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

Pretreatment Microvessel Density for Predicting of Tumor Responsiveness to Neoadjuvant Chemoradiotherapy of Locally Advanced Rectal Cancer

OBJECTIVE

This study aimed to assess whether pretreatment tumor tissue microvessel density (MVD) could be a potential predictive marker for Mandard response in LARC treated with nCRT.

METHODS

A retrospective analysis was performed in pretreatment paraffin-embedded specimens of 31 pathologically confirmed rectal adenocarcinoma. All patients received nCRT and subsequent total mesorectal resection. Tumor MVD was determined by an average number of counted CD34-stained endothelial cells from two selected fields at 200x magnification in each slide and categorized into two groups: low MVD ( 60). The tumor response was determined using the Mandard tumor regression grading system. The subjects were grouped according to their TRG into responder (TRG 1-3) and non-responder (TRG 4-5).

RESULT

Twenty out of thirty-one patients (64.5%) were defined as responders. Eleven patients (35.5%) were defined as non-responders. MVD was significantly associated with tumor responsiveness to nCRT (p < 0.05). High MVD was shown to be an independent risk factor associated with tumor resistance to nCRT (OR, 22.58; 95% CI, 1.943-262.34; p = 0.013). A strong correlation was found between MVD and TRG (correlation coefficient value of 0.642, p <0.01), between MVD and vascular invasion (correlation coefficient value of 0.618, p <0.01), and between nodal involvement and vascular invasion (correlation coefficient value of 0.521, p <0.01). A moderate correlation was found between nodal involvement and vascular invasion (correlation coefficient value of 0.406, p <0.05).

CONCLUSION

High MVD in pretreatment tumor tissue was significantly associated with the tumor resistance to nCRT.

Predicting Factors of Complete Pathological Response in Locally Advanced Rectal Cancer

Background: Current treatment of choice for locally advanced rectal cancer is neoadjuvant chemoradiotherapy (neo-CRT) followed by surgical resection and adjuvant chemotherapy. Some patients may experience complete pathological response (cPR) after the neoadjuvant treatment. However, the predicting factors are still debated. Methods: In this registry-based retrospective cohort study, 258 patients with locally advanced rectal cancer were included. Patients were categorized into two groups with or without cPR. Logistic regression analysis was recruited to investigate the odds ratio for all independent variables, and those with significant results were included in multivariate regression analysis. Results: Achievement of cPR was 21.3%. The odds ratio of cPR was significantly lower when the tumor distance from the anal verge was>10 centimeters (OR=0.24, P=0.040). Also, the odds of cPR with N1 involvement in comparison with N0 involvement decreased for 0.41 (P=0.043). It was also true for patients with N2 involvement in comparison with N0 involvement (OR=0.31, P=0.031). Higher odds ratio of cPR was observed in patients who underwent surgery in>12 weeks after neo-CRT (OR=2.9, P=0.022). Furthermore, the odds of cPR decreased for 0.9 with increasing in carcinoembryonic antigen (CEA) level (P=0.044). Conclusion: Patients with rectal cancer in clinical stage II or lower, without the involvement of the lymphatic system at diagnosis, and with tumors located in the lower parts of the rectum, with lower levels of CEA, and longer duration between neo-CRT and surgery were more likely to achieve cPR after neo-CRT. With the current knowledge, the "wait and watch policy" is still debated and needs to be defined more precisely by upcoming studies.

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.

The value of the tumour-stroma ratio for predicting neoadjuvant chemoradiotherapy response in locally advanced rectal cancer: a case control study

BACKGROUND

The tumour-stroma ratio (TSR) is recognized as a practical prognostic factor in colorectal cancer. However, TSR assessment generally utilizes surgical specimens. This study aims to investigate whether the TSR evaluated from preoperative biopsy specimens by a semi-automatic quantification method can predict the response after neoadjuvant chemoradiotherapy (nCRT) of patients with locally advanced rectal cancer (LARC).

METHODS

A total of 248 consecutive patients diagnosed with LARC and treated with nCRT followed by resection were included. Haematoxylin and eosin (HE)-stained sections of biopsy specimens were collected, and the TSR was evaluated by a semi-automatic quantification method and was divided into three categories, using the cut-offs determined in the whole cohort to balance the proportion of patients in each category. The response to nCRT was evaluated on the primary tumour resection specimen by an expert pathologist using the four-tier tumour regression grade (TRG) system.

RESULTS

The TSR can discriminate patients that are major-responders (TRG 0-1) from patients that are non-responders (TRG 2-3). Patients were divided into stroma-low (33.5%), stroma-intermediate (33.9%), and stroma-high (32.7%) groups using 56.3 and 72.8% as the cutoffs. In the stroma-low group, 58 (69.9%) patients were major-responders, and only 39 (48.1%) patients were considered major-responders in the stroma-high group (P = 0.018). Multivariate analysis showed that the TSR was the only pre-treatment predictor of response to nCRT (adjusted odds ratio 0.40, 95% confidence interval 0.21-0.76, P = 0.002).

CONCLUSION

An elevated TSR in preoperative biopsy specimens is an independent predictor of nCRT response in LARC. This semi-automatic quantified TSR could be easily translated into routine pathologic assessment due to its reproducibility and reliability.

Identification of potential metabolic biomarkers of rectal cancer and of the effect of neoadjuvant radiochemotherapy

We report a pilot study on the feasibility of determinations of circulating levels of paraoxonase-1 (PON1) and compounds related to energy metabolism as biomarkers for the evaluation of patients with rectal cancer (RC), and the effects produced by neoadjuvant radiochemotherapy (NRCT). We studied 32 patients treated with radiotherapy plus capecitabine concomitant chemotherapy and 48 control subjects. We identified pre-NRCT PON1 and α-ketoglutarate as the parameters that best discriminated between RC patients and the control group. Receiver operating characteristics analysis of the combination of the two parameters showed an area under the curve (AUC) of 0.918. Moreover, patients who presented a pathological complete response (pCR) to treatment had lower plasma pre-NRCT valine concentrations (AUC of 0.826). Patients who had a relapse had lower concentrations of succinate (AUC of 0.833). The results of the present study illustrate the usefulness of investigating alterations in oxidative stress and metabolism in RC. Due to the small number of patients studied, our results must be considered preliminary, but they suggest that the determination of circulating levels of PON1 and α-ketoglutarate might be a valuable tool for the early diagnosis of RC, while the determination of valine and succinate might effectively predict pCR and the appearance of relapse.

Machine learning for predicting pathological complete response in patients with locally advanced rectal cancer after neoadjuvant chemoradiotherapy

For patients with locally advanced rectal cancer (LARC), achieving a pathological complete response (pCR) after neoadjuvant chemoradiotherapy (CRT) provides them with the optimal prognosis. However, no reliable prediction model is presently available. We evaluated the performance of an artificial neural network (ANN) model in pCR prediction in patients with LARC. Predictive accuracy was compared between the ANN, k-nearest neighbor (KNN), support vector machine (SVM), naïve Bayes classifier (NBC), and multiple logistic regression (MLR) models. Data from two hundred seventy patients with LARC were used to compare the efficacy of the forecasting models. We trained the model with an estimation data set and evaluated model performance with a validation data set. The ANN model significantly outperformed the KNN, SVM, NBC, and MLR models in pCR prediction. Our results revealed that the post-CRT carcinoembryonic antigen is the most influential pCR predictor, followed by intervals between CRT and surgery, chemotherapy regimens, clinical nodal stage, and clinical tumor stage. The ANN model was a more accurate pCR predictor than other conventional prediction models. The predictors of pCR can be used to identify which patients with LARC can benefit from watch-and-wait approaches.

Pathological Predictors of Response to Neoadjuvant Treatment in Rectal Carcinoma

PURPOSE

Neoadjuvant chemoradiotherapy has now become a standard treatment for rectal cancer. Recently, attempts have been made to predict the response rate to this treatment to decide whether or not it must be performed. However, tissue factors for predicting the response rate is not cohesively reviewed.

METHODS

Eighty-three patients with rectal cancer, all under neoadjuvant chemoradiotherapy and subsequent surgery, were examined for tissue factors in the biopsy sample. The tissue factors examined include tumor differentiation grade, lymphovascular invasion, perineural invasion, pathological stage, and lymphocytic infiltration. Lymphocytic infiltration was investigated by immunohistochemistry for CD8 T lymphocyte in biopsy samples.

RESULTS

In this study, tissue factors were found to play a decisive role in predicting response to neoadjuvant treatment. The most important factor was the pathological stage, which has the highest correlation with response to treatment. There is a significant relationship between CD8 lymphocyte infiltration and response to treatment (P value = 0.018). Primary perineural invasion and lymphovascular invasion also have a significant meaningful relationship with response to treatment (P value = 0.021 and P value = 0.036).

CONCLUSION

In this study, it was determined that the investigated factors have a significant relationship with response to treatment and could be used to predict the response to treatment, and if a low possibility of positive response exists, prevention of the complications of neoadjuvant chemoradiotherapy for the patients could occur.

Predicting poor response to neoadjuvant chemoradiotherapy for locally advanced rectal cancer: Model constructed using pre-treatment MRI features of structured report template

PURPOSE

To develop a predictive model with pre-treatment magnetic resonance imaging (MRI) findings of the structured report template and clinical parameters for poor responses prediction after neoadjuvant chemoradiotherapy (neoCRT) in locally advanced rectal cancers (LARC) patients.

METHOD

Patients with clinicopathologically confirmed LARC (training and validation datasets, n = 100 and 71, respectively) were enrolled. Patients' clinical data were retrospectively collected. MRI findings of the structured report template were analysed. The tumour regression grade (TRG) system as proposed by Mandard et al was used. Poor response was defined as TRG 3-5. Univariate logistic regression analysis and a lasso regression model were performed to select the significant predictive features from the training set. A nomogram was constructed based on a multivariable logistic regression analysis. Calibration, discrimination, and clinical usefulness of the nomogram were assessed. The calibrative and discriminative ability of our model were compared with those of models including the tumour-node-metastasis (TNM) stage and clinical factors.

RESULTS

The MRI-reported T4b stage, MRI-reported extramural venous invasion (EMVI) positivity, MRI-detected number of positive mesorectal lymph nodes (LNs) > 0, and preoperative oxaliplatin and capecitabine (CAPOX) chemotherapy regimen were incorporated into our nomogram. The nomogram showed good discrimination, with areas under the receiver operating characteristic (ROC) curves of 0·823 and 0·820 in the training and test sets, respectively, and good calibration in both datasets. The decision curve analysis confirmed that the nomogram was clinically useful. The calibrative and discriminative ability of our model were better than those models including the TNM stage and clinical factors.

CONCLUSION

A nomogram based on pre-treatment MRI features of the structured report template and clinical risk factors has potential for use as a non-invasive tool to preoperatively predict poor responses in LARC patients after neoCRT.

Clinical significance of serum tumor markers for advanced gastric cancer with the first-line chemotherapy

Background

Tumor markers play an important role in the diagnosis, monitoring and prognostic prediction of cancers. But the predictive value of serum tumor markers in gastric cancer is still unclear.

Methods

In this study, we detected serum levels of tumor markers to evaluate their relation to treatment response and prognosis in patients with unresectable advanced or metastatic gastric cancer.

Results

We collected the clinical data of 109 patients with unresectable advanced or metastatic gastric cancer who had received the first-line chemotherapy in Peking University Cancer Hospital from July 2013 to May 2015, and collected the value of serum carcinoembryonic antigen (CEA), carbohydrate antigen 199 (CA199), carbohydrate antigen 72.4 (CA72.4) and carbohydrate antigen 125 (CA125) before and after chemotherapy. At diagnosis, the positive rates of CEA, CA199, CA72.4 and CA125 were 46.8%, 40.2%, 53.5% and 35.0%, respectively. And the positive rate of combined detection of the four markers was 87.2%. Although patients with prechemotherapy CA199 ≥80 U/mL (92.3% vs. 68.5%, P=0.016) or CA72.4 ≥20 U/mL (91.4% vs. 62.5%, P=0.003) had higher clinical benefit rate after chemotherapy, they showed poorer prognosis (P=0.023 and P=0.006, respectively). CA72.4 ≥20 U/mL was an independent unfavorable prognostic factor (Hazard Ratio 4.84; 95% confidence interval: 1.910–12.262; P=0.001). In patients with increased levels of tumor markers before treatment, the levels of tumor markers decreased after chemotherapy, especially in those with clinical benefit (CEA, CA72.4 reached statistical significance, P=0.013 and P=0.029, respectively). A decrease of CEA ≥35%, CA199 ≥30%, or CA72.4 ≥40% after chemotherapy had positive prediction value for the response to chemotherapy (P=0.016, P=0.029, and P=0.008, respectively).

Conclusions

The results showed that both high pre-chemotherapy serum levels of tumor markers (CA199 ≥80 U/mL or CA72.4 ≥20 U/mL) and a substantial decrease in tumor markers after chemotherapy (CEA ≥35%, CA199 ≥30%, or CA72.4 ≥40%) could predict a higher clinical benefit rate in patients with unresectable advanced or metastatic gastric cancer. However, this advantage in short-term response to chemotherapy failed to convert into prolonged survival benefits.

Do Acellular Mucin Pools in Resection Margins for Rectal Cancer Influence Outcomes?

Positive resection margins predict poor prognosis in rectal cancer (RC). Literature on the impact of acellular mucin (ACM) in circumferential resection margin (CRM) or distal resection margin (DRM) of proctectomy specimens on RC recurrence and outcomes is lacking. The retrospective study was conducted to determine the oncological outcomes of the RC patients with ACM in or within 1 mm of margins of the rectal resection specimens. Histopathology reports of RC resection specimens dated from June 2013 till May 2016 were reviewed to identify cases with ACM in CRM (n = 10) and DRM (n = 2). Relevant details of these patients were gathered from the electronic medical record. Pattern of recurrence was studied. In cases with only ACM in CRM (n = 10), disease (primary tumor or nodes) was radiologically reaching the mesorectal fascia except two, who had extra mesorectal nodes. Median distance of tumor from anal verge was 2 cm. All patient received neoadjuvant therapy: four patients received chemoradiotherapy (NACTRT), one received short-course radiotherapy, and five received NACTRT followed by neoadjuvant chemotherapy. Abdominoperineal resection, intersphincteric resection and total pelvic exenteration were done for six, three, and one patient, respectively. In two additional cases of anterior resection with ACM in DRM, one underwent upfront resection while the other received NACTRT. Over a mean follow-up period of 43 months, four patients developed recurrences. Two of them had local recurrence and only one had isolated local recurrence. ACM in resection margins of RC resection specimens does not seem to increase likelihood of local recurrence.

HER2 as a limited predictor of the therapeutic response to neoadjuvant therapy in locally advanced rectal cancer

Human epidermal growth factor 2 (HER2) is a candidate therapeutic and prognostic marker for rectal cancer treated with neoadjuvant chemoradiotherapy. The specific frequency and prognostic role of HER2 protein expression and HER2 gene amplification in those rectal cancers has not been fully investigated. Pretreatment biopsied and surgically resected formalin-fixed paraffin-embedded tissues from 74 patients were retrospectively evaluated for HER2 protein expression and HER2 gene copy number using immunohistochemistry (IHC) and silver in situ hybridization (SISH), respectively. The tumor response to chemoradiation was evaluated with TNM staging and tumor regression grading (TRG) systems. Good response to chemoradiation therapy (TRG3), poor response (22 TRG1 and 19 TRG2), and TNM downstaging achieved in 33 (44.6%), 41 (55.4%), and 42 (56.8%) patients, respectively. The frequency of HER2 positivity is 17.6%, all of which were low-level HER2 gene amplification with 2.2 of median gene copy number ratio, detected in IHC0 (3/39), IHC1+ (2/18), IHC2+ (5/14) and IHC3+ (2/3). There was no association of HER2 positivity with clinicopathological parameters or survival. However, older age (≥61 years) and HER2 positivity were the independent predictive factors for non-down staging, while poorly differentiation and the papillary pattern were predictors for poor response. In multivariate analysis, good response proved as an only independent favorable prognostic factor affecting survivals. In conclusion, HER2 positivity may be predictive for a high-risk therapeutic resistance in rectal cancers. The discrepancy between IHC and gene amplification may result from the low-level amplification, which may explain lack of prognostic impact of HER2 positivity.

Association of tumor differentiation and prognosis in patients with rectal cancer undergoing neoadjuvant chemoradiation therapy

Background and objective

Neoadjuvant chemoradiation therapy (NCRT) followed by radical resection has been a common practice for patients with locally advanced rectal cancer. This study aimed to analyse the association of tumor differentiation and prognosis in rectal-cancer patients undergoing NCRT.

Methods

Patients with locally advanced, non-mucinous rectal cancer who underwent NCRT followed by radical resection between 2007 and 2017 were identified from an electronic health record system at the Sixth Affiliated Hospital of Sun Yat-sen University (Guangzhou, China). Multivariable logistic regression and multivariate Cox regression were performed to analyse the association of response to NCRT and survival with clinicopathological characteristics of all these patients.

Results

We identified 325 patients (241 males and 84 females; mean age, 54.4 ± 11.2 years) who underwent NCRT followed by radical resection, including 26 (8.0%) with poorly-differentiated rectal cancer, 182 (56.0%) with moderately-differentiated cancer and 117 (36.0%) with well differentiated cancer. Propensity score matching analysis and multivariable logistic regression analysis results showed that tumor differentiation was significantly associated with response to NCRT. In the poor differentiation and non-poor differentiation groups, the 3-year overall survival (OS) rates were 74.6 and 93.5%, respectively, whereas the 3-year local recurrence rates were 18.6 and 3.7%, respectively. Multivariable Cox regression analyses revealed that poor differentiation was an independent risk factor for local recurrence and OS.

Conclusions

Among the patients with locally advanced, non-mucinous rectal cancer, the patients with poorly-differentiated cancer who underwent NCRT had a worse response to NCRT and poorer prognosis than those with moderately- and well-differentiated diseases.

miR-21, miR-99b and miR-375 combination as predictive response signature for preoperative chemoradiotherapy in rectal cancer

Introduction

Preoperative chemoradiotherapy (CRT) is a standard treatment for locally advanced rectal cancer patients. Despite the benefits of CRT, its use in non-responder patients can be associated with increased toxicities and surgical resection delay. The identification of CRT response biomarkers, such as microRNAs, could improve the management of these patients. We have studied the microRNA expression in pretreatment endoscopy biopsies from rectal cancer patients treated with CRT to identify potential microRNAs able to predict CRT response and clinical outcome of these patients.

Material and methods

RNA from pretreatment endoscopy biopsies from 96 rectal cancer patients treated with preoperative CRT were studied. Pathological response was graded according to the tumor regression grade (TRG) Dworak classification. In the screening phase, 377 miRNAs were studied in 12 patients with extreme responses (TRG0-1 vs TRG4). The potential role as predictive biomarkers for CRT response, disease-free survival (DFS) and overall survival (OS) of the miRNAs identified in the screening phase were validated in the whole cohort.

Results

In the screening phase, an 8-miRNAs CRT-response signature was identified: let-7b, let-7e, miR-21, miR-99b, miR-183, miR-328, miR-375 and miR-483-5p. In the validation phase, miR-21, miR-99b and miR-375 emerged as CRT response-related miRNAs while miR-328 and let-7e emerged as prognostic markers for DFS and OS. Interestingly, ROC curve analysis showed that the combination of miR-21, miR-99b and miR-375 had the best capacity to distinguish patients with maximum response (TRG4) from others.

Conclusions

miR-21, miR-99b and miR-375 could add valuable information for individualizing treatment in locally advanced rectal cancer patients.

Clinical and molecular diagnosis of pathologic complete response in rectal cancer: an update

INTRODUCTION

The standard of care for locally advanced rectal cancer includes neoadjuvant chemoradiation with subsequent total mesorectal excision. This approach has shown various degrees of response to neoadjuvant chemoradiation (ranging from complete response to further tumor growth), which have substantial prognostic and therapeutic implications. A total regression of the tumor is a predictor of superior oncologic outcomes compared with partial responders and non-responders. Further, this concept has opened the possibility of nonoperative strategies for complete responders and explains the widespread research interest in finding clinical, radiographic, pathologic, and biochemical parameters that allow for identification of these patients. Areas covered: The present review evaluates the most recent efforts in the literature to identify predictors of patients likely to achieve a complete response following neoadjuvant treatment for the management of rectal cancer. This includes clinical predictors of pathologic complete response such as tumor location, size, and stage, molecular predictors such as tumor biology and microRNA, serum biomarkers such as carcinoembryogenic antigen and nomograms. Expert commentary: There has been significant progress in our ability to predict pathological complete response. However, more high-quality research is still needed to use this concept to confidently dictate clinical management.

Oxaliplatin-containing adjuvant chemotherapy improves the survival of locally advanced rectal cancer patients with pathological complete response after pre-operative chemoradiotherapy

Background

The necessity for adjuvant chemotherapy (ACT) in locally advanced rectal cancer (LARC) patients who achieve pathological complete response (pCR) after pre-operative chemoradiotherapy (CRT) is still not identified. We aimed to investigate the therapeutic value of ACT in these patients.

Methods

Clinical data were retrospectively collected from 105 consecutive LARC patients who achieved pCR after pre-operative CRT and underwent radical tumor resection between December 2008 and April 2014 in a comprehensive cancer center. Perioperative chemotherapy (CT) was administered by combining oxaliplatin with capecitabine (XELOX regimen). Disease-free survival (DFS) and overall survival (OS) rates of patients with or without ACT were compared.

Results

Eighty-three (79.0%) patients received ACT and 22 (21.0%) did not. With a median follow-up of 49 months, the ACT group had a significantly higher 3-year DFS rate (92.8 vs 86.4%, p = 0.029) and 3-year OS rate (95.1 vs 86.1%, p = 0.026) than the non-ACT group. In multivariable analyses, the presence of ACT was an independent prognostic factor for DFS (hazard ratio [HR]: 0.271; 95% confidence interval (CI): 0.080–0.916; p = 0.036) but not for OS. This benefit was more obvious in patients younger than 60 years via subgroup analysis (adjusted HR: 0.106; 95% CI: 0.019–0.606; p = 0.012).

Conclusions

Oxaliplatin-containing ACT may confer survival benefits to patients with pCR, particularly younger patients. However, the routine use of ACT in patients with pCR needs further validation.

Genetic variations in the PI3K/PTEN/AKT/mTOR pathway predict tumor response and disease-free survival in locally advanced rectal cancer patients receiving preoperative chemoradiotherapy and radical surgery

Objective: Although preoperative chemoradiotherapy (CRT) followed by total mesorectal excision (TME) is the standard treatment for locally advanced rectal cancer (LARC), the clinical efficacy differs among patients. This study was conducted to determine the association between genetic variations in the PI3K/PTEN/AKT/mTOR pathway and clinical outcomes in LARC patients. Methods: Sixteen tagging single-nucleotide polymorphisms (SNPs) in five core genes (PIK3CA, PTEN, AKT1, AKT2, and FRAP1) were genotyped. The associations of these SNPs with tumor response to preoperative CRT, postoperative disease-free survival (DFS) and overall survival (OS) were identified. Crude odds ratios (ORs) and hazard ratios (HRs) were adjusted by age, sex, clinical stage, tumor differentiation, tumor location, cycles of preoperative chemotherapy and time interval from CRT completion to surgery. Results: In an analysis of 97 LARC patients, the G/T+G/G genotype of AKT1:rs2498804 was associated with an increased tumor response rate (adjusted OR = 2.909, 95% confidence interval (CI), 1.127-7.505, P = 0.027). At a median of 65.7 months of follow-up, the G/C+C/C genotype of AKT2:rs8100018 was associated with a reduced risk of postoperative recurrence (adjusted HR = 0.414; 95% CI, 0.187-0.914, P = 0.029). Patients carrying the G/C+C/C genotype in AKT2:rs8100018 presented a higher 5-year DFS rate than those with the wild-type genotype (79.2% vs. 62.3%, P = 0.038). None of the SNPs were significantly associated with pathological complete response (pCR) or 5-year OS. Conclusions: The current study indicates that genetic variations within the PI3K/ PTEN/AKT/mTOR signaling pathway are associated with the clinical outcomes of LARC patients undergoing preoperative CRT followed by radical surgery.

Difference in Tumor Area as a Predictor of a Pathological Complete Response for Patients With Locally Advanced Rectal Cancer

Purpose

This study was conducted to discover the clinical factors that can predict pathologically complete remission (pCR) after neoadjuvant chemoradiotherapy (CRT), so that those factors may help in deciding on a treatment program for patients with locally advanced rectal cancer.

Methods

A total of 137 patients with locally advanced rectal cancer were retrospectively enrolled in this study, and data were collected retrospectively. The patients had undergone a total mesorectal excision after neoadjuvant CRT. Histologic response was categorized as pCR vs. non-pCR. The tumor area was defined as (tumor length) × (maximum tumor depth). The difference in tumor area was defined as pre-CRT tumor area - post-CRT tumor area. Univariate and multivariate logistic regression analyses were conducted to find the factors affecting pCR. A P-value < 0.05 was considered significant.

Results

Twenty-three patients (16.8%) achieved pCR. On the univariate analysis, endoscopic tumor circumferential rate <50%, low pre-CRT T & N stage, low post-CRT T & N stage, small pretreatment tumor area, and large difference in tumor area before and after neoadjuvant CRT were predictive factors of pCR. A multivariate analysis found that only the difference in tumor area before and after neoadjuvant CRT was an independent predictor of pCR (P < 0.001).

Conclusion

The difference in tumor area, as determined using radiologic tools, before and after neoadjuvant CRT may be important predictor of pCR. This clinical factor may help surgeons to determine which patients who received neoadjuvant CRT for locally advanced rectal cancer should undergo surgery.

Density of CD8+ lymphocytes in biopsy samples combined with the circulating lymphocyte ratio predicts pathologic complete response to chemoradiotherapy for rectal cancer

Objectives

The systemic status and local immune status, as determined by the neutrophil–lymphocyte ratio (NLR) or the lymphocyte ratio (LYMR) and tumor-infiltrating lymphocyte (TIL) count, respectively, have been suggested as predictors of the tumor response to neoadjuvant chemoradiotherapy (nCRT) in rectal cancer, although the utility of these measures remains controversial. We aimed to investigate the values of the LYMR, NLR and TIL count and their combinations (TIL–LYMR/TIL–NLR) in predicting pathologic complete response (pCR) after nCRT.

Patients and methods

Pretreatment biopsy samples and data from the blood tests of 92 patients with rectal cancer who underwent curative resection after nCRT were retrospectively obtained. CD8+ TILs were immunostained using an antibody against CD8. The density of CD8+ TILs was recorded as the number of CD8+ T cells per square millimeter, and the results were classified as either “high” or “low”. The LYMR and NLR were calculated using pretreatment blood test data and categorized into either “high” or “low” groups. TIL–LYMR was graded as “low,” “mid” or “high” when neither, one or both the CD8+ TIL count and LYMR were “high,” respectively. TIL–NLR was graded similarly. The associations between TILs and LYMR, NLR and their combinations (TIL–LYMR/TIL–NLR) were evaluated.

Results

pCR was significantly associated with a high LYMR, a low NLR and increased chemotherapy cycles (P=0.039, P=0.043 and P=0.015, respectively), but not with the CD8+ TIL count or carcinoembryonic antigen (CEA) level (P=0.100 and P=0.590, respectively). Additionally, 40% of patients with high LYMR and 40.7% with low NLR achieved pCR, whereas only 19.7% with low LYMR and 20.3% with high NLR did so. When the combinations were assessed, TIL–LYMR showed a positive correlation with pCR (P=0.038), while no association between TIL–NLR and pCR was found (P=0.916). In multivariate analysis, TIL–LYMR remained an independent predictor of pCR (odds ratio [OR]=1.833, 95% confidence interval [CI]=1.069–3.142, P=0.028).

Conclusion

High LYMR, low NLR and high TIL–LYMR at baseline are predictive of pCR to nCRT for patients with rectal cancer. These parameters may help identify pCR patients and provide additional information for therapeutic decision-making.

A Distal Resection Margin of ≤1 mm and Rectal Cancer Recurrence After Sphincter-Preserving Surgery: The Role of a Positive Distal Margin in Rectal Cancer Surgery

BACKGROUND

There is little information about the prognostic value of a microscopically positive distal margin in patients who have rectal cancer.

OBJECTIVE

We aimed to investigate the influence of a distal margin of ≤1 mm on oncologic outcomes after sphincter-preserving resection for rectal cancer.

DESIGN

This is a retrospective cohort study.

SETTINGS

The study was conducted at 2 hospitals.

PATIENTS

A total of 6574 patients underwent anterior resection for rectal cancer from January 1999 to December 2014; 97 (1.5%) patients with a distal margin of ≤1 mm were included in this study. For comparative analyses, patients were matched with 194 patients with a negative distal margin (>1 mm) according to sex, age, BMI, ASA score, neoadjuvant treatment, tumor location, and stage.

MAIN OUTCOME MEASURES

The oncologic outcomes of the 2 groups were compared.

RESULTS

Perineural and lymphovascular invasion rates were significantly higher in patients with a positive distal margin (54.6% vs 28.9%; 67.0% vs 42.8%; both p < 0.001) compared with to patients with negative distal margin. Comparison between microscopically positive and negative distal margin showed worse oncologic outcomes in patients with a microscopically positive distal margin, including 5-year local recurrence rate (24.1% vs 12.0%, p = 0.005); 5-year distant recurrence rate (35.5% vs 20.2%, p = 0.011); 5-year disease-free survival (45.5% vs 69.5%, p < 0.001); and 5-year OS (69.2% vs 79.7%, p = 0.004). Among the 97 patients with a microscopically positive distal margin, the 5-year disease-free survival rate was higher in patients who received adjuvant therapy (52.0% vs 30.7%, p = 0.089).

LIMITATIONS

This is a retrospective study; bias may exist.

CONCLUSIONS

A distal margin of 1 mm is associated with worse oncologic results. Our data indicate the importance of achieving a clear distal margin in the surgical treatment of rectal cancer. Adjuvant therapy should be used in these patients to reduce recurrence. See Video Abstract at http://links.lww.com/DCR/A408.

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.

Pathologic Complete Response Rates After Neoadjuvant Treatment in Rectal Cancer: An Analysis of the National Cancer Database

BACKGROUND

Pathologic complete response (pCR) of rectal cancer following neoadjuvant therapy is associated with decreased local recurrence and increased overall survival. This study utilizes a national dataset to identify predictors of pCR in patients with rectal cancer.

METHODS

The National Cancer Database was queried for patients with nonmetastatic rectal cancer (2004-2014) who underwent neoadjuvant therapy and surgical resection. Unadjusted associations were assessed using rank-sum tests and χ ² tests where appropriate. Backward elimination and forward selection multivariable logistic regression models were created to determine the relationship of annual surgical volume with pCR rate, adjusting for preoperative characteristics and radiation-surgery interval. Statistical tests were two-sided, with a significance level of p ≤ 0.05. Analyses were performed using SAS version 9.4.

RESULTS

A total of 27,532 patients from 1179 participating hospitals met the inclusion criteria. Generalized linear mixed models demonstrated that the odds of achieving pCR was independently associated with more recent diagnosis, female sex, private insurance, lower grade, lower clinical T classification, lower clinical N classification, increasing interval between the end of radiation and surgery, and treatment at higher-volume institutions.

CONCLUSIONS

pCR was associated with favorable tumor factors, insurance status, time between radiation and surgery, and institutional volume. It is not clear what is driving the higher rates of pCR at high-volume institutions. Research targeted at understanding processes that are associated with pCR in high-volume institutions is needed so that similar results can be achieved across the spectrum of facilities caring for patients in this population.

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 factors of post-chemoradiotherapy as valuable indicators for pathological complete response in locally advanced rectal cancer

OBJECTIVES

Pathological complete response has shown a better prognosis for patients with locally advanced rectal cancer after preoperative chemoradiotherapy. However, correlations between post-chemoradiotherapy clinical factors and pathologic complete response are not well confirmed. The aim of the current study was to identify post-chemoradiotherapy clinical factors that could serve as indicators of pathologic complete response in locally advanced rectal cancer.

METHODS

This study retrospectively analyzed 544 consecutive patients with locally advanced rectal cancer treated at Sun Yat-sen University Cancer Center from December 2003 to June 2014. All patients received preoperative chemoradiotherapy followed by surgery. Univariate and multivariate regression analyses were performed to identify post-chemoradiotherapy clinical factors that are significant indicators of pathologic complete response.

RESULTS

In this study, 126 of 544 patients (23.2%) achieved pathological complete response. In multivariate analyses, increased pathological complete response rate was significantly associated with the following factors: post-chemoradiotherapy clinical T stage 0-2 (odds ratio=2.098, 95% confidence interval=1.023-4.304, p=0.043), post-chemoradiotherapy clinical N stage 0 (odds ratio=2.011, 95% confidence interval=1.264-3.201, p=0.003), interval from completion of preoperative chemoradiotherapy to surgery of >7 weeks (odds ratio=1.795, 95% confidence interval=1.151-2.801, p=0.010) and post-chemoradiotherapy carcinoembryonic antigen ≤2 ng/ml (odds ratio=1.579, 95% confidence interval=1.026-2.432, p=0.038).

CONCLUSIONS

Post-chemoradiotherapy clinical T stage 0-2, post-chemoradiotherapy clinical N stage 0, interval from completion of chemoradiotherapy to surgery of >7 weeks and post-chemoradiotherapy carcinoembryonic antigen ≤2 ng/ml were independent clinical indicators for pathological complete response. These findings demonstrate that post-chemoradiotherapy clinical factors could be valuable for post-operative assessment of pathological complete response.