Keywords:
Gastrointestinal tract, Oncology, MR, MR-Diffusion/Perfusion, Outcomes analysis, Diagnostic procedure, Cancer
Authors:
L. Yang, B. Wu; Chengdu/CN
DOI:
10.1594/ecr2018/C-0510
Aims and objectives
Neoadjuvant chemoradiotherapy (NCRT) following with total mesorectal excision a period later has become the standard of care for locally advanced rectal cancer (LARC).[1] Some patients can even achieve a pathological complete response (pCR) after NCRT,
associated with an improved local control,
and increased disease-free survival.
Although still controversial,
a “wait and watch” policy or a more conservative surgical treatment has been proposed for patients with complete response to improve their life quality and to reduce the morbidity of surgery.
[2,
3] Therefore it’s important to precisely evaluate tumor regression grade (TRG) before operation to assist in making an individualized and multidisciplinary therapeutic regime in clinical.
Traditionally,
a TRG is determined with histopathologic examination after surgery.
However,
if the determination of the TRG before surgery would influence the subsequent treatment choice,
an accurate clinical preoperational assessment of response becomes essential.
The MERCURY study group showed that TRG evaluated based on high resolution MR images (mrTRG) was an independent prognostic factor to survival.[4] Also,
mrTRG has been evaluated in several prospective trials and is emerging as a promising imaging biomarker for the prediction of outcome.[5,
6] However,
there were limited literatures on the reliability and reproducibility of mrTRG,
as well as it’s discriminability of pCR and good response.
Therefore,
the purpose of this study was to identify whether the MRI tumor response grade (mrTRG) assessed by T2-weighted imaging and diffusion imaging was well corresponding to pathological tumor regression grade (pTRG),
and to explore its ability in selecting good and complete response patients after neoadjuvant combined radiation therapy with chemotherapy (NCRT) in locally advanced rectal cancer (LARC).