European Radiology

, Volume 30, Issue 1, pp 224–238 | Cite as

The split scar sign as an indicator of sustained complete response after neoadjuvant therapy in rectal cancer

  • Inês SantiagoEmail author
  • Maria Barata
  • Nuno Figueiredo
  • Oriol Parés
  • Vanessa Henriques
  • António Galzerano
  • Carlos Carvalho
  • Celso Matos
  • Richard J. Heald



To measure the diagnostic performance of a new radiologic pattern on restaging magnetic resonance (MR) high-resolution T2-weighted imaging (T2-WI)—the split scar sign—for the identification of sustained complete response (SCR) after neoadjuvant therapy in rectal cancer.


Institutional review board approval was obtained for this retrospective study and the informed consent requirement was waived. Fifty-eight consecutive patients with rectal cancer who underwent neoadjuvant therapy were enrolled. Two radiologists blindly and independently reviewed restaging pelvic MR imaging and recorded the presence/absence of the split scar sign (mrSSS). On a second round, they also assessed the relative proportion of intermediate signal intensity on T2-WI (mrT2) and of high signal intensity on high b-value diffusion-weighted imaging (mrDWI). Endoscopic response grading records were retrieved. Qui-square test was employed in search for associations between SCR, defined as pathologic complete response or long-term recurrence-free clinical follow-up, and mrSSS, mrT2, mrDWI and endoscopy. Interobserver agreement for imaging parameters was estimated using Cohen’s kappa (k).


mrSSS was significantly associated with SCR, with specificity = 0.97/0.97, sensitivity = 0.52/0.64, PPV = 0.93/0.94, NPV = 0.73/0.78, and AuROC = 0.78/0.83, for observers 1/2, respectively. mrDWI was significantly associated with SCR for observer 2, with specificity = 0.76, sensitivity = 0.60, PPV = 0.65, NPV = 0.71, and AuROC = 0.69. mrT2 and endoscopy were not discriminative. Interobserver agreement was substantial for mrSSS (k = 0.69), moderate for mrDWI (k = 0.46), and poor for mrT2 (k = 0.17).


The split scar sign is a simple morphologic pattern visible on restaging T2-WI which, although not sensitive, is very specific for the identification of sustained complete responders after neoadjuvant therapy in rectal cancer.

Key Points

• The split scar sign is a morphologic pattern visible on high-resolution T2-weighted MR imaging in rectal cancer patients after neoadjuvant therapy. It therefore does not require any changes to standard protocol.

• At first restaging pelvic MR imaging (mean: 9.1 weeks after the end of radiotherapy), the split scar sign identified patients who sustained a complete response with very high specificity (0.97) and positive predictive value (0.93–0.94).

• The split scar sign has the potential to improve patient selection for “watch-and-wait” after neoadjuvant therapy in rectal cancer.


Rectal neoplasms Neoadjuvant therapy Watchful waiting Magnetic resonance imaging 



Relative proportion of high signal intensity on high b-value diffusion-weighted images (≤ 25% vs > 25%)


Split scar sign


Relative proportion of intermediate signal intensity on T2-WI (≤ 25% vs > 25%)


Sustained complete response



The authors would like to thank all personnel from the Radiology Department and all personnel from the Digestive Unit of the Champalimaud Foundation.


The authors state that this work has not received any funding and is in compliance with ethical standards.

Compliance with ethical standards


The scientific guarantor of this publication is Richard J. Heald, MD, CBE, MChir, FRCS.

Conflict of interest

The authors declare that they have no competing interest.

Statistics and biometry

One of the authors has significant statistical expertise, and 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.


• This is a retrospective

• observational

• cross sectional study


  1. 1.
    Heald RJ, Ryall RD (1986) Recurrence and survival after total mesorectal excision for rectal cancer. Lancet 1:1479–1482CrossRefGoogle Scholar
  2. 2.
    Schneider EB, Hyder O, Brooke BS et al (2012) Patient readmission and mortality after colorectal surgery for colon cancer: impact of length of stay relative to other clinical factors. J Am Coll Surg 214:390–398CrossRefGoogle Scholar
  3. 3.
    Chiappa A, Bertani E, Ferrari C, Venturino M, Andreoni B (2014) The impact of total mesorectal excision for rectal cancer on survival. Eur J Surg Oncol 40(11):S97Google Scholar
  4. 4.
    Maas M, Nelemans PJ, Valentini V et al (2010) Long-term outcome in patients with a pathological complete response after chemoradiation for rectal cancer: a pooled analysis of individual patient data. Lancet Oncol 11:835–844CrossRefGoogle Scholar
  5. 5.
    Garcia-Aguilar J, Shi Q, Thomas CR Jr et al (2012) A phase II trial of neoadjuvant chemoradiation and local excision for T2N0 rectal cancer: preliminary results of the ACOSOG Z6041 trial. Ann Surg Oncol 19:384–391CrossRefGoogle Scholar
  6. 6.
    Habr-Gama A, Perez RO, Proscurshim I et al (2006) Patterns of failure and survival for nonoperative treatment of stage c0 distal rectal cancer following neoadjuvant chemoradiation therapy. J Gastrointest Surg 10:1319–1328CrossRefGoogle Scholar
  7. 7.
    Park IJ, Yu CS (2014) Current issues in locally advanced colorectal cancer treated by preoperative chemoradiotherapy. World J Gastroenterol 20:2023–2029CrossRefGoogle Scholar
  8. 8.
    Chan AK, Wong A, Jenken D, Heine J, Buie D, Johnson D (2005) Posttreatment TNM staging is a prognostic indicator of survival and recurrence in tethered or fixed rectal carcinoma after preoperative chemotherapy and radiotherapy. Int J Radiat Oncol Biol Phys 61:665–677CrossRefGoogle Scholar
  9. 9.
    Glynne-Jones R, Wallace M, Livingstone JI, Meyrick-Thomas J (2008) Complete clinical response after preoperative chemoradiation in rectal cancer: is a “wait and see” policy justified? Dis Colon Rectum 51:10–19CrossRefGoogle Scholar
  10. 10.
    Hatfield P, Hingorani M, Radhakrishna G et al (2009) Short-course radiotherapy, with elective delay prior to surgery, in patients with unresectable rectal cancer who have poor performance status or significant co-morbidity. Radiother Oncol 92(2):210–214CrossRefGoogle Scholar
  11. 11.
    Radu C, Berglund A, Påhlman L, Glimelius B (2008) Short-course preoperative radiotherapy with delayed surgery in rectal cancer - a retrospective study. Radiother Oncol 87(3):343–349CrossRefGoogle Scholar
  12. 12.
    Pettersson D, Holm T, Iversen H, Blomqvist L, Glimelius B, Martling A (2012) Preoperative short-course radiotherapy with delayed surgery in primary rectal cancer. Br J Surg 99(4):577–583CrossRefGoogle Scholar
  13. 13.
    São Julião GP, Habr-Gama A, Vailati BB, Perez RO (2017) The good, the bad and the ugly: rectal cancers in the twenty-first century. Tech Coloproctol 21:573–575CrossRefGoogle Scholar
  14. 14.
    Pozo ME, Fang SH (2015) Watch and wait approach to rectal cancer: a review. World J Gastrointest Surg 7(11):306–312CrossRefGoogle Scholar
  15. 15.
    Lorimer PD, Motz BM, Kirks RC et al (2017) Pathologic complete response rates after neoadjuvant treatment in rectal cancer: an analysis of the national cancer database. Ann Surg Oncol 24:2095–2103CrossRefGoogle Scholar
  16. 16.
    Kong JC, Guerra GR, Warrier SK, Ramsay RG, Heriot AG (2017) Outcome and salvage surgery following “watch and wait” for rectal cancer after neoadjuvant therapy: a systematic review. Dis Colon Rectum 60(3):335–345CrossRefGoogle Scholar
  17. 17.
    Bhoday J, Smith F, Siddiqui MR et al (2016) Magnetic resonance tumor regression grade and residual mucosal abnormality as predictors for pathological complete response in rectal cancer postneoadjuvant chemoradiotherapy. Dis Colon Rectum 59(10):925–933CrossRefGoogle Scholar
  18. 18.
    Smith FM, Wiland H, Mace A, Pai RK, Kalady MF (2014) Clinical criteria underestimate complete pathological response in rectal cancer treated with neoadjuvant chemoradiotherapy. Dis Colon Rectum 57(3):311–315CrossRefGoogle Scholar
  19. 19.
    Ryan JE, Warrier SK, Lynch AC, Heriot AG (2015) Assessing pathological complete response to neoadjuvant chemoradiotherapy in locally advanced rectal cancer: a systematic review. Colorectal Dis 17:849–861CrossRefGoogle Scholar
  20. 20.
    Sassen S, de Booij M, Sosef M et al (2013) Locally advanced rectal cancer: is diffusion weighted MRI helpful for the identification of complete responders (ypT0N0) after neoadjuvant chemoradiation therapy? Eur Radiol 23:3440–3449CrossRefGoogle Scholar
  21. 21.
    Nougaret S, Reinhold C, Mikhael HW, Rouanet P, Bibeau F, Brown G (2013) The use of MR imaging in treatment planning for patients with rectal carcinoma: have you checked the “DISTANCE”? Radiology 268(2):330–344CrossRefGoogle Scholar
  22. 22.
    Beets GL, Figueiredo NL, Habr-Gama A, van de Velde CJ (2015) A new paradigm for rectal cancer: organ preservation: Introducing the International Watch & Wait Database (IWWD). Eur J Surg Oncol 41(12):1562–1564Google Scholar
  23. 23.
    Patel U, Taylor F, Blomqvist L et al (2011) Magnetic resonance imaging–detected tumor response for locally advanced rectal cancer predicts survival outcomes: MERCURY experience. J Clin Oncol 29(28):3753–3760CrossRefGoogle Scholar
  24. 24.
    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
  25. 25.
    Sclafani F, Brown G, Cunningham D et al (2017) Comparison between MRI and pathology in the assessment of tumor regression grade in rectal cancer. Br J Cancer 21:1–8Google Scholar
  26. 26.
    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
  27. 27.
    Lambregts DMJ, 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
  28. 28.
    Lambregts DMJ, 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(3):328–337Google Scholar
  29. 29.
    Cui Y, Yang X, Shi Z et al (2018) Radiomics analysis of multiparametric MRI for prediction of pathological complete response to neoadjuvant chemoradiotherapy in locally advanced rectal cancer. Eur Radiol 29(3):1211–1220CrossRefGoogle Scholar
  30. 30.
    Lambregts DMJ, van Heeswijk MM, Delli Pizzi A et al (2017) Diffusion-weighted MRI to assess response to chemoradiotherapy in rectal cancer: main interpretation pitfalls and their use for teaching. Eur Radiol 27(10):4445–4454CrossRefGoogle Scholar
  31. 31.
    Smith FM, Chang KH, Sheahan K, Hyland J, O'Connell PR, Winter DC (2012) The surgical significance of residual mucosal abnormalities in rectal cancer following neoadjuvant chemoradiotherapy. Br J Surg 99:993–1001Google Scholar
  32. 32.
    Smith FM, Winter D (2014) Watch and wait for rectal cancer: where are we really at? Colorectal Dis 16:332–334CrossRefGoogle Scholar
  33. 33.
    van der Sande ME, Beets GL, Hupkens BJ et al (2018) Response assessment after (chemo)radiotherapy for rectal cancer: why are we missing complete responses with MRI and endoscopy? Eur J Surg Oncol S0748-7983(18):32017–32011Google Scholar
  34. 34.
    Nahas SC, Rizkallah Nahas CS, Sparapan Marques CF et al (2016) Pathologic complete response in rectal cancer: can we detect it? Lessons learned from a proposed randomized trial of watch-and-wait treatment of rectal cancer. Dis Colon Rectum 59:255–263CrossRefGoogle Scholar
  35. 35.
    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 multicenter registry study. Lancet 391(10139):2537–2545Google Scholar

Copyright information

© European Society of Radiology 2019

Authors and Affiliations

  • Inês Santiago
    • 1
    • 2
    Email author
  • Maria Barata
    • 1
  • Nuno Figueiredo
    • 3
  • Oriol Parés
    • 4
  • Vanessa Henriques
    • 5
  • António Galzerano
    • 5
  • Carlos Carvalho
    • 6
  • Celso Matos
    • 1
  • Richard J. Heald
    • 3
  1. 1.Radiology DepartmentChampalimaud FoundationLisbonPortugal
  2. 2.Nova Medical SchoolLisbonPortugal
  3. 3.Colorectal Surgery, Digestive UnitChampalimaud FoundationLisbonPortugal
  4. 4.Radiation Oncology DepartmentChampalimaud FoundationLisbonPortugal
  5. 5.Pathology DepartmentChampalimaud FoundationLisbonPortugal
  6. 6.Medical Oncology, Digestive UnitChampalimaud FoundationLisbonPortugal

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