Faculty Collaboration Database

Prospective Correlation of Magnetic Resonance Tumor Regression Grade With Pathologic Outcomes in Total Neoadjuvant Therapy for Rectal Adenocarcinoma. J Clin Oncol 2023 Oct 10;41(29):4643-4651

Date

07/21/2023

Pubmed ID

37478389

Pubmed Central ID

PMC10564288

DOI

10.1200/JCO.22.02525

Scopus ID

2-s2.0-85174713393 (requires institutional sign-in at Scopus site)   37 Citations

Abstract

PURPOSE: Total neoadjuvant therapy (TNT) is a newly established standard treatment for rectal adenocarcinoma. Current methods to communicate magnitudes of regression during TNT are subjective and imprecise. Magnetic resonance tumor regression grade (MR-TRG) is an existing, but rarely used, regression grading system. Prospective validation of MR-TRG correlation with pathologic response in patients undergoing TNT is lacking. Utility of adding diffusion-weighted imaging to MR-TRG is also unknown.

METHODS: We conducted a multi-institutional prospective imaging substudy within NRG-GI002 (ClinicalTrials.gov identifier: NCT02921256) examining the ability of MR-based imaging to predict pathologic complete response (pCR) and correlate MR-TRG with the pathologic neoadjuvant response score (NAR). Serial MRIs were needed from 110 patients. Three radiologists independently, then collectively, reviewed each MRI for complete response (mriCR), which was tested for positive predictive value (PPV), negative predictive value (NPV), sensitivity, and specificity with pCR. MR-TRG was examined for association with the pathologic NAR score. All team members were blinded to pathologic data.

RESULTS: A total of 121 patients from 71 institutions met criteria: 28% were female (n = 34), 84% White (n = 101), and median age was 55 (24-78 years). Kappa scores for T- and N-stage after TNT were 0.38 and 0.88, reflecting fair agreement and near-perfect agreement, respectively. Calling an mriCR resulted in a kappa score of 0.82 after chemotherapy and 0.56 after TNT reflected near-perfect agreement and moderate agreement, respectively. MR-TRG scores were associated with pCR (P < .01) and NAR (P < .0001), PPV for pCR was 40% (95% CI, 26 to 53), and NPV was 84% (95% CI, 75 to 94).

CONCLUSION: MRI alone is a poor tool to distinguish pCR in rectal adenocarcinoma undergoing TNT. However, the MR-TRG score presents a now validated method, correlated with pathologic NAR, which can objectively measure regression magnitude during TNT.

Author List

Hall WA, Li J, You YN, Gollub MJ, Grajo JR, Rosen M, dePrisco G, Yothers G, Dorth JA, Rahma OE, Russell MM, Gross HM, Jacobs SA, Faller BA, George S, Al Baghdadi T, Haddock MG, Valicenti R, Hong TS, George TJ

Author

William Adrian Hall MD Chair, Professor in the Radiation Oncology department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Adenocarcinoma
Chemoradiotherapy
Female
Humans
Magnetic Resonance Imaging
Magnetic Resonance Spectroscopy
Male
Middle Aged
Neoadjuvant Therapy
Neoplasm Staging
Prospective Studies
Rectal Neoplasms
Treatment Outcome