# IDEA collaboration

Source: https://onco.cc/trials/idea-collaboration/  
OnCo record `idea-collaboration` (Trial). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Six national trials pooled their results to ask whether three months of chemotherapy after bowel cancer surgery is as good as six. For low-risk disease it is, and it causes far less nerve damage.

## Summary

IDEA was a prospective, preplanned pooled analysis of six concurrent phase 3 non-inferiority trials in resected stage III colon cancer. Across 12,834 patients and 3,263 events the non-inferiority of three months was not confirmed overall (hazard ratio 1.07, 95% CI 1.00 to 1.15 against a margin of 1.12), but it held for CAPOX (0.95, 0.85 to 1.06) and not for FOLFOX (1.16, 1.06 to 1.26). In the exploratory low-risk group (T1 to T3 and N1) three-year disease-free survival was 83.1 against 83.3 percent (hazard ratio 1.01); in T4 or N2 disease six months was better. Grade 2 or worse neuropathy roughly halves with the shorter course. The result is the two-tier recommendation in every guideline: three months of CAPOX for low-risk stage III, six months of FOLFOX or CAPOX for T4 or N2 disease.

## Fields

- Kind: Trial
- Status: mixed
- Last checked: 2026-09-24
- Also known as: International Duration Evaluation of Adjuvant chemotherapy; IDEA
- Phase: 3
- Setting: Stage III colon cancer after resection: three months of adjuvant FOLFOX or CAPOX against six months, pooled across six trials
- Sponsor: Six concurrent trial groups (SCOT, TOSCA, IDEA France, CALGB/SWOG 80702, ACHIEVE, HORG)
- Enrolled: 12834
- Result: Three months non-inferior to six for CAPOX and for low-risk (T1-3 N1) disease; six months better for T4 or N2.
- Outcomes: Disease-free survival at 3 years (overall): 3 months 1.07 hazard ratio vs 6 months 1 hazard ratio, HR 1.07; Disease-free survival at 3 years (T1-3 N1): 3 months 83.1 percent vs 6 months 83.3 percent, HR 1.01

## Sources

- IDEA: duration of adjuvant chemotherapy for stage III colon cancer (New England Journal of Medicine 2018): https://doi.org/10.1056/NEJMoa1713709

## Connected records

- cancers: [Colon cancer (adenocarcinoma of the colon)](https://onco.cc/cancers/colon-cancer/), [Colorectal cancer](https://onco.cc/cancers/colorectal/)
- technologies: [Cytotoxic chemotherapy](https://onco.cc/technologies/cytotoxic-chemotherapy/), [Platinum agents](https://onco.cc/technologies/platinum/)
- drugs: [Capecitabine](https://onco.cc/drugs/capecitabine/), [CAPOX (capecitabine, oxaliplatin)](https://onco.cc/drugs/capox/), [Fluorouracil (5-FU)](https://onco.cc/drugs/fluorouracil/), [FOLFOX (5-FU, leucovorin, oxaliplatin)](https://onco.cc/drugs/folfox/), [Oxaliplatin](https://onco.cc/drugs/oxaliplatin/)
- terms: [De-escalation, escalation and response-adapted therapy](https://onco.cc/terms/de-escalation/), [Neoadjuvant / adjuvant / perioperative](https://onco.cc/terms/neoadjuvant-adjuvant/)
- trials: [ATOMIC (Alliance A021502)](https://onco.cc/trials/atomic/), [CHALLENGE (CCTG CO.21)](https://onco.cc/trials/challenge/), [MOSAIC](https://onco.cc/trials/mosaic/), [QUASAR](https://onco.cc/trials/quasar/), [SCOT](https://onco.cc/trials/scot/), [TOSCA](https://onco.cc/trials/tosca/)

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