# Sauer 2004: chemoradiotherapy before rather than after surgery for rectal cancer (CAO/ARO/AIO-94)

Source: https://onco.cc/key-papers/paper-sauer-preoperative-chemoradiotherapy-rectal-nejm-2004/  
OnCo record `paper-sauer-preoperative-chemoradiotherapy-rectal-nejm-2004` (Key paper). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Giving chemotherapy and radiotherapy before surgery rather than after halved local recurrences of rectal cancer, caused less toxicity and let more patients keep their anal sphincter, without changing overall survival.

## Summary

The German Rectal Cancer Study Group randomised 823 patients with locally advanced rectal cancer (clinical stage T3 or T4 or node-positive) to fluorouracil-based chemoradiotherapy either before or after total mesorectal excision, with both groups receiving further chemotherapy. Preoperative treatment reduced five-year local recurrence, lowered acute and long-term toxicity and increased sphincter-preserving surgery among patients whose tumours had been judged to need an abdominoperineal resection, while overall survival was the same in both arms.

## Fields

- Kind: Key paper
- Last checked: 2026-09-08
- Journal: New England Journal of Medicine
- Year: 2004
- DOI: 10.1056/NEJMoa040694
- Authors: Sauer R, Becker H, Hohenberger W, et al.
- Findings: 823 patients with locally advanced rectal cancer; chemoradiotherapy before or after total mesorectal excision.; Five-year local recurrence 6% with preoperative vs 13% with postoperative treatment.; Five-year overall survival 76% vs 74%, not significantly different.; Grade 3 or 4 acute toxicity 27% vs 40%; long-term toxicity 14% vs 24%; sphincter preservation rose in patients initially judged to need an abdominoperineal resection.
- What it means: This trial made preoperative chemoradiotherapy the standard for locally advanced rectal cancer worldwide and is the foundation on which total neoadjuvant therapy and watch-and-wait organ preservation were later built.
- Caveats: Overall survival was unchanged; the gain is in local control, toxicity and function.; Chemotherapy was fluorouracil alone by the standards of 2004.; Staging relied on endorectal ultrasound and CT rather than modern MRI.

## Sources

- Full text (DOI): https://doi.org/10.1056/NEJMoa040694

## Connected records

- roadmaps: [Colorectal cancer roadmap: from the adenoma-carcinoma sequence and the first screening trials to total mesorectal excision, oxaliplatin, RAS testing, immunotherapy for mismatch repair-deficient disease, ctDNA-guided treatment and organ preservation](https://onco.cc/roadmaps/colorectal-roadmap/)
- key papers: [Preoperative radiotherapy combined with total mesorectal excision for resectable rectal cancer (Dutch TME trial)](https://onco.cc/key-papers/paper-kapiteijn-dutch-tme-preoperative-radiotherapy-nejm-2001/), [Preoperative radiotherapy versus selective postoperative chemoradiotherapy in patients with rectal cancer (MRC CR07 and NCIC-CTG C016)](https://onco.cc/key-papers/paper-sebag-montefiore-cr07-preoperative-radiotherapy-lancet-2009/)
- cancers: [Colorectal cancer](https://onco.cc/cancers/colorectal/), [Rectal cancer](https://onco.cc/cancers/rectal-cancer/)
- drugs: [Fluorouracil (5-FU)](https://onco.cc/drugs/fluorouracil/)
- terms: [Chemoradiation (chemoradiotherapy, CRT)](https://onco.cc/terms/chemoradiation/), [Neoadjuvant / adjuvant / perioperative](https://onco.cc/terms/neoadjuvant-adjuvant/), [Organ preservation (watch-and-wait, bladder-sparing, larynx preservation)](https://onco.cc/terms/organ-preservation/), [Total neoadjuvant therapy (TNT, rectal cancer)](https://onco.cc/terms/total-neoadjuvant-therapy/)
- trials: [CAO/ARO/AIO-94 (German Rectal Cancer Study)](https://onco.cc/trials/cao-aro-aio-94/)

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