Diagnostic Accuracy of Post-Neoadjuvant Treatment Restaging Magnetic Resonance Imaging in Rectal Cancer in the Era of Total Neoadjuvant Treatment

Abstract

Introduction

The diagnostic accuracy of a restaging magnetic resonance imaging (MRI) scan after neoadjuvant treatment (NAT), especially total neoadjuvant treatment (TNT), is not well established. We aimed to study the diagnostic accuracy of the restaging MRI after NAT including TNT.

Methods

This was a retrospective study conducted at a tertiary cancer center of patients undergoing radical surgery after various types of NAT for rectal cancer between 2020 and 2023. The patients were grouped according to the type of NAT received. The findings on the restaging MRI were correlated with the gold standard of the histopathology report of the resected specimen to estimate its diagnostic accuracy overall as well as for the different types of NAT.

Results

Among the 131 patients included in this study, 68% received TNT. The restaging MRI showed an overall accuracy of 74.4% for T-stage and 60.1% for N-stage and overestimated the T- and N-stage in 20.6 and 12.2% of patients and underestimated them in 41.2 and 47.3% patients, respectively. MRI had a higher accuracy for T-stage among patients who did not receive TNT compared with those who received it (79.6 vs. 75.2%) but not for N-stage or CRM involvement. The overall sensitivity, specificity, positive predictive value, negative predictive value (NPV), and accuracy of the restaging MRI for CRM involvement were 74.1, 73, 26.8, 95.5, and 74%, respectively.

Conclusion

We found a moderate level of accuracy for posttreatment MRI in predicting the pathological stage and a high NPV in determining an involved CRM. Use of TNT reduced the diagnostic accuracy of restaging MRI for T-stage but not for N-stage or predicting CRM involvement. Further studies are required to assess the diagnostic accuracy of posttreatment MRI after different regimens of NAT that are currently recommended in rectal cancer.

Keywords

rectal cancer - total neoadjuvant treatment - magnetic resonance imaging - diagnostic accuracy - restaging

Publication History

Article published online:
30 May 2025

• References

• 1 National Comprehensive Cancer Network. Clinical practice guidelines in oncology (NCCN Guidelines): rectal cancer—version 4.2024. Published on August 22, 2024. Accessed November 10, 2024 at: https://www.nccn.org/professionals/physician_gls/pdf/rectal.pdf
• 2 Glynne-Jones R, Wyrwicz L, Tiret E. et al; ESMO Guidelines Committee. Rectal cancer: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up. Ann Oncol 2017; 28 (Suppl. 04) iv22-iv40 (Erratum in: Ann Oncol. 2018 Oct 1;29(Suppl 4):iv263)
• 3 Nagtegaal ID, Quirke P. What is the role for the circumferential margin in the modern treatment of rectal cancer?. J Clin Oncol 2008; 26 (02) 303-312
• 4 Adam IJ, Mohamdee MO, Martin IG. et al. Role of circumferential margin involvement in the local recurrence of rectal cancer. Lancet 1994; 344 (8924) 707-711
• 5 Mari G, Crippa J, Montroni I. et al. MRI-pathology agreement in rectal cancer: real-world data from a prospective rectal cancer registry. Chirurgia (Bucur) 2021; 116 (05) 583-590
• 6 Brown G, Radcliffe AG, Newcombe RG, Dallimore NS, Bourne MW, Williams GT. Preoperative assessment of prognostic factors in rectal cancer using high-resolution magnetic resonance imaging. Br J Surg 2003; 90 (03) 355-364
• 7 Brown G, Richards CJ, Newcombe RG. et al. Rectal carcinoma: thin-section MR imaging for staging in 28 patients. Radiology 1999; 211 (01) 215-222
• 8 Blomqvist L, Rubio C, Holm T, Machado M, Hindmarsh T. Rectal adenocarcinoma: assessment of tumour involvement of the lateral resection margin by MRI of resected specimen. Br J Radiol 1999; 72 (853) 18-23
• 9 Patel UB, Taylor F, Blomqvist L. et al. Magnetic resonance imaging-detected tumor response for locally advanced rectal cancer predicts survival outcomes: MERCURY experience. J Clin Oncol 2011; 29 (28) 3753-3760
• 10 Sclafani F, Brown G, Cunningham D. et al. Comparison between MRI and pathology in the assessment of tumour regression grade in rectal cancer. Br J Cancer 2017; 117 (10) 1478-1485
• 11 Hanly AM, Ryan EM, Rogers AC, McNamara DA, Madoff RD, Winter DC. MERRION Study Group. Multicenter evaluation of rectal cancer ReImaging pOst neoadjuvant (MERRION) therapy. Ann Surg 2014; 259 (04) 723-727
• 12 Yuval JB, Thompson HM, Firat C. et al. MRI at restaging after neoadjuvant therapy for rectal cancer overestimates circumferential resection margin proximity as determined by comparison with whole-mount pathology. Dis Colon Rectum 2022; 65 (04) 489-496
• 13 Wei MZ, Zhao ZH, Wang JY. The diagnostic accuracy of magnetic resonance imaging in restaging of rectal cancer after preoperative chemoradiotherapy: a meta-analysis and systematic review. J Comput Assist Tomogr 2020; 44 (01) 102-110
• 14 Moreno CC, Sullivan PS, Mittal PK. MRI evaluation of rectal cancer: staging and restaging. Curr Probl Diagn Radiol 2017; 46 (03) 234-241
• 15 Gefen R, Garoufalia Z, Horesh N. et al. How reliable is restaging MRI after neoadjuvant therapy in rectal cancer?. Colorectal Dis 2023; 25 (08) 1631-1637
• 16 Aker M, Boone D, Chandramohan A, Sizer B, Motson R, Arulampalam T. Diagnostic accuracy of MRI in assessing tumor regression and identifying complete response in patients with locally advanced rectal cancer after neoadjuvant treatment. Abdom Radiol (NY) 2018; 43 (12) 3213-3219
• 17 Kulkarni T, Gollins S, Maw A, Hobson P, Byrne R, Widdowson D. Magnetic resonance imaging in rectal cancer downstaged using neoadjuvant chemoradiation: accuracy of prediction of tumour stage and circumferential resection margin status. Colorectal Dis 2008; 10 (05) 479-489
• 18 Seo N, Kim H, Cho MS, Lim JS. Response assessment with MRI after chemoradiotherapy in rectal cancer: current evidences. Korean J Radiol 2019; 20 (07) 1003-1018
• 19 Jia X, Zhang Y, Wang Y. et al. MRI for restaging locally advanced rectal cancer: detailed analysis of discrepancies with the pathologic reference standard. AJR Am J Roentgenol 2019; 213 (05) 1081-1090
• 20 Lambregts DM, Vandecaveye V, Barbaro B. et al. Diffusion-weighted MRI for selection of complete responders after chemoradiation for locally advanced rectal cancer: a multicenter study. Ann Surg Oncol 2011; 18 (08) 2224-2231
• 21 Chandramohan A, Siddiqi UM, Mittal R. et al. Diffusion weighted imaging improves diagnostic ability of MRI for determining complete response to neoadjuvant therapy in locally advanced rectal cancer. Eur J Radiol Open 2020; 7: 100223