Profiling of rectal cancers MRI in pathological complete remission states after neoadjuvant concurrent chemoradiation therapy

H. Kim, H. M. Kim, W. S. Koom, N. K. Kim, M. J. Kim, H. Kim, H. Hur, J. S. Lim

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Aim To fully characterise the magnetic resonance imaging (MRI) traits of rectal cancers in a large sample of patients, each experiencing pathological complete remission (PCR) after neoadjuvant concurrent chemoradiation therapy (CCRT). Materials and methods A total of 120 patients (77 male, 43 female; median age, 59.5 years; range, 32-81 years) with rectal cancers in CCRT-induced PCR states who underwent pre- and post-CCRT MRI and eventual surgery between July, 2005 and September, 2014 were retrospectively reviewed. In most (n=100), diffusion-weighted imaging was also performed. Tumour volume, tumour regression grade (TRG), T-stage, mesorectal fascia (MRF) status, and T2 signal intensity (T2-SI) were analysed. Paired t-test and McNemar's test were applied for statistical comparisons. Results Tumour volume declined sharply after CCRT (pre-CCRT, 21.5±22.4cm3; post-CCRT, 6.6±8.4cm3; p<0.001). TRG distribution was as follows: G1 (clinical CR), 3; G2, 38; G3, 78; G4, 1; and G5 (marked progression), 0. Downstaging of T-stage (34%,16/47) and MRF status (19.7%,13/66) did occur; but on post-CCRT MRI, 25.8% (31/120) remained at T3≥5 mm or T4 stage, and 44.2% (53/120) were MRF-positive. A majority (88.3%, 106/120) of patients displayed intermediate T2-SI prior to CCRT. Most converted to dark T2-SI after CCRT, with 12.5% (15/120) unchanged. On post-CCRT MRI, 11% (11/100) of patients showed diffusion restriction. Conclusion MRI findings in CCRT-induced PCR-status rectal cancers were highly variable. Tumour volume and T2-SI mostly decreased; however, such lesions occasionally presented with unexpected atypical features, such as large residual volume and/or intermediate T2-SI.

Original languageEnglish
Pages (from-to)250-257
Number of pages8
JournalClinical Radiology
Volume71
Issue number3
DOIs
Publication statusPublished - 2016 Mar 1

All Science Journal Classification (ASJC) codes

  • Radiology Nuclear Medicine and imaging

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