# International Watch & Wait Database

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

## TL;DR

The worldwide register of people who kept their rectum after treatment. A quarter of the cancers regrow, almost all within two years and almost all in the bowel wall where they can be found and removed.

## Summary

The International Watch & Wait Database pooled individual patient data from 47 institutes in 15 countries for people whose rectal cancer was managed without surgery after a clinical complete response to neoadjuvant treatment. Of 1,009 patients identified, 880 had a clinical complete response. The two-year cumulative incidence of local regrowth was 25.2 percent (95% CI 22.2 to 28.5); 88 percent of regrowth appeared in the first two years and 97 percent was in the bowel wall, where endoscopic surveillance finds it and salvage surgery is possible. Distant metastases occurred in 8 percent. Five-year overall survival was 85 percent and disease-specific survival 94 percent. The registry is the evidence base for offering watch and wait outside a trial and sets the surveillance schedule: endoscopy and MRI every three to four months for two years.

## Fields

- Kind: Trial
- Status: active
- Last checked: 2026-09-24
- Also known as: IWWD
- Phase: observational
- Setting: Rectal cancer with a clinical complete response after neoadjuvant treatment: no surgery, with endoscopic and MRI surveillance, pooled from 47 institutes in 15 countries
- Sponsor: European Registration of Cancer Care / European Society of Surgical Oncology
- Enrolled: 1009
- Result: Two-year local regrowth 25.2 percent, 97 percent of it in the bowel wall; five-year overall survival 85 percent, disease-specific survival 94 percent.
- Outcomes: Cumulative local regrowth at 2 years: Watch and wait after clinical complete response 25.2 percent; Overall survival at 5 years: Watch and wait after clinical complete response 85 percent

## Sources

- IWWD: long-term outcomes of clinical complete responders after neoadjuvant treatment for rectal cancer (Lancet 2018): https://doi.org/10.1016/S0140-6736(18)31078-X
- International Watch & Wait Database: https://www.iwwd.org/

## Connected records

- cancers: [Colorectal cancer](https://onco.cc/cancers/colorectal/), [Rectal cancer](https://onco.cc/cancers/rectal-cancer/)
- technologies: [IMRT / IGRT (modern external beam)](https://onco.cc/technologies/imrt-igrt/)
- terms: [Chemoradiation (chemoradiotherapy, CRT)](https://onco.cc/terms/chemoradiation/), [Clinical complete response (cCR)](https://onco.cc/terms/clinical-complete-response/), [Pathologic complete response (pCR)](https://onco.cc/terms/pcr/)
- trials: [AZUR-1](https://onco.cc/trials/azur-1/), [OPRA](https://onco.cc/trials/opra/), [PRODIGE 23](https://onco.cc/trials/prodige-23/), [PROSPECT (Alliance N1048)](https://onco.cc/trials/prospect/), [RAPIDO](https://onco.cc/trials/rapido/)

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JSON: https://onco.cc/api/v1/entities/iwwd.json