Predictive factors of tumor response after neoadjuvant chemoradiation for locally advanced rectal cancer

Construction and validation of a progression prediction model for locally advanced rectal cancer patients received neoadjuvant chemoradiotherapy followed by total mesorectal excision based on machine learning

Background

We attempted to develop a progression prediction model for local advanced rectal cancer(LARC) patients who received preoperative neoadjuvant chemoradiotherapy(NCRT) and operative treatment to identify high-risk patients in advance.

Methods

Data from 272 LARC patients who received NCRT and total mesorectal excision(TME) from 2011 to 2018 at the Fourth Hospital of Hebei Medical University were collected. Data from 161 patients with rectal cancer (each sample with one target variable (progression) and 145 characteristic variables) were included. One Hot Encoding was applied to numerically represent some characteristics. The K-Nearest Neighbor (KNN) filling method was used to determine the missing values, and SmoteTomek comprehensive sampling was used to solve the data imbalance. Eventually, data from 135 patients with 45 characteristic clinical variables were obtained. Random forest, decision tree, support vector machine (SVM), and XGBoost were used to predict whether patients with rectal cancer will exhibit progression. LASSO regression was used to further filter the variables and narrow down the list of variables using a Venn diagram. Eventually, the prediction model was constructed by multivariate logistic regression, and the performance of the model was confirmed in the validation set.

Results

Eventually, data from 135 patients including 45 clinical characteristic variables were included in the study. Data were randomly divided in an 8:2 ratio into a data set and a validation set, respectively. Area Under Curve (AUC) values of 0.72 for the decision tree, 0.97 for the random forest, 0.89 for SVM, and 0.94 for XGBoost were obtained from the data set. Similar results were obtained from the validation set. Twenty-three variables were obtained from LASSO regression, and eight variables were obtained by considering the intersection of the variables obtained using the previous four machine learning methods. Furthermore, a multivariate logistic regression model was constructed using the data set; the ROC indicated its good performance. The ROC curve also verified the good predictive performance in the validation set.

Conclusions

We constructed a logistic regression model with good predictive performance, which allowed us to accurately predict whether patients who received NCRT and TME will exhibit disease progression.

Relevance of shrinkage versus fragmented response patterns in rectal cancer

AIMS

Partial response to neoadjuvant chemoradiotherapy (CRT) presents with one of two main response patterns: shrinkage or fragmentation. This study investigated the relevance of these response patterns in rectal cancer, correlation with other response indicators, and outcome.

METHODS AND RESULTS

The study included a test (n = 197) and a validation cohort (n = 218) of post-CRT patients with rectal adenocarcinoma not otherwise specified and a partial response. Response patterns were scored by two independent observers using a previously developed three-step flowchart. Tumour regression grading (TRG) was established according to both the College of American Pathologists (CAP) and Dworak classifications. In both cohorts, the predominant response pattern was fragmentation (70% and 74%), and the scoring interobserver agreement was excellent (k = 0.85). Patients with a fragmented pattern presented with significantly higher pathological stage (ypTNM II-IV, 78% versus 35%; P < 0.001), less tumour regression with Dworak (P = 0.004), and CAP TRG (P = 0.005) compared to patients with a shrinkage pattern. As a predictor of prognosis, the shrinkage pattern outperformed the TRG classification and stratified patients better in overall (fragmented pattern, hazard ratio [HR] 2.04, 95% confidence interval [CI] 1.19-3.50, P = 0.008) and disease-free survival (DFS; fragmented pattern, HR 2.50, 95% CI 1.23-5.10, P = 0.011) in the combined cohorts. The multivariable regression analyses revealed pathological stage as the only independent predictor of DFS.

CONCLUSIONS

The heterogeneous nature of tumour response following CRT is reflected in fragmentation and shrinkage. In rectal cancer there is a predominance of the fragmented pattern, which is associated with advanced stage and less tumour regression. While not independently associated with survival, these reproducible patterns give insights into the biology of tumour response.

Long-term follow-up of HER2 overexpression in patients with rectal cancer after preoperative radiotherapy: A prospective cohort study

BACKGROUND

The role of HER2 overexpression in rectal cancer is controversial.

AIM

To assess the role of HER2 overexpression in the long-term prognosis of rectal cancer.

METHODS

Data from patients with locally advanced rectal cancer who underwent total mesorectal excision after short-course radiotherapy at Beijing Cancer Hospital between May 2002 and October 2005 were collected. A total of 151 tissue samples of rectal cancer were obtained using rigid proctoscopy before neoadjuvant radiotherapy, followed by immunohistochemistry and fluorescence in situ hybridisation to determine the patients’ HER2 expression status. Univariate and multivariate analyses of the associations between the clinicopathological factors and HER2 status were performed. Survival was estimated and compared using the Kaplan-Meier method based on HER2 expression status, and the differences between groups were verified using the log-rank test.

RESULTS

A total of 151 patients were enrolled in this study. A total of 27 (17.9%) patients were ultimately confirmed to be HER2-positive. The follow-up duration ranged from 9 mo to 210 mo, with a median of 134 mo. Distant metastasis and local recurrence occurred in 60 (39.7%) and 24 (15.9%) patients, respectively. HER2 positivity was significantly associated with the pre-treatment lymph node stage (pre-N) (P = 0.040), while there were no differences between HER2 status and age, sex, preoperative CEA levels (pre-CEA), T stage, and lympho-vascular invasion. In terms of prognosis, HER2 overexpression was correlated with distant metastasis (P = 0.002) rather than local recurrence (P > 0.05). The multivariate analysis demonstrated that elevated pre-CEA [P = 0.002, odds ratio (OR) = 3.277, 97.5% confidence interval (CI): 1.543-7.163], post N(+) (P = 0.022, OR = 2.437, 97.5%CI: 1.143-5.308) and HER2(+) (P = 0.003, OR = 4.222, 97.5%CI: 1.667-11.409) were risk factors for distant metastasis. The survival analysis showed that there were significant differences between rectal cancer patients in terms of disease-free survival (DFS) [hazard ratio: 1.69 (95%CI: 0.91-3.14); P = 0.048] and overall survival (OS) [1.95 (1.05-3.63); P = 0.0077].

CONCLUSION

HER2 overexpression is a potential biomarker for predicting lymph node metastasis and distant metastasis, which are associated with worse long-term DFS and OS in rectal cancer patients with locally advanced disease.

Circulating Biomarkers in Predicting Pathological Response to Neoadjuvant Therapy for Colorectal Cancer

Circulating biomarkers show promise in the management of many cancers. They have become the novel non-invasive approach to complement the current strategies in colorectal cancer (CRC) management. Their ability in guiding diagnosis, evaluating response to treatment, screening and prognosis is phenomenal, especially when it comes to their minimally invasive nature. These “liquid biopsies,” which show potential for replacing invasive surgical biopsies, provide useful information on the primary and metastatic disease by providing an insight into cancer biology. Analysis of blood and body fluids for circulating tumour DNA (ctDNA), carcinoembryonic antigen (CEA), circulating tumour cells (CTC), or circulating micro RNA (miRNA) shows potential for improving CRC management. Recognizing a predictive model to assess response to neoadjuvant chemotherapy would help in better patient selection. This review was conducted with the aim of outlining the use of circulatory biomarkers in current practice and their effectiveness in the management of patients having CRC with a focus on response to neoadjuvant therapy.

Predictors of pathologic complete response in patients with residual flat mucosal lesions after neoadjuvant chemoradiotherapy for locally advanced rectal cancer

OBJECTIVE

The accurate prediction of tumor response to neoadjuvant chemoradiotherapy (nCRT) remains challenging. Few studies have investigated pathologic complete response (ypCR) prediction in patients with residual flat mucosal lesions after treatment. This study aimed to identify variables for predicting ypCR in patients with residual flat mucosal lesions after nCRT for locally advanced rectal cancer (LARC).

METHODS

Data of patients with residual flat mucosal lesions after nCRT who underwent radical resection between 2009 and 2015 were retrospectively collected from the LARC database at Peking University Cancer Hospital. Univariate and multivariate analyses of the association between clinicopathological factors and ypCR were performed, and a nomogram was constructed by incorporating the significant predictors.

RESULTS

Of the 246 patients with residual flat mucosal lesions included in the final analysis, 56 (22.8%) had ypCR. Univariate and multivariate analyses showed that pretreatment cT stage (pre-cT) ≤T2 (P=0.016), magnetic resonance tumor regression grade (MR-TRG) 1-3 (P=0.001) and residual mucosal lesion depth =0 mm (P<0.001) were associated with a higher rate of ypCR. A nomogram was developed with a concordance index (C-index) of 0.759 and the calibration curve showed that the nomogram model had good predictive consistency. The follow-up time ranged from 3.0 to 113.3 months, with a median follow-up time of 63.77 months. The multivariate Cox regression model showed that the four variables in the nomogram model were not risk factors for disease-free survival (DFS) or overall survival (OS).

CONCLUSIONS

Completely flat mucosa, early cT stage and good MR-TRG were predictive factors for ypCR instead of DFS or OS in patients with LARC with residual flat mucosal lesions after nCRT. Endoscopic mucosal re-evaluation before surgery is important, as it may contribute to decision-making and facilitate nonoperative management or organ preservation.

Predicting neoadjuvant chemoradiotherapy response with functional imaging and liquid biomarkers in locally advanced rectal cancer

INTRODUCTION

Non-invasive predictive quantitative biomarkers are required to guide treatment individualization in patients with locally advanced rectal cancer (LARC) in order to maximise therapeutic outcomes and minimise treatment toxicity. Magnetic resonance imaging (MRI), positron emission tomography (PET) and blood biomarkers have the potential to predict chemoradiotherapy (CRT) response in LARC.

AREAS COVERED

This review examines the value of functional imaging (MRI and PET) and liquid biomarkers (circulating tumor cells (CTCs) and circulating tumor nucleic acid (ctNA)) in the prediction of CRT response in LARC. Selected imaging and liquid biomarker studies are presented and the current status of the most promising imaging (apparent diffusion co-efficient (ADC), K^trans, SUV_max, metabolic tumor volume (MTV) and total lesion glycolysis (TLG) and liquid biomarkers (circulating tumor cells (CTCs), circulating tumor nucleic acid (ctNA)) is discussed. The potential applications of imaging and liquid biomarkers for treatment stratification and a pathway to clinical translation are presented.

EXPERT OPINION

Functional imaging and liquid biomarkers provide novel ways of predicting CRT response. The clinical and technical validation of the most promising imaging and liquid biopsy biomarkers in multi-centre studies with harmonised acquisition techniques is required. This will enable clinical trials to investigate treatment escalation or de-escalation pathways in rectal cancer.

Predicting response to neoadjuvant chemoradiotherapy in rectal cancer: from biomarkers to tumor models

Colorectal cancer (CRC) is a major contributor to cancer-associated morbidity worldwide and over one-third of CRC is located in the rectum. Neoadjuvant chemoradiotherapy (nCRT) followed by surgical resection is commonly applied to treat locally advanced rectal cancer (LARC). In this review, we summarize current and novel concepts of neoadjuvant therapy for LARC such as total neoadjuvant therapy and describe how these developments impact treatment response. Moreover, as response to nCRT is highly divergent in rectal cancers, we discuss the role of potential predictive biomarkers. We review recent advances in biomarker discovery, from a clinical as well as a histopathological and molecular perspective. Furthermore, the role of emerging predictive biomarkers derived from the tumor environment such as immune cell composition and gut microbiome is presented. Finally, we describe how different tumor models such as patient-derived cancer organoids are used to identify novel predictive biomarkers for chemoradiotherapy (CRT) in rectal cancer.

Tumor-Infiltrating Lymphocytes as Biomarkers of Treatment Response and Long-Term Survival in Patients with Rectal Cancer: A Systematic Review and Meta-Analysis

Simple Summary

This study investigated tumor-infiltrating lymphocytes (TILs) in pretherapeutic biopsies as biomarkers of treatment response and long-term prognosis in patients with locally advanced rectal cancer undergoing neoadjuvant chemoradiotherapy. A systematic review and meta-analysis was performed in accordance with the PRISMA guidelines. The results indicate that it is possible to identify a sub-group of patients with improved treatment response and long-term prognosis by assessing the density of CD8⁺ TILs at the time of diagnosis.

Abstract

Neoadjuvant chemoradiotherapy (NCRT) is indicated in locally advanced rectal cancer (LARC) to downstage tumors before surgery. Watchful waiting may be a treatment option to avoid surgery in patients, obtaining a complete clinical response. However, biomarkers predictive of treatment response and long-term prognosis are lacking. Here we investigated tumor-infiltrating lymphocytes (TILs) in pretherapeutic biopsies as predictive and prognostic biomarkers. A systematic review and meta-analysis was performed in accordance with the PRISMA guidelines. In total, 429 articles were identified, of which 19 studies were included in the systematic review and 14 studies in the meta-analysis. Patients with high pretherapeutic CD8⁺ TILs density had an increased likelihood of achieving a pathological complete response (RR = 2.71; 95% CI: 1.58–4.66) or a complete or near-complete pathological treatment response (RR = 1.86; 95% CI: 1.50–2.29). Furthermore, high CD8⁺ TILs density was a favorable prognostic factor for disease-free survival (HR = 0.57; 95% CI: 0.38–0.86) and overall survival (HR = 0.43; 95% CI: 0.27–0.69). CD3⁺, CD4⁺, and FOXP3⁺ TILs were not identified as predictive or prognostic biomarkers. Thus, assessing pretherapeutic CD8⁺ TILs density may assist in identifying patients with increased sensitivity to NCRT and favorable long-term prognosis.

Overexpression of MLPH in Rectal Cancer Patients Correlates with a Poorer Response to Preoperative Chemoradiotherapy and Reduced Patient Survival

Data mining of a public transcriptomic rectal cancer dataset (GSE35452) from the Gene Expression Omnibus, National Center for Biotechnology Information identified the melanophilin (MLPH) gene as the most significant intracellular protein transport-related gene (GO:0006886) associated with a poor response to preoperative chemoradiation. An MLPH immunostain was performed on biopsy specimens from 172 rectal cancer patients receiving preoperative chemoradiation; samples were divided into high- and low-expression groups by H-scores. Subsequently, the correlations between MLPH expression and clinicopathologic features, tumor regression grade, disease-specific survival (DSS), local recurrence-free survival (LRFS), and metastasis-free survival (MeFS) were analyzed. MLPH expression was significantly associated with CEA level (p = 0.001), pre-treatment tumor status (p = 0.022), post-treatment tumor status (p < 0.001), post-treatment nodal status (p < 0.001), vascular invasion (p = 0.028), and tumor regression grade (p < 0.001). After uni- and multi-variable analysis of five-year survival, MLPH expression was still associated with lower DSS (hazard ratio (HR), 10.110; 95% confidence interval (CI), 2.178–46.920; p = 0.003) and MeFS (HR, 5.621; 95% CI, 1.762–17.931; p = 0.004). In conclusion, identifying MLPH expression could help to predict the response to chemoradiation and survival, and aid in personal therapeutic modification.

Multiparametric MRI-based Radiomics approaches on predicting response to neoadjuvant chemoradiotherapy (nCRT) in patients with rectal cancer

PURPOSE

To investigate the value of multiparametric MRI-based radiomics on predicting response to nCRT in patients with rectal cancer.

METHODS

This study enrolled 193 patients with pathologically confirmed LARC who received nCRT treatment between Apr. 2014 and Jun. 2018. All patients underwent baseline T1-weighted (T1W), T2-weighted (T2W) and T2-weighted fat-suppression (T2FS) MRI scans before neoadjuvant chemoradiotherapy. Radiomics features were extracted and selected from the MRI data to establish the radiomics signature. Important clinical predictors were identified by Mann-Whitney U test and Chi-square test. The nomogram integrating the radiomics signature and important clinical predictors was constructed using multivariate logistic regression. Prediction capabilities of each model were assessed with receiver operating characteristic (ROC) curve analysis. Performance of the nomogram was evaluated by its calibration and potential clinical usefulness.

RESULTS

For the prediction of good response (GR) and pathologic complete response (pCR), the developed radiomics signature comprising 10 and 7 features, respectively, were significantly associated with the therapeutic response to nCRT. The nomogram incorporating the radiomics signature and important clinical predictors (CEA and CA19-9 for predicting GR; CEA, posttreatment length and posttreatment thickness for predicting pCR) achieved favorable prediction efficacy, with AUCs of 0.918 (95% confidence interval [CI]: 0.867-0.971, Sen = 0.972, Spe = 0.828) and 0.944 (95% CI: 0.891-0.997, Sen = 0.943, Spe = 0.828) in the training and validation cohort for predicting GR, respectively; with AUCs of 0.959 (95% CI: 0.927-0.991, Sen = 1.000, Spe = 0.833) and 0.912 (95% CI: 0.843-0.982, Sen = 1.000, Spe = 0.815) in the training and validation cohort for predicting pCR, respectively. Decision curve analysis confirmed potential clinical usefulness of our nomogram.

CONCLUSIONS

This study demonstrated that the MRI-based radiomics nomogram is predictive of response to nCRT and can be considered as a promising tool for facilitating treatment decision-making for patients with LARC.

Biomarkers and cell-based models to predict the outcome of neoadjuvant therapy for rectal cancer patients

Rectal cancer constitutes approximately one-third of all colorectal cancers and contributes to considerable mortality globally. In contrast to colon cancer, the standard treatment for localized rectal cancer often involves neoadjuvant chemoradiotherapy. Tumour response rates to treatment show substantial inter-patient heterogeneity, indicating a need for treatment stratification. Consequently researchers have attempted to establish new means for predicting tumour response in order to assist in treatment decisions. In this review we have summarized published findings regarding potential biomarkers to predict neoadjuvant treatment response for rectal cancer tumours. In addition, we describe cell-based models that can be utilized both for treatment prediction and for studying the complex mechanisms involved.

Association Between Pathological Complete Response and Tumor Location in Patients with Rectal Cancer After Neoadjuvant Chemoradiotherapy, a Prospective Cohort Study

Background: Colorectal cancers are the third common malignancies after lung and breast neoplasms. Some contributing factors for pathological complete response (pCR) to neoadjuvant therapy of rectal cancer have been defined. Despite various studies in this era, there are few studies on the location of tumors. Objectives: Regarding the high prevalence of colorectal cancer in Iran and the importance of neoadjuvant chemoradiation for survival and morbidity, this study was carried out to determine the association between pathologic complete response and tumor location in patients with rectal cancer after neoadjuvant chemoradiotherapy. Methods: In this prospective cohort, 100 cases with rectal adenocarcinoma from 2017 to 2019 were enrolled. Distance between anal verge and tumor was measured by clinical examination, colonoscopy, endo-sonography, and MRI. Tumors were defined as distal (less than 5 cm from the anal verge) and none distal (more than 5 cm from the anal verge). Another subdivision was inferior (0 - 4.99 cm), middle (5 - 9.99 cm), and superior (10 - 15 cm). The pathological response was compared across the groups. Results: In this study, the pCR was seen in 30%. In univariate analysis body mass index (BMI), grade, N-stage, and distance from anal verge were related to pCR. In cases with BMI over 25 kg/m2 and in tumors with low to medium grade N0/N1, and distance less than 5 cm from the anal verge (low lying tumors) the pCR to neoadjuvant treatment was higher. In multivariate analysis tumor grade, N stage, and distance from anal verge were still related to pCR. Conclusions: According to the obtained results in this study, there may be some association between rectal tumor location and pathologic complete response.

Can normalized carcinoembryonic antigen following neoadjuvant chemoradiation predict tumour recurrence after curative resection for locally advanced rectal cancer?

AIM

The aim of this work was to evaluate whether normalized carcinoembryonic antigen (CEA) following neoadjuvant chemoradiation predicts the prognosis following curative resection in locally advanced rectal cancer.

METHOD

Patients who underwent neoadjuvant chemoradiation and curative resection for locally advanced rectal cancer between 2010 and 2015 were divided into three groups: Group A (n = 119, normal-to-normal): normal CEA before and after neoadjuvant chemoradiation; Group B (n = 37, high-to-normal): elevated CEA before and normal CEA after neoadjuvant chemoradiation; Group C (n = 36, high-to-high): elevated CEA before and after neoadjuvant chemoradiation. Overall and disease-free survival were compared. Univariate and multivariate analyses identified potential predictors for recurrence.

RESULTS

One hundred and ninety two patients [median age 59 years (range 31-87), 65.1% male] were identified: 54.7% had low rectal cancer: 12.5% were clinical stage T4 and 70.3% were clinically node positive; 21.9% achieved complete pathological response; 24.5% had abdominoperineal resection (APR); and 70.3% underwent adjuvant chemotherapy following curative resection. Significantly more patients in Group C underwent APR (p = 0.0209), had advanced pathological T stage (P = 0.0065) and a higher prevalence of perineural invasion (p = 0.0042). Overall and disease-free survival were significantly higher for Group A than for Group C [hazard ratio (HR) = 4.32, 95% CI = 1.66-11.21, p = 0.0026 and HR=2.68, 95% CI = 1.33-5.40, p = 0.0057, respectively]. No significant difference was noted between Groups A and B for overall (p = 0.0591) or disease-free (p = 0.2834) survival. Another risk factor associated with recurrence and death was clinical T4 stage; nodal positivity was a risk factor only for recurrence.

CONCLUSION

Elevated CEA after neoadjuvant chemoradiation and clinical stage T4 disease were unfavourable predictors for overall and disease-free survival. Normalized CEA during neoadjuvant chemoradiation may serve as a prognosticator, although pretreatment CEA may significantly affect survival.

Can Pre-Treatment Inflammatory Parameters Predict the Probability of Sphincter-Preserving Surgery in Patients with Locally Advanced Low-Lying Rectal Cancer?

There is evidence suggesting that pre-treatment clinical parameters can predict the probability of sphincter-preserving surgery in rectal cancer; however, to date, data on the predictive role of inflammatory parameters on the sphincter-preservation rate are not available. The aim of the present cohort study was to investigate the association between inflammation-based parameters and the sphincter-preserving surgery rate in patients with low-lying locally advanced rectal cancer (LARC). A total of 848 patients with LARC undergoing radiotherapy from 2004 to 2019 were retrospectively reviewed in order to identify patients with rectal cancer localized ≤6 cm from the anal verge, treated with neo-adjuvant radiochemotherapy (nRCT) and subsequent surgery. Univariable and multivariable analyses were used to investigate the role of pre-treatment inflammatory parameters, including the C-reactive protein (CRP), neutrophil-to-lymphocyte ratio (NLR), and platelet-to-lymphocyte ratio (PLR) for the prediction of sphincter preservation. A total of 363 patients met the inclusion criteria; among them, 210 patients (57.9%) underwent sphincter-preserving surgery, and in 153 patients (42.1%), an abdominoperineal rectum resection was performed. Univariable analysis showed a significant association of the pre-treatment CRP value (OR = 2.548, 95% CI: 1.584–4.097, p < 0.001) with sphincter preservation, whereas the pre-treatment NLR (OR = 1.098, 95% CI: 0.976–1.235, p = 0.120) and PLR (OR = 1.002, 95% CI: 1.000–1.005, p = 0.062) were not significantly associated with the type of surgery. In multivariable analysis, the pre-treatment CRP value (OR = 2.544; 95% CI: 1.314–4.926; p = 0.006) was identified as an independent predictive factor for sphincter-preserving surgery. The findings of the present study suggest that the pre-treatment CRP value represents an independent parameter predicting the probability of sphincter-preserving surgery in patients with low-lying LARC.

Predicting pathological response to chemoradiotherapy for rectal cancer: a systematic review

Introduction: Pathological complete response (pCR) rates of approximately 20% following neoadjuvant long-course chemoradiotherapy for rectal cancer have given rise to non-operative or watch-and-wait (W&W) management. To improve outcomes there has been significant research into predictors of response. The goal is to optimize selection for W&W, avoid chemoradiotherapy in those who won't benefit and improve treatment to maximize the clinical complete response (cCR) rate and the number of patients who can be considered for W&W.Areas covered: A systematic review of articles published 2008-2018 and indexed in PubMed, Embase or Medline was performed to identify predictors of pathological response (including pCR and recognized tumor regression grades) to fluoropyrimidine-based chemoradiotherapy in patients who underwent total mesorectal excision for rectal cancer. Evidence for clinical, biomarker and radiological predictors is discussed as well as potential future directions.Expert opinion: Our current ability to predict the response to chemoradiotherapy for rectal cancer is very limited. cCR of 40% has been achieved with total neoadjuvant therapy. If neoadjuvant treatment for rectal cancer continues to improve it is possible that the treatment for rectal cancer may eventually parallel that of anal squamous cell carcinoma, with surgery reserved for the minority of patients who don't respond to chemoradiotherapy.

Clinical predictors of response to chemoradiotherapy for rectal cancer as an aid to organ preservation

AIM

Clinical predictors of pathological response to chemoradiotherapy for rectal cancer can influence patient management including selection for organ preservation. This study aimed to identify clinical predictors at a tertiary referral hospital.

METHODS

A retrospective review of clinical records was undertaken after identifying all patients with stage 1-3 rectal cancer treated with long course chemoradiotherapy and total mesorectal excision from 2013 to 2018. Clinicopathological factors were recorded and multivariate analysis performed to identify predictors of pathological complete response (pCR) and good response (AJCC TRG 0-1).

RESULTS

A total of 470 patients with rectal cancer were identified of which 164 met the inclusion criteria for the study. The pCR rate was 14.6% and good response (TRG 0-1) rate 43.7%. On univariate analysis, lower T stage, older age, node negative status, anterior tumour position and shorter tumour length on magnetic resonance imaging (MRI) were associated with good response (TRG 0-1). On univariate analysis cN stage, carcinoembryonic antigen <5 and shorter tumour length on MRI were associated with pCR. On binary logistic regression shorter length on MRI and lower clinical nodal stage were predictive of pCR and lower body mass index, anterior tumour position and higher haemoglobin were predictive of good response (TRG 0-1).

CONCLUSION

Anterior tumour position is newly identified as an independent predictor of good response (TRG 0-1) to nCRT for rectal cancer and this should be explored in future studies. Higher haemoglobin and lower body mass index were also independent predictors of good response (TRG 0-1) and optimisation of these factors should be considered when using neoadjuvant chemoradiotherapy for rectal cancer.

Ten-year survival after pathologic complete response in rectal adenocarcinoma

BACKGROUND

Multimodal treatment is the standard of care for rectal adenocarcinoma, with a subset of patients achieving a pathologic complete response (pCR). While pCR is associated with improved overall survival (OS), long-term data on patients with pCR is limited.

METHODS

This is a single institution retrospective cohort study of all patients with clinical stages II/III rectal adenocarcinoma who underwent neoadjuvant chemoradiation therapy and operative resection (January 1, 2004-December 31, 2017). PCR was defined as no tumor identified in the rectum or associated lymph nodes by final pathology.

RESULTS

Of 370 patients in this cohort, 50 had a pCR (13.5%). For pCR patients, 5-year disease-free survival (DFS) was 92%, 5-year OS was 95%. Twenty-six patients had surgery > 10 years before the study end date, of which 20 had an OS > 10 years (77%) with median OS 12.1 years and 95% alive to date (19/20). Of the 50 pCR patients, there was a single recurrence in the lung at 44.3 months after proctectomy which was surgically resected.

CONCLUSION

For patients with rectal adenocarcinoma that undergo neoadjuvant chemoradiation and surgical resection, pCR is associated with excellent long-term DFS and OS. Many patients live greater than 10 years with no evidence of disease recurrence.

The impact of sarcopenia on pathologic complete response following neoadjuvant chemoradiation in rectal cancer

PURPOSE

The role of sarcopenia in pathologic complete response (pCR) following neoadjuvant chemoradiotherapy (nCRT) in non-metastatic locally advanced rectal cancer is currently unknown. The present study investigates the association between sarcopenia and post-nCRT pCR.

METHODS

The data of patients operated on following nCRT between January 2013 and January 2020 were collected retrospectively. Sarcopenia was diagnosed based on the calculation of the skeletal muscle index (SMI) from computed tomography carried out at the time of the initial diagnosis. A statistical analysis was then conducted for predictors of pCR.

RESULTS

The study included 61 patients with an average age of 57.3 years, 28 of whom formed the non-sarcopenic group (NSG) and 33 the sarcopenic group (SG). Of the patients, 32.7% were at clinical stage 2, and 67.3% were at clinical stage 3. Pathologic data following a mesorectal excision revealed a pCR rate of 21.4% in the NSG compared with 3% in the SG, which was a statistically significant difference (p = 0.025). The TNM downstaging rate was higher in the NSG than in the SG, although the difference was not statistically significant (50% vs. 33.3%, p = 0.28). A univariate analysis revealed the factors affecting pCR to be non-sarcopenia (p = 0.025), age < 61 years (p = 0.004), interval to surgery ≥ 8 weeks (p = 0.029), and serum CEA < 2.5 ng/ml (p = 0.035).

CONCLUSION

Sarcopenia was found to be a negative marker of pCR following nCRT in non-metastatic locally advanced rectal cancer.

Systemic inflammatory indices predict tumor response to neoadjuvant chemoradiotherapy for locally advanced rectal cancer

Systemic inflammatory responses are associated with the prognosis of patients with colorectal cancer. However, the value in predicting tumor responses to neoadjuvant chemoradiotherapy (nCRT) remains to be elucidated. The current study aimed to investigate the association between systemic inflammatory indices and pathological complete response (pCR). The training and validation cohorts included 225 and 96 patients with locally advanced rectal cancer. The neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio were recorded prior to nCRT and radical surgery. Univariate and multivariate analysis were used to investigate the association between systemic inflammatory indices and pCR. Systemic inflammatory indices prior to or following treatment had no significant association with pCR; however, the percentage change in NLR from pre-nCRT to post-nCRT was associated with a poor response, and a percentage change of >21.5% NLR (P=0.006; OR=0.413; 95% CI=0.22–0.773) was a predictor of poor pCR. Therefore, in rectal cancer, the percentage change in NLR from pre- to post-nCRT was found to be a predictor of poor pCR.

Clinical parameters predictive for sphincter-preserving surgery and prognostic outcome in patients with locally advanced low rectal cancer

Background

Although controversial, there are data suggesting that clinical parameters can predict the probability of sphincter preserving procedures in rectal cancer. The purpose of this study was to investigate the association between clinical parameters and the sphincter-preserving surgery rate in patients who had undergone neoadjuvant combination therapy for advanced low rectal cancer.

Methods

In this single center study, the charts of 540 patients with locally advanced rectal cancer who had been treated with induction chemotherapy-and/or neoadjuvant concomitant radiochemotherapy (nRCT) over an 11-year period were reviewed in order to identify patients with rectal cancer ≤6 cm from the anal verge, who had received the prescribed nRCT only. Univariate and multivariate analyses were used to identify pretreatment patient- and tumor associated parameters correlating with sphincter preservation. Survival rates were calculated using Kaplan-Meier analyses.

Results

Two hundred eighty of the 540 patients met the selection criteria. Of the 280 patients included in the study, 158 (56.4%) underwent sphincter-preserving surgery. One hundred sixty-four of 280 patients (58.6%) had a downsizing of the primary tumor (ypT < cT) and 39 (23.8%) of these showed a complete histopathological response (ypT0 ypN0). In univariate analysis, age prior to treatment, Karnofsky performance status, clinical T-size, relative lymphocyte value, CRP value, and interval between nRCT and surgery, were significantly associated with sphincter-preserving surgery. In multivariate analysis, age (hazard ratio (HR) = 1.05, CI95%: 1.02–1.09, p = 0.003), relative lymphocyte value (HR = 0.94, CI95%: 0.89–0.99, p = 0.029), and interval between nRCT and surgery (HR = 2.39, CI95%: 1.17–4.88, p = 0.016) remained as independent predictive parameters.

Conclusions

These clinical parameters can be considered in the prognostication of sphincter-preserving surgery in case of low rectal adenocarcinoma. More future research is required in this area.

Predictive Significance of Mucinous Histology on Pathologic Complete Response Rate Following Capecitabine-Based Neoadjuvant Chemoradiation in Rectal Cancer: a Comparative Study

INTRODUCTION

Currently, neoadjuvant fluoropyrimidine-based chemoradiation followed by surgery is considered the standard of care for locally advanced rectal cancer. The current study aimed to investigate the predictive significance of mucinous histology on the pathologic complete response rate following neoadjuvant chemoradiation in locally advanced rectal cancer and to propose potential new treatment protocol for this specific histology.

MATERIAL AND METHOD

This retrospective study was conducted on 403 patients with locally advanced (clinically T3-4 and/or N1-2) rectal adenocarcinoma who had been treated at three tertiary academic hospitals between 2010 and 2015. Among those 403 patients, 46 (11%) had mucinous rectal cancer (MRC) and 358 (89%) had non-mucinous rectal cancer (NMRC). All patients underwent neoadjuvant chemoradiation with capecitabine followed by low anterior or abdominoperineal resection.

RESULTS

There were 268 men and 135 women with a median age of 55 years (range, 26-82 years). Patients with MRC were younger (p = 0.002) and presented with a larger tumor size (p < 0.001) and a more advanced tumor stage (p = 0.033) compared to the ones with MNRC. In the univariate analysis, female gender (p = 0.009), distal tumor location (p = 0.035), higher tumor stage (p = 0.049), node positivity (p = 0.001), MRC histology (p = 0.017), and high pretreatment CEA level (p = 0.013) were observed to be predictive of a poor pathologic complete response. However, in the multivariate analysis, tumor stage was the single most predictive factor of response to neoadjuvant chemoradiation.

CONCLUSION

Mucinous adenocarcinoma is a significant predictive factor for poor pathologic complete response to neoadjuvant capecitabine-based chemoradiation in patients with locally advanced rectal cancer. New treatment modality based on biomarkers may be considered in future prospective studies because of MRC poor prognosis. Immunotherapy combined with chemotherapy and/or radiotherapy may be an attractive option because of the tumor microsatellite instability-high status.

Predictors for complete pathological response for stage II and III rectal cancer following neoadjuvant therapy - A systematic review and meta-analysis

BACKGROUND

There has been an increasing interest in the complete pathological response (pCR) in rectal cancers following neoadjuvant therapy. The aim of this study was to identify predictive factors of pCR in locally advanced rectal cancer following neoadjuvant therapy.

METHODS

The studies identified were appraised with standard selection criteria. The selection criteria included studies on patients with stage II or III rectal cancer who underwent neoadjuvant therapy.

RESULTS

Patients with pCR are more likely to be older (p = 0.0002), have cancers closer distance to the anal verge (p < 0.00001), smaller tumors (P < 0.0001), no clinical lymph nodes involvement (p=<0.00001) and waited more than eight weeks until definitive surgery (p = 0.002). There was no difference in gender (p = 0.15) and tumor differentiation (p = 0.21).

CONCLUSIONS

The 'Watch and Wait' approach may be appropriate for selected patients. Patients with lower rectal cancers, smaller tumors, and negative clinical lymph node involvement may be more likely to achieve pCR following neoadjuvant therapy.

Predictive value of carcinoembryonic antigen and carbohydrate antigen 19-9 related to downstaging to stage 0-I after neoadjuvant chemoradiotherapy in locally advanced rectal cancer

Objective

To explore the value of carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9) in predicting downstaging to stage 0–I cancer after neoadjuvant chemoradiotherapy (nCRT) in locally advanced rectal cancer.

Materials and methods

We respectively investigated pretreatment CEA, pretreatment CA19-9, posttreatment CEA, posttreatment CA19-9, pre–post-CA19-9 ratio, and pre–post-CEA ratio in 674 patients with locally advanced rectal cancer receiving nCRT and determined the patients’ thresholds by using the receiver operating characteristic curve analysis. The association between downstaging (stage 0–I after nCRT), pathological complete response, and clinicopathological parameters was evaluated using the Pearson χ2 test. The clinicopathological parameters which were found to be significantly associated with downstaging were analyzed by logistic regression models and were incorporated into a scoring system.

Results

Multivariate analysis showed that pretreatment CA19-9 level, posttreatment CEA level, pre–post-CEA ratio, and pre–post-CA19-9 ratio were significantly correlated with downstaging. Area under the curve of the scoring system was higher than that of parameters alone.

Conclusion

The 4-factor scoring system with CA19-9 level, posttreatment CEA level, pre– post-CEA ratio, and pre–post-CA19-9 ratio is of more value in predicting downstaging to stage 0–I patients with locally advanced rectal cancer after nCRT than using the parameters alone.

Analysis of Clinical characteristics to predict pathologic complete response for patients with locally advanced rectal cancer treated with neoadjuvant chemoradiotherapy

To explore clinical characteristics which could be applied to predict pathologic complete response (pCR) for patients with locally advanced rectal cancer treated with neoadjuvant chemoradiotherapy (neo-CRT) and total mesorectal excision (TME). 297 patients with locally advanced rectal cancer (cT3-4 or cN+) who were treated with neo-CRT followed by TME were retrospectively reviewed. Clinical characteristics including age, gender, tumor distance from anus, serum CEA, hemoglobin levels before treatment and clinical TN stage were used to investigate the association with pCR after neo-CRT. Seventy-nine (26.6%) patients achieved pCR after neo-CRT. pCR were achieved in 42 (34.4%) patients in cT1-3 stage and 37 (21.1%) in cT4 stage. pCR rate was 36.4% and 16.4% for patients with pre-treatment serum CEA ≤5.33ng/ml and >5.33ng/ml, respectively. Uni- and multi-variate analyses revealed that pre-treatment serum CEA level ≤5.33ng/ml and clinical T stage, (i.e., cT1-3 versus cT4) were highly correlated with pCR (p < 0.05). Clinical T stage and pre-treatment serum CEA level were strongly associated with pCR for patients with locally advanced rectal cancer treated with neo-CRT followed by TME which could be applied as clinical predictors for pCR.

The predictive and prognostic potential of plasma telomerase reverse transcriptase (TERT) RNA in rectal cancer patients

BACKGROUND

Preoperative chemoradiotherapy (CRT) followed by surgery is the standard care for locally advanced rectal cancer, but tumour response to CRT and disease outcome are variable. The current study aimed to investigate the effectiveness of plasma telomerase reverse transcriptase (TERT) levels in predicting tumour response and clinical outcome.

METHODS

176 rectal cancer patients were included. Plasma samples were collected at baseline (before CRT=T0), 2 weeks after CRT was initiated (T1), post-CRT and before surgery (T2), and 4-8 months after surgery (T3) time points. Plasma TERT mRNA levels and total cell-free RNA were determined using real-time PCR.

RESULTS

Plasma levels of TERT were significantly lower at T2 (P<0.0001) in responders than in non-responders. Post-CRT TERT levels and the differences between pre- and post-CRT TERT levels independently predicted tumour response, and the prediction model had an area under curve of 0.80 (95% confidence interval (CI) 0.73-0.87). Multiple analysis demonstrated that patients with detectable TERT levels at T2 and T3 time points had a risk of disease progression 2.13 (95% CI 1.10-4.11)-fold and 4.55 (95% CI 1.48-13.95)-fold higher, respectively, than those with undetectable plasma TERT levels.

CONCLUSIONS

Plasma TERT levels are independent markers of tumour response and are prognostic of disease progression in rectal cancer patients who undergo neoadjuvant therapy.

Pathologic response following treatment for locally advanced rectal cancer: Does location matter?

BACKGROUND

Despite advances in the treatment of rectal adenocarcinoma, the management of locally advanced disease remains a challenge. The standard of care for patients with stages II and III rectal cancer includes neoadjuvant chemoradiation followed by total mesorectal excision and postoperative chemotherapy. Much effort has been dedicated to the identification of predictive factors associated with pathologic complete response (pCR). The aim of our study was to examine our institutional experience and determine whether any association exists between anatomic tumor location and the rate of pCR. We hypothesized that lesions more than 6 cm from the anal verge are more likely to achieve a pCR.

METHODS

Using data from our prospectively maintained tumor registry, a query was completed to identify all patients with locally advanced rectal adenocarcinoma who underwent treatment at Fox Chase Cancer Center from 2002 to 2015. Demographics, pretreatment, posttreatment, and final pathologic TNM staging data were collected as well as treatment intervals in days, recurrence status, overall survival, and disease-free survival. Patients with incomplete endoscopic data, staging information, survival, or recurrence status were excluded. The primary outcome measured was the degree of pathologic response. Logistic regression was used to adjust for covariates.

RESULTS

Of the 135 patients eligible in the study cohort, 39% were female and 61% were male. Regarding initial clinical stage, 43% were stage II and 57% were stage III. A total of 29% had a pCR, 43% had partial pathologic response, and 28% had no response to neoadjuvant treatment. Tumor location ranged from 0 to 13 cm from the anal verge. Longitudinal tumor length was recorded in 111 patients, facilitating the calculation of mean tumor distance from the anal verge. This ranged from 0 to 15.5 cm. Univariate and multivariable analyses were completed using pCR as a primary outcome. No statistically significant difference was noted based on tumor location, regardless of measurement approach.

CONCLUSIONS

Anatomic location of cancer of the rectum does not affect pCR after neoadjuvant therapy and subsequent surgical resection.

Pre-treatment carcinoembryonic antigen and outcome of patients with rectal cancer receiving neo-adjuvant chemo-radiation and surgical resection: a systematic review and meta-analysis

Neo-adjuvant chemo-radiation is the standard of care for patients with locally advanced rectal carcinoma. The aim of the present paper is to evaluate the relationship of the baseline serologic concentration of the carcinoembryonic antigen with the outcome. Data sources included MEDLINE and Web of Science databases. A systematic search of the databases by a predefined criterion has been conducted. Chemo-radiation followed by surgical resection of rectal tumors was the intervention of interest. From selected studies, the relationships between carcinoembryonic antigen and pathologic complete response, disease-free survival and overall survival were assessed. Carcinoembryonic antigen correlated significantly and inversely with the rate of pathologic complete responses (OR 2.00). Similar to this relationship, a low baseline carcinoembryonic antigen concentration was associated with a better disease-free survival (OR 1.88) and a better overall survival (OR 1.85). Heterogeneity of studies and publication bias were considerable in evaluating the relationship of baseline carcinoembryonic antigen and pathologic complete response. Baseline carcinoembryonic antigen should be regarded as a predictor of outcome of patients undergoing neo-adjuvant chemo-radiation. A calibration of the cutoff value from 5 to 3 ng/ml appears more appropriate to this patient population and should be evaluated in prospective trials.

What has preoperative radio(chemo)therapy brought to localized rectal cancer patients in terms of perioperative and long-term outcomes over the past decades? A systematic review and meta-analysis based on 41,121 patients

We asked what preoperative radiotherapy/chemoradiotherapy (PRT/PCRT) has brought to patients in terms of perioperative and long-term outcomes over the past decades. A systematic review and meta-analysis was conducted using PubMed, Embase and Web of Science databases. All original comparative studies published in English that were related to PRT/PCRT and surgical resection and which analyzed survival, postoperative and quality of life outcomes were included. Data synthesis and statistical analysis were carried out using Stata software. Data from 106 comparative studies based on 80 different trials enrolling 41,121 patients were included in our study. Based on our overall analyses, PRT/PCRT significantly improved patients' local recurrence-free survival (LRFS), but neither overall survival (OS) nor metastasis-free survival (MFS) showed improvement. In addition, PRT significantly increased the postoperative morbidity and mortality but PCRT did not have a significant effect. Furthermore, PRT/PCRT significantly increased the risk of postoperative wound complications but not anastomotic leakage and bowel obstruction. Our comprehensive subgroup analyses further supported the aforementioned results. Meanwhile, long-term anorectal symptoms (impaired squeeze pressures, use of pads, incontinence and urgency) and erectile dysfunction were also significantly increased in patients after PRT/PCRT. The benefits of PRT/PCRT as applied over the last several decades have not been sufficient to improve OS. Metastases of primary tumor and postoperative adverse effects were the two primary obstacles for an improved OS. In fact, the greatest advantage of PRT/PCRT is still local tumor control and a significantly improved LRFS.

Predictive and Prognostic Molecular Biomarkers for Response to Neoadjuvant Chemoradiation in Rectal Cancer

The standard of care in locally advanced rectal cancer is neoadjuvant chemoradiation (nCRT) followed by radical surgery. Response to nCRT varies among patients and pathological complete response is associated with better outcome. However, there is a lack of effective methods to select rectal cancer patients who would or would not have a benefit from nCRT. The utility of clinicopathological and radiological features are limited due to lack of adequate sensitivity and specificity. Molecular biomarkers have the potential to predict response to nCRT at an early time point, but none have currently reached the clinic. Integration of diverse types of biomarkers including clinicopathological and imaging features, identification of mechanistic link to tumor biology, and rigorous validation using samples which represent disease heterogeneity, will allow to develop a sensitive and cost-effective molecular biomarker panel for precision medicine in rectal cancer. Here, we aim to review the recent advance in tissue- and blood-based molecular biomarker research and illustrate their potential in predicting nCRT response in rectal cancer.

Clinical utility of pretreatment prediction of chemoradiotherapy response in rectal cancer: a review

Approximately 20% of all patients with locally advanced rectal cancer experience pathologically complete responses following neoadjuvant chemoradiotherapy (CRT) and standard surgery. The utility of radical surgery for patients exhibiting good CRT responses has been challenged. Organ-sparing strategies for selected patients exhibiting complete clinical responses include local excision or no immediate surgery. The subjects of this tailored management are patients whose presenting disease corresponds to current indications of neoadjuvant CRT, and their post-CRT tumor response is assessed by clinical and radiological examinations. However, a model predictive of the CRT response, applied before any treatment commenced, would be valuable to facilitate such a personalized approach. This would increase organ preservation, particularly in patients for whom upfront CRT is not generally prescribed. Molecular biomarkers hold the greatest promise for development of a pretreatment predictive model of CRT response. A combination of clinicopathological, radiological, and molecular markers will be necessary to render the model robust. Molecular research will also contribute to the development of drugs that can overcome the radioresistance of rectal tumors. Current treatments for rectal cancer are based on the expected prognosis given the presenting disease extent. In the future, treatment schemes may be modified by including the predicted CRT response evaluated at presentation.

A retrospective comparison of outcome and toxicity of preoperative image-guided intensity-modulated radiotherapy versus conventional pelvic radiotherapy for locally advanced rectal carcinoma

The aim of the study was to compare clinical outcomes and toxicity between 3D conformal radiotherapy (3DCRT) and image-guided intensity-modulated radiotherapy (IG-IMRT) administered through helical tomotherapy in locally advanced rectal cancer (LARC) patients receiving preoperative chemoradiotherapy. We reviewed 144 patients with Stage II-III rectal cancer receiving preoperative fluoropyrimidine-based chemoradiotherapy followed by radical resection. Tumor responses following chemoradiotherapy were evaluated using the Dworak tumor regression grade (TRG). Of the 144 patients, 45 received IG-IMRT and 99 received 3DCRT. A significant reduction in Grade 3 or 4 acute gastrointestinal toxicity (IG-IMRT, 6.7%; 3DCRT, 15.1%; P = 0.039) was observed by IG-IMRT. The pathologic complete response (pCR) rate did not differ between the IG-IMRT and the 3DCRT group (17.8% vs 15.1%, P = 0.52). Patients in the IG-IMRT group had the trend of favorable tumor regressions (TRG 3 or 4) compared with those in the 3DCRT group (66.7% vs 43.5%, P = 0.071). The median follow-up was 53 months (range, 18-95 months) in the 3DCRT group and 43 months (range, 17-69 months) in the IG-IMRT group. Four-year overall, disease-free, and local failure-free survival rates of the IG-IMRT and 3DCRT groups were 81.6% and 67.9% (P = 0.12), 53.8% and 51.8% (P = 0.51), and 88% and 75.1% (P = 0.031), respectively. LARC patients treated with preoperative IG-IMRT achieved lower acute gastrointestinal adverse effects and a higher local control rate than those treated with 3DCRT, but there was no prominent difference in distant metastasis rate and overall survival between two treatment modalities.

Potential predictive factors for pathologic complete response after the neoadjuvant treatment of rectal adenocarcinoma: a single center experience

OBJECTIVE

: To assess the response rate of patients with rectal adenocarcinoma to neoadjuvant therapy and to identify the predictors of histological regression after neoadjuvant radiotherapy (RT) or concurrent chemoradiotherapy (CCRT).

METHODS

: This study recruited 64 patients. The patients had resectable cancer of the lower and the middle rectum (T3/T4 and/or N+) without distant metastasis and received neoadjuvant RT or CCRT followed by radical surgery with total mesorectal excision (TME) between January 2006 and December 2011. The patients were classified into non-response (NR), partial response (PR), and pathologic complete response (pCR) based on the Dworak tumor regression grading system.

RESULTS

: The median age of patients was 57 years (ranging from 22 to 85). A total of 24 patients were treated with neoadjuvant CCRT, whereas 40 patients were treated with RT alone. Abdominoperineal resection (APR) was performed on 29 patients (45%). Anterior resection with TME was performed on 34 patients (53%). One patient had local resection. Histologically, 12 (19%), 24 (73%), and 28 (44%) patients exhibited pCR, PR, and NR, respectively. Univariate analysis revealed that the predictors of tumor regression were as follows: the absence of lymph node involvement from initial imaging (cN0) (P=0.021); normal initial carcinoembryonic antigen (CEA) level (P=0.01); hemoglobin level ≥12 g/dl (P=0.009); CCRT (P=0.021); and tumor downstaging in imaging (P=0.001). Multivariate analysis showed that the main predictors of pCR were CT combined with neoadjuvant RT, cN0 stage, and tumor regression on imaging.

CONCLUSIONS

: Identifying the predictors of pCR following neoadjuvant therapy aids the selection of responsive patients for non-aggressive surgical treatment and possible surveillance.

Distance to the anal verge is associated with pathologic complete response to neoadjuvant therapy in locally advanced rectal cancer

BACKGROUND AND OBJECTIVES

Achieving a pathologic complete response (pCR) after neoadjuvant therapy has been associated with better prognosis in rectal cancer patients. The objective of this study was to investigate the relationship between distance to the anal verge (DTAV) and pCR.

METHODS

Review of a prospectively maintained database of patients with locally advanced rectal cancer who received neoadjuvant treatment was completed. Uni- and multivariate analysis assessed the association between DTAV and pCR after neoadjuvant therapy.

RESULTS

Of 827 included patients, 20% had a pCR. We found that pCR rates were 11% for tumors <4 cm, 24% for tumors 4-6 cm, 30% for tumors at 6-8 cm, 17% for tumors 8-10 cm, and 14% for tumors >10 cm from the anal verge (P = 0.002). Multivariate analysis also showed a strong association between DTAV and pCR (P = 0.008). The bimodal distribution of pCR resulted in a lower odds ratio of pCR for tumors <4 and >8 cm from the anal verge.

CONCLUSIONS

Patients with low tumors (<4 cm) and higher tumors (>8 cm), were less likely to have a pCR. Further investigation is warranted to determine if these observations are related to tumor biology or possibly differences in radiation technique. J. Surg. Oncol. 2016;114:637-641. © 2016 Wiley Periodicals, Inc.

Can serum dynamics of carcinoembryonic antigen level during neoadjuvant chemoradiotherapy in rectal cancer predict tumor response and recurrence? A multi-institutional retrospective study

PURPOSE

We evaluate whether the change of carcinoembryonic antigen (CEA) level before and after preoperative chemoradiotherapy (CRT) in rectal cancer affects tumor response and recurrence or not.

METHODS

We retrospectively analyzed 1447 rectal cancer patients who underwent preoperative CRT followed by curative surgery. All patients received preoperative radiotherapy of 50.4 Gy in 28 fractions with 5-fluorouracil or capecitabine. Total mesorectal excision was performed 4 to 8 weeks after preoperative CRT. CEA levels were checked before and after CRT. Clinical and pathologic factors were analyzed for tumor response and recurrence.

RESULTS

Post-CRT CEA level (cutoff value, 2.5 ng/mL) was not a significant factor for tumor response on the multivariate analysis (p = 0.095). Patients were categorized according to the pre- and post-CRT CEA level (group A: pre-CRT CEA ≤5 ng/mL; group B: pre-CRT CEA >5 ng/mL and post-CRT CEA ≤2.5 ng/mL; group C: pre-CRT CEA >5 ng/mL and post-CRT CEA >2.5 ng/mL). The relapse-free survival (RFS) at 5 years was significantly higher in group A than in groups B and C (82.6 vs. 73.7 % vs. 72.2 %, p < 0.001). The overall survival (OS) at 5 years was significantly higher in group A than in groups B and C (90.1 vs. 84.4 % vs. 83.4 %, p < 0.001). However, there is no significant difference for RFS and OS between groups B and C (all, p > 0.05).

CONCLUSIONS

Decline of elevated CEA level (>5 ng/mL) during preoperative chemoradiotherapy has no significant effect on tumor response and recurrence in rectal cancer.

Predicting pathological complete response to neoadjuvant chemoradiotherapy in locally advanced rectal cancer: a systematic review

AIM

Approximately 20% of patients treated with neoadjuvant chemoradiotherapy (nCRT) for locally advanced rectal cancer achieve a pathological complete response (pCR) while the remainder derive the benefit of improved local control and downstaging and a small proportion show a minimal response. The ability to predict which patients will benefit would allow for improved patient stratification directing therapy to those who are likely to achieve a good response, thereby avoiding ineffective treatment in those unlikely to benefit.

METHOD

A systematic review of the English language literature was conducted to identify pathological factors, imaging modalities and molecular factors that predict pCR following chemoradiotherapy. PubMed, MEDLINE and Cochrane Database searches were conducted with the following keywords and MeSH search terms: 'rectal neoplasm', 'response', 'neoadjuvant', 'preoperative chemoradiation', 'tumor response'. After review of title and abstracts, 85 articles addressing the prediction of pCR were selected.

RESULTS

Clear methods to predict pCR before chemoradiotherapy have not been defined. Clinical and radiological features of the primary cancer have limited ability to predict response. Molecular profiling holds the greatest potential to predict pCR but adoption of this technology will require greater concordance between cohorts for the biomarkers currently under investigation.

CONCLUSION

At present no robust markers of the prediction of pCR have been identified and the topic remains an area for future research. This review critically evaluates existing literature providing an overview of the methods currently available to predict pCR to nCRT for locally advanced rectal cancer. The review also provides a comprehensive comparison of the accuracy of each modality.

Predictive Response Value of Pre- and Postchemoradiotherapy Variables in Rectal Cancer: An Analysis of Histological Data

Background. Neoadjuvant chemoradiotherapy (nCRT) followed by curative surgery in locally advanced rectal cancer (LARC) improves pelvic disease control. Survival improvement is achieved only if pathological response occurs. Mandard tumor regression grade (TRG) proved to be a valid system to measure nCRT response. Potential predictive factors for Mandard response are analyzed. Materials and Methods. 167 patients with LARC were treated with nCRT and curative surgery. Tumor biopsies and surgical specimens were reviewed and analyzed regarding mitotic count, necrosis, desmoplastic reaction, and inflammatory infiltration grade. Surgical specimens were classified according to Mandard TRG. The patients were divided as "good responders" (Mandard TRG1-2) and "bad responders" (Mandard TRG3-5). According to results from our previous data, good responders have better prognosis than bad responders. We examined predictive factors for Mandard response and performed statistical analysis. Results. In univariate analysis, distance from anal verge and ten other postoperative variables related with nCRT tumor response had predictive value for Mandard response. In multivariable analysis only mitotic count, necrosis, and differentiation grade in surgical specimen had predictive value. Conclusions. There is a lack of clinical and pathological preoperative variables able to predict Mandard response. Only postoperative pathological parameters related with nCRT response have predictive value.

Watch and Wait?--Elevated Pretreatment CEA Is Associated with Decreased Pathological Complete Response in Rectal Cancer

INTRODUCTION

Between 10 and 30% of rectal cancer patients experience pathological complete response after neoadjuvant treatment. However, physiological factors predicting which patients will experience tumor response are largely unknown. Previous single-institution studies have suggested an association between elevated pretreatment carcinoembryonic antigen and decreased pathological complete response.

METHODS

Clinical stage II-III rectal cancer patients undergoing neoadjuvant chemoradiotherapy and surgical resection were selected from the 2006-2011 National Cancer Data Base. Multivariable analysis was used to examine the association between elevated pretreatment carcinoembryonic antigen and pathological complete response, pathological tumor regression, tumor downstaging, and overall survival.

RESULTS

Of the 18,113 patients meeting the inclusion criteria, 47% had elevated pretreatment carcinoembryonic antigen and 13% experienced pathological compete response. Elevated pretreatment carcinoembryonic antigen was independently associated with decreased pathological complete response (OR = 0.65, 95% CI = 0.52-0.77, p < 0.001), pathological tumor regression (OR = 0.74, 95% CI = 0.67-0.70, p < 0.001), tumor downstaging (OR = 0.77, 95% CI = 0.63-0.92, p < 0.001), and overall survival (HR = 1.45, 95% CI = 1.34-1.58, p < 0.001).

CONCLUSION

Rectal cancer patients with elevated pretreatment carcinoembryonic antigen are less likely to experience pathological complete response, pathological tumor regression, and tumor downstaging after neoadjuvant treatment and experience decreased survival. These patients may not be suitable candidates for an observational "watch-and-wait" strategy. Future prospective studies should investigate the relationships between CEA levels, neoadjuvant treatment response, recurrence, and survival.

Pathologic Assessment of Rectal Carcinoma after Neoadjuvant Radio(chemo)therapy: Prognostic Implications

Neoadjuvant radio(chemo)therapy is increasingly used in rectal cancer and induces a number of morphologic changes that affect prognostication after curative surgery, thereby creating new challenges for surgical pathologists, particularly in evaluating morphologic changes and tumour response to preoperative treatment. Surgical pathologists play an important role in determining the many facets of rectal carcinoma patient care after neoadjuvant treatment. These range from proper handling of macroscopic specimens to accurate microscopic evaluation of pathological features associated with patients' prognosis. This review presents the well-established pathological prognostic indicators and discusses challenging features in order to provide both surgical pathologists and treating physicians with a checklist that is useful in a neoadjuvant setting.

Clinical parameters predicting pathologic complete response following neoadjuvant chemoradiotherapy for rectal cancer

Introduction

Preoperative chemoradiotherapy (CRT), followed by total mesorectal excision, has become the standard of care for patients with clinical stages II and III rectal cancer. Patients with pathologic complete response (pCR) to preoperative CRT have been reported to have better outcomes than those without pCR. However, the factors that predict the response to neoadjuvant CRT have not been well defined. In this study, we aimed to investigate the impact of clinical parameters on the development of pCR after neoadjuvant chemoradiation for rectal cancer.

Methods

A total of 323 consecutive patients from a single institution who had clinical stage II or III rectal cancer and underwent a long-course neoadjuvant CRT, followed by curative surgery, between 2005 and 2013 were included. Patients were divided into two groups according to their responses to neoadjuvant therapy: the pCR and non-pCR groups. The clinical parameters were analyzed by univariate and multivariate analyses, with pCR as the dependent variable.

Results

Of the 323 patients, 75 (23.2%) achieved pCR. The two groups were comparable in terms of age, sex, body mass index, tumor stage, tumor location, tumor differentiation, radiation dose, and chemotherapy regimen. On multivariate analysis, a pretreatment carcinoembryonic antigen (CEA) level of ≤5 ng/mL [odds ratio (OR) = 2.170, 95% confidence interval (CI) = 1.195–3.939, P = 0.011] and an interval of >7 weeks between the completion of chemoradiation and surgical resection (OR = 2.588, 95% CI = 1.484–4.512, P = 0.001) were significantly associated with an increased rate of pCR.

Conclusions

The pretreatment CEA level and neoadjuvant chemoradiotherapy-surgery interval were independent clinical predictors for achieving pCR. These results may help clinicians predict the prognosis of patients and develop adaptive treatment strategies.

Biomarkers and Molecular Imaging as Predictors of Response to Neoadjuvant Chemoradiotherapy in Patients With Locally Advanced Rectal Cancer

Standard treatment of patients with locally advanced rectal cancer (LARC) includes neoadjuvant chemoradiotherapy (NCRT) followed by surgery. Tumor regression after NCRT varies substantially among individuals and pathological complete response is a known prognostic factor for LARC. The identification of a predictive model for response to chemoradiotherapy would help clinicians to identify patients who would probably benefit from multimodal treatment and to perform an early assessment of individual prognosis. Carcinoembryonic antigen has proven to be a good predictor of response in several clinical trials. Other widely studied predictive models in LARC include molecular biomarkers, analyzed at various levels and by different techniques, and molecular imaging, in particular magnetic resonance imaging and positron emission tomography/computed tomography. Although none of the studied markers have been approved in clinical practice, their evaluation in larger, prospective trials and in combined predictive models could be of use to define tailored therapeutic strategies.

Prognostic significance of clinical and pathological stages on locally advanced rectal carcinoma after neoadjuvant chemoradiotherapy

Objective

To investigate prognostic significance of clinical and pathological stages in patients with locally advanced rectal carcinoma treated with neoadjuvant chemoradiotherapy (neo-CRT) and total mesorectal excision.

Patients and methods

210 patients with locally advanced rectal carcinoma (cT3-4 or cN+) treated with neo-CRT followed by total mesorectal excision. Treatment outcomes were compared according to clinical and pathological stage. Overall survival (OS), disease free survival (DFS) among patients with different clinical stage and pathological stage after neo-CRT.

Results

The median follow-up time was 47 months (range, 14–98 months). Clinical T stage was associated with 5 year OS (p = 0.042) and 5 year DFS (p = 0.014) while clinical N stage was not associated with 5 year OS (p = 0.440), 5 year DFS (p = 0.711). Pathological T stage was associate with 5 year OS (p = 0.001) and 5 year DFS (p = 0.046); and N stage was associated with 5 year OS (p = 0.001), 5 year DFS (p = 0.002). The pathological stage was further classified into three groups: ypT0–2N0 in 91 patients (43.3 %), ypT3–4N0 in 69 patients (32.9 %) and ypT0–4N+ in 50 patients (23.8 %). While pathological stage (ypT0–2 vs ypT3–4N0 vs ypT0–4N+) was associated with 5 year OS (87.9 %, 75.5 %, 56.7 %, p = 0.000), 5 year DFS (74.5 %, 77.4 %, 50.5 %, p = 0.003). Multivariate analysis showed that ypN stage was an independent prognostic factor for patients 5 year DFS.

Conclusions

Pathological stage is strongly associated with treatment outcomes in patients with locally advanced rectal carcinoma treated with neo-CRT followed by total mesorectal excision, which may be used as guidance for further individualized treatment.

Predictive and prognostic biomarkers for neoadjuvant chemoradiotherapy in locally advanced rectal cancer

Locally advanced rectal cancer is regularly treated with trimodality therapy consisting of neoadjuvant chemoradiation, surgery and adjuvant chemotherapy. There is a need for biomarkers to assess treatment response, and aid in stratification of patient risk to adapt and personalise components of the therapy. Currently, pathological stage and tumour regression grade are used to assess response. Experimental markers include proteins involved in cell proliferation, apoptosis, angiogenesis, the epithelial to mesenchymal transition and microsatellite instability. As yet, no single marker is sufficiently robust to have clinical utility. Microarrays that screen a tumour for multiple promising candidate markers, gene expression and microRNA profiling will likely have higher yield and it is expected that a combination or panel of markers would prove most useful. Moving forward, utilising serial samples of circulating tumour cells or circulating nucleic acids can potentially allow us to demonstrate tumour heterogeneity, document mutational changes and subsequently measure treatment response.

Factors influencing response to neoadjuvant chemoradiation and outcomes in rectal cancer patients: tertiary Indian cancer hospital experience

BACKGROUND

In the treatment of rectal cancers several randomized trials have demonstrated benefits of neoadjuvant chemoradiotherapy (NACRT) in downstaging as well as survival among these patients. We investigated the patient and tumor related variables dictating the outcomes in these patients.

METHODS

Biopsy proven treatment naive 182 rectal cancer patients underwent NACRT from June 2006 to December 2010. The entire patients received long course conventionally fractionated external beam radiotherapy with concurrent oral Capecitabine. At 6 weeks from completion of NACRT clinico-radiological assessment was carried out for surgical feasibility. All patients were given postoperative adjuvant chemotherapy either single agent or multi drug regimen depending upon biopsy report.

RESULTS

Among 182 patients, 131 (72%) underwent surgery and initial T stage and signet ring cell morphology were major determinant of operability. Among the 131 operated patients at median follow up of 36 months, 94 (72%) are alive and disease free. With a median follow up of 42 months the 5-year disease free survival (DFS) and overall survival (OS) was 60% and 77%. The majority of the failures were distal but with more advanced disease at presentation both local and distal failures were similar. While assessing survival by multivariate analysis patients having positive nodes post-surgery had a significantly poorer DFS (P=0.001), while signet ring cell morphology and pre-treatment carcino-embryonic antigen (CEA) levels strongly influenced OS (P=0.03).

CONCLUSIONS

The outcome of our patients were similar to World Literature and signet ring cell morphology, pre-treatment CEA level, and pathological nodal staging all were influential in determining survival. Besides this, the study also highlights the fact that tumours with signet ring cell morphology appearing in younger population with poor survival needs prospective evaluation for more intense CRT regimen and aggressive surgical resections.

Prognostic value of tumor shrinkage versus fragmentation following radiochemotherapy and surgery for rectal cancer

Most patients with rectal cancer receive neoadjuvant radiochemotherapy (RCT), causing a variable decrease in tumor mass. We evaluated the prognostic impact of pathologic parameters reflecting tumor response to RCT, either directly or indirectly. Seventy-six rectal cancer patients receiving neoadjuvant RCT between 2006 and 2009 were included. We studied the association between disease-free survival (DFS) and the "classical" clinicopathologic features as well as tumor deposits, circumferential resection margin (CRM), Dworak regression grade, and tumor and nodal downstaging. Patients with tumor downstaging had a longer DFS (p = 0.05), indicating a more favorable prognosis when regression was accompanied by a decrease in tumor infiltrative depth, referred to as tumor shrinkage. Moreover, tumor downstaging was significantly associated with larger CRM and nodal downstaging (p = 0.02), suggesting that shrinkage of the primary tumor was associated with a decreased nodal tumor load. Higher Dworak grade did not correlate with tumor downstaging, nor with higher CRM or prolonged DFS. This implies that tumor mass decrease was sometimes due to fragmentation rather than shrinkage of the primary tumor. Lastly, the presence of tumor deposits was clearly associated with reduced DFS (p = 0.01). Assessment of tumor shrinkage after RCT via tumor downstaging and CRM is a good way of predicting DFS in rectal cancer, and shrinkage of the primary tumor is associated with a decreased nodal tumor load. Assessing regression based on the amount of tumor in relation to stromal fibrosis does not accurately discern tumor fragmentation from tumor shrinkage, which is most likely the reason why Dworak grade had less prognostic relevance.

Nomogram predicting response after chemoradiotherapy in rectal cancer using sequential PETCT imaging: a multicentric prospective study with external validation

PURPOSE

To develop and externally validate a predictive model for pathologic complete response (pCR) for locally advanced rectal cancer (LARC) based on clinical features and early sequential (18)F-FDG PETCT imaging.

MATERIALS AND METHODS

Prospective data (i.a. THUNDER trial) were used to train (N=112, MAASTRO Clinic) and validate (N=78, Università Cattolica del S. Cuore) the model for pCR (ypT0N0). All patients received long-course chemoradiotherapy (CRT) and surgery. Clinical parameters were age, gender, clinical tumour (cT) stage and clinical nodal (cN) stage. PET parameters were SUVmax, SUVmean, metabolic tumour volume (MTV) and maximal tumour diameter, for which response indices between pre-treatment and intermediate scan were calculated. Using multivariate logistic regression, three probability groups for pCR were defined.

RESULTS

The pCR rates were 21.4% (training) and 23.1% (validation). The selected predictive features for pCR were cT-stage, cN-stage, response index of SUVmean and maximal tumour diameter during treatment. The models' performances (AUC) were 0.78 (training) and 0.70 (validation). The high probability group for pCR resulted in 100% correct predictions for training and 67% for validation. The model is available on the website www.predictcancer.org.

CONCLUSIONS

The developed predictive model for pCR is accurate and externally validated. This model may assist in treatment decisions during CRT to select complete responders for a wait-and-see policy, good responders for extra RT boost and bad responders for additional chemotherapy.

Detection of circulating tumor cells in patients with locally advanced rectal cancer undergoing neoadjuvant therapy followed by curative surgery

PURPOSE

Circulating tumor cells (CTCs) represent an independent prognostic factor in metastatic colorectal cancer, while their significance in early stages is still an open issue. The aim of the study is to investigate the role of CTCs in rectal cancer patients undergoing neoadjuvant chemoradiotherapy (CT-RT).

METHODS

In this prospective single institutional study, cT3-4 and/or N+ rectal cancer was treated with neoadjuvant CT-RT. The primary endpoints were as follows: evaluation of CTCs at baseline (t0), after CT-RT (t1), within 7 days after surgery (t2), and at 6 months from surgery (t3) and correlation with main patient/tumor characteristics, CEA, response to neoadjuvant therapy, and disease-free survival (DFS). CTCs were enumerated with the CellSearch System in 22.5 ml peripheral blood. A repeated measure analysis for binary outcome was used to evaluate over time changes in the percentage of CTCs detectable in blood samples.

RESULTS

Of the 90 patients enrolled in this study, 85 were eligible consisting of 52 males and 33 females. Median age was 63 years and median follow-up was 38 months. CTCs were available for all patients at t0, for 67 at t1, for 68 at t2, and for 62 at t3. CTCs >0 were reported on 16 (19%) at t0, on 5 (7.5%) at t1, on 6 (9%) at t2, and on 3 (5%) at t3 (P value for trend 0.039). Only for CT-RT responders, CTCs reduced from t0 to t1. No statistically significant association was found between CTCs and main patient/tumor characteristics and DFS.

CONCLUSIONS

Sixteen patients (19%) had CTCs ≥1 at t0 with reduction in CTC number in case of objective remissions. The proportion of patients with CTCs ≥1 decreased over the time as the therapeutic course proceeded. Much effort should be oriented toward increasing CTC detection rate by enhancing technical tests and achieving better patient characterization.

The impact of pathologic nodal status on survival following neoadjuvant chemoradiation for locally advanced rectal cancer

PURPOSE

For patients with locally advanced rectal cancer, the accuracy rates of preneoadjuvant therapy nodal staging and potential nodal downstaging make the prognostic significance of nodal status unclear. We therefore sought to review our experience in order to better understand the impact of clinical and pathologic nodal status upon patient outcomes.

METHODS

174 patients were identified as having undergone neoadjuvant chemoradiation and resection for rectal cancer. For analytic purposes, patients were grouped into four nodal categories (uN( 0)· pN( 0), uN( 0)· pN( +), uN (+) · pN( 0), and uN (+) · pN( +)). Univariate and multivariate analyses were performed.

RESULTS

104 men and 70 women of median age 60 years (29-85 years) were followed for a median of 31 months (1-121 months). Nodal staging was available for 129 patients, with a median of 8 lymph nodes (range 0-39) evaluated. Disease recurred in 3 of 41 (7%) uN   (0) ·pN (  0), 10 of 52 (20%) uN (   +)·pN (  0), 7 of 18 (41%) uN (  0)·pN (   +), and 6 of 17 (35%) uN (  +)·pN (  +) patients. Those patients having nodal downstaging (uN (  +)·pN (  0)) experienced superior overall survival (p = 0.03). Only pathologic nodal status was a significant predictor of both disease-free and overall survival in multivariate modeling. Adjuvant chemotherapy did not impact disease-free or overall survival for patients with pN0.

CONCLUSIONS

Pathologic nodal status may represent a superior predictor of survival for patients with local advanced rectal cancers. Our findings may have potential implications for the application of adjuvant therapy.