Prediction in rectal cancer. Semin Radiat Oncol. 2012;22:175-183. [PMID: 22385923 DOI: 10.1016/j.semradonc.2011.12.005]

Tissue-Based Markers as a Tool to Assess Response to Neoadjuvant Radiotherapy in Rectal Cancer-Systematic Review

According to current guidelines, the current treatment for locally advanced rectal cancer is neoadjuvant therapy, followed by a total mesorectal excision. However, radiosensitivity tends to differ among patients due to tumor heterogeneity, making it difficult to predict the possible outcomes of the neoadjuvant therapy. This review aims to investigate different types of tissue-based biomarkers and their capability of predicting tumor response to neoadjuvant therapy in patients with locally advanced rectal cancer. We identified 169 abstracts in NCBI PubMed, selected 48 reports considered to meet inclusion criteria and performed this systematic review. Multiple classes of molecular biomarkers, such as proteins, DNA, micro-RNA or tumor immune microenvironment, were studied as potential predictors for rectal cancer response; nonetheless, no literature to date has provided enough sufficient evidence for any of them to be introduced into clinical practice.

Clinical Implications of Combined Lymphocyte and Neutrophil Count in Locally Advanced Rectal Cancer After Preoperative Chemoradiotherapy

BACKGROUND

There are controversies about the ability of neutrophil to lymphocyte ratio to predict the recurrence and survival in patients with locally advanced rectal cancer (LARC) treated with neoadjuvant chemoradiation. The objective of this study is to investigate the prognostic potential of combined lymphocyte count (LC) and neutrophil count (NC) in LARC patients treated with chemoradiotherapy (CRT) followed by curative surgery.

METHODS

Patients with LARC who underwent surgical resection between January 2010 and December 2017 were reviewed retrospectively. We divided the patients into three groups: high LC and low NC, low LC and high NC, and the remaining patients. The cut-off values of LC and NC were determined by receiver operating characteristic curve analysis and log-rank test statistics. We compared the disease-free survival (DFS) rate between the groups.

RESULTS

A total of 176 consecutive patients were included in this study. The 5 year DFS rate was significantly different among the three groups in pathologic node (pN)+ patients (73.2% vs. 61.9% vs. 14.2%; P = 0.025). Cox multivariate analysis for pN+ patients demonstrated that combination of low LC and high NC (hazard ratio, 3.630; 95% confidence interval [CI], 1.306-10.093; P = 0.013) was significantly correlated with decreased DFS.

CONCLUSIONS

This study showed that the combination of LC and NC is a powerful predictive factor for disease recurrence in pN+ LARC patients who underwent CRT.

Comprehensive Analysis of DNA Methylation and Prediction of Response to NeoadjuvantTherapy in Locally Advanced Rectal Cancer

The treatment for locally advanced rectal carcinomas (LARC) is based on neoadjuvant chemoradiotherapy (nCRT) and surgery, which results in pathological complete response (pCR) in up to 30% of patients. Since epigenetic changes may influence response to therapy, we aimed to identify DNA methylation markers predictive of pCR in LARC patients treated with nCRT. We used high-throughput DNA methylation analysis of 32 treatment-naïve LARC biopsies and five normal rectal tissues to explore the predictive value of differentially methylated (DM) CpGs. External validation was carried out with The Cancer Genome Atlas-Rectal Adenocarcinoma (TCGA-READ 99 cases). A classifier based on three-CpGs DM (linked to OBSL1, GPR1, and INSIG1 genes) was able to discriminate pCR from incomplete responders with high sensitivity and specificity. The methylation levels of the selected CpGs confirmed the predictive value of our classifier in 77 LARCs evaluated by bisulfite pyrosequencing. Evaluation of external datasets (TCGA-READ, GSE81006, GSE75546, and GSE39958) reproduced our results. As the three CpGs were mapped near to regulatory elements, we performed an integrative analysis in regions associated with predicted cis-regulatory elements. A positive and inverse correlation between DNA methylation and gene expression was found in two CpGs. We propose a novel predictive tool based on three CpGs potentially useful for pretreatment screening of LARC patients and guide the selection of treatment modality.

Correlation of ultra-high field MRI with histopathology for evaluation of rectal cancer heterogeneity

Current clinical MRI techniques in rectal cancer have limited ability to examine cancer stroma. The differentiation of tumour from desmoplasia or fibrous tissue remains a challenge. Standard MRI cannot differentiate stage T1 from T2 (invasion of muscularis propria) tumours. Diffusion tensor imaging (DTI) can probe tissue structure and organisation (anisotropy). The purpose of this study was to examine DTI-MRI derived imaging markers of rectal cancer stromal heterogeneity and tumour extent ex vivo. DTI-MRI at ultra-high magnetic field (11.7 tesla) was used to examine the stromal microstructure of malignant and normal rectal tissue ex vivo, and the findings were correlated with histopathology. Images obtained from DTI-MRI (A0, apparent diffusion coefficient and fractional anisotropy (FA)) were used to probe rectal cancer stromal heterogeneity. FA provided the best discrimination between cancer and desmoplasia, fibrous tissue and muscularis propria. Cancer had relatively isotropic diffusion (mean FA 0.14), whereas desmoplasia (FA 0.31) and fibrous tissue (FA 0.34) had anisotropic diffusion with significantly higher FA than cancer (p < 0.001). Tumour was distinguished from muscularis propria (FA 0.61) which was highly anisotropic with higher FA than cancer (p < 0.001). This study showed that DTI-MRI can assist in more accurately defining tumour extent in rectal cancer.

Functional MRI for quantitative treatment response prediction in locally advanced rectal cancer

Despite advances in multimodality treatment strategies for locally advanced rectal cancer and improvements in locoregional control, there is still a considerable variation in response to neoadjuvant chemoradiotherapy (CRT). Accurate prediction of response to neoadjuvant CRT would enable early stratification of management according to good responders and poor responders, in order to adapt treatment to improve therapeutic outcomes in rectal cancer. Clinical studies in diffusion-weighted imaging (DWI) and dynamic contrast-enhanced (DCE) MRI have shown promising results for the prediction of therapeutic response in rectal cancer. DWI allows for assessment of tumour cellularity. DCE-MRI enables evaluation of factors of the tumour microvascular environment and changes in perfusion in response to treatment. Studies have demonstrated that predictors of good response to CRT include lower tumour pre-CRT apparent diffusion coefficient (ADC), greater percentage increase in ADC during and post CRT, and higher pre-CRT K^trans. However, the mean ADC and K^trans values do not adequately reflect tumour heterogeneity. Multiparametric MRI using quantitative DWI and DCE-MRI in combination, and a histogram analysis technique can assess tumour heterogeneity and its response to treatment. This strategy has the potential to improve the accuracy of therapeutic response prediction in rectal cancer and warrants further investigation.

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.

Dianthin-EGF is an effective tumor targeted toxin in combination with saponins in a xenograft model for colon carcinoma

ABSTRACT 

Aims: The intention of this work was to lift saponin supported tumor targeted therapies onto the next level by using targeted toxins in nude mice xenotransplant models. Materials & methods: Combined application of dianthin coupled to EGF and saponin SO-1861 was tested in a xenograft model of colon carcinoma. In vitro cytotoxicity was tested in real-time in NIH3T3 cells (no human EGF receptor expression), HER14 and human colon carcinoma HCT116 (both EGF receptor overexpressing) cells. A xenograft model was established using HCT116 cells and tumor-bearing animals were treated with SO-1861 (30 µg/treatment) and dianthin coupled to EGF (0.35 µg/treatment). Tumor progression was monitored, using 18F-2-fluor-2-desoxy-d-glucose, by small animal PET and by x-ray computed tomography. Results: In vitro results demonstrated a high-receptor specificity and the in vivo experiment showed a progressive reduction of the tumor volume and glycolytic activity in the treated group (>95% reduction; p < 0.05). Conclusion: This therapy has great advantage because of high specificity, low side effects and great effectiveness for future development in the treatment of colon cancer.

Predictive markers of response to neoadjuvant therapy in rectal cancer

BACKGROUND

Neoadjuvant therapy followed by radical surgery is the standard treatment in locally advanced rectal cancer. It is important to predict the response because the treatment has side effects and is costly. The aim of this study was to establish the relationship among clinical, pathologic, and molecular biomarkers and the response to neoadjuvant therapy.

METHOD

A total of 130 patients with locally advanced mid and low rectal cancer who underwent long-course radiotherapy with 5-FU based chemotherapy followed by radical surgical resection were included in the study. Clinical and pathologic data were collected. Paraffin-embedded sections obtained in diagnostic biopsies were assessed by immunohistochemical staining for molecular markers and classified using a semiquantitative method. Results were related with T-downstaging and tumor regression grade using Mandard scoring system on surgical specimens.

RESULTS

Pathologic complete response was found in 19 patients (14.6%), while in another 18 (13.8%) only minor residual disease was seen in the rectal wall. T-downstaging was observed in 63 (48.5%). The average of lymph node retrieval in the surgical specimens was 9.4. Regarding predictive markers of response, there was significant correlation between the expression of B-cell lymphoma 2 (P = 0.005), β-catenin (P = 0.03), vascular endothelial growth factor (P = 0.048) and apoptotic protease activating factor 1 (P = 0.03), tumor differentiation grade (P < 0.001), and response in the univariate analysis. T-downstaging was associated with vascular endothelial growth factor expression (P = 0.03) and tumor differentiation grade (P < 0.001). Significant parameters found in the multivariate analysis were tumor differentiation grade and Bcl-2 expression.

CONCLUSIONS

Pathologic and molecular biomarkers in the diagnostic biopsies may help us predict tumor response to chemoradiation in rectal cancer patients.

Use of blood-based biomarkers for early diagnosis and surveillance of colorectal cancer

Early screening for colorectal cancer (CRC) holds the key to combat and control the increasing global burden of CRC morbidity and mortality. However, the current available screening modalities are severely inadequate because of their high cost and cumbersome preparatory procedures that ultimately lead to a low participation rate. People simply do not like to have colonoscopies. It would be ideal, therefore, to develop an alternative modality based on blood biomarkers as the first line screening test. This will allow for the differentiation of the general population from high risk individuals. Colonoscopy would then become the secondary test, to further screen the high risk segment of the population. This will encourage participation and therefore help to reach the goal of early detection and thereby reduce the anticipated increasing global CRC incidence rate. A blood-based screening test is an appealing alternative as it is non-invasive and poses minimal risk to patients. It is easy to perform, can be repeated at shorter intervals, and therefore would likely lead to a much higher participation rate. This review surveys various blood-based test strategies currently under investigation, discusses the potency of what is available, and assesses how new technology may contribute to future test design.

Clinical outcomes of local excision following preoperative chemoradiotherapy for locally advanced rectal cancer

PURPOSE

To evaluate the treatment outcomes of local excision following preoperative chemoradiotherapy in patients with locally advanced rectal cancer who have not undergone radical surgery for any reason.

MATERIALS AND METHODS

The data of 27 patients with locally advanced rectal cancer who underwent preoperative chemoradiotherapy followed by local excision were analyzed retrospectively. The primary endpoint was the 5-year relapse-free survival rate, and the secondary endpoint was the pattern of recurrence.

RESULTS

The median follow-up time was 81.8 months (range, 28.6 to 138.5 months). The 5-year local relapse-free survival (LRFS), distant metastasis-free survival (DMFS), relapse-free survival (RFS), and overall survival (OS) were 88.9%, 81.1%, 77.8%, and 85.0%, respectively. Six (22%) patients developed treatment failure; one (4%) patient had local recurrence only, three (11%) patients had distant recurrence only, and two (7%) patients had both. The 5-year LRFS, DMFS, RFS, and OS for patients with ypT0-1 compared with ypT2-3 were 94.1% vs. 77.8% (p=0.244), 94.1% vs. 55.6% (p=0.016), 88.2% vs. 55.6% (p=0.051), and 94.1% vs. 66.7% (p=0.073), respectively.

CONCLUSION

Local excision following preoperative chemoradiotherapy may be an alternative treatment for highly selected patients with locally advanced rectal cancer who have achieved ypT0-1 after preoperative chemoradiotherapy.

Effectiveness of neoadjuvant concurrent chemoradiotherapy versus up-front proctectomy in clinical stage II-III rectal cancer: A population-based study

AIMS

Neoadjuvant concurrent chemoradiotherapy (NCCRT) is currently the preferred treatment for rectal cancer of clinical stage II-III based on its efficacy in clinical trials. The population-based effectiveness of NCCRT is rarely reported on in the literature. The purpose of our study is to investigate the nationwide population-based effectiveness of NCCRT as compared with up-front proctectomy.

METHODS

In this retrospective cohort study, we identified the study population by linking datasets including the cancer registry, death registry and other related files in Taiwan. We identified all patients with rectal adenocarcinoma of American Joint Committee on Cancer clinical stage II or III who were diagnosed in 2007 or 2008 and received either NCCRT or up-front proctectomy. We included patients' age, gender, residence, socioeconomic status and clinical stage as covariables. We used overall survival as the measure of effectiveness. The Cox proportional-hazards regression model was used for statistical analyses. We further conducted sensitivity analyses, one in only those who received optimal postoperative chemotherapy and one in two subgroups matched for propensity score.

RESULTS

We included 1933 patients (NCCRT: 424; up-front proctectomy: 1509) in the study population. NCCRT was associated with improved survival as compared with up-front proctectomy (adjusted hazard ratio of death 0.656; 95% confidence interval 0.495-0.871). Our results were robust in the sensitivity analyses.

CONCLUSION

We demonstrated that the use of neoadjuvant concurrent systemic therapy and radiotherapy is associated with better effectiveness in rectal adenocarcinoma of clinical stage II-III as compared with up-front proctectomy. Further studies are needed to elucidate the subgroups most likely to benefit and to clarify NCCRT's cost-effectiveness.

Carbohydrate antigen 19-9 levels associated with pathological responses to preoperative chemoradiotherapy in rectal cancer

PURPOSE

To investigate whether pretreatment serum carbohydrate antigen 19-9 (CA 19-9) levels are associated with pathological responses to preoperative chemoradiotherapy (CRT) in patients with rectal cancer.

MATERIALS AND METHODS

In total, 260 patients with locally advanced rectal cancer (cT3-4NanyM0) who underwent preoperative CRT and radical surgery were analyzed retrospectively. CRT consisted of 50.4 Gy pelvic radiotherapy and concurrent chemotherapy. Radical surgery was performed at a median of 7 weeks after CRT completion. Pathological CRT response criteria included downstaging (ypStage 0-I) and ypT0-1. A discrimination threshold of CA 19-9 level was determined using a receiver operating characteristics analysis.

RESULTS

The median CA 19-9 level was 8.0 (1.0-648.0) U/mL. Downstaging occurred in 94 (36.2%) patients and ypT0-1 in 50 (19.2%). The calculated optimal threshold CA 19-9 level was 10.2 U/mL for downstaging and 9.0 U/mL for ypT0-1. On multivariate analysis, CA 19-9 (≤ 9.0 U/mL) was significantly associated with downstaging (odds ratio, 2.089; 95% confidence interval, 1.189-3.669; P=0.010) or ypT0-1 (OR, 2.207; 95%CI, 1.079-4.512; P=0.030), independent of clinical stage or carcinoembryonic antigen.

CONCLUSIONS

This study firstly showed a significant association of pretreatment serum CA 19-9 levels with pathological CRT responses of rectal cancer. The CA 19-9 level is suggested to be valuable in predicting CRT responses of rectal cancer cases before treatment.

A Predictive Genetic Signature for Response to Fluoropyrimidine-Based Neoadjuvant Chemoradiation in Clinical Stage II and III Rectal Cancer

PURPOSE

Pre-operative chemoradiation (CRT) is currently the standard of care for patients with clinical stage II and III rectal cancer but only about 45% of patients achieve tumor downstaging and <20% of patients achieve a pathologic complete response. Better methods to stratify patients according to potential neoadjuvant treatment response are needed. We used microarray analysis to identify a genetic signature that correlates with a pathological complete response (pCR) to neoadjuvant CRT. We performed a gene network analysis to identify potential signaling pathways involved in determining response to neoadjuvant treatment.

PATIENTS AND METHODS

We identified 31 T3-4 N0-1 rectal cancer patients who were treated with neoadjuvant fluorouracil-based CRT. Eight patients were identified to have achieved a pCR to treatment while 23 patients did not. mRNA expression was analyzed using cDNA microarrays. The correlation between mRNA expression and pCR from pre-treatment tumor biopsies was determined. Gene network analysis was performed for the genes represented by the predictive signature.

RESULTS

A genetic signature represented by expression levels of the three genes EHBP1, STAT1, and GAPDH was found to correlate with a pCR to neoadjuvant treatment. The difference in expression levels between patients who achieved a pCR and those who did not was greatest for EHBP1. Gene network analysis showed that the three genes can be connected by the gene ubiquitin C (UBC).

CONCLUSION

This study identifies a 3-gene signature expressed in pre-treatment tumor biopsies that correlates with a pCR to neoadjuvant CRT in patients with clinical stage II and III rectal cancer. These three genes can be connected by the gene UBC, suggesting that ubiquitination is a molecular mechanism involved in determining response to treatment. Validating this genetic signature in a larger number of patients is proposed.

Epigenetic status of LINE-1 predicts clinical outcome in early-stage rectal cancer

BACKGROUND

We evaluated the clinical prognostic value of methylation of two non-coding repeat sequences, long interspersed element 1 (LINE-1) and Alu, in rectal tumour tissues. In addition to DNA methylation, expression of histone modifications H3K27me3 and H3K9Ac was studied in this patient cohort.

METHODS

LINE-1 and Alu methylation were assessed in DNA extracted from formalin-fixed paraffin-embedded tissues. A pilot (30 tumour and 25 normal tissues) and validation study (189 tumour and 53 normal tissues) were performed. Histone modifications H3K27me3 and H3K9Ac were immunohistochemically stained on tissue microarrays of the study cohort.

RESULTS

In early-stage rectal cancer (stage I-II), hypomethylation of LINE-1 was an independent clinical prognostic factor, showing shorter patient survival (P=0.014; HR: 4.6) and a higher chance of tumour recurrence (P=0.001; HR: 9.6). Alu methylation did not show any significant correlation with clinical parameters, suggesting an active role of LINE-1 in tumour development. Expression of H3K27me3 (silencing gene expression) and H3K9Ac (activating gene expression) in relation to methylation status of LINE-1 and Alu supported this specific role of LINE-1 methylation.

CONCLUSION

The epigenetic status of LINE-1, but not of Alu, is prognostic in rectal cancer, indicating an active role for LINE-1 in determining clinical outcome.

Timing of surgery after long-course neoadjuvant chemoradiotherapy for rectal cancer: a systematic review of the literature

BACKGROUND

Neoadjuvant long-course chemoradiotherapy is commonly used to improve the local control and resectability of locally advanced rectal cancer, with surgery performed after an interval of a number of weeks.

OBJECTIVE

We report an evidence-based systematic review of published data supporting the optimal time to perform surgical resection after long-course neoadjuvant therapy.

DATA SOURCES

A systematic literature search was undertaken of the MEDLINE and Embase electronic databases from 1995 to 2012.

STUDY SELECTION

English language articles were included that compared outcomes following rectal cancer surgery performed at different times after a long course of neoadjuvant radiation-based therapy.

INTERVENTIONS

: Patients received a long course of neoadjuvant therapy followed by radical surgical resection after an interval period.

MAIN OUTCOME MEASURES

The rates of tumor response, R0 resection, sphincter preservation, surgical complications, and disease recurrence were the primary outcomes measured.

RESULTS

Fifteen studies were identified: 1 randomized controlled trial, 1 prospective nonrandomized interventional study, and 13 observational studies. Studies compared time intervals that varied between <5 days and >12 weeks, with a large degree of variation in what the standard interval length was considered to be. Four of the 7 studies that reported rates of pathological complete response identified significantly higher rates with an extended interval between chemoradiotherapy and surgery; 3 of 8 studies demonstrated increased primary tumor downstaging with a longer interval. No significant differences have been consistently demonstrated in rates of surgical complications, sphincter preservation, or long-term recurrence and survival.

LIMITATIONS

Neoadjuvant regimes, indications for neoadjuvant therapy, and time intervals after chemoradiotherapy were heterogeneous between studies; consequently, meta-analysis could not be performed.

CONCLUSIONS

There is limited evidence to support decisions regarding when to resect rectal cancer following chemoradiotherapy. There may be benefits in prolonging the interval between chemoradiotherapy and surgery beyond the 6 to 8 weeks that is commonly practiced. However, outcomes need to be studied further in robust randomized studies.

Evidence-based Guidelines for Precision Risk Stratification-Based Screening (PRSBS) for Colorectal Cancer: Lessons learned from the US Armed Forces: Consensus and Future Directions

Colorectal cancer (CRC) is the third most common cause of cancer-related death in the United States (U.S.), with estimates of 143,460 new cases and 51,690 deaths for the year 2012. Numerous organizations have published guidelines for CRC screening; however, these numerical estimates of incidence and disease-specific mortality have remained stable from years prior. Technological, genetic profiling, molecular and surgical advances in our modern era should allow us to improve risk stratification of patients with CRC and identify those who may benefit from preventive measures, early aggressive treatment, alternative treatment strategies, and/or frequent surveillance for the early detection of disease recurrence. To better negotiate future economic constraints and enhance patient outcomes, ultimately, we propose to apply the principals of personalized and precise cancer care to risk-stratify patients for CRC screening (Precision Risk Stratification-Based Screening, PRSBS). We believe that genetic, molecular, ethnic and socioeconomic disparities impact oncological outcomes in general, those related to CRC, in particular. This document highlights evidence-based screening recommendations and risk stratification methods in response to our CRC working group private-public consensus meeting held in March 2012. Our aim was to address how we could improve CRC risk stratification-based screening, and to provide a vision for the future to achieving superior survival rates for patients diagnosed with CRC.

An update on preoperative radiotherapy for locally advanced rectal cancer

Even in patients undergoing an optimal surgical technique (e.g., total mesorectal excision), radiotherapy provides a significant benefit in the local control of rectal cancer. Compared with postoperative treatment, chemoradiotherapy given preoperatively has been shown to decrease local recurrence rates and toxicity. Additionally, preoperative chemoradiotherapy permits the early identification of tumor responses to this cytotoxic treatment by surgical pathology. Pathological parameters reflecting the tumor response to chemoradiotherapy have been shown to be surrogate markers for long-term clinical outcomes. Post-chemoradiotherapy downstaging from cStage II-III to ypStage 0-I indicates a favorable prognosis, with no difference between ypStage 0 and ypStage I. Research is ongoing to develop useful tools (clinical, molecular, and radiological) for clinical determination of the pathologic chemoradiotherapeutic response before surgery, and possibly even before preoperative treatment. In the future, risk-adapted strategies, including intensification of preoperative therapy, conservative surgery, or the selective administration of postoperative chemotherapy, will be realized for locally-advanced rectal cancer patients based on their response to preoperative chemoradiotherapy.