Prognostic impact of deficient DNA mismatch repair in patients with stage III colon cancer from a randomized trial of FOLFOX-based adjuvant chemotherapy

Genomic and epigenomic biomarkers in colorectal cancer: From diagnosis to therapy

Colorectal cancer (CRC) is the second leading cause of cancer-related deaths in the United States. Despite ongoing efforts aimed at increasing screening for CRC and early detection, and development of more effective therapeutic regimens, the overall morbidity and mortality from this malignancy remains a clinical challenge. Therefore, identifying and developing genomic and epigenomic biomarkers that can improve CRC diagnosis and help predict response to current therapies are of paramount importance for improving survival outcomes in CRC patients, sparing patients from toxicity associated with current regimens, and reducing the economic burden associated with these treatments. Although efforts to develop biomarkers over the past decades have achieved some success, the recent availability of high-throughput analytical tools, together with the use of machine learning algorithms, will likely hasten the development of more robust diagnostic biomarkers and improved guidance for clinical decision-making in the coming years. In this chapter, we provide a systematic and comprehensive overview on the current status of genomic and epigenomic biomarkers in CRC, and comment on their potential clinical significance in the management of patients with this fatal malignancy, including in the context of precision medicine.

Microsatellite Instability in Patients With Stage III Colon Cancer Receiving Fluoropyrimidine With or Without Oxaliplatin: An ACCENT Pooled Analysis of 12 Adjuvant Trials

PURPOSE

In patients with stage III colon cancer (CC) whose tumors demonstrate microsatellite instability (MSI), the efficacy of adjuvant fluoropyrimidine (FP) with or without oxaliplatin has not been clearly demonstrated and the prognostic value of MSI remains uncertain.

MATERIALS AND METHODS

Individual patient data from the ACCENT database were used to evaluate the effect of FP with or without oxaliplatin on disease-free survival (DFS) and overall survival (OS) among patients with MSI stage III CC and the prognostic value of MSI in patients treated with FP plus oxaliplatin, by stratified Cox models adjusted for demographic and clinicopathological factors.

RESULTS

MSI status was available for 5,457 patients (609 MSI, 11.2%; 4848 microsatellite stable [MSS], 88.8%) from 12 randomized clinical trials (RCTs). Oxaliplatin significantly improved OS of MSI patients from the two RCTs testing FP with or without oxaliplatin (n = 185; adjusted hazard ratio [aHR] = 0.52, 95% CI, 0.28 to 0.93). Among the 4,250 patients treated with FP plus oxaliplatin (461 MSI and 3789 MSS), MSI was associated with better OS in the N1 group compared with MSS (aHR = 0.66; 95% CI, 0.46 to 0.95) but similar survival in the N2 population (aHR = 1.13; 95% CI, 0.86 to 1.48; P interaction = .029). The main independent prognosticators of MSI patients treated with FP plus oxaliplatin were T stage (aHR = 2.09; 95% CI, 1.29 to 3.38) and N stage (aHR = 3.57; 95% CI, 2.32 to 5.48). Similar results were observed for DFS in all analyses.

CONCLUSION

Adding oxaliplatin to FP improves OS and DFS in patients with MSI stage III CC. Compared with MSS, MSI patients experienced better outcomes in the N1 group but similar survival in the N2 group.

Prognostic and Predictive Cross-Roads of Microsatellite Instability and Immune Response to Colon Cancer

Understanding molecular features of colon cancer has shed light on its pathogenesis and progression. Over time, some of these features acquired clinical dignity and were incorporated in decision making. Namely, microsatellite instability (MSI) due to mismatch repair of defects, which primarily was adopted for the diagnosis of Lynch syndrome, became recognized as the biomarker of a different disease type, showing a less aggressive behavior. MSI tumors harbor high amounts of tumor infiltrating lymphocytes (TILs) due to their peculiar load in neoantigens. However, microsatellite stable colon cancer may also show high amounts of TILs, and this feature is as well associated with better outcomes. High TIL loads are in general associated with a favorable prognosis, especially in stage II colon cancer, and therein identifies a patient subset with the lowest probability of relapse. With respect to post-surgical adjuvant treatment, particularly in stage III, TILs predictive ability seems to weaken along with the progression of the disease, being less evident in high risk patients. Moving from cohort studies to the analysis of a series from clinical trials contributed to increase the robustness of TILs as a biomarker. The employment of high TIL densities as an indicator of good prognosis in early-stage colon cancers is strongly advisable, while in late-stage colon cancers the employment as an indicator of good responsiveness to post-surgical therapy requires refinement. It remains to be clarified whether TILs could help in identifying those patients with node-positive cancers to whom adjuvant treatment could be spared, at least in low-risk groups as defined by the TNM staging system.

Adjuvant chemotherapy in colon cancer: state of the art and future perspectives

PURPOSE OF REVIEW

This article will review the results of recent studies, which have investigated the duration of adjuvant chemotherapy and also suggest, which aspects of adjuvant treatment need investigation in future studies.

RECENT FINDINGS

The IDEA collaboration investigated whether the duration of adjuvant chemotherapy with an oxaliplatin doublet could be reduced from 6 to 3 months. Although this study did not demonstrate noninferiority for 3 months treatment, it did show noninferiority for patients receiving 3 months CAPOX chemotherapy and for those patients with low-risk stage III disease receiving 3 months' treatment. There was also significantly less toxicity seen with 3 months' treatment. Recent studies have shown that detectable ctDNA postoperatively can predict those patients most likely to relapse and so benefit from adjuvant treatment.

SUMMARY

It has been shown that for patients receiving adjuvant CAPOX chemotherapy, or those receiving adjuvant chemotherapy for low-risk stage III colon 3 months' chemotherapy gives similar outcomes to 6 months' treatment with significantly less toxicity.

Duration of FOLFOX Adjuvant Chemotherapy in High-Risk Stage II and Stage III Colon Cancer With Deficient Mismatch Repair

Background

We evaluated the impact of 3 months of mFOLFOX6 adjuvant chemotherapy or surgery alone in comparison with 6 months of mFOLFOX6 on disease-free survival (DFS) in deficient mismatch repair (dMMR) colon cancer (CC) patients.

Methods

This retrospective study identified a cohort of patients with high-risk stage II and III dMMR CC who underwent curative surgery between May 2011 and July 2019. DFS was compared using the Kaplan-Meier survival methods and Cox proportional hazards models. Propensity-score matching was performed to reduce imbalance in baseline characteristics.

Results

A total of 242 dMMR CC patients were identified; 66 patients received 6 months of mFOLFOX6, 87 patients received 3 months of mFOLFOX6, and 89 patients were treated with surgery alone. The 3-year DFS rate was 72.8% in 3-month therapy group and 86.1% in 6-month therapy group, with a hazard ratio (HR) of 2.78 (95CI%, 1.18 to 6.47; P= 0.019). The difference in DFS between surgery alone group and 6-month therapy group was also observed but was nonsignificant (HR= 2.30, 95%CI, 0.99 to 5.38; P=0.054). The benefit of 6-month therapy in DFS compared with 3-month therapy group was pronounced for patients with stage III (HR=2.81, 95%CI, 1.03 to 7.67; P=0.044) but not for high-risk stage II patients. Propensity score matched analysis confirmed a DFS benefit in the 6-month therapy group.

Conclusion

This study suggested that a 6-month duration of mFOLFOX6 adjuvant chemotherapy in dMMR CC patients may be associated with improved DFS compared with 3-month therapy, particularly in patients with stage III. The observational nature of the study implies caution should be taken in the interpretation of these results.

Nomogram model characterized by mutant genes and clinical indexes to identify high-risk patients with stage III/IV colorectal cancer

Background

The aim of the present study was to construct a nomogram model of high-risk stage III/IV colorectal cancer (CRC).

Methods

Gene mutation and clinical information of 251 CRC patients were downloaded from The Cancer Genome Atlas (TCGA). Targeted next-generation sequencing was performed on 44 patients to screen shared mutation genes with frequency >5% between TCGA and clinical cohorts. Univariable and multivariable logistic regression analyses were used to analyze the mutant genes and clinical indexes, and a high-risk stage III/IV nomogram model was constructed. The nomogram model was further validated in the clinical cohort.

Results

SMAD family member 4 (SMAD4), zinc finger homeobox 3 (ZFHX3), and phosphatidylinositol 3,4,5-trisphosphate-dependent Rac exchanger 2 (PREX2) mutations; pathological location; and preoperative carcinoembryonic antigen (CEA) value were screened out to compose a high-risk III/IV nomogram model. The nomogram had good calibration and discriminative ability, with an area under the curve of 0.76 [95% confidence interval (CI): 0.69-0.84]. Hosmer-Leme show test indicated that the model had good goodness of fit (P=0.83). The decision curve revealed this a nomogram model was feasible in clinical practice. In our clinical cohort, the calibration curve did not show good calibration and discrimination.

Conclusions

We established a nomogram model, including the mutation status of SMAD4, ZFHX3, and PREX2; pathological location; and preoperative CEA value, which showed accuracy in the risk prediction of stage III/IV CRC patients.

The Role of BRAF in Metastatic Colorectal Carcinoma-Past, Present, and Future

With a global incidence of 1.8 million cases, colorectal cancer represents one of the most common cancers worldwide. Despite impressive improvements in treatment efficacy through cytotoxic and biological agents, the cancer-related death burden of metastatic colorectal cancer (mCRC) is still high. mCRC is not a genetically homogenous disease and various mutations influence disease development. Up to 12% of mCRC patients harbor mutations of the signal transduction molecule BRAF, the most prominent being BRAFV600E. In mCRC, BRAFV600E mutation is a well-known negative prognostic factor, and is associated with a dismal prognosis. The currently approved treatments for BRAF-mutated mCRC patients are of little impact, and there is no treatment option superior to others. However, the gradual molecular understanding over the last decades of the extracellular signal-regulated kinase/mitogen-activated protein kinase pathway, resulted in the development of new therapeutic strategies targeting the involved molecules. Recently published and ongoing studies administering a combination of different inhibitors (e.g., BRAF, MEK, and EGFR) showed promising results and represent the new standard of care. In this review, we present, both, the molecular and clinical aspects of BRAF-mutated mCRC patients, and provide an update on the current and future treatment approaches that might direct the therapy of mCRC in a new era.

Molecular Biomarkers according to Primary Tumor Location in Colorectal Cancer: Current Standard and New Insights

According to the 2018 GLOBOCAN database, colorectal cancer is one of the most common malignancies and leading causes of cancer-related death worldwide. During the last decades, considerable progress has been made in understanding the complex pathogenetic mechanisms involved in this neoplastic disease. Due to the need to improve treatment responses and clinical outcomes of colorectal cancer patients, the identification of new molecular biomarkers became a crucial spot in clinical oncology. As biological indicators of a specific pathological or physiological process, molecular markers play a central role in cancer detection, diagnosis, outcome prediction, and treatment choice. Considering the existing evidence that malignancies originating from distinct colonic regions behave differently, it is clear that specific biomarkers can be associated to right- or left-sided colon carcinomas, reflecting the distinct molecular signatures of these different tumor entities. The aim of this review is to summarize the main differences among tumors arising from proximal and distal colon in terms of current and emerging biomarkers.

Survival outcome of adjuvant chemotherapy in deficient mismatch repair stage III colon cancer

BACKGROUND

The prognostic impact of DNA mismatch repair (MMR) status remains controversial in patients with stage III colon cancer who are treated with adjuvant chemotherapy (AC). The aim of this study was to evaluate the survival outcome of AC in deficient mismatch repair (dMMR)/microsatellite instable (MSI) stage III CC.

METHODS

Patients with pathological stage III CC between 2010 and 2013 were identified from the National Cancer Database using International Classification of Diseases for Oncology (3rd Edition) morphology and topography codes 8140, 8480, and C18.0-18.8. Patients with pathologic stage T3N2, T4N1, or T4N were considered high risk; patients with stage T3N1 were considered low risk. Univariate and multivariable analyses were conducted, and Kaplan-Meier analysis and Cox proportional hazards models were used to identify the association between AC and overall survival (OS).

RESULTS

A total of 9226 patients with pathological stage III CC were identified, of which 2384 (25.8%) were MSI-high (MSI-H) and met the inclusion criteria of the final analysis. MSI-low (MSI-L) patients (n = 6842) were excluded. There was a preponderance of women (55.0% [n = 1311]), and 76.6% (n = 1825) of patients were non-Hispanic white. The median age was 65 years (range, 19-90 years). The primary sites were the cecum (29.7% [n = 707]), ascending colon (26.0% [n = 620]), sigmoid colon (17.2% [n = 410]), and transverse colon (10.8% [n = 257]). The most common tumor grade was moderately differentiated (n = 50.4% [1202]), followed by poorly differentiated (34.1% [n = 813]) and well differentiated (5.1% [n = 121]). High-risk pathologic stage III CC (T4N1, TxN2) constituted 51.0% (n = 1215) of the study population. High-risk stage III was associated with worse OS compared with low-risk stage III on univariate (P < .001) analysis and displayed a similar trend on multivariable analysis, without a statistically significant difference. Multiagent AC was associated with improved OS compared with no treatment on univariate (P < .001) and multivariable (P < .001) analysis. When stratified by risk status, multiagent AC was associated with improved OS compared with no treatment for high-risk (P < .001) and low-risk (P < .001) stage III disease.

CONCLUSION

Adjuvant chemotherapy is associated with better OS in stage III dMMR/MSI-H CC. An enhanced benefit was shown for high-risk stage III disease.

Enhanced expression of GABRD predicts poor prognosis in patients with colon adenocarcinoma

Neurotransmitters are reported to be involved in tumor initiation and progression. This study aimed to elucidate the prognostic value of γ-aminobutyric acid type A receptor δ subunit (GABRD) in colon adenocarcinoma (COAD) using the data from The Cancer Genome Atlas (TCGA) database. The GABRD mRNA expression levels in the COAD and normal tissues were compared using the Wilcoxon rank-sum test. The correlation between clinicopathologic characteristics and GABRD expression was analyzed by Wilcoxon rank-sum test or Kruskal-Wallis test and logistic regression. The prognostic value of GABRD mRNA expression in patients with COAD was determined using the Kaplan-Meier curve and Cox regression analysis. Finally, the molecular mechanisms of GABRD in COAD were predicted by gene set enrichment analysis (GSEA). The COAD tissues exhibited higher GABRD mRNA expression levels than the normal tissues. The logistic regression analysis revealed that GABRD mRNA expression was correlated with TNM stage, N stage, M stage, and microsatellite instability (MSI) status. The Kaplan-Meier survival curve and log-rank test revealed that patients with COAD exhibiting high GABRD mRNA expression were associated with poor overall survival (OS). The multivariate analysis indicated that increased GABRD mRNA expression was an independent prognostic factor and was correlated with a poor OS. The GSEA revealed that GABRD was involved in signaling pathways, including cell adhesion molecules, gap junction, melanogenesis, and mTOR signaling pathway, as well as the signaling pathways associated with basal cell carcinoma or bladder cancer development. In summary, enhanced GABRD mRNA expression may be a potential independent prognostic biomarker for COAD.

Clinicopathological and molecular features of colorectal cancer with synchronous adenoma

OBJECTIVE

To investigate the clinicopathological and molecular features of colorectal cancer (CRC) with synchronous adenoma and to describe features of synchronous adenomas in CRC patients.

METHODS

Single-centre retrospective cohort of 180 patients were included. The clinicopathological and endoscopic data were collected. The expression mismatch repair (MMR) proteins were detected by immunohistochemistry. The determination of microsatellite instability (MSI) was performed by multiple fluorescence PCR, and the mutations of genes were detected by real-time PCR.

RESULTS

Among all cases, 49 were diagnosed as CRC with synchronous adenoma, and 131 were diagnosed as solitary CRC. Some of the differences between the groups are: higher incidence was found in male (71.4 vs. 52.6%, p = .023) and in patients with habit drinking (34.7 vs. 14.5%, p = .030) and with other neoplastic diseases (42.7 vs. 26%, p = .028). Less tumors in the synchronous group were diagnosed as stage III and IV than in the solitary group (28.6 vs. 45%, p = .045). One and four mutant subtypes of KRAS gene mutations were detected insynchronous group and solitary group respectively.The prevalence of BRAF mutations in solitary group was higher than that in the synchronous group (7.4 vs. 0%, p = .045). A total of 123 adenomas were found in synchronous group and they tend to be smaller than 10 mm (74%).

CONCLUSION

Gender, a habit of drinking and other neoplastic diseases are risk factors for the development of a synchronous adenoma. With a low rate of BRAF mutations, the responses to monoclonal antibody and prognosis of patients with synchronous adenomas may be better than that of solitary CRC.

Early stage colon cancer: Current treatment standards, evolving paradigms, and future directions

Colon cancer continues to be one of the leading causes of mortality and morbidity throughout the world despite the availability of reliable screening tools and effective therapies. The majority of patients with colon cancer are diagnosed at an early stage (stages I to III), which provides an opportunity for cure. The current treatment paradigm of early stage colon cancer consists of surgery followed by adjuvant chemotherapy in a select group of patients, which is directed at the eradication of minimal residual disease to achieve a cure. Surgery alone is curative for the vast majority of colon cancer patients. Currently, surgery and adjuvant chemotherapy can achieve long term survival in about two-thirds of colon cancer patients with nodal involvement. Adjuvant chemotherapy is recommended for all patients with stage III colon cancer, while the benefit in stage II patients is not unequivocally established despite several large clinical trials. Contemporary research in early stage colon cancer is focused on minimally invasive surgical techniques, strategies to limit treatment-related toxicities, precise patient selection for adjuvant therapy, utilization of molecular and clinicopathologic information to personalize therapy and exploration of new therapies exploiting the evolving knowledge of tumor biology. In this review, we will discuss the current standard treatment, evolving treatment paradigms, and the emerging biomarkers, that will likely help improve patient selection and personalization of therapy leading to superior outcomes.

Current Microsatellite Instability Testing in Management of Colorectal Cancer

Colorectal cancer (CRC) is the third most common cancer worldwide. In the past decade, mismatch repair deficiency (dMMR), manifested as microsatellite instability-high (MSI-H), has been recognized as a distinct mechanism promoting tumorigenesis in 15% of CRCs including 3% Lynch syndrome and 12% sporadic CRCs. As the molecular classifications of CRCs are continuously evolving, MSI-H CRCs appear to be the most homogeneous CRCs with distinct molecular, morphologic, and clinical features. MSI-H CRCs have dMMR causing MSI-H and genetic hypermutation but with diploid chromosomes. Morphologically, MSI-H CRCs appear as poorly differentiated or mucinous adenocarcinoma with characteristic lymphocytic infiltration. Most importantly, MSI-H CRCs have better stage-adjusted survival, do not respond well to standard 5-fluorouracil-based adjuvant chemotherapy, but do respond to immunotherapy. The United States Food and Drug Administration granted accelerated approval to immune checkpoint inhibitors, anti-programmed cell death protein-1 antibodies pembrolizumab and nivolumab, and the combination of nivolumab with anti-CTLA4 antibody ipilimumab for the second-line treatment of patients with stage IV MSI-H CRCs in 2017. There are still ongoing phase III clinical trials evaluating pembrolizumab and anti-programmed death-ligand 1 antibody atezolizumab as the first-line treatment in stage IV MSI-H CRCs and a phase I study on the combination of nivolumab and ipilimumab in patients with early stage CRC. These ongoing clinical studies on immunotherapy may lead to practice-changing results in the management of MSI-H CRCs. The National Comprehensive Cancer Network 2018 guidelines recommended MSI to be tested in all newly diagnosed CRCs. The MSI test will become increasingly vital in guiding adjuvant chemotherapy and immunotherapy in the management of CRCs.

Genomic Alterations of NTRK, POLE, ERBB2, and Microsatellite Instability Status in Chinese Patients with Colorectal Cancer

Background

The increasing molecular characterization of colorectal cancers (CRCs) has spurred the need to look beyond RAS, BRAF, and microsatellite instability (MSI). Genomic alterations, including ERBB2 amplifications and mutations, POLE mutations, MSI, and NTRK1–3 fusions, have emerged as targets for matched therapies. We sought to study a clinically annotated Chinese cohort of CRC subjected to genomic profiling to explore relative target frequencies.

Methods

Tumor and matched whole blood were collected from 609 Chinese patients with CRC. Extracted DNA was analyzed for all classes of genomic alterations across 450 cancer‐related genes, including single‐nucleotide variations (SNVs), short and long insertions and deletions (indels), copy number variations, and gene rearrangements. Next‐generation sequencing–based computational algorithms also determined tumor mutational burden and MSI status.

Results

Alterations in TP53 (76%), APC (72%), and KRAS (46%) were common in Chinese patients with CRC. For the first time, the prevalence of NTRK gene fusion was observed to be around 7% in the MSI‐high CRC cohort. Across the cohort, MSI was found in 9%, ERBB2 amplification in 3%, and POLE pathogenic mutation in 1.5% of patients. Such results mostly parallel frequencies observed in Western patients. However, POLE existed at a higher frequency and was associated with large tumor T‐cell infiltration.

Conclusion

Comparing to the Western counterparts, POLE mutations were increased in our cohort. The prevalence of NTRK gene fusion was around 7% in the MSI‐high CRC cohort. Increased adoption of molecular profiling in Asian patients is essential for the improvement of therapeutic outcomes.

Implications for Practice

The increasing use of genomic profiling assays in colorectal cancer (CRC) has allowed for the identification of a higher number of patient subsets benefiting from matched therapies. With an increase in the number of therapies, assays simultaneously evaluating all candidate biomarkers are critical. The results of this study provide an early support for the feasibility and utility of genomic profiling in Chinese patients with CRC.

The emergence of precision medicine has identified genomic variants, such as NTRK gene fusion, microsatellite instability (MSI), HER2 amplification, and POLE pathogenic mutation, as potential agonistic biomarkers for immune or targeted therapies. This article examines NTRK, HER2, and POLE in a cohort of Chinese patients with colorectal cancer.

Imaging predictors of BRAF mutation in colorectal cancer

BACKGROUND

Colorectal cancer (CRC) is one of the leading causes of cancer deaths and is associated with various genetic mutations. BRAF mutations, found in approximately 10% of all CRCs, are associated with negative predictive outcomes. The goal of this study was to assess the relationship between the imaging findings and BRAF statuses of CRC patients.

MATERIALS AND METHODS

The study population was colorectal cancer patients who underwent biopsy or surgery in a single institution from September 2004 to October 2018, and in whom the pathologic specimens were tested for BRAF mutation. The exclusion criteria were (1) patients without pre-operative cross-sectional imaging, and (2) patients whose tumors were invisible on imaging. Two hundred and eighty-three patients met the inclusion criteria. Among them, 128 were excluded, and a total of 155 patients were enrolled in the study.

RESULTS

BRAF mutations were significantly more common in female patients (p = 0.007). Patients with mutated BRAF were significantly older than those with wild-type BRAF (p = 0.001). BRAF-mutant tumors were predominant in right-sided colon (p = 0.001) with higher numbers of polypoid- or mass-like morphology (p = 0.019) and heterogeneous enhancement (p = 0.009). Compared to their wild-type counterparts, BRAF-mutated CRCs have a lower occurrence of non-peritoneal, and overall metastases (p = 0.013 and p = 0.004, respectively). Logistic regression analysis showed three significant factors for the prediction of BRAF mutations in CRC patients: right-sided location (p = 0.002), heterogeneous tumor enhancement (p = 0.039), and lack of non-peritoneal metastasis (p = 0.043).

CONCLUSION

By recognizing the specific imaging features of BRAF-mutant CRCs, it would be possible to identify a patient who has a higher risk of carrying BRAF mutation.

Immunotherapy for Early Stage Colorectal Cancer: A Glance into the Future

Immune checkpoint inhibitors (ICI) have reshaped therapeutic strategies for cancer patients. The development of ICI for early stage colorectal cancer is accompanied by specific challenges: (i) the selection of patients who are likely to benefit from these treatments, i.e., patients with tumors harboring predictive factors of efficacy of ICI, such as microsatellite instability and/or mismatch repair deficiency (MSI/dMMR), or other potential parameters (increased T cell infiltration using Immunoscore® or others, high tumor mutational burden, POLE mutation), (ii) the selection of patients at risk of disease recurrence (poor prognostic features), and (iii) the choice of an accurate clinical trial methodological framework. In this review, we will discuss the ins and outs of clinical research of ICI for early stage MSI/dMMR CC patients in adjuvant and neoadjuvant settings. We will then summarize data that might support the development of ICI in localized colorectal cancer beyond MSI/dMMR.

The impact of mismatch repair status to the preoperative staging of colon cancer: implications for clinical management

Aims: We sought to investigate if mismatch repair (MMR) status influences the preoperative staging of local colon cancer. Methods: Data from 590 patients in the Danish Colorectal Cancer Group national clinical database who were operated on for stage I-III colon cancer in 2010-15 were included. MMR status was determined by immunohistochemistry. Results: 22.9% had deficient(d) MMR tumors. Correlation of the clinical and pathological T-category was significant for both groups. The correlation of pre- and postoperative N-category was inferior (p >0.05) in dMMR cancers compared to a significant (p <0.01) correlation in proficient MMR cancers. 64.8% of dMMR tumors assessed node-positive demonstrated no sign of metastatic involvement at the postoperative assessment. Conclusion: MMR status seems to impact the accuracy of preoperative lymph node staging.

Personalized Adjuvant Treatment of Colon Cancer

Introduction

Colon cancer (CC) is one of the most frequent malignant diseases. Adjuvant chemotherapy is of utmost importance in the management of localized disease. With the emergence of precision medicine, treatment approaches are becoming increasingly personalized and complex. This review contributes to a broader understanding of the role and relevance of personalized adjuvant treatment strategies in colon carcinoma, and summarizes the current status in this disease entity.

Methods

We searched the websites ClinicalTrials.gov, PubMed, and ASCO (American Society of Medical Oncology) Meeting Library for clinical trials and retrospective analyses in the field of adjuvant treatment of CC with special attention to personalized approaches.

Results

Various factors, including gender, age, sidedness, stage, dMMR/MSI-H, mutations, molecular profile, CMS, immunoscore, minimal residual disease, type of adjuvant therapy, therapy duration, and the patient's wish play an important role in the adjuvant setting of CC and should be considered in treatment decision making.

Conclusion

Future molecular profiling ideally assessed and monitored by liquid biopsy might personalize decision making even more in the adjuvant setting of CC patients. Further research and clinical trials are needed to clarify relevant questions and to highlight important clinical aspects.

Combination of preoperative tumour markers and lymphovascular invasion with TNM staging as a cost and labour efficient subtyping of colorectal cancer

Tumour-Node-Metastasis (TNM) staging of colorectal cancer (CRC) needs further classification for better treatment because of disease heterogeneity. Although molecular classifications which are expensive and laborious are under study, cost and labour efficient subtyping is desirable. We assessed the combinations of preoperative tumour marker (TM) elevation and tumour lymphovascular invasion (LVI) as a solution. We used the pooled data of 7151 colon cancer (CC) patients and 4620 rectal cancer (RC) patients who received curative surgery between 2004 and 2008 in Japan. The best-matched subtyping for predicting relapse-free survival (RFS) was statistically selected using the c-index and Akaike's information criterion. This subtyping (TM-LVI), which consisted of three categories by TM elevation status and severity of LVI status, was an independent prognostic factor for RFS of CC (stage IIa, IIIb, and IIIc) and RC (stage I, IIa, IIb, IIIa, and IIIb) and also for disease specific survival of CC (stage IIa, IIb, IIIb, and IIIc) and RC (all stage except for IIc). Although TM-LVI classified CRC patients into low and high recurrence risk groups, the application of adjuvant therapy was not accordance with the TM-LVI status. TM-LVI may be a cost and labour efficient subtyping of colorectal cancer for better treatment strategy.

Copy Number Alterations of Depressed Colorectal Neoplasm Predict the Survival and Response to Oxaliplatin in Proximal Colon Cancer

Depressed colorectal neoplasm exhibits high malignant potential and shows rapid invasiveness. We investigated the genomic profile of depressed neoplasms and clarified the survival outcome and treatment response of the cancers arising from them. We examined 20 depressed and 13 polypoid neoplasms by genome-wide copy number analysis. Subsequently, we validated the identified copy number alterations (CNAs) in an independent cohort of 37 depressed and 42 polypoid neoplasms. Finally, the CNAs were tested as biomarkers in 530 colorectal cancers (CRCs) to clarify the clinical outcome of depressed neoplasms. CNAs in MYC, CCNA1, and BIRC7 were significantly enriched in depressed neoplasms and designated as the D-marker panel. CRCs with a D-marker panel have significantly shorter progression-free survival compared with those without (p = 0.012), especially in stage I (p = 0.049), stages T₁₊₂ (p = 0.027), and proximal cancers (p = 0.002). The positivity of the D-marker panel was an independent risk factor of cancer progression (hazard ratio (95% confidence interval) = 1.52 (1.09–2.11)). Furthermore, the proximal CRCs with D-marker panels had worse overall and progression-free survival when taking oxaliplatin as chemotherapy than those that did not. The D-marker panel may help to optimize treatment and surveillance in proximal CRC and develop a molecular test. However, the current result remains preliminary, and further validation in prospective trials is warranted in the future.

The Impact of KRAS Mutation on the Presentation and Prognosis of Non-Metastatic Colon Cancer: an Analysis from the National Cancer Database

INTRODUCTION

Approximately 40% of colorectal cancers have a KRAS mutation. The prognostic significance of KRAS mutations in patients with non-metastatic colon cancer has not been well elucidated. The National Cancer Database (NCDB) was used to analyze factors associated with KRAS mutation as well as its impact on the presentation and survival of patients with stages I-III colon cancer.

METHODS

The NCDB was queried to identify patients diagnosed with stages I-III adenocarcinoma of the colon from 2004 to 2015.

RESULTS

A total of 19,877 patients with known KRAS status were identified: mutation rates were 33% in stage I, 35% in stage II, and 38% in stage III patients (p < 0.01). On multivariable analysis, black race and right-sided location were independently associated with KRAS-mutated cancers (all p < 0.01). On univariate analysis for overall survival (OS), KRAS mutation was not significantly associated with a worse 5-year OS for stages I and II patients (p = 0.60 and 0.88, respectively). However, stage III KRAS-mutated colon cancers had a lower OS as compared with KRAS wild type cancers both on univariate and multivariable analysis. Right-sided colon cancers were independently associated with a worse prognosis compared with left-sided lesions (p < 0.01).

CONCLUSIONS

KRAS-mutated colon cancers were more frequently observed in black patients, right-sided locations, and higher-stage tumors. These mutations had a negative prognostic impact for stage III patients, suggesting that the incorporation of genotypic data into colon cancer staging may help to guide systemic therapy and prognostication of colon cancer patients.

Neoadjuvant immunotherapy leads to pathological responses in MMR-proficient and MMR-deficient early-stage colon cancers

PD-1 plus CTLA-4 blockade is highly effective in advanced-stage, mismatch repair (MMR)-deficient (dMMR) colorectal cancers, yet not in MMR-proficient (pMMR) tumors. We postulated a higher efficacy of neoadjuvant immunotherapy in early-stage colon cancers. In the exploratory NICHE study (ClinicalTrials.gov: NCT03026140), patients with dMMR or pMMR tumors received a single dose of ipilimumab and two doses of nivolumab before surgery, the pMMR group with or without celecoxib. The primary objective was safety and feasibility; 40 patients with 21 dMMR and 20 pMMR tumors were treated, and 3 patients received nivolumab monotherapy in the safety run-in. Treatment was well tolerated and all patients underwent radical resections without delays, meeting the primary endpoint. Of the patients who received ipilimumab + nivolumab (20 dMMR and 15 pMMR tumors), 35 were evaluable for efficacy and translational endpoints. Pathological response was observed in 20/20 (100%; 95% exact confidence interval (CI): 86-100%) dMMR tumors, with 19 major pathological responses (MPRs, ≤10% residual viable tumor) and 12 pathological complete responses. In pMMR tumors, 4/15 (27%; 95% exact CI: 8-55%) showed pathological responses, with 3 MPRs and 1 partial response. CD8⁺PD-1⁺ T cell infiltration was predictive of response in pMMR tumors. These data indicate that neoadjuvant immunotherapy may have the potential to become the standard of care for a defined group of colon cancer patients when validated in larger studies with at least 3 years of disease-free survival data.

Contribution of Immunoscore and Molecular Features to Survival Prediction in Stage III Colon Cancer

Background

The American Joint Committee on Cancer staging and other prognostic tools fail to account for stage-independent variability in outcome. We developed a prognostic classifier adding Immunoscore to clinicopathological and molecular features in patients with stage III colon cancer.

Methods

Patient (n = 559) data from the FOLFOX arm of adjuvant trial NCCTG N0147 were used to construct Cox models for predicting disease-free survival (DFS). Variables included age, sex, T stage, positive lymph nodes (+LNs), N stage, performance status, histologic grade, sidedness, KRAS/BRAF, mismatch repair, and Immunoscore (CD3⁺, CD8⁺ T-cell densities). After determining optimal functional form (continuous or categorical) and within Cox models, backward selection was performed to analyze all variables as candidate predictors. All statistical tests were two-sided.

Results

Poorer DFS was found for tumors that were T4 vs T3 (hazard ratio [HR] = 1.76, 95% confidence interval [CI] = 1.19 to 2.60; P = .004), right- vs left-sided (HR = 1.52, 95% CI = 1.14 to 2.04; P = .005), BRAF ^V600E (HR = 1.74, 95% CI = 1.26 to 2.40; P < .001), mutant KRAS (HR = 1.66, 95% CI = 1.08 to 2.55; P = .02), and low vs high Immunoscore (HR = 1.69, 95% CI = 1.22 to 2.33; P = .001) (all P < .02). Increasing numbers of +LNs and lower continuous Immunoscore were associated with poorer DFS that achieved significance (both Ps< .0001). After number of +LNs, T stage, and BRAF/KRAS, Immunoscore was the most informative predictor of DFS shown multivariately. Among T_1–3 N₁ tumors, Immunoscore was the only variable associated with DFS that achieved statistical significance. A nomogram was generated to determine the likelihood of being recurrence-free at 3 years.

Conclusions

The Immunoscore can enhance the accuracy of survival prediction among patients with stage III colon cancer.

Analysis of tumor microenvironmental features to refine prognosis by T, N risk group in patients with stage III colon cancer (NCCTG N0147) (Alliance)

BACKGROUND

Tumor-infiltrating lymphocytes (TILs), tumor budding, and micropapillary architecture may influence tumor growth and metastatic potential, thereby enhancing prognostic stratification. We analyzed these features and their relative contribution to overall outcome and in low (T1-3 N1) and high (T4 and/or N2) risk groups that are used to inform the duration of adjuvant chemotherapy in patients with resected stage III colon cancers.

PATIENTS AND METHODS

Among 1532 patients treated in a phase III adjuvant trial of FOLFOX-based therapy, intraepithelial TIL densities, tumor budding, and micropapillary features were analyzed and quantified in routine histopathological sections with light microscopy. Optimal cut-points were determined in association with disease-free survival (DFS) in training and validation sets. Associations or relative contributions of individual features or combined variables with DFS were determined using multivariable Cox regression models.

RESULTS

TILs, tumor budding, and micropapillary features were shown to differ significantly by T, N risk groups and by mismatch repair (MMR) status. Low TILs, high budding, and their combined variable [hazard ratio = 2.07 (95% CI, 1.50% to 2.88%); Padj < 0.0001], but not micropapillary features, were each significantly associated with poorer DFS in a training data set and confirmed in a validation set. TILs were prognostic in proficient mismatch repair (pMMR) and deficient mismatch repair (dMMR) tumors; budding was prognostic only in pMMR tumors. The percentage relative contribution of budding/TILs to DFS was second only to nodal status overall, was second (24.4%) after KRAS in low-risk patients, and was the most important contributor (45.4%) in high-risk patients.

CONCLUSIONS

TIL density and tumor budding were each validated as significant prognostic variables and their combined variable provided robust prognostic stratification by T, N risk groups, being the strongest predictor of DFS among high-risk stage III patients. CLINICALTRIALS.

GOV IDENTIFIER

NCT00079274.

Study of the Relationship between ERCC1 Polymorphisms and Response to Platinum-based Chemotherapy in Iranian Patients with Colorectal and Gastric Cancers

This study was designed to evaluate the effect of excision repair cross complementing group 1 (ERCC1) rs11615 codon 118C/T gene polymorphisms on treatment outcomes in Iranian patients receiving oxaliplatin-based regimens for colorectal (CRC) and gastric cancers (GC). Patients, who were candidates to receive oxaliplatin-based chemotherapy, entered into the study. In 2-week intervals, the patients received combination regimen of oxaliplatin, fluorouracil, and leucovorin (FOLFOX) for 3 months. ERCC1 rs11615 codon 118C/T polymorphism was tested by restriction fragment length polymorphism polymerase chain reaction (RFLP-PCR) method using patients’ peripheral blood lymphocytes. The tumor response to chemotherapy was evaluated by examining the size of the tumor using CT scan. Association between response rates, according to the RECIST criteria, and patients’ genotypes was evaluated. Any relationship between response rate and possible explanatory factors was also determined. Overall, 40 patients (13 females (32.5%), and 27 males (67.5%)) enrolled in the study. Four patients (10.0%) carried the homo­zygous mutation (T/T genotype), ten patients (25.0%) were heterozygous (C/T genotype), and twenty-six patients (65%) were homo­zygous (C/C genotype). Response rate were 30.77%, 20.00%, and 0.00% for the genotypes C/C, C/T, and T/T, respectively. No significant association between response rate and genotypes was observed (p = 0.64). Patients with well- and moderately-differentiated histological grade of the tumor showed a better response rate (100.00% of 2 patients and 66.66% of 12 patients, respectively) compared to those with poorly differentiated (0.00% of 26 patients) histological grade (p < 0.001). Further multicenter studies are recommended to confirm conclusively our findings.

Long-term efficacy of capecitabine plus oxaliplatin chemotherapy on stage III colon cancer: A meta-analysis

BACKGROUND

Many clinical studies for the long-term survival or efficacy of capecitabine plus oxaliplatin (XELOX) in colon cancer have already been studied, but its clinical benefit is controversial.

AIM

To evaluate the long-term efficacy of XELOX regimen in comparison with other adjuvant chemotherapy protocols in colon cancer.

METHODS

By searching the PubMed, EMBASE and Cochrane databases, a total of 12 randomized controlled trials involving 6698 stage III colon cancer cases (XELOX protocol: n = 3298 cases; other adjuvant chemotherapy protocol: n = 3268 cases) were included. The parameter outcomes included the overall survival and the disease-free survival. The quality control of selected literature was based on the Jadad scale and the GRADE system.

RESULTS

In comparison to other adjuvant chemotherapy regimen, XELOX regimen showed a better overall survival (odds ratio = 1.29, 95% confidence interval: 1.15-1.44, P < 0.0001) and a better disease-free survival (odds ratio = 1.32, 95% confidence interval: 1.18-1.46, P < 0.0001) for colon cancer patients, suggesting the XELOX regimen can be a good option for postoperative treatment of stage III colon cancer.

CONCLUSION

The XELOX regimen can be a preferred option for adjuvant treatment of stage III colon cancer after surgery.

Clinical Outcomes in Patients With Colon Cancer With Microsatellite Instability of Sporadic or Familial Origin Treated With Adjuvant FOLFOX With or Without Cetuximab: A Pooled Analysis of the PETACC8 and N0147 Trials

PURPOSE

The microsatellite instability (MSI) or deficient mismatch repair (dMMR) phenotype is usually regarded as a single biologic entity, given the absence of comparative analyses regarding prognosis and response to chemotherapy between sporadic and familial dMMR cancers.

PATIENTS AND METHODS

Patients with stage III colon cancers were randomly assigned to FOLFOX (leucovorin, fluorouracil, and oxaliplatin) with or without cetuximab in 2 large adjuvant phase III trials (N = 5,577). Among patients with MSI and KRAS exon 2 wild-type (WT) tumors, the prognostic and predictive impacts of sporadic versus familial dMMR cancers and BRAF V600E mutational status were determined. Multivariable Cox proportional hazards models were used to assess disease-free survival (DFS) by treatment arm, adjusting for age, sex, tumor grade, Eastern Cooperative Oncology Group performance status, pT/pN stage, and primary tumor location.

RESULTS

Among patients with MSI status with complete data for dMMR mechanism analysis (n = 354), 255 (72%) had sporadic (BRAF mutation and/or MLH1 methylation) and 99 (28%) had familial tumors (BRAF WT and unmethylated MLH1 or loss of MSH2/MSH6/PMS2 protein expression). A large proportion of dMMR sporadic tumors were mutated for BRAF (n = 200). In patients treated with FOLFOX, DFS did not differ statistically by dMMR mechanism, whereas in patients treated with FOLFOX plus cetuximab, those with sporadic tumors had worse DFS than those with familial cancers (multivariable hazard ratio, 2.69; 95% CI, 1.02 to 7.08; P = .04). Considering the predictive utility, the interaction between treatment and dMMR mechanism was significant (P = .03). Furthermore, a nonsignificant trend toward a deleterious effect of adding cetuximab to FOLFOX was observed in patients with BRAF-mutant but not BRAF WT tumors.

CONCLUSION

The addition of cetuximab to adjuvant FOLFOX was associated with shorter DFS in patients with sporadic dMMR colon cancer. Additional studies are needed to validate these results in metastatic disease.

Immunogenomic pathways associated with cytotoxic lymphocyte infiltration and survival in colorectal cancer

Background

Colorectal cancer (CRC) is the second leading cancer killer in the US today and patients with metastatic disease have only a 14% 5-year survival. One of the most impactful recent advances in cancer therapy, immune checkpoint inhibition, has not been shown to be effective for the majority of these patients. In this study, we use The Cancer Genome Atlas (TCGA) and recently developed informatic-based tools to identify targets for immune based therapy in colorectal cancer patients.

Methods

Open access, pre-processed (level 3) mRNA data and clinical data from colorectal patients from the TCGA was downloaded from FireCloud. Using the Microenvironment Cell Populations-Counter method (MCP-Counter), cytotoxic lymphocyte scores were calculated for all patients. Patients were then grouped by cytotoxic lymphocyte score (High vs Low), pathologic stage, and location to identify differentially expressed genes. Pathway enrichment analysis was performed using Reactome to determine differentially expressed genes associated with immune pathways. Survival analysis was performed with identified differentially expressed genes.

Results

In the TCGA dataset, there are 461 colon and 172 rectal cancer patients. After stratifying patients by cytotoxic lymphocyte score, anatomical location, and stage, we found a significant number of differentially expressed genes. We identified one pathway, “immunoregulatory interactions between a lymphoid and non-lymphoid cell”, that was highly enriched and included in all tumor locations and stages. Survival analysis performed with differentially expressed genes in this pathway identified 21 different genes associated with survival and cytotoxic lymphocyte infiltration, with ~ 70% of these genes occurring in the metastatic right-sided CRC group. Specifically, all genes associated with survival in the metastatic right-sided colorectal cancer group with low cytotoxic lymphocyte scores positively impacted survival.

Conclusions

Utilizing the TCGA, a publicly available dataset, and informatics-based analyses, we identified potential targets to improve immune based therapy in colorectal cancer. Additionally, we note the most targets in metastatic right-sided CRC patients, the patient group with the worst predicted survival. The results from this study demonstrate the ability of informatics-based analytic techniques to identify new therapeutic targets as well as improve patient selection for intervention, helping us to achieve the goals of precision-based oncology.

Prognostic and Predictive Molecular Biomarkers for Colorectal Cancer: Updates and Challenges

Colorectal cancer (CRC) is a leading cause of death among cancer patients. This heterogeneous disease is characterized by alterations in multiple molecular pathways throughout its development. Mutations in RAS, along with the mismatch repair gene deficiency, are currently routinely tested in clinics. Such biomarkers provide information for patient risk stratification and for the choice of the best treatment options. Nevertheless, reliable and powerful prognostic markers that can identify “high-risk” CRC patients, who might benefit from adjuvant chemotherapy, in early stages, are currently missing. To bridge this gap, genomic information has increasingly gained interest as a potential method for determining the risk of recurrence. However, due to several limitations of gene-based signatures, these have not yet been clinically implemented. In this review, we describe the different molecular markers in clinical use for CRC, highlight new markers that might become indispensable over the next years, discuss recently developed gene expression-based tests and highlight the challenges in biomarker research.

Microsatellite instability and survival after adjuvant chemotherapy among stage II and III colon cancer patients: results from a population-based study

Previous studies have reported conflicting results regarding the benefit of administering 5‐FU‐based chemotherapy to colon cancer (CC) patients with microsatellite‐instable (MSI‐high) tumors, and results from stage‐specific analyses are scarce. Patients with stage II or III CC were recruited as part of a population‐based study between 2003 and 2015. The Cox regression models including propensity score weighting were used to calculate hazard ratios and confidence intervals for the association between chemotherapy and cancer‐specific (CSS), relapse‐free (RFS), and overall survival (OS) by stage of disease and MSI status of the tumor. Median follow‐up was 6.2 years. A total of 1010 CC patients were included in the analysis (54% stage II, 46% stage III, 20% MSI‐high). Adjuvant chemotherapy was administered to 48 (8.7%) stage II and 366 (79%) stage III patients. Overall, patients who received adjuvant chemotherapy had better CSS [HR = 0.65 (0.49–0.86)] than those who received surgery alone. Among stage II patients, only 64 (12%) cancer‐related deaths occurred, none of which in MSI‐high patients who received chemotherapy. Patients with MSI‐high tumors who received adjuvant treatment showed better CSS and a tendency toward better RFS compared to MSI‐high patients who did not receive chemotherapy [HR_CSS = 0.36 (0.15–0.82), HR_RFS = 0.49 (0.22–1.06)]. Patients with microsatellite‐stable (MSS) tumors receiving adjuvant chemotherapy also had significantly better survival [HR_CSS = 0.65 (0.48–0.87) and HR_RFS = 0.68 (0.52–0.88)]. In this population‐based study including stage II and III CC patients, we observed a survival benefit of adjuvant chemotherapy for both MSS and MSI‐high tumors. Adjuvant chemotherapy seemed to be beneficial among high‐risk stage II patients with MSI‐high tumors.

Pathways of Colorectal Carcinogenesis

Colorectal cancer is a heterogeneous disease that develops via stepwise accumulation of well-characterized genetic and epigenetic alterations. We review the genetic changes associated with the development of precancerous colorectal adenomas and their progression to tumors, as well as the effects of defective DNA repair, chromosome instability, microsatellite instability, and alterations in the serrated pathway and DNA methylation. We provide insights into the different molecular subgroups of colorectal tumors that develop via each of these different mechanisms and their associations with patient outcomes.

Biomarker-guided therapy for colorectal cancer: strength in complexity

The number of molecularly stratified treatment options available to patients with colorectal cancer (CRC) is increasing, with a parallel rise in the use of biomarkers to guide prognostication and treatment decision-making. The increase in both the number of biomarkers and their use has resulted in a progressively complex situation, evident both from the extensive interactions between biomarkers and from their sometimes complex associations with patient prognosis and treatment benefit. Current and emerging biomarkers also reflect the genomic complexity of CRC, and include a wide range of aberrations such as point mutations, amplifications, fusions and hypermutator phenotypes, in addition to global gene expression subtypes. In this Review, we provide an overview of current and emerging clinically relevant biomarkers and their role in the management of patients with CRC, illustrating the intricacies of biomarker interactions and the growing treatment opportunities created by the availability of comprehensive molecular profiling.

BRAF-Mutated Colorectal Cancer: Clinical and Molecular Insights

Colorectal cancer (CRC) is one of the leading causes of mortality and morbidity in the world. It is a heterogeneous disease, which can be classified into different subtypes, characterized by specific molecular and morphological alterations. In this context, BRAF mutations are found in about 10% of CRC patients and define a particular subtype, characterized by a dismal prognosis, with a median survival of less than 12 months. Chemotherapy plus bevacizumab is the current standard therapy in first-line treatment of BRAF-mutated metastatic CRC (mCRC), with triplet (FOLFOXIRI) plus bevacizumab as a valid option in patients with a good performance status. BRAF inhibitors are not so effective as compared to melanoma, because of various resistance mechanisms. However, the recently published results of the BEACON trial will establish a new standard of care in this setting. This review provides insights into the molecular underpinnings underlying the resistance to standard treatment of BRAF-mutated CRCs, with a focus on their molecular heterogeneity and on the research perspectives both from a translational and a clinical point of view.

Is microsatellite instability-high really a favorable prognostic factor for advanced colorectal cancer? A meta-analysis

Background

Stage II colorectal cancer with microsatellite instability-high (MSI-H) has been proven to have a better prognosis. However, in advanced stage, this trend remains controversial. This study aimed to explore the prognostic role of MSI-H in stage III and IV colorectal cancer (CRC) through meta-analysis.

Methods

A comprehensive search was performed in PubMed, Cochrane Central Library, and Embase databases. All randomized clinical trials and non-randomized studies were included based on inclusion and exclusion criteria and on survival after a radical operation with or without chemotherapy. The adjusted log hazard ratios (HRs) were used to estimate the prognostic value between MSI-H and microsatellite-stable CRCs. The random-effects model was used to estimate the pooled effect size.

Results

Thirty-six studies were included. Randomized controlled trials (RCT) and non-RCT were analyzed separately. For stage III CRCs, pooled HR for overall survival (OS) was 0.96 (95% confidence interval [CI] 0.75–.123) in the RCT subgroup and 0.89 (95% CI 0.62–1.28) in the non-RCT subgroup. For disease-free survival (DFS), the HR for the RCT group was 0.83 (95% CI 0.65–1.07), similar to the non-RCT subgroup (0.83, 95% CI 0.65–1.07). Disease-specific survival (DSS) was also calculated, which had an HR of 1.07 (95% CI 0.68–1.69) in the non-RCT subgroup. All these results showed that MSI-H has no beneficial effects in stage III CRC. For stage IV CRC, the HR for OS in the RCT subgroup was 1.23 (95% CI 0.92–1.64) but only two RCTs were included. For non-RCT study, the combined HR for OS and DFS was 1.10 (95% CI 0.77–1.51) and 0.72 (95% CI 0.53–0.98), respectively, suggesting the beneficial effect for DFS and non-beneficial effect for OS.

Conclusion

For stage III CRC, MSI-H had no prognostic effect for OS, DFS, and DSS. For stage IV CRC, DFS showed a beneficial result, whereas OS did not; however, the included studies were limited and needed further exploration.

Targeting Histone Chaperone FACT Complex Overcomes 5-Fluorouracil Resistance in Colon Cancer

Fluorouracil (5-FU) remains a first-line chemotherapeutic agent for colorectal cancer. However, a subset of colorectal cancer patients who have defective mismatch-repair (dMMR) pathway show resistance to 5-FU. Here, we demonstrate that the efficacy of 5-FU in dMMR colorectal cancer cells is largely dependent on the DNA base excision repair (BER) pathway. Downregulation of APE1, a key enzyme in the BER pathway, decreases IC₅₀ of 5-FU in dMMR colorectal cancer cells by 10-fold. Furthermore, we discover that the facilitates chromatin transcription (FACT) complex facilitates 5-FU repair in DNA via promoting the recruitment and acetylation of APE1 (AcAPE1) to damage sites in chromatin. Downregulation of FACT affects 5-FU damage repair in DNA and sensitizes dMMR colorectal cancer cells to 5-FU. Targeting the FACT complex with curaxins, a class of small molecules, significantly improves the 5-FU efficacy in dMMR colorectal cancer in vitro (∼50-fold decrease in IC₅₀) and in vivo xenograft models. We show that primary tumor tissues of colorectal cancer patients have higher FACT and AcAPE1 levels compared with adjacent nontumor tissues. Additionally, there is a strong clinical correlation of FACT and AcAPE1 levels with colorectal cancer patients' response to chemotherapy. Together, our study demonstrates that targeting FACT with curaxins is a promising strategy to overcome 5-FU resistance in dMMR colorectal cancer patients.

Role of Deficient DNA Mismatch Repair Status in Patients With Stage III Colon Cancer Treated With FOLFOX Adjuvant Chemotherapy: A Pooled Analysis From 2 Randomized Clinical Trials

Importance

The prognostic impact of DNA mismatch repair (MMR) status in stage III colon cancer patients receiving FOLFOX (folinic acid, fluorouracil, and oxaliplatin) adjuvant chemotherapy remains controversial.

Objective

To determine the association of MMR status with disease-free survival (DFS) in patients with stage III colon cancer treated with FOLFOX.

Design, Setting, and Participants

The evaluated biomarkers for MMR status were determined from prospectively collected tumor blocks from patients treated with FOLFOX in 2 open-label, phase 3 randomized clinical trials: NCCTG N0147 and PETACC8. The studies were conducted in general community practices, private practices, and institutional practices in the United States and Europe. All participants had stage III colon adenocarcinoma. They were enrolled in NCCTG N0147 from February 2004 to November 2009 and in PETACC8 from December 2005 to November 2009.

Interventions

Patients in the clinical trials were randomly assigned to receive 6 months of chemotherapy with FOLFOX or FOLFOX plus cetuximab. Only those patients treated with FOLFOX alone were included in the present study.

Main Outcomes and Measures

Association of MMR status with DFS was analyzed using a stratified Cox proportional hazards model. Multivariable models were adjusted for age, sex, tumor grade, pT/pN stage, tumor location, ECOG (Eastern Cooperative Oncology Group) performance status, and BRAF V600E mutational status.

Results

Among 2636 patients with stage III colon cancer treated with FOLFOX, MMR status was available for 2501. Of these, 252 (10.1%) showed deficient MMR status (dMMR; 134 women, 118 men; median age, 59 years), while 2249 (89.9%) showed proficient MMR status (pMMR; 1020 women, 1229 men; median age, 59 years). The 3-year DFS rates in the dMMR and pMMR groups were 75.6% and 74.4%, respectively. By multivariate analysis, patients with dMMR phenotype had significantly longer DFS than those with pMMR (adjusted hazard ratio, 0.73; 95% CI, 0.54-0.97; P = .03).

Conclusions and Relevance

The deficient MMR phenotype remains a favorable prognostic factor in patients with stage III colon cancer receiving FOLFOX adjuvant chemotherapy.

Trial Registration

clinicaltrials.gov Identifier: NCT00079274 for the NCCTG N0147 trial and EudraCT identifier: 2005-003463-23 for the PETACC8 trial.

Advances in the therapy of BRAFV600E metastatic colorectal cancer

Introduction: BRAF^V600E metastatic colorectal cancer (CRC) is an aggressive tumor subset with an approximate 8% incidence. In these patients, standard chemotherapy has limited efficacy, and the recent development of novel-targeted treatment regimens may significantly improve clinical outcome. Area covered: This review provides an overview of available data regarding advances in the first-line treatment of BRAF^V600E metastatic CRC including patient tumors with microsatellite instability. The implications of BRAF^V600E in earlier stage CRC are also discussed. Expert opinion: Recently, significant progress has been achieved in improving tumor response rates using a novel-targeted regimen in patients with BRAF^V600E metastatic CRC. The implications of BRAF^V600E in non-metastatic CRC are also becoming more evident and remains an area of ongoing investigation. The majority of CRCs with microsatellite instability high are sporadic and frequently harbor BRAF^V600E. All patients with microsatellite instability high metastatic CRCs, irrespective of BRAF^V600E, are candidates for immune checkpoint inhibitors. The optimal sequencing of treatment regimens for patients with BRAF^V600E metastatic CRCs is an important area for future research.

Exploring the best treatment options for BRAF-mutant metastatic colon cancer

The BRAFV600E mutation is a well-accepted poor prognostic factor in patients with metastatic colorectal cancer (mCRC), as it confers Ras-independent stimulation of the extracellular signal-regulated kinase/mitogen-activated protein kinase pathway involved in proliferation, migration, angiogenesis and the suppression of apoptosis. Analysis of the potential predictive value of BRAF for treatment efficacy is inherently confounded by this known prognostic impact. Currently, approved therapeutic strategies for patients with BRAF-mutant (BRAF-mt) mCRC are suboptimal, and uncertainty exists regarding how to best treat these patients. Based on the available evidence, it is currently not possible to confirm the superiority of any available treatment options cited in European Society for Medical Oncology and National Comprehensive Cancer Network guidelines (that is, doublet or triplet chemotherapy regimens plus anti-vascular endothelial growth factor or anti-epidermal growth factor receptors), even if triplet chemotherapy plus bevacizumab is the most accepted standard regimen. In this review, we highlight still-emerging strategies that could be deployed to combat BRAF-mt mCRC, including triplet chemotherapy plus available biologic agents, rationally derived combinations of targeted agents and immunotherapy. While it is clear that the needs of patients with BRAF-mt mCRC are currently unmet, we are cautiously optimistic that the recently renewed research interest in these patients will yield clinically relevant insights and therapeutic strategies.

Preoperative inflammatory response as prognostic factor of patients with colon cancer

PURPOSE

This study aimed to investigate the abilities of the modified Glasgow prognostic score (mGPS) and other inflammatory scores to predict recurrence-free survival (RFS) among patients with colon cancer (CC). In addition, we evaluated the abilities of the mGPS to predict recurrence of stage II disease and the efficacy of adjuvant chemotherapy (AC) for stage III disease.

METHODS

This retrospective study evaluated 477 patients with stage I-III CC who underwent curative surgery. These patients were categorized as having a low mGPS (mGPS 0) or a high mGPS (mGPS 1-2).

RESULTS

Patients in the high mGPS group had significantly poorer RFS than patients in the low mGPS group (p < 0.01). Multivariate analysis revealed that a high mGPS independently predicted poor RFS (p < 0.01). Among patients with stage II CC, multivariate analysis revealed that the independent predictors of poor RFS were pT4 status (p < 0.01) and a high mGPS (p = 0.04). Among patients with stage III CC, AC was not significantly associated with the 5-year RFS for patients with a low mGPS (p = 0.38), although AC significantly improved the 5-year RFS for patients with a high mGPS (p < 0.01).

CONCLUSION

The preoperative mGPS significantly predicted recurrence among patients with CC, even among patients with stage II CC. In addition, mGPS may provide valuable information regarding subgroups of patients with stage III CC who might benefit from AC.

External validation of molecular subtype classifications of colorectal cancer based on microsatellite instability, CIMP, BRAF and KRAS

Background

Competing molecular classification systems have been proposed to complement the TNM staging system for a better prediction of survival in colorectal cancer (CRC). However, validation studies are so far lacking. The aim of this study was to validate and extend previously published molecular classifications of CRC in a large independent cohort of CRC patients.

Methods

CRC patients were recruited into a population-based cohort study (DACHS). Molecular subtypes were categorized based on three previously published classifications. Cox-proportional hazard models, based on the same set of patients and using the same confounders as reported by the original studies, were used to determine overall, cancer-specific, or relapse-free survival for each subtype. Hazard ratios and confidence intervals, as well as Kaplan-Meier plots were compared to those reported by the original studies.

Results

We observed similar patterns of worse survival for the microsatellite stable (MSS)/BRAF-mutated and MSS/KRAS-mutated subtypes in our validation analyses, which were included in two of the validated classifications. Of the two MSI subtypes, one defined by additional presence of CIMP-high and BRAF-mutation and the other by tumors negative for CIMP, BRAF and KRAS-mutations, we could not confirm associations with better prognosis as suggested by one of the classifications. For two of the published classifications, we were able to provide results for additional subgroups not included in the original studies (men, other disease stages, other locations).

Conclusions

External validation of three previously proposed classifications confirmed findings of worse survival for CRC patients with MSS subtypes and BRAF or KRAS mutations. Regarding MSI subtypes, other patient characteristics such as stage of the tumor, may influence the potential survival benefit. Further integration of methylation, genetic, and immunological information is needed to develop and validate a comprehensive classification that will have relevance for use in clinical practice.

Analysis of KRAS, NRAS, BRAF, PIK3CA and TP53 mutations in a large prospective series of locally advanced rectal cancer patients

Little information is available on the clinical significance of cancer-related genes such as KRAS, NRAS, BRAF, PIK3CA and TP53 in nonmetastatic rectal cancer. We investigated mutations of these genes in a large prospective series of locally advanced rectal cancer (LARC) patients who were recruited into two phase II trials. Mutational analyses were performed with diagnostically validated methods including polymerase chain reaction, capillary electrophoresis single-strand conformational analysis, Sanger sequencing and next-generation sequencing. Associations between single or multiple gene mutations and clinicopathological characteristics and treatment outcomes were explored. Of these 269, 210 (78%) patients were assessable. Mutations of KRAS, NRAS, BRAF, PIK3CA and TP53 occurred in 43, 9, 4, 9 and 60% of patients, respectively. Concordance between paired biopsy and resection specimens was 82% for KRAS, 95% for NRAS, 99% for BRAF, 96% for PIK3CA and 63% for TP53. TP53 mutations were associated with extramural venous invasion on baseline MRI (78% vs. 65%, p = 0.04), poor pathological tumour regression (23% vs. 36%, p = 0.05) and a trend toward a worse 5-year progression-free survival (PFS; 60% vs. 74%, HR 1.59, p = 0.06). Patients with tumours harbouring mutation of TP53 and either KRAS or NRAS (32%) had a worse 5-year PFS than those with TP53/KRAS/NRAS wild-type tumours (54% vs. 72%, HR 1.75, p = 0.02). In univariate analysis, BRAF mutation predicted poor 5-year overall survival only among patients treated without cetuximab (20% vs. 73%, HR 3.29, p = 0.03). This is one of the largest biomarker studies in a prospective, largely homogeneous, LARC population. Our findings are hypothesis generating and require validation in independent series.

Chemotherapy, Still an Option in the Twenty-First Century in Metastatic Colorectal Cancer?

Substantial improvements have been made in the systemic treatment of colorectal cancer over the last two decades. Median overall survival (OS) of patients with metastatic colorectal cancer (mCRC) has been constantly increased and the most recent first-line studies exceeded the 30-month median overall survival. The standard first-line regimen for mCRC is a combination of chemotherapy plus a biological agent either targeting the main angiogenic growth factor vascular endothelial growth factor (VEGF) via Bevacizumab or by antibodies targeting the epidermal growth factor receptor (EGRF) via Panitumumab or Cetuximab. Recent improvements have been shown in the efficacy of the biological agent by stratifying these agents according to the primary tumor location. In this context EGFR-inhibitors showed improved OS when used first-line in tumors derived from the left-sided colon or rectum, while tumor sidedness was not predictive for anti-VEGF-antibodies. Furthermore, the biological activity of anti-EGFR antibodies is restricted to tumors with a rat sarcoma virus (RAS)-wild-type genotype but not RAS-mutated tumors. The RAS-mutation status is not predictive for VEGF-inhibitors. Recent developments in the molecular characterisation of tumor cells led to the development of specific so called targeted therapies in colorectal cancer.

Adjuvant chemotherapy in resected colon cancer: When, how and how long?

The benefit of adjuvant chemotherapy has been clearly established in the adjuvant setting for node-positive colon cancer. A number of trials in the adjuvant setting have analyzed the efficacy of multiple-agent combinations, including irinotecan, oxaliplatin, bevacizumab and cetuximab. Only oxaliplatin added to fluorouracil/capecitabine has been shown to be superior beyond a fluropyrimidine alone in the adjuvant setting. As such, standard treatment options include fluorouracil (FU) or capecitabine with or without oxaliplatin. However, oxaliplatin is associated with cumulative dose-dependent neurotoxicity, characterized by distal or perioral paresthesias or dysesthesias; for this reason, in this review we discuss the results of the International Duration Evaluation of Adjuvant Chemotherapy (IDEA) trial. The IDEA trail is the largest prospective clinical trial ever conducted in colorectal cancer, wherein patients were treated with either 3 months or 6 months of adjuvant chemotherapy. In the era of cancer gene expression-based subtyping, the Colorectal Cancer Subtyping Consortium has proposed a four-subgroup molecular classification system for colorectal cancer, consisting of CMS1 (immune), CMS2 (canonical), CMS3 (metabolic) and CMS4 (mesenchymal). In this review, we present and analyze the available data on efficacy and toxicity of the combination regimen approved for treatment of resected colon cancer, and discuss the questions of when, how and how long we need to treat such patients.

Pseudoprogression during treatment with pembrolizumab followed by rechallenge with chemotherapy in metastatic colorectal cancer: A case report

Disease progression during immunotherapy in colorectal cancer does not always indicate treatment failure. A case argues that carcinoembryonic antigen (CEA) may serve as an early marker to distinguish between pseudoprogression and real progression. Presentation of results from reintroduction of chemotherapy after progression on immunotherapy that suggest increased efficiency.

Evaluation of a Fully Automated Idylla Test System for Microsatellite Instability in Colorectal Cancer

BACKGROUND

Microsatellite instability (MSI) is a phenotype commonly observed in colorectal cancer, and is caused by a deficient mismatch repair system. Determining MSI status greatly aids tumor prognosis and treatment plans in colorectal cancer, and plays a critical role in recent United States Food and Drug Administration-approved immunotherapies. As recognition of its importance grows, MSI has been identified in more types of cancers, underscoring the importance of accurate assays for determining MSI status in tumor cells. Currently, tumor MSI status is detected via polymerase chain reaction-based methods or immunohistochemistry.

MATERIALS AND METHODS

In this study, we tested a new, fully automated MSI detection system (Idylla MSI detection kit) released by Biocartis. We evaluated 42 formalin-fixed paraffin-embedded tumor tissues, which were clinically tested for MSI status using the polymerase chain reaction or immunohistochemistry method, with the Idylla MSI detection system.

RESULTS

The Idylla MSI detection system showed an overall 97.62% concordance rate with previously used methods. Moreover, this fully automated system requires less than 5 minutes "hands on" preparation time and 150 minutes total run time per sample.

CONCLUSION

The Biocartis Idylla MSI kit proves a powerful tool to accurately detect MSI status in tumor cells in a rapid and almost labor-free manner.

Expressions of 10 genes as candidate predictors of recurrence in stage III colon cancer patients receiving adjuvant oxaliplatin-based chemotherapy

Approximately 30% patients with stage III colon cancer (CC) develop local recurrence and/or distant metastasis, even if postoperative adjuvant chemotherapy with oxaliplatin plus 5-fluorouracil and leucovorin (5-FU/LV) has been completed. In the present study, molecular analysis was performed to identify molecular markers of tumor recurrence in patients with stage III CC receiving oxaliplatin-based adjuvant chemotherapy. The FACOS study was conducted as a phase II study to evaluate the safety and efficacy of oxaliplatin-based treatment for stage III CC patients. Of the 132 CC patients enrolled in the present study, gene expression analysis using a microarray was conducted in 51 patients. Of these 51 patients, 6 developed recurrence within 5 years. The topmost 5% genes that showed differential expressions between cases that developed/did not develop recurrence were selected, and a set of predictive molecular markers for recurrence was identified. Of the 34,694 genes in the microarray, 1,734 genes were extracted as topmost 5% genes showing differential expressions between cases with and without recurrence. Among these, 10 genes, includingADH1A, ADH1C, CA12, CHP2, HMGCS2, SNAR-A1, TPI1, MS4A12, PLA2G10 and PTPRO, were identified as markers that could clearly divide patients with and without recurrence. Although several prediction models of tumor recurrence have been reported for CC, the set of 10 genes that the present study identified may be useful to predict the risk of recurrence in stage III CC patients receiving oxaliplatin-based adjuvant chemotherapy. Based on these results, high-risk patients with CC should be carefully observed to detect tumor recurrence during the follow-up period.

High expression of MMP19 is associated with poor prognosis in patients with colorectal cancer

Background

Matrix metalloproteinase 19 (MMP19) is a member of zinc-dependent endopeptidases, which have been involved in various physiological and pathological processes. Its expression has been demonstrated in some types of cancers, but the clinical significance of MMP19 in colorectal cancer (CRC) has not been reported. Thus, we aimed to analyze the clinical significance of MMP19 in CRC in present study.

Methods

The expression of MMP19 was first explored in The Cancer Genome Atlas (TCGA) cohort, and then validated in the GSE39582 cohort and our own database. Clinicopathological features and survival rate were also investigated.

Results

MMP19 was found to be a predictor for overall survival (OS) in both univariate (hazard ratio [HR]: 1.449, 95% confidence interval [CI]: 1.108–1.893, P = 0.007) and multivariate survival analyses (HR: 1.401, 95% CI: 1.036–1.894, P = 0.028) in the TCGA database. MMP19 was further validated as an independent factor for recurrence free survival in the GSE39582 database by both univariate analysis (HR: 2.061, 95%CI: 1.454–2.921, P < 0.001) and multivariate analysis (HR = 1.470, 95% CI: 1.025–2.215, P = 0.032). In an in-house cohort, MMP19 was significantly upregulated in CRC tissues when compared with their adjacent normal controls (P < 0.001). Ectopic MMP19 expression was positively associated with lymph node metastases (P = 0.029), intramural vascular invasion (P = 0.015) and serum carcinoembryonic antigen levels (P = 0.045). High MMP19 expression correlated with a shorter OS (HR = 5.595; 95% CI: 2.573–12.164; P < 0.001) and disease free survival (HR = 4.699; 95% CI: 2.461–8.974; P < 0.001) in multivariate cox regression analysis.

Conclusions

Expression of MMP19 was upregulated in CRC. High expression of MMP19 was determined to be an independent and poor prognostic factor in CRC. These results suggest that MMP19 may be a good biomarker for CRC.

Association of pathway mutation with survival after recurrence in colorectal cancer patients treated with adjuvant fluoropyrimidine and oxaliplatin chemotherapy

Background

Although the prognostic biomarkers associated with colorectal cancer (CRC) survival are well known, there are limited data on the association between the molecular characteristics and survival after recurrence (SAR). The purpose of this study was to assess the association between pathway mutations and SAR.

Methods

Of the 516 patients with stage III or high risk stage II CRC patients treated with surgery and adjuvant chemotherapy, 87 who had distant recurrence were included in the present study. We analyzed the association between SAR and mutations of 40 genes included in the five critical pathways of CRC (WNT, P53, RTK-RAS, TGF-β, and PI3K).

Results

Mutation of genes within the WNT, P53, RTK-RAS, TGF-β, and PI3K pathways were shown in 69(79.3%), 60(69.0%), 57(65.5%), 21(24.1%), and 19(21.8%) patients, respectively. Patients with TGF-β pathway mutation were younger and had higher incidence of mucinous adenocarcinoma (MAC) histology and microsatellite instability-high. TGF-β pathway mutation (median SAR of 21.6 vs. 44.4 months, p = 0.021) and MAC (20.0 vs. 44.4 months, p = 0.003) were associated with poor SAR, and receiving curative resection after recurrence was associated with favorable SAR (Not reached vs. 23.6 months, p <  0.001). Mutations in genes within other critical pathways were not associated with SAR. When MAC was excluded as a covariate, multivariate analysis revealed TGF-β pathway mutation and curative resection after distant recurrence as an independent prognostic factor for SAR. The impact of TGF-β pathway mutations were predicted using the PROVEAN, SIFT, and PolyPhen-2. Among 25 mutations, 23(92.0%)-24(96.0%) mutations were predicted to be damaging mutation.

Conclusions

Mutation in genes within TGF-β pathway may have negative prognostic role for SAR in CRC. Other pathway mutations were not associated with SAR.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5650-0) contains supplementary material, which is available to authorized users.