the blood. It can also damage nerves, which causes discomfort, numbness and tingling; in some cases, this can go on for years. These side effects are more likely to develop with longer treatment. This study looked at whether or not shortening the time over which patients were given oxaliplatin and fluoropyrimidine chemotherapy reduced its effectiveness. In this large study of over 6000 patients, half of the patients were allocated by chance to be treated for 3 months and the other half to be treated for 6 months. Reducing the time that patients had chemotherapy from 6 months to 3 months did not make the treatment less effective. When patients treated with chemotherapy over 3 months were compared with those treated over 6 months, 77% of patients in both groups were well with no detectable disease 3 years after surgery. Patients were less likely to get side effects with 3-month chemotherapy. In particular, the chance of persistent long-term nerve damage was lower, resulting in patients with 3-month chemotherapy having better health-related quality of life. Overall, the study showed that 3-month adjuvant chemotherapy for patients with bowel cancer is as effective as 6-month adjuvant chemotherapy and causes fewer side effects.

Déclaration de conflit d'intérêts

Timothy Iveson reports honoraria from Amgen Inc. (Thousand Oaks, CA, USA), Bayer AG (Leverkusen, Germany), Bristol-Myers Squibb (New York, NY, USA), Celgene Corporation (Summit, NJ, USA), Pierre-Fabre (Paris, France), Roche (Roche Holding AG, Basel, Switzerland) and Servier (Laboratories Servier, Suresnes, France). Kathleen A Boyd reports grants from the Medical Research Council during the conduct of the study. Mark P Saunders reports personal fees from Servier, Amgen, Merck (Merck and Co., Kenilworth, New Jersey, USA), Eisai (Eisai Co., Ltd., Tokyo, Japan) and Roche outside the submitted work. Jim Cassidy reports grants from the Medical Research Council during the conduct of the study and is currently an employee of Celgene Corporation. Josep Tabernero reports personal fees from Array Biopharma (Boulder, CO, USA), AstraZeneca (Cambridge, UK), Bayer AG (Leverkusen, Germany), BeiGene (Beijing, China), Boehringer Ingelheim (Ingelheim am Rhein, Germany), Chugai (Chugai Pharmaceutical Co., Tokyo, Japan), Genentech, Inc. (South San Francisco, CA, USA), Genmab A/S (Copenhagen, Denmark), Halozyme (Halozyme Therapeutics, San Diego, CA, USA), Imugene Limited (Sydney, NSW, Australia), Inflection Biosciences Limited (Blackrock, Dublin), Ipsen (Paris, France), Kura Oncology (San Diego, CA, USA), Eli Lilly and Company (Indianapolis, IN, USA), Merck, Menarini (The Menarini Group, Florence, Italy), Merck Serono (Rockland, MA, USA), Merrimack Pharmaceuticals (MA, USA), Merus (Utrecht, the Netherlands), Molecular Partners (Molecular Partners AG, Zurich, Switzerland), Novartis (Novartis International AG, Basel, Switzerland), Peptomyc, Pfizer Inc. (New York, NY, USA), Pharmacyclics (Pharmacyclics LLC, Sunnyvale, CA, USA), ProteoDesign SL (Barcelona, Spain), Rafael Pharmaceuticals (Stony Brook, NY, USA), F. Hoffmann-La Roche Ltd, Sanofi (Sanofi S. A., Paris, France), Seattle Genetics (Bothwell, WA, USA), Servier, Symphogen (Symphogen A/S, Ballerup, Denmark), Taiho Pharmaceutical (Tokyo, Japan), VCN Biosciences (Barcelona, Spain), Biocartis (Biocartis Group, Mechelen, Belgium), Foundation Medicine (Cambridge, MA, USA), HalioDX (Marseille, France), SAS Pharmaceuticals (Delhi, India) and Roche Diagnostics outside the submitted work. Bengt Glimelius reports support from PledPharma AB for being on advisory boards. Sherif Raouf reports grants, personal fees and non-financial support from Roche, grants and personal fees from Amgen, and grants and personal fees from Merck outside the submitted work. David Farrugia reports that he received honoraria for speaking in educational events and support for meeting attendance from Bristol-Myers Squibb, Novartis, Ipsen, Amgen, AstraZeneca and Merck. David Cunningham reports grants from 4SC (4SC AG, Planegg, Germany), AstraZeneca, Bayer, Amgen, Celgene, Clovis Oncology (Boulder, CO, USA), Eli Lilly and Company, Janssen Pharmaceuticals (Beerse, Belgium), MedImmune (Gaithersburg, MD, USA), Merck, Merrimack and Sanofi, outside the submitted work. Tamish Hickish reports grants from Pfizer, Roche, Pierre Fabre (Paris, France) and personal fees from Eli Lilly and Company during the conduct of the study. John Bridgewater reports funding from the University College London Hospitals NHS Foundation Trust/University College London Biomedical Research Centre. David Cunningham reports funding from the National Institute for Health Research Biomedical Research Centres at the Royal Marsden.