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Br J Cancer. 2017 Nov 7;117(10):1478-1485. doi: 10.1038/bjc.2017.320. Epub 2017 Sep 21.

Comparison between MRI and pathology in the assessment of tumour regression grade in rectal cancer.

Author information

1
Department of Medicine, The Royal Marsden NHS Foundation Trust, London and Surrey, UK.
2
Department of Radiology, The Royal Marsden NHS Foundation Trust, London and Surrey, UK.
3
Department of Histopathology, The Royal Marsden NHS Foundation Trust, London and Surrey, UK.
4
Clinical Research & Development, The Royal Marsden NHS Foundation Trust, London and Surrey, UK.
5
Department of Medical Oncology, Vall d'Hebron University Hospital, Universitat Autònoma de Barcelona, Barcelona, Spain.
6
Department of Immunology, Genetics and Pathology, Section of Experimental and Clinical Oncology, University of Uppsala, Uppsala, Sweden.
7
Department of Haematology and Medical Oncology, Biomedical Research Institute INCLIVA, University of Valencia, Valencia, Spain.

Abstract

BACKGROUND:

Limited data exist regarding the correlation between MRI tumour regression grade (mrTRG) and pathological TRG (pTRG) in rectal cancer.

METHODS:

mrTRG and pTRG were compared in rectal cancer patients from two phase II trials (EXPERT and EXPERT-C). The agreement between radiologist and pathologist was assessed with the weighted κ test while the Kaplan-Meier method was used to estimate survival outcomes.

RESULTS:

One hundred ninety-one patients were included. Median time from completion of neoadjuvant treatment to pre-operative MRI and surgery was 4.1 weeks (interquartile range (IQR): 3.7-4.7) and 6.6 weeks (IQR: 5.9-7.6), respectively. Fair agreement was found between mrTRG and pTRG when regression was classified according to standard five-tier systems (κ=0.24) or modified three-tier systems (κ=0.25). Sensitivity and specificity of mrTRG 1-2 (complete/good radiological regression) for the prediction of pathological complete response was 74.4% (95% CI: 58.8-86.5) and 62.8% (95% CI: 54.5-70.6), respectively. Survival outcomes of patients with intermediate pathological regression (pTRG 2) were numerically better if complete/good regression was also observed on imaging (mrTRG 1-2) compared to poor regression (mrTRG 3-5) (5-year recurrence-free survival 76.9% vs 65.9%, P=0.18; 5-year overall survival 80.6% vs 68.8%, P=0.22).

CONCLUSIONS:

The agreement between mrTRG and pTRG is low and mrTRG cannot be used as a surrogate of pTRG. Further studies are warranted to assess the ability of mrTRG to identify pathological complete responders for the adoption of non-operative management strategies and to provide complementary prognostic information to pTRG for better risk-stratification after surgery.

PMID:
28934761
PMCID:
PMC5680467
DOI:
10.1038/bjc.2017.320
[Indexed for MEDLINE]
Free PMC Article

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