Defining response to radiotherapy in rectal cancer using magnetic resonance imaging and histopathological scales

Abstract

AIMTo define good and poor regression using pathology and magnetic resonance imaging (MRI) regression scales after neo-adjuvant chemotherapy for rectal cancer.METHODSA systematic review was performed on all studies up to December 2015, without language restriction, that were identified from MEDLINE, Cochrane Controlled Trials Register (1960-2015), and EMBASE (1991-2015). Searches were performed of article bibliographies and conference abstracts. MeSH and text words used included “tumour regression”, “mrTRG”, “poor response” and “colorectal cancers”. Clinical studies using either MRI or histopathological tumour regression grade (TRG) scales to define good and poor responders were included in relation to outcomes [local recurrence (LR), distant recurrence (DR), disease-free survival (DFS), and overall survival (OS)]. There was no age restriction or stage of cancer restriction for patient inclusion. Data were extracted by two authors working independently and using pre-defined outcome measures.RESULTSQuantitative data (prevalence) were extracted and analysed according to meta-analytical techniques using comprehensive meta-analysis. Qualitative data (LR, DR, DFS and OS) were presented as ranges. The overall proportion of poor responders after neo-adjuvant chemo-radiotherapy (CRT) was 37.7% (95%CI: 30.1-45.8). There were 19 different reported histopathological scales and one MRI regression scale (mrTRG). Clinical studies used nine and six histopathological scales for poor and good responders, respectively. All studies using MRI to define good and poor response used one scale. The most common histopathological definition for good response was the Mandard grades 1 and 2 or Dworak grades 3 and 4; Mandard 3, 4 and 5 and Dworak 0, 1 and 2 were used for poor response. For histopathological grades, the 5-year outcomes for poor responders were LR 3.4%-4.3%, DR 14.3%-20.3%, DFS 61.7%-68.1% and OS 60.7-69.1. Good pathological response 5-year outcomes were LR 0%-1.8%, DR 0%-11.6%, DFS 78.4%-86.7%, and OS 77.4%-88.2%. A poor response on MRI (mrTRG 4,5) resulted in 5-year LR 4%-29%, DR 9%, DFS 31%-59% and OS 27%-68%. The 5-year outcomes with a good response on MRI (mrTRG 1,2 and 3) were LR 1%-14%, DR 3%, DFS 64%-83% and OS 72%-90%.CONCLUSIONFor histopathology regression assessment, Mandard 1, 2/Dworak 3, 4 should be used for good response and Mandard 3, 4, 5/Dworak 0, 1, 2 for poor response. MRI indicates good and poor response by mrTRG1-3 and mrTRG4-5, respectively.

Efficacy and safety of self-expanding metallic stent placement followed by neoadjuvant chemotherapy and scheduled surgery for treatment of obstructing left-sided colonic cancer

“…An important concern with neoadjuvant chemotherapy, especially when administered after SEMS for obstructive colorectal cancer, is the toxicity of the drugs used [20]. In our series, only one (9.1%) patient had a grade 3 toxicity (diarrhea).…”

Efficacy and safety of self-expanding metallic stent placement followed by neoadjuvant chemotherapy and scheduled surgery for treatment of obstructing left-sided colonic cancer

“…An important concern with neoadjuvant chemotherapy, especially when administered after SEMS for obstructive colorectal cancer, is the toxicity of the drugs used. 20 In our series, only one (9.1%) patient had a grade 3 toxicity (diarrhea). Neoadjuvant chemotherapy was generally well tolerated, and all patients were able to undergo surgery after completion of chemotherapy.…”

A Comparison of Diagnostic Performance of Signal Intensity and Volume Related MRI Multiparameters for Assessing Different Response of Rectal Cancer to Neoadjuvant Chemoradiotherapy

“…The multidisciplinary treatment of locally advancedrectal cancer (LARC) has markedly improved and led to better patient outcomes over the last three decades. The reasons for this are multifactorial, but one important factor is the use of Neoadjuvant chemoradiation (CRT) [1,2]. Tumors after CRT will have different TRG and downsizing, and has been shown to be an independent and important prognosticating factor for survival [3].…”

“…Tumors after CRT will have different TRG and downsizing, and has been shown to be an independent and important prognosticating factor for survival [3]. Therefore, it is important to predict the tumour regression grade (TRG) before surgery because of approximately 10-30% of rectal cancer patients achieve pathological complete remission (pCR) after CRT [1,2,4]. A wait-and-see policy has been proposed as a possible method of treatment in clinical complete responders [2,4].…”

“…MR as optional non-invasive examination has also played an increasingly important role and become the gold standard for rectal cancer staging and assessment of response to neoadjuvant treatment as restaging after CRT [4]. mrTRG as a potential biomarker for predicting pTRG to preoperative CRT and disease-free survival and overall survival in patients with LARC, was reported [1,[5][6][7][8][9][10]. However, mrTRG suffers from different interreader agreement.…”