European Radiology

, Volume 30, Issue 1, pp 272–280 | Cite as

Long-term imaging characteristics of clinical complete responders during watch-and-wait for rectal cancer—an evaluation of over 1500 MRIs

  • Doenja M. J. LambregtsEmail author
  • Monique Maas
  • Thierry N. Boellaard
  • Andrea Delli Pizzi
  • Marit E. van der Sande
  • Britt J. P. Hupkens
  • Max J. Lahaye
  • Frans C. H. Bakers
  • Geerard L. Beets
  • Regina G. H. Beets-Tan



Rectal cancer patients with a clinical complete response after chemoradiotherapy (CRT) may be followed with a ‘watch-and-wait’ (W&W) approach as an alternative to surgery. MRI plays an important role in the follow-up of these patients, but basic knowledge on what to expect from the morphology of the irradiated tumour bed during follow-up is lacking, which can hamper image interpretation. The objective was to establish the spectrum of non-suspicious findings during long-term (> 2 years) follow-up in patients with a sustained clinical complete response undergoing W&W.


A total of 1509 T2W MRIs of 164 sustained complete responders undergoing W&W were retrospectively evaluated. Morphology of the tumour bed was evaluated (2 independent readers) on the restaging MRI and on the various follow-up MRIs and classified as (a) no fibrosis, (b) minimal fibrosis, (c) full thickness fibrosis, or (d) irregular fibrosis. Any changes occurring during follow-up were documented.


A total of 104 patients (63%) showed minimal fibrosis, 38 (23%) full thickness fibrosis, 8 (5%) irregular fibrosis, and 14 (9%) no fibrosis. In 93% of patients, the morphology remained completely stable during follow-up; in 7%, a minor increase/decrease in fibrosis was observed. Interobserver agreement was excellent (κ 0.90).


Typically, the morphology as established at restaging remains completely unchanged. The majority of patients show fibrosis with the predominant pattern being a minimal fibrosis confined to the rectal wall. Complete absence of fibrosis occurs in only 1/10 cases. Once validated in independent cohorts, these findings may serve as a reference for radiologists involved in the clinical follow-up of W&W patients.

Key Points

• In rectal cancer patients with a sustained complete response after chemoradiation, the rectal wall morphology as established on restaging MRI typically remains unchanged during long-term MRI follow-up.

• The vast majority of complete responders show fibrosis with the predominant pattern being a minimal fibrotic remnant that remains confined to the rectal wall; complete absence of fibrosis occurs in only 10% of the cases.

• Once validated in independent cohorts, the findings of this study may serve as a reference for radiologists involved in the clinical follow-up of rectal cancer patients undergoing watch-and-wait.


Rectal neoplasms Magnetic resonance imaging Fibrosis 





Diffusion-weighted imaging


European Society of Gastrointestinal and Abdominal Radiology


Fast spin echo









The authors state that this work has not received any funding.

Compliance with ethical standards


The scientific guarantor of this publication is Doenja Lambregts.

Conflict of interest

The authors of this manuscript declare no relationships with any companies, whose products or services may be related to the subject matter of the article.

Statistics and biometry

No complex statistical methods were necessary for this paper.

Informed consent

Written informed consent was waived by the Institutional Review Board.

Ethical approval

Institutional Review Board approval was obtained.

Study subjects or cohorts overlap

The study patients were all selected from consecutive cohorts of previously reported and ongoing clinical trials focussing on the oncological and functional outcome of a watch-and-wait policy (Maas et al JCO 2011, Martens et al J Natl Cancer Inst 2016, van der Valk et al Lancet 2018, and an ongoing clinical study registered at clinical under NCT03426397). In addition, 47 of the patients included in the current study were included in a previous study on the use of MRI+DWI to detect local tumour regrowths during follow-up (Lambregts et al Eur Rad 2016). This previous study concerned a diagnostic accuracy study focussing on detecting recurrent tumours with a specific focus on DWI, while the current report is a descriptive study focussing on T2W morphology which included only non-recurrent patients.


• Retrospective

• Diagnostic or prognostic study

• Multicentre study


  1. 1.
    Habr-Gama A, Perez RO, Nadalin W et al (2014) Operative versus nonoperative treatment for stage 0 distal rectal cancer following chemoradiation therapy: long-term results. Ann Surg 240:711–717 discussion 7-8Google Scholar
  2. 2.
    Martens MH, Maas M, Heijnen LA et al (2016) Long-term outcome of an organ preservation program after neoadjuvant treatment for rectal cancer. J Natl Cancer Inst 108Google Scholar
  3. 3.
    Smith JD, Ruby JA, Goodman KA et al (2012) Nonoperative management of rectal cancer with complete clinical response after neoadjuvant therapy. Ann Surg 256:965–972CrossRefGoogle Scholar
  4. 4.
    Appelt AL, Ploen J, Harling H et al (2015) High-dose chemoradiotherapy and watchful waiting for distal rectal cancer: a prospective observational study. Lancet Oncol 16:919–927CrossRefGoogle Scholar
  5. 5.
    Hupkens BJP, Martens MH, Stoot JH et al (2017) Quality of life in rectal cancer patients after chemoradiation: Watch-and-Wait Policy versus standard resection - a matched-controlled study. Dis Colon Rectum 60:1032–1040CrossRefGoogle Scholar
  6. 6.
    van der Valk MJM, Hilling DE, Bastiaannet E et al (2018) Long-term outcomes of clinical complete responders after neoadjuvant treatment for rectal cancer in the International Watch & Wait Database (IWWD): an international multicentre registry study. Lancet 391:2537–2545CrossRefGoogle Scholar
  7. 7.
    Lambregts DM, Lahaye MJ, Heijnen LA et al (2016) MRI and diffusion-weighted MRI to diagnose a local tumour regrowth during long-term follow-up of rectal cancer patients treated with organ preservation after chemoradiotherapy. Eur Radiol 26:2118–2125CrossRefGoogle Scholar
  8. 8.
    Lambregts DM, Maas M, Bakers FC et al (2011) Long-term follow-up features on rectal MRI during a wait-and-see approach after a clinical complete response in patients with rectal cancer treated with chemoradiotherapy. Dis Colon Rectum 54:1521–1158CrossRefGoogle Scholar
  9. 9.
    Maas M, Beets-Tan RG, Lambregts DM et al (2011) Wait-and-see policy for clinical complete responders after chemoradiation for rectal cancer. J Clin Oncol 2011(29):4633–4640CrossRefGoogle Scholar
  10. 10.
    Lambregts D, Delli Pizzi A, Lahaye M et al (2018) A pattern-based approach combining tumor morphology on MRI with distinct signal patterns on diffusion-weighted imaging to assess response of rectal tumors after chemoradiotherapy. Dis Colon Rectum 61:328–337PubMedGoogle Scholar
  11. 11.
    Kim SH, Lee JM, Hong SH et al (2009) Locally advanced rectal cancer: added value of diffusion-weighted MR imaging in the evaluation of tumor response to neoadjuvant chemo- and radiation therapy. Radiology 253:116–125CrossRefGoogle Scholar
  12. 12.
    Lambregts DM, Vandecaveye V, Barbaro B et al (2011) Diffusion-weighted MRI for selection of complete responders after chemoradiation for locally advanced rectal cancer: a multicenter study. Ann Surg Oncol 18:2224–2231CrossRefGoogle Scholar
  13. 13.
    Song I, Kim SH, Lee SJ, Choi JY, Kim MJ, Rhim H (2012) Value of diffusion-weighted imaging in the detection of viable tumor after neoadjuvant chemoradiation therapy in patients with locally advanced rectal cancer: comparison with T2-weighted and PET/CT imaging. Br J Radiol 85:577–586CrossRefGoogle Scholar
  14. 14.
    Foti PV, Privitera G, Piana S et al (2016) Locally advanced rectal cancer: qualitative and quantitative evaluation of diffusion-weighted MR imaging in the response assessment after neoadjuvant chemo-radiotherapy. Eur J Radiol Open 3:145–152CrossRefGoogle Scholar
  15. 15.
    Beets-Tan RGH, Lambregts DMJ, Maas M et al (2018) Magnetic resonance imaging for clinical management of rectal cancer: updated recommendations from the 2016 European Society of Gastrointestinal and Abdominal Radiology (ESGAR) consensus meeting. Eur Radiol 28:1465–1475CrossRefGoogle Scholar
  16. 16.
    Heijnen LA, Maas M, Beets-Tan RG et al (2016) Nodal staging in rectal cancer: why is restaging after chemoradiation more accurate than primary nodal staging? Int J Colorectal Dis 31:1157–1162CrossRefGoogle Scholar

Copyright information

© European Society of Radiology 2019

Authors and Affiliations

  • Doenja M. J. Lambregts
    • 1
    Email author
  • Monique Maas
    • 1
  • Thierry N. Boellaard
    • 1
  • Andrea Delli Pizzi
    • 2
  • Marit E. van der Sande
    • 3
    • 4
  • Britt J. P. Hupkens
    • 4
    • 5
  • Max J. Lahaye
    • 1
  • Frans C. H. Bakers
    • 6
  • Geerard L. Beets
    • 3
    • 4
  • Regina G. H. Beets-Tan
    • 1
    • 4
  1. 1.Department of RadiologyNetherlands Cancer InstituteAmsterdamThe Netherlands
  2. 2.ITAB – Institute of Advanced Biomedical Technologies“G. d’Annunzio” UniversityChietiItaly
  3. 3.Department of SurgeryNetherlands Cancer InstituteAmsterdamThe Netherlands
  4. 4.GROW School for Oncology and Developmental Biology – University of MaastrichtMaastrichtThe Netherlands
  5. 5.Department of SurgeryMaastricht University Medical CentreMaastrichtThe Netherlands
  6. 6.Department of RadiologyMaastricht University Medical CentreMaastrichtThe Netherlands

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