Therapy for Metastatic Colorectal Cancer

High-accuracy prediction of colorectal cancer chemotherapy efficacy using machine learning applied to gene expression data

Introduction: FOLFOX and FOLFIRI chemotherapy are considered standard first-line treatment options for colorectal cancer (CRC). However, the criteria for selecting the appropriate treatments have not been thoroughly analyzed. Methods: A newly developed machine learning model was applied on several gene expression data from the public repository GEO database to identify molecular signatures predictive of efficacy of 5-FU based combination chemotherapy (FOLFOX and FOLFIRI) in patients with CRC. The model was trained using 5-fold cross validation and multiple feature selection methods including LASSO and VarSelRF methods. Random Forest and support vector machine classifiers were applied to evaluate the performance of the models. Results and Discussion: For the CRC GEO dataset samples from patients who received either FOLFOX or FOLFIRI, validation and test sets were >90% correctly classified (accuracy), with specificity and sensitivity ranging between 85%-95%. In the datasets used from the GEO database, 28.6% of patients who failed the treatment therapy they received are predicted to benefit from the alternative treatment. Analysis of the gene signature suggests the mechanistic difference between colorectal cancers that respond and those that do not respond to FOLFOX and FOLFIRI. Application of this machine learning approach could lead to improvements in treatment outcomes for patients with CRC and other cancers after additional appropriate clinical validation.

The clinical relevance and prediction efficacy from therapy of tumor microenvironment related signature score in colorectal cancer

Introduction

As the top 3 cancer in terms of incidence and mortality, the first-line treatment for CRC includes FOLFOX, FOLFIRI, Cetuximab or immunotherapy. However, the drug sensitivity of patients to regimens is different. There has been increasing evidence that immune components of TME can affect the sensitivity of patients to drugs. Therefore, it is necessary to define novo molecular subtypes of CRC based on TME immune components, and screen patients who are sensitive to the treatments, to make personalized therapy possible.

Methods

We analyzed the expression profiles and 197 TME-related signatures of 1775 patients using ssGSEA, univariate Cox proportional risk model and LASSO-Cox regression model, and defined a novo molecular subtype (TMERSS) of CRC. Simultaneously, we compared the clinicopathological factors, antitumor immune activity, immune cell abundance and differences of cell states in different TMERSS subtypes. In addition, patients sensitive to the therapy were screened out by correlation analysis between TMERSS subtypes and drug responses.

Results

Compared with low TMERSS subtype, high TMERSS subtype has a better outcome, which may be associated to higher abundance of antitumor immune cell in high TMERSS subtype. Our findings suggested that the high TMERSS subtype may have a higher proportion of respondents to Cetuximab agent and immunotherapy, while the low TMERSS subtype may be more suitable for treatment with FOLFOX and FOLFIRI regimens.

Discussion

In conclusion, the TMERSS model may provide a partial reference for the prognosis evaluation of patients, the prediction of drug sensitivity, and the implementation of clinical decision-making.

Drug-Resistant Stem Cells: Novel Approach for Colon Cancer Therapy

Metastatic progression of female breast and colon cancer represents a major cause of mortality in women. Spontaneous/acquired resistance to conventional and targeted chemo-endocrine therapy is associated with the emergence of drug-resistant tumor-initiating cancer stem cell populations. The cancer-initiating premalignant stem cells exhibit activation of select cancer cell signaling pathways and undergo epithelial–mesenchymal transition, leading to the evolution of a metastatic phenotype. The development of reliable cancer stem cell models provides valuable experimental approaches to identify novel testable therapeutic alternatives for therapy-resistant cancer. Drug-resistant stem cell models for molecular subtypes of clinical breast cancer and for genetically predisposed colon cancer are developed by selecting epithelial cells that survive in the presence of cytostatic concentrations of relevant therapeutic agents. These putative stem cells are characterized by the expression status of select cellular and molecular stem cell markers. The stem cell models are utilized as experimental approaches to examine the stem-cell-targeted growth inhibitory efficacy of naturally occurring dietary phytochemicals. The present review provides a systematic discussion on (i) conceptual and experimental aspects relevant to the chemo-endocrine therapy of breast and colon cancer, (ii) molecular/cellular aspects of cancer stem cells and (iii) potential stem-cell-targeting lead compounds as testable alternatives against the progression of therapy-resistant breast and colon cancer.

Microwave Ablation for Colorectal Liver Metastases: A Systematic Review and Pooled Oncological Analyses

Simple Summary

Liver resection for colorectal liver metastases (CRLM) represents the best curative option; however, few patients are candidates for surgery. Microwave ablation (MWA) can be a valid alternative in selected patients. This systematic review reports the oncological results of MWA for CRLM. The literature available on the Web was analyzed for reports concerning MWA for resectable CRLM, published before January 2021. Finally, 12 papers concerning MWA complications, recurrence-free (RF) cases, patients free from local recurrence (FFLR), and overall survival rates (OS) were selected. Global RF rates at 1, 3, and 5 years were 65.1%, 44.6%, and 34.3%, respectively. Global FFLR at 3, 6, and 12 months were 96.3%, 89.6%, and 83.7%, respectively. Global OS rates at 1, 3, and 5 years were 86.7%, 59.6%, and 44.8%, respectively. A better FFLR was achieved with an MWA surgical approach at 3, 6, and 12 months, with 97.1%, 92.7%, and 88.6%, respectively. Surgical MWA for CRLM smaller than 3 cm was a safe and valid option. MWA can be entered as part of the flowchart decision of CRLM curative treatment, especially for use in the parenchyma-sparing strategy and as a complement to surgery.

Abstract

(1) Background: colorectal liver metastases (CRLM) are the most common extra-lymphatic metastases in colorectal cancer; however, few patients are fit for curative surgery. Microwave ablation (MWA) showed promising outcomes in this cohort of patients. This systematic review and pooled analysis aimed to analyze the oncological results of MWA for CRLM. (2) Methods: Following PRISMA guidelines, PubMed, Scopus, EMBASE, Google Scholar, Science Direct, and the Wiley Online Library databases were searched for reports published before January 2021. We included papers assessing MWA, treating resectable CRLM with curative intention. We evaluated the reported MWA-related complications and oncological outcomes as being recurrence-free (RF), free from local recurrence (FFLR), and overall survival rates (OS). (3) Results: Twelve out of 4822 papers (395 patients) were finally included. Global RF rates at 1, 3, and 5 years were 65.1%, 44.6%, and 34.3%, respectively. Global FFLR rates at 3, 6, and 12 months were 96.3%, 89.6%, and 83.7%, respectively. Global OS at 1, 3, and 5 years were 86.7%, 59.6%, and 44.8%, respectively. A better FFLR was reached using the MWA surgical approach at 3, 6, and 12 months, with reported rates of 97.1%, 92.7%, and 88.6%, respectively. (4) Conclusions: Surgical MWA treatment for CRLM smaller than 3 cm is a safe and valid option. This approach can be safely included for selected patients in the curative intent approaches to treating CRLM.

Drug-Resistant Stem Cells: Novel Approach for Colon Cancer Therapy

BACKGROUND

Next to breast cancer, advanced stage metastatic colon cancer represents a major cause for mortality in women. Germline or somatic mutations in tumor suppressor genes or in DNA mismatch repair genes represent risk factors for genetic predisposition of colon cancer that are also detectable in sporadic colon cancer. Conventional chemotherapy for colon cancer includes combination of 5-fluoro-uracil with oxaliplatin and irinotecan or targeted therapy with non-steroid anti-inflammatory drugs and selective cyclooxygenase-2 inhibitors. Major limitations of these therapeutic interventions are associated with systemic toxicity, acquired tumor resistance and the emergence of drug resistant stem cells that favor initiation, progression and metastasis of therapy-resistant disease. These limitations emphasize an unmet need to identify tumor stem cell selective testable alternatives. Drug-resistant stem cell models facilitate the identification of new testable alternatives from natural phytochemicals and herbal formulations. The goal of this review is to provide an overview relevant to the current status of conventional/targeted therapy, the role of cancer stem cells and the status of testable alternatives for therapy-resistant colon cancer. Experimental models: Hyper-proliferative and tumorigenic cell lines from genetically predisposed colonic tissues of female mice represent experimental models. Chemotherapeutic agents select drug-resistant phenotypes that exhibit upregulated expressions of cellular and molecular stem cell markers. Mechanistically distinct natural phytochemicals effectively inhibit stem cell growth and downregulate the expressions of stem cell markers.

CONCLUSIONS

The present review discusses the status of colon cancer therapy and inherent limitations, cancer stem cell biology, potential lead compounds and their advantages over chemotherapy. The present experimental approaches will facilitate the identification of pharmacological and naturally-occurring agents as lead compounds for stem cell targeted therapy of colon cancer.

Isolation and Characterization of Chemo-Resistant Stem Cells from a Mouse Model of Hereditary Non-Polyposis Colon Cancer

Rationale

Loss of function mutations in DNA mismatch repair genes is the primary genetic defects in high-risk hereditary non-polyposis colon cancer (HNPCC). Cytotoxic chemotherapy and anti-inflammatory drugs are potential treatment options. These treatment options lead to systemic toxicity, acquired tumor resistance and the emergence of drug-resistant stem cells. A colonic epithelial cell culture model expressing the relevant genetic defects in chemo-resistant stem cells provides a relevant experimental system for HNPCC.

Objective

To develop a colonic epithelial cell culture system from a mouse model for HNPCC and to isolate and characterize drug-resistant stem cells.

Experimental Models and Biomarkers

The Mlh₁^[-/-]/Apc ^[-/-] Mlh₁/1638N COL-Cl₁ cells is a mouse model for HNPCC, and the 5-fluoro-uracil resistant (5-FU-R) phenotype represents a model for the drug-resistant stem cells. Tumor spheroid formation, and the expression of CD44, CD133 and c-Myc represent stem cell markers.

Results

The HNPCC model exhibits aneuploidy, hyper-proliferation, accelerated cell cycle progression and downregulated cellular apoptosis. Long-term exposure to 5-FU selects for the drug-resistant phenotype. These resistant cells exhibit increased formation of tumor spheroids and upregulated expression of cancer stem cell markers CD44, CD133 and c-Myc.

Conclusion

In the present study, a stem cell model for HNPCC was validated and offered a novel experimental approach to test stem cell-targeted alternatives to drug-resistant therapy.

A tumor microenvironment-specific gene expression signature predicts chemotherapy resistance in colorectal cancer patients

Studies have shown that tumor microenvironment (TME) might affect drug sensitivity and the classification of colorectal cancer (CRC). Using TME-specific gene signature to identify CRC subtypes with distinctive clinical relevance has not yet been tested. A total of 18 "bulk" RNA-seq datasets (total n = 2269) and four single-cell RNA-seq datasets were included in this study. We constructed a "Signature associated with FOLFIRI resistant and Microenvironment" (SFM) that could discriminate both TME and drug sensitivity. Further, SFM subtypes were identified using K-means clustering and verified in three independent cohorts. Nearest template prediction algorithm was used to predict drug response. TME estimation was performed by CIBERSORT and microenvironment cell populations-counter (MCP-counter) methods. We identified six SFM subtypes based on SFM signature that discriminated both TME and drug sensitivity. The SFM subtypes were associated with distinct clinicopathological, molecular and phenotypic characteristics, specific enrichments of gene signatures, signaling pathways, prognosis, gut microbiome patterns, and tumor lymphocytes infiltration. Among them, SFM-C and -F were immune suppressive. SFM-F had higher stromal fraction with epithelial-to-mesenchymal transition phenotype, while SFM-C was characterized as microsatellite instability phenotype which was responsive to immunotherapy. SFM-D, -E, and -F were sensitive to FOLFIRI and FOLFOX, while SFM-A, -B, and -C were responsive to EGFR inhibitors. Finally, SFM subtypes had strong prognostic value in which SFM-E and -F had worse survival than other subtypes. SFM subtypes enable the stratification of CRC with potential chemotherapy response thereby providing more precise therapeutic options for these patients.

Adenocarcinoma Ex-Goblet Cell: a Retrospective Experience

PURPOSE

Adenocarcinoma ex-goblet cell carcinoids (AGCCs) are rare appendiceal tumors with mixed neuroendocrine and glandular features. They tend to behave more aggressively than typical carcinoid tumors, affect younger patients, and have a greater predilection for spreading to the peritoneum. Outcomes of AGCC patients treated with chemotherapy, extrapolated from colon cancer regimens, in the adjuvant or metastatic setting have not been explicitly reported. We sought to explore outcomes of AGCC patients with either local disease treated with adjuvant FOLFOX or metastatic disease treated with FOLFOX/FOLFIRI post-cytoreductive debulking (or CRS plus HIPEC in the peritoneal-limited setting).

METHODS

We performed a single-institution retrospective analysis of 23 pathologically identified AGCC patients from Vanderbilt University Medical Center treated with chemotherapy in either the adjuvant or metastatic settings. Each patient's tumor was categorized as group B or group C based on the criteria from Tang et al. Median progression-free survival (PFS) or disease-free survival (DFS) (in the curative setting) and overall survival (OS) were determined for each patient and specified patient subgroup.

RESULTS AND CONCLUSION

AGCC patients who were treated with FOLFOX chemotherapy in the adjuvant setting or FOLFOX/FOLFIRI in the metastatic setting experienced prolonged PFS, DFS, and OS. Five patients with peritoneal-limited disease treated with CRS plus HIPEC have not yet reached median PFS or OS. While small sample size, patient selection, and retrospective nature limit the generalizability of findings from our analysis, the efficacy signals we observed suggest prospective evaluation with chemotherapy and CRS plus HIPEC is warranted in AGCC patients.

Fecal Microbiota Transplantation Prevents Intestinal Injury, Upregulation of Toll-Like Receptors, and 5-Fluorouracil/Oxaliplatin-Induced Toxicity in Colorectal Cancer

FOLFOX (5-fluorouracil, leucovorin, and oxaliplatin), a 5-fluorouracil (5-FU)-based chemotherapy regimen, is one of most common therapeutic regimens for colorectal cancer. However, intestinal mucositis is a common adverse effect for which no effective preventive strategies exist. Moreover, the efficacy and the safety of fecal microbiota transplants (FMT) in cancer patients treated with anti-neoplastic agents are still scant. We investigated the effect of FMT on FOLFOX-induced mucosal injury. BALB/c mice implanted with syngeneic CT26 colorectal adenocarcinoma cells were orally administered FMT daily during and two days after five-day injection of FOLFOX regimen for seven days. Administration of FOLFOX significantly induced marked levels of diarrhea and intestinal injury. FMT reduced the severity of diarrhea and intestinal mucositis. Additionally, the number of goblet cells and zonula occludens-1 decreased, while apoptotic and NF-κB-positive cells increased following FOLFOX treatment. The expression of toll-like receptors (TLRs), MyD88, and serum IL-6 were upregulated following FOLFOX treatment. These responses were attenuated following FMT. The disrupted fecal gut microbiota composition was also restored by FMT after FOLFOX treatment. Importantly, FMT did not cause bacteremia and safely alleviated FOLFOX-induced intestinal mucositis in colorectal cancer-bearing mice. The putative mechanism may involve the gut microbiota TLR-MyD88-NF-κB signaling pathway in mice with implanted colorectal carcinoma cells.

Phase III randomized, placebo-controlled, double-blind study of monosialotetrahexosylganglioside for the prevention of oxaliplatin-induced peripheral neurotoxicity in stage II/III colorectal cancer

Background

Monosialotetrahexosylganglioside (GM1) is a neuroprotective glycosphingolipid that repairs nerves. Oxaliplatin‐based chemotherapy is neurotoxic. This study assessed the efficacy of GM1 for preventing oxaliplatin‐induced peripheral neurotoxicity (OIPN) in colorectal cancer (CRC) patients receiving oxaliplatin‐based chemotherapy.

Methods

In total, 196 patients with stage II/III CRC undergoing adjuvant chemotherapy with mFOLFOX6 were randomly assigned to intravenous GM1 or a placebo. The primary endpoint was the rate of grade 2 or worse cumulative neurotoxicity (NCI‐CTCAE). The secondary endpoints were chronic cumulative neurotoxicity (EORTCQLQ‐CIPN20), time to grade 2 neurotoxicity (NCI‐CTCAE or the oxaliplatin‐specific neuropathy scale), acute neurotoxicity (analog scale), rates of dose reduction or withdrawal due to OIPN, 3‐year disease‐free survival (DFS) and adverse events.

Results

There were no significant differences between the arms in the rate of NCI‐CTCAE grade 2 or worse neurotoxicity (GM1: 33.7% vs placebo: 31.6%; P = .76) or neuropathy measured by the EORTCQLQ‐CIPN20 or time to grade 2 neurotoxicity using NCI‐CTCAE and the oxaliplatin‐specific neuropathy scale. GM1 substantially decreased participant‐reported acute neurotoxicity (sensitivity to cold items [P < .01], discomfort swallowing cold liquids [P < .01], throat discomfort [P < .01], muscle cramps [P < .01]). The rates of dose reduction or withdrawal were not significantly different between the arms (P = .08). The 3‐year DFS rates were 85% and 83% in the GM1 and placebo arms, respectively (P = .19). There were no differences in toxicity between the arms.

Conclusion

Patients receiving GM1 were less troubled by the symptoms of acute neuropathy. However, we do not support the use of GM1 to prevent cumulative neurotoxicity. (http://ClinicalTrials.gov number, NCT02251977).

Efficacy and safety of anti-EGFR monoclonal antibodies combined with different chemotherapy regimens in patients with RAS wild-type metastatic colorectal cancer: A meta-analysis

OBJECTIVES

To investigate the efficacy and safety of adding anti-epidermal growth factor receptor [EGFR] MoAbs to various chemotherapy regimens in patients with RAS wild-type metastasized colorectal cancer (RAS WT metastatic colorectal cancer [mCRC]) and to identify the optimal combination regimens.

METHODS

We searched MEDLINE, EMBASE, and CENTRAL from the inception date to 20th May 2019. Randomized clinical trials investigating chemotherapy with or without anti-EGFR MoAbs in treatment of patients with RAS WT mCRC were included.

RESULTS

Eighteen studies involving 8848 participants were eligible. Comparing with oxaliplatin-based chemotherapy, adding anti-EGFR MoAbs benefited only in progression-free survival (PFS) (hazard ratio [HR] = 0.80, 95% confidence interval [CI]: 0.67 to 0.94), but not in overall survival (OS) (HR = 0.89, 95% CI: 0.78 to 1.02). Further sensitivity analysis indicated that adding anti-EGFR MoAbs to FOLFOLX regimen as a first-line treatment showed benefits in both PFS and OS (PFS: HR = 0.74, 95% CI: 0.64 to 0.84; OS: HR = 0.83, 95% CI: 0.73 to 0.95, respectively). Comparing with irinotecan-based chemotherapy or best supportive care, adding anti-EGFR MoAbs revealed an improvement in both PFS (HR = 0.77, 95% CI: 0.69 to 0.86; HR = 0.46, 95% CI: 0.40 to 0.54, respectively) and OS (HR = 0.89, 95% CI: 0.80 to 0.98; HR = 0.65, 95% CI: 0.54 to 0.78, respectively).

CONCLUSION

Anti-EGFR MoAbs as a monotherapy or in combination with either irinotecan-based chemotherapy or FOLFOX in patients with RAS wild-type mCRC have better response and survival outcome, whereas OS does not benefit from adding anti-EGFR MoAbs to another oxaliplatin-based regimen. Anti-EGFR MoAbs have increased the risk of adverse effects than chemotherapy alone. More high-quality randomized controlled trials for RAS wild type are necessary.

Efficacy and Toxicity of Addition of Bevacizumab to Chemotherapy in Patients with Metastatic Colorectal Cancer

BACKGROUND

Pre-treated patients with first-line treatment can be offered a second treatment with the aim of improving their poor clinical prognosis. The therapy of metastatic colorectal cancer (CRC) patients who did not respond to first-line therapy has limited treatment options. Recently, many studies have paid much attention to the efficacy of bevacizumab as an adjuvant treatment for metastatic colorectal cancer.

OBJECTIVES

We aimed to evaluate the efficacy and toxicity of bevacizumab plus chemotherapy compared with bevacizumab-naive based chemotherapy as second-line treatment in people with metastatic CRC.

METHODS

Electronic databases were searched for eligible studies updated to March 2018. Randomized-controlled trials comparing addition of bevacizumab to chemotherapy without bevacizumab in MCRC patients were included, of which, the main interesting results were the efficacy and safety profiles of the addition of bevacizumab in patients with MCRC as second-line therapy.

RESULT

Five trials were eligible in the meta-analysis. Patients who received the combined bevacizumab and chemotherapy treatment in MCRC as second-line therapy showed a longer overall survival (OS) (OR=0.80,95%CI=0.72-0.89, P<0.0001) and progression-free survival (PFS) (OR=0.69,95%CI=0.61-0.77, P<0.00001). In addition, there was no significant difference in objective response rate (ORR) (RR=1.36,95%CI=0.82-2.24, P=0.23) or severe adverse event (SAE) (RR=1.02,95%CI=0.88-1.19, P=0.78) between bevacizumab-based chemotherapy and bevacizumabnaive based chemotherapy.

CONCLUSION

Our results suggest that the addition of bevacizumab to the chemotherapy therapy could be an efficient and safe treatment option for patients with metastatic colorectal cancer as second-line therapy and without increasing the risk of an adverse event.

Bcl-2-dependent synthetic lethal interaction of the IDF-11774 with the V0 subunit C of vacuolar ATPase (ATP6V0C) in colorectal cancer

Background

The IDF-11774, a novel clinical candidate for cancer therapy, targets HSP70 and inhibits mitochondrial respiration, resulting in the activation of AMPK and reduction in HIF-1α accumulation.

Methods

To identify genes that have synthetic lethality to IDF-11774, RNA interference screening was conducted, using pooled lentiviruses expressing a short hairpin RNA library.

Results

We identified ATP6V0C, encoding the V0 subunit C of lysosomal V-ATPase, knockdown of which induced a synergistic growth-inhibitory effect in HCT116 cells in the presence of IDF-11774. The synthetic lethality of IDF-11774 with ATP6V0C possibly correlates with IDF-11774-mediated autolysosome formation. Notably, the synergistic effect of IDF-11774 and the ATP6V0C inhibitor, bafilomycin A1, depended on the PIK3CA genetic status and Bcl-2 expression, which regulates autolysosome formation and apoptosis. Similarly, in an experiment using conditionally reprogramed cells derived from colorectal cancer patients, synergistic growth inhibition was observed in cells with low Bcl-2 expression.

Conclusions

Bcl-2 is a biomarker for the synthetic lethal interaction of IDF-11774 with ATP6V0C, which is clinically applicable for the treatment of cancer patients with IDF-11774 or autophagy-inducing anti-cancer drugs.

Ipatasertib, a novel Akt inhibitor, induces transcription factor FoxO3a and NF-κB directly regulates PUMA-dependent apoptosis

Colon cancer is one of the three common malignant tumors, with a lower survival rate. Ipatasertib, a novel highly selective ATP-competitive pan-Akt inhibitor, shows a strong antitumor effect in a variety of carcinoma, including colon cancer. However, there is a lack of knowledge about the precise underlying mechanism of clinical therapy for colon cancer. We conducted this study to determine that ipatasertib prevented colon cancer growth through PUMA-dependent apoptosis. Ipatasertib led to p53-independent PUMA activation by inhibiting Akt, thereby activating both FoxO3a and NF-κB synchronously that will directly bind to PUMA promoter, up-regulating PUMA transcription and Bax-mediated intrinsic mitochondrial apoptosis. Remarkably, Akt/FoxO3a/PUMA is the major pathway while Akt/NF-κB/PUMA is the secondary pathway of PUMA activation induced by ipatasertib in colon cancer. Knocking out PUMA eliminated ipatasertib-induced apoptosis both in vitro and in vivo (xenografts). Furthermore, PUMA is also indispensable in combinational therapies of ipatasertib with some conventional or novel drugs. Collectively, our study demonstrated that PUMA induction by FoxO3a and NF-κB is a critical step to suppress the growth of colon cancer under the therapy with ipatasertib, which provides some theoretical basis for clinical assessment.

Colorectal liver metastases: surgery versus thermal ablation (COLLISION) - a phase III single-blind prospective randomized controlled trial

Background

Radiofrequency ablation (RFA) and microwave ablation (MWA) are widely accepted techniques to eliminate small unresectable colorectal liver metastases (CRLM). Although previous studies labelled thermal ablation inferior to surgical resection, the apparent selection bias when comparing patients with unresectable disease to surgical candidates, the superior safety profile, and the competitive overall survival results for the more recent reports mandate the setup of a randomized controlled trial. The objective of the COLLISION trial is to prove non-inferiority of thermal ablation compared to hepatic resection in patients with at least one resectable and ablatable CRLM and no extrahepatic disease.

Methods

In this two-arm, single-blind multi-center phase-III clinical trial, six hundred and eighteen patients with at least one CRLM (≤3 cm) will be included to undergo either surgical resection or thermal ablation of appointed target lesion(s) (≤3 cm). Primary endpoint is OS (overall survival, intention-to-treat analysis). Main secondary endpoints are overall disease-free survival (DFS), time to progression (TTP), time to local progression (TTLP), primary and assisted technique efficacy (PTE, ATE), procedural morbidity and mortality, length of hospital stay, assessment of pain and quality of life (QoL), cost-effectiveness ratio (ICER) and quality-adjusted life years (QALY).

Discussion

If thermal ablation proves to be non-inferior in treating lesions ≤3 cm, a switch in treatment-method may lead to a reduction of the post-procedural morbidity and mortality, length of hospital stay and incremental costs without compromising oncological outcome for patients with CRLM.

Trial registration

NCT03088150, January 11th 2017.

Idelalisib induces PUMA-dependent apoptosis in colon cancer cells

Idelalisib, a PI3K inhibitor, specifically targeting p110δ, has been approved for the treatment of chronic lymphocytic leukemia/small lymphocytic lymphoma and follicular lymphoma. However, the mechanisms of action of idelalisib in colon cancer cells are not well understood. We investigated how idelalisib suppresses colon cancer cells growth and potentiates effects of other chemotherapeutic drugs. In this study, we found that idelalisib treatment induces PUMA in colon cancer cells irrespective of p53 status through the p65 pathway following AKT inhibition and glycogen synthase kinase 3β (GSK3β) activation. PUMA is necessary for idelalisib-induced apoptosis in colon cancer cells. Idelalisib also synergized with 5-FU or regorafenib to induce marked apoptosis via PUMA in colon cancer cells. Furthermore, PUMA deficiency suppressed apoptosis and antitumor effect of idelalisib in xenograft model. These results demonstrate a critical role of PUMA in mediating the anticancer effects of idelalisib in colon cancer cells and suggest that PUMA induction can be used as an indicator of idelalisib sensitivity, and also have important implications for it clinical applications.

Oncogenic function of angiopoietin-2 in vitro and its modulation of tumor progression in colorectal carcinoma

Angiopoietin-2 (Ang-2) has been investigated in cancer primarily in terms of its angiogenic function, and its role as an oncogene has yet to be elucidated. The current study hypothesized that Ang-2 may be an oncogene and have a function in tumor progression. An investigation of the function of Ang-2 in the LoVo colorectal cancer (CRC) cell line in vitro, which expresses a high level of Ang-2, was performed by knocking down endogenous expression with a targeted short hairpin RNA. The aggressive phenotypic effects of Ang-2 on experimental and control group cells were assessed using cell proliferation, migration and invasion assays. The association between Ang-2 expression levels and clinicopathological factors was evaluated in 415 CRC tissues using immunohistochemistry. Suppressing Ang-2 expression decreased cellular proliferation, invasion and migration in an in vitro study. Ang-2 overexpression was observed in 46% of patients with CRC and was significantly associated with pT (P=0.048), pN (P<0.001), venous invasion (P=0.023), lymphatic invasion (P<0.001) and tumor-node-metastasis stage (P=0.022). Furthermore, Ang-2 overexpression was an independent prognostic factor in pN stages 1 and 2. These results reveal that Ang-2 may be an oncogene in colorectal carcinogenesis and its expression may exert aggressive phenotypic effects during tumor progression. In addition, Ang-2 expression may serve as a prognostic marker and a potential drug target.

Second-line systemic therapy for metastatic colorectal cancer

BACKGROUND

The therapeutic management of people with metastatic colorectal cancer (CRC) who did not respond to first-line treatment represents a formidable challenge.

OBJECTIVES

To determine the efficacy and toxicity of second-line systemic therapy in people with metastatic CRC.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library 2016, Issue 4), Ovid MEDLINE (1950 to May 2016), Ovid MEDLINE In-process & Other Non-Indexed Citations (1946 to May 2016) and Ovid Embase (1974 to May 2016). There were no language or date of publication restrictions.

SELECTION CRITERIA

Randomized controlled trials (RCTs) assessing the efficacy (survival, tumour response) and toxicity (incidence of severe adverse effects (SAEs)) of second-line systemic therapy (single or combined treatment with any anticancer drug, at any dose and number of cycles) in people with metastatic CRC that progressed, recurred or did not respond to first-line systemic therapy.

DATA COLLECTION AND ANALYSIS

Authors performed a descriptive analysis of each included RCT in terms of primary (survival) and secondary (tumour response, toxicity) endpoints. In the light of the variety of drug regimens tested in the included trials, we could carry out meta-analysis considering classes of (rather than single) anticancer regimens; to this aim, we applied the random-effects model to pool the data. We used hazard ratios (HRs) and risk ratios (RRs) to describe the strength of the association for survival (overall (OS) and progression-free survival (PFS)) and dichotomous (overall response rate (ORR) and SAE rate) data, respectively, with 95% confidence intervals (CI).

MAIN RESULTS

Thirty-four RCTs (enrolling 13,787 participants) fulfilled the eligibility criteria. Available evidence enabled us to address multiple clinical issues regarding the survival effects of second-line systemic therapy of people with metastatic CRC.1. Chemotherapy (irinotecan) was more effective than best supportive care (HR for OS: 0.58, 95% CI 0.43 to 0.80; 1 RCT; moderate-quality evidence); 2. modern chemotherapy (FOLFOX (5-fluorouracil plus leucovorin plus oxaliplatin), irinotecan) is more effective than outdated chemotherapy (5-fluorouracil) (HR for PFS: 0.59, 95% CI 0.49 to 0.73; 2 RCTs; high-quality evidence) (HR for OS: 0.69, 95% CI 0.51 to 0.94; 1 RCT; moderate-quality evidence); 3. irinotecan-based combinations were more effective than irinotecan alone (HR for PFS: 0.68, 95% CI 0.60 to 0.76; 6 RCTs; moderate-quality evidence); 4. targeted agents improved the efficacy of conventional chemotherapy both when considered together (HR for OS: 0.84, 95% CI 0.77 to 0.91; 6 RCTs; high-quality evidence) and when bevacizumab was used alone (HR for PFS: 0.67, 95% CI 0.60 to 0.75; 4 RCTs; high-quality evidence).With regard to secondary endpoints, tumour response rates generally paralleled the survival results; moreover, higher anticancer efficacy was generally associated with worse treatment-related toxicity, with the important exception of bevacizumab-containing regimens, where the addition of the targeted agent to chemotherapy did not result in a significant increase in the rate of SAE. Finally, we found that oral (instead of intravenous) fluoropyrimidines significantly reduced the incidence of adverse effects (without compromising efficacy) in people treated with oxaliplatin-based regimens.We could not draw any conclusions on other debated aspects in this field of oncology, such as ranking of treatments (not all possible comparisons have been tested and many comparisons were based on single trials enrolling a small number of participants) and quality of life (virtually no data available).

AUTHORS' CONCLUSIONS

Systemic therapy offers a survival benefit to people with metastatic CRC who did not respond to first-line treatment, especially when targeted agents are combined with conventional chemotherapeutic drugs. Further research is needed to define the optimal regimen and to identify people who most benefit from each treatment.

Molecular profiling of cetuximab and bevacizumab treatment of colorectal tumours reveals perturbations in metabolic and hypoxic response pathways

Angiogenesis and epidermal growth factor receptor (EGFR) inhibition has been shown to have anti-tumour efficacy, and enhance the therapeutic effects of cytotoxic chemotherapy in metastatic colorectal cancer. The interplay of signalling alterations and changes in metabolism and hypoxia in tumours following anti-VEGF and anti-EGFR treatment is not well understood. We aimed to explore the pharmacodynamics of cetuximab and bevacizumab treatment in human colon carcinoma tumour cells in vitro and xenograft models through proteomic profiling, molecular imaging of metabolism and hypoxia, and evaluation of therapy-induced changes in tumour cells and the tumour microenvironment. Both cetuximab and bevacizumab inhibited tumour growth in vivo, and this effect was associated with selectively perturbed glucose metabolism and reduced hypoxic volumes based on PET/MRI imaging. Global proteomic profiling of xenograft tumours (in presence of cetuximab, bevacizumab, and combination treatments) revealed alterations in proteins involved in glucose, lipid and fatty acid metabolism (e.g., GPD2, ATP5B, STAT3, FASN), as well as hypoxic regulators and vasculogenesis (e.g., ATP5B, THBS1, HSPG2). These findings correlated with western immunoblotting (xenograft lysates) and histological examination by immunohistochemistry. These results define important mechanistic insight into the dynamic changes in metabolic and hypoxic response pathways in colorectal tumours following treatment with cetuximab and bevacizumab, and highlight the ability of these therapies to selectively impact on tumour cells and extracellular microenvironment.

Overweight and obesity predict better overall survival rates in cancer patients with distant metastases

Recent studies conducted in patients with chronic diseases have reported an inverse association between body mass index (BMI) and mortality. However, the question as to whether BMI may predict prognosis in patients with metastatic cancer remains open. We therefore designed the current retrospective study to investigate the potential association between BMI and overall survival (OS) in patients with distant metastases (DM) and a favorable performance status. Between 2000 and 2012, a total of 4010 cancer patients with DM who required radiotherapy (RT) and had their BMI measured at the initiation of RT were identified. The relation between BMI and OS was examined by univariate and multivariable analysis. The median OS time was 3.23 months (range: 0.1–122.17) for underweight patients, 6.08 months (range: 0.03–149.46) for normal‐weight patients, 7.99 months (range: 0.07–158.01) for overweight patients, and 12.49 months (range, 0.2–164.1) for obese patients (log‐rank: P < 0.001). Compared with normal‐weight patients, both obese (HR = 0.676; 95% P < 0.001) and overweight individuals (HR = 0.84; P < 0.001) had a reduced risk of all‐cause mortality in multivariable analysis. Conversely, underweight patients had a significantly higher risk of death from all causes (HR = 1.41; P < 0.001). Overweight and obesity are independent predictors of better OS in metastatic patients with a good performance status. Increased BMI may play a role to identify metastatic patients with superior survival outcome and exhibit a potential to encourage aggressive management in those patients even with metastases.

Patterns of Treatment Sequences in Chemotherapy and Targeted Biologics for Metastatic Colorectal Cancer: Findings from a Large Community-Based Cohort of Elderly Patients

Background

Over the last decade, multiple chemotherapies/targeted biologics have been approved for metastatic colorectal cancer (mCRC). However, evidence is limited with regards to the array of treatments received by mCRC patients.

Objective

This study examines treatment sequences (first- to third-line chemotherapy/targeted biologics) and the factors associated with first-line targeted biologics and common treatment sequences for elderly mCRC patients treated in a community setting.

Methods

A retrospective cohort study was conducted in mCRC patients diagnosed from January 2004 through December 2009 using the Surveillance, Epidemiology and End Results Medicare-linked database. The treatment sequences administered to elderly mCRC patients were empirically identified.

Results

Of 4418 mCRC patients who received treatment, 1370 (31 %) received first, second, and third line; 1164 (26 %) received first and second line; and 1884 (43 %) received only first line. The most common first line of treatment for mCRC patients was 5-fluorouracil/leucovorin + oxaliplatin (FOLFOX) + bevacizumab (23 %) and FOLFOX (23 %). 5-fluorouracil/leucovorin + irinotecan (FOLFIRI)-based regimens were commonly (22 %) administered in second line. The most common treatment sequence was first-line oxaliplatin or irinotecan followed by second-line oxaliplatin or irinotecan + bevacizumab followed by a third-line targeted biologic. Of patients who received first-line therapy, 47 % also received a targeted biologic, and the factors associated were age, comorbidity score, cancer site, geographic location, and year of diagnosis.

Conclusion

Elderly mCRC patients receive a multitude of treatments in various sequences. Further exploration of the comparative effectiveness of treatment sequences may yield important information for improving mCRC survival.

Electronic supplementary material

The online version of this article (doi:10.1007/s40801-015-0059-9) contains supplementary material, which is available to authorized users.

Synergistic therapeutic effects of Schiff's base cross-linked injectable hydrogels for local co-delivery of metformin and 5-fluorouracil in a mouse colon carcinoma model

In situ formed hydrogels based on Schiff base reaction were formulated for the co-delivery of metformin (ME) and 5-fluorouracil (5FU). The reactive aldehyde-functionalized four-arm polyethylene glycol (PFA) was synthesized by end-capping of 4-arm PEG with 4-formylbenzoic acid (FA) and used as a cross-linking agent. The injectable hydrogels are designed through the quick gelation induced by the formation of covalent bonds via Schiff-base reaction of PFA with 4-arm poly (ethylene glycol)-b-poly (L-lysine) (PPLL). This formulation eliminated the need for metal catalysts and complicated processes in the preparation of in situ-forming hydrogels. In vitro degradation and drug release studies demonstrated that both ME and 5FU were released through PFA/PPLL hydrogels in a controlled and pH-dependent manner. When incubated with mouse colon adenocarcinoma cells (C26), the ME/5FU-incorporated PFA/PPLL hydrogels had synergistic inhibitory effects on the cell cycle progression and cell proliferation in colon cancer cells. After a single subcutaneous injection of the hydrogel containing ME/5FU beside the tumors of BALB/c mice inoculated with C26 cells, the dual-drug-loaded hydrogels displayed superior therapeutic activity resulted from a combination of p53-mediated G1 arrest and apoptosis in C26 cells. Hence, the Schiff's base cross-linked hydrogels containing ME and 5FU may have potential therapeutic applications in the treatments of colon cancer.

A Case Report of Long-Term Survival following Hepatic Arterial Infusion of L-Folinic Acid Modulated 5-Fluorouracil Combined with Intravenous Irinotecan and Cetuximab Followed by Hepatectomy in a Patient with Initially Unresectable Colorectal Liver Metastases

A 43-year-old women admitted to our hospital for weight loss, anorexia, and abdominal pain was diagnosed with sigmoid neoplasm and multiple bilobar liver metastases. This patient received six cycles of systemic FOLFOX prior to a laparoscopically assisted anterior resection of the rectosigmoid for a poorly differentiated invasive adenocarcinoma T2N2M1, K-RAS negative (wild type). Hepatic arterial infusion (HAI) of L-folinic acid modulated 5-fluorouracil (LV/5-FU) with intravenous (iv) irinotecan (FOLFIRI) and cetuximab as adjuvant therapy resulted in a complete metabolic response (CR) with CEA normalization. A right hepatectomy extended to segment IV was performed resulting in (FDG-)PET negative remission for 7 months. Solitary intrahepatic recurrence was effectively managed by local radiofrequent ablation following 6c FOLFIRI plus cetuximab iv. Multiple lung lesions and recurrence of pulmonary and local lymph node metastases were successfully treated with fractionated stereotactic radiotherapy (50 Gy) and iv LV/5-FU/oxaliplatin (FOLFOX) plus cetuximab finally switched to panitumumab with CR as a result. At present the patient is in persistent complete remission of her stage IV colorectal cancer, more than 5 years after initial diagnosis of the advanced disease. Multidisciplinary treatment with HAI of chemotherapy (LV/5-FU + CPT-11) plus EGFR-inhibitor can achieve CR of complex unresectable LM and can even result in hepatectomy with possible long-term survival.

Beyond KRAS status and response to anti-EGFR therapy in metastatic colorectal cancer

In patients with metastatic colorectal cancer, overall survival has improved over the last decade mainly due to the use of effective targeted therapies such as anti-EGFR. However, survival improvement is linked to proper selection of patients expected to benefit from these treatments. KRAS codons 12 and 13 mutation status was the first validated molecular biomarker for anti-EGFR antibodies. Today, rare KRAS alterations and NRAS mutations were implemented, defining the 'RAS' status as the new validated marker of response to anti-EGFR antibodies. Moreover, other biomarkers are under investigation to screen for other targets and help with patients selection. Here, we reviewed these promising biomarkers: mutations in the RAS-MAPK and PI3K-AKT pathways genes, MET activation, HER/ErbB receptors activation (EGFR, HER2 and HER3), EGFR ligands, antibody-dependent cell-mediated cytotoxicity) and miRNAs. Further data are needed to define their impact for the treatment of patients with metastatic colorectal cancer.

Role of capecitabine in treating metastatic colorectal cancer in Chinese patients

The China Food and Drug Administration approved the use of capecitabine in patients with metastatic colorectal cancer (mCRC) in 2004. This paper reviews the available information of capecitabine in Chinese patients with mCRC, focusing on its effectiveness and safety against mCRC. Identification of all eligible studies was made by searching the PubMed and Wanfang database from 2000 to 2013. Published data examining various aspects of clinical response and tolerability with capecitabine alone or in combination with other chemotherapeutic or biological agents for first- and second-line mCRC were examined. Capecitabine and its combination displayed high efficacy in Chinese patients with mCRC. Toxicities are generally manageable, and elderly patients can tolerate capecitabine well.

A contemporary analysis of morbidity and outcomes in cytoreduction/hyperthermic intraperitoneal chemoperfusion

The risks and benefits of cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy (CS/HIPEC) continue to be debated by the oncology community. A retrospective analysis of contemporary data (2003–2011) was performed to provide objective information regarding surgical morbidity, mortality, and survival for patients undergoing CS/HIPEC at a comprehensive cancer center. While procedure-associated morbidity was comparable to other major surgical oncology procedures, there was no operative or 30-day mortality and 60-day mortality was 2.7%. Increasing numbers of bowel resections were found to correlate to an increased incidence of deep surgical site infections (including abscess and enterocutaneous fistula) and need for reoperation which was in turn associated with a decreased overall survival (OS) and progression-free survival (PFS). Five-year OS rates varied by site of tumor origin and histology (disseminated peritoneal adenomucinosis [91.3%], Mesothelioma [80.8%], Appendiceal Adenocarcinoma [38.7%], and Colorectal Adenocarcinoma [38.2%]). With an acceptable morbidity and mortality rate, CS/HIPEC should be included as an effective treatment modality in the multidisciplinary care of select patients with peritoneal metastases.

PTB-associated splicing factor (PSF) is a PPARγ-binding protein and growth regulator of colon cancer cells

Peroxisome proliferator-activated receptor gamma (PPARγ) is a nuclear receptor that plays an essential role in cell proliferation, apoptosis, and inflammation. It is over-expressed in many types of cancer, including colon, stomach, breast, and lung cancer, suggesting that regulation of PPARγ might affect cancer pathogenesis. Here, using a proteomic approach, we identify PTB-associated splicing factor (PSF) as a novel PPARγ-interacting protein and demonstrate that PSF is involved in several important regulatory steps of colon cancer cell proliferation. To investigate the relationship between PSF and PPARγ in colon cancer, we evaluated the effects of PSF expression in DLD-1 and HT-29 colon cancer cell lines, which express low and high levels of PPARγ, respectively PSF affected the ability of PPARγ to bind, and expression of PSF siRNA significantly suppressed the proliferation of colon cancer cells. Furthermore, PSF knockdown induced apoptosis via activation of caspase-3. Interestingly, DLD-1 cells were more susceptible to PSF knockdown-induced cell death than HT-29 cells. Our data suggest that PSF is an important regulator of cell death that plays critical roles in the survival and growth of colon cancer cells. The PSF-PPARγ axis may play a role in the control of colorectal carcinogenesis. Taken together, this study is the first to describe the effects of PSF on cell proliferation, tumor growth, and cell signaling associated with PPARγ.

Promoter CpG island methylation markers in colorectal cancer: the road ahead

Despite increasing knowledge on the biology, detection and treatment of colorectal cancer (CRC), the disease is still a major health problem. Hypermethylation of promoter regions of genes has been studied extensively as a contributor in CRC carcinogenesis. In addition, it is the topic of many studies focusing on biomarkers for the early detection, prediction of prognosis and treatment outcome. Methylation markers may be preferred over current screening and test methods as they are stable and easy to detect. However, almost no methylation marker is currently being used in clinical practice, often due to a lack of sensitivity, specificity, or validation of the results. This review summarizes the current knowledge of hypermethylation biomarkers for CRC detection, progression and treatment outcome.

Comparative proteomic analysis of irinotecan-sensitive colorectal carcinoma cell line and its chemoresistant counterpart

In this study, we used two-dimensional gel electrophoresis and MALDI-Q-TOF-MS/MS analysis to examine the global protein expression of a pair of colorectal carcinoma cell lines, SW620 and irinotecan-resistant SW620. Of the 30 spots identified as differentially expressed proteins (±over twofold, P<0.05) between the two cell lines, 26 spots (corresponding to 26 unique proteins) were positively identified by MALDI-Q-TOF-MS/MS analysis. These proteins could be grouped into main classes including metabolism (15.38%), cell SSproliferation/differentiation (11.53%), molecular chaperone (11.53%), mRNA splicing (11.53%), and so on. The proteins, which might be involved in the development of tumor drug resistance, such as α-enolase, cofilin, and thioredoxin-dependent peroxide 1, have been validated by western blot analysis and have been discussed. The proteins identified in this study may be useful in showing the mechanisms underlying irinotecan resistance.

Systemic Therapy for Metastatic Colorectal Cancer: Patterns of Chemotherapy and Biologic Therapy Use in US Medical Oncology Practice

PURPOSE

With the emergence of new chemotherapies and biologic agents in the treatment of metastatic colorectal cancer (mCRC), the optimal combination and sequencing of these therapies are yet to be determined. This study examined the extent and pattern of chemotherapy and biologic therapy use by line of treatment. Biologic continuation and dose escalation were also examined.

METHODS

This study used an integrated electronic medical record database of 91 US oncology practices. Records were analyzed for 1,655 adult patients with mCRC who were treated from January 1, 2004 to January 31, 2008 with systemic therapy and could be observed for ≥ 3 months beyond their diagnosis of metastatic disease. Combination and sequence of individual drugs and regimens were examined.

RESULTS

For first-line therapy, the most common chemotherapy backbone was infused fluorouracil, leucovorin, and oxaliplatin (FOLFOX; 40.5% of patients), and the most common treatment regimen was FOLFOX plus bevacizumab (26.2%). For second-line therapy, fluorouracil, leucovorin, and irinotecan (FOLFIRI) was the most common chemotherapy backbone (25.7%), and FOLFIRI plus bevacizumab was the most common treatment regimen (18.3%). Across the study period, 68.6%, 22%, and 7% of patients received bevacizumab, cetuximab, and panitumumab, respectively. Among 412 patients receiving bevacizumab-containing regimens as first-line therapy who then received second-line therapy, 58% continued receiving bevacizumab, with dose escalation observed in 44%.

CONCLUSION

The most commonly used chemotherapy backbones for mCRC treatment were first-line FOLFOX and second-line FOLFIRI. Bevacizumab was the most frequently administered biologic therapy. Continuation and dose escalation with bevacizumab were frequently observed across lines of therapy.

Combining capecitabine, oxaliplatin, and gemcitabine (XELOXGEM) for colorectal carcinoma patients pretreated with irinotecan: a multicenter phase I/II trial

PURPOSE

Capecitabine plus oxaliplatin (XELOX) is an effective second-line regimen for advanced colorectal carcinoma (CRC) patients pretreated with irinotecan. Previous studies have shown supra-additive anti-tumor activity of gemcitabine (GEM) when administered with oxaliplatin. We investigated the dose, toxicity, and efficacy of a second-line XELOXGEM regimen in CRC patients pretreated with irinotecan.

METHODS

Patients with metastatic or recurrent CRC who failed after a first-line irinotecan-containing regimen received escalating doses of gemcitabine (600, 800, 1,000 mg/m(2) d1, d8) followed by capecitabine (1,000 mg/m(2) b.i.d d1-14) and oxaliplatin (100 mg/m(2) d1) on a 21-day cycle.

RESULTS

A total of 38 patients were treated. At 800 mg/m(2), two of six patients experienced dose-limiting toxicities (diarrhea and thrombocytopenia). Therefore, the clinically recommended dose was defined as 600 mg/m(2) gemcitabine (d1, d8) followed by 1,000 mg/m(2) capecitabine (b.i.d dl-14) and 100 mg/m(2) oxaliplatin (d1). The most common grade 3/4 toxicities were neutropenia (32%), thrombocytopenia (13%), anemia (11%), and peripheral neuropathy (11%). Ten (26.3%) and 23 (60.5%) patients experienced partial response and stable disease, respectively. The median progression-free survival and overall survival were 5.4 months (95% CI 3.8-6.9 months) and 17.7 months (95% CI 8.4-26.9 months), respectively.

CONCLUSIONS

The XELOXGEM triplet combination is an active and safe second-line regimen for advanced CRC patients pretreated with irinotecan.

Molecular Prognostic and Predictive Markers in Colorectal Cancer: Current Status

In parallel with our growing understanding of the molecular pathways underlying colorectal neoplasia, significant advances have been made in the treatment of colorectal cancer (CRC). For the past few decades, 5-fluorouracil-based therapy has been the cornerstone of adjuvant therapy. More recently, additional cytotoxic drugs and molecular-targeted therapies have provided additional clinical benefit in certain patient populations. Unfortunately, overall survival remains about 45%. Notably, our understanding of why certain patients do or do not respond to treatment remains limited. Thus, as therapeutic options for CRC continue to expand, there is now an even greater imperative to identify reliable biomarkers that have the potential to predict prognosis as well as response to chemotherapy. In this review, we will summarize the current status of such molecular prognostic and predictive biomarkers in CRC and assess their usefulness in tailoring therapeutic options.

Progress in metastatic colorectal cancer: growing role of cetuximab to optimize clinical outcome

The prognosis of metastatic colorectal cancer remains poor despite advances made in recent years, particularly with new treatments directed towards molecular targets. Cetuximab, a chimeric immunoglobulin (Ig)G1 monoclonal antibody that targets the ligand-binding domain of the epidermal growth factor receptor (EGFR), is active in metastatic colorectal cancer. As an IgG1 antibody, cetuximab may exert its antitumour efficacy through both EGFR antagonism and antibody-dependent cell-mediated cytotoxicity. The benefits of cetuximab in metastatic colorectal cancer are well documented in clinical trials and are acknowledged in the approval and licensing of this agent. There is evidence of the role of cetuximab not only in irinotecan-refractory or heavily pretreated patients, but also of the efficacy and safety of the addition of this agent to FOLFIRI (irinotecan/5-fluorouracil/leucovorin) in first-line metastatic colorectal cancer, with an enhanced effect in 5-fluorouracil patients with Kirsten rat sarcoma (KRAS) wild-type tumours. In these patients, a recent meta-analysis of the pooled Cetuximab Combined with Irinotecan in First-Line Therapy for Metastatic Colorectal Cancer (CRYSTAL) and Oxaliplatin and Cetuximab in First-Line Treatment of mCRC (OPUS) patient populations confirms that the addition of cetuximab to first-line chemotherapy achieves a statistically significant improvement in the best overall response, overall survival time, and progression-free survival (PSF) compared with chemotherapy alone. In nonresectable colorectal liver metastases, cetuximab plus FOLFOX-6 (oxaliplatin/5-fluorouracil/leucovorin) or cetuximab plus FOLFIRI increased significantly resectability of liver metastases, including R0 resections. Also, preliminary data indicate that cetuximab can be administered in a more convenient 2-week schedule in combination with standard chemotherapy. Cetuximab is generally well tolerated. Acne-form rash is the most frequent toxicity. Up to the present time, the results obtained with targeted therapy combinations are not as encouraging as initially expected. The identification of biomarkers associated with disease control, including KRAS and BRAF mutation status in patients treated with cetuximab, is changing the current management of metastatic colorectal cancer. Clinical and molecular predictive markers of response are under active evaluation in order to better select patients who could benefit from cetuximab treatment, with the aim of both optimising patient outcomes and avoiding unnecessary toxicities.

Treatment patterns and metastasectomy among mCRC patients receiving chemotherapy and biologics

BACKGROUND

Several long-standing chemotherapy regimens are available to treat metastatic colorectal cancer (mCRC) including: oxaliplatin plus 5-fluorouracil (5-FU) and leucovorin (FOLFOX); and irinotecan plus 5-FU and leucovorin (FOLFIRI). More recently, new biologic therapies were approved for use in mCRC.

OBJECTIVES

This study examined treatment patterns and trends in metastasectomy among newly diagnosed mCRC patients after the introduction of capecitabine (CAP) in 2001 and the biologic therapies in 2004.

METHODS

Using a large, US-based administrative medical claims database of a national commercially insured population, patients with newly diagnosed mCRC were identified from 2001 to 2005. At least 6 months of patient history prior to mCRC diagnosis were required to confirm patients were newly diagnosed. Patients were followed from initial mCRC diagnosis to death, disenrollment, or 12/31/2006. Chemotherapy and biologic treatments and rates of metastasectomy over time were analyzed.

RESULTS

A total of 3781 mCRC patients met the study criteria. The average time from mCRC diagnosis to initiation of systemic treatment decreased from 134.4 days (SD 261.2) to 61.7 days (SD 89.3) in 2001-2005 (p < 0.001). The most common first-line regimens were FOLFIRI (40%), 5-FU/LV (31%), and capecitabine (21%) in 2001, and FOLFOX plus bevacizumab (22%), FOLFOX alone (15%), 5-FU/LV (15%), and capecitabine (15%) in 2005. Among patients with ≥1 year of follow-up, the use of biologics increased from 37.3% in 2004 to 52.0% in 2005 (p < 0.001). The percentage of patients who underwent resection after systemic treatment increased from 2.9% to 5.6% in 2001-2005 (p = 0.169).

CONCLUSIONS

Over time the standard of care chemotherapy for 1st-line mCRC has changed from FOLFIRI to FOLFOX, and the use of biologics has become common. The percentage of patients who underwent resection after systemic treatment almost doubled during the study period.

Gene expression profiling of primary and metastatic colon cancers identifies a reduced proliferative rate in metastatic tumors

The objective of this study was to gain insights into the biological basis of the metastatic process by characterizing the gene expression differences between primary and metastatic colon cancers. Recent studies have demonstrated that few new mutational changes are acquired during the metastatic progression of colon tumors [Jones et al., Proc Natl Acad Sci USA 105 (11): 4283-4288, 2008]. However, the extent to which epigenetic and transcriptional changes occur between primary and metastatic colon cancer remains unknown. We approached these issues using Affymetrix microarrays to assess the similarities and differences in gene expression profiles between macro-dissected primary and metastatic colon tumors. Unexpectedly, we found that expression of a number of cell proliferation markers were reduced in the liver metastases of colon tumors when compared to primary tumors. This finding was validated by immunohistochemical staining of Ki67 and Cyclin D1 in Formalin-Fixed Paraffin-Embedded (FFPE) section of the same samples, and in an independent cohort of FFPE matched tumor and metastatic tissue samples. These results indicate that significant transcriptional differences exist between primary and metastatic colon tumors, and demonstrate that metastatic lesions have a lower proliferative rate compared to primary tumors. These findings may have implications for interpreting differences in response rates between primary and metastatic lesions and suggest that measurement of expression-based biomarkers in metastatic tissue will be most informative for understanding the basis of response of metastatic tumors to therapeutic intervention.

Second-line chemotherapy in advanced and metastatic CRC

BACKGROUND

Chemotherapy is widely used in colorectal cancer that has relapsed or failed to respond to first-line treatment.

OBJECTIVES

To determine the efficacy of second-line chemotherapy for the treatment of advanced colorectal cancer.

SEARCH STRATEGY

We performed electronic searches in the following databases: MEDLINE (via PubMed; 1964-September 2007), EMBASE (via OVID; 1980-September 2007) and The Cochrane Library 2007, Issue 2.

SELECTION CRITERIA

Studies assessing the efficacy of second-line chemotherapy (single or combined treatment with any chemotherapeutic agent, at any dose and number of cycles) in patients with advanced colorectal cancer that progressed, recurred or did not respond to first-line chemotherapy.

DATA COLLECTION AND ANALYSIS

A descriptive analysis of the included trials was performed, due to the huge clinical heterogeneity between them.

MAIN RESULTS

Seven randomized controlled trials (RCTs) were included; one of high quality, five of moderate quality, and one conference abstract. Second-line chemotherapy (irinotecan) showed moderate benefits in overall survival and progression-free survival over Best Supportive Care (BSC) and fluorouracil (5-FU). Fractionated administration has not proven to be more beneficial and is more toxic. Definitive results concerning the benefits and risks of oxaliplatin are pending publication.

AUTHORS' CONCLUSIONS

Second-line chemotherapy is effective in prolonging time to progression and survival in patients with advanced colorectal cancer. Further RCTs are needed to assess the optimal chemotherapy regimen.

Strong association of a common dihydropyrimidine dehydrogenase gene polymorphism with fluoropyrimidine-related toxicity in cancer patients

Background

Cancer patients carrying mutations in the dihydropyrimidine dehydrogenase gene (DPYD) have a high risk to experience severe drug-adverse effects following chemotherapy with fluoropyrimidine drugs such as 5-fluorouracil (5-FU) or capecitabine. The pretreatment detection of this impairment of pyrimidine catabolism could prevent serious, potentially lethal side effects. As known deleterious mutations explain only a limited proportion of the drug-adverse events, we systematically searched for additional DPYD variations associated with enhanced drug toxicity.

Methodology/Principal Findings

We performed a whole gene approach covering the entire coding region and compared DPYD genotype frequencies between cancer patients with good (n = 89) and with poor (n = 39) tolerance of a fluoropyrimidine-based chemotherapy regimen. Applying logistic regression analysis and sliding window approaches we identified the strongest association with fluoropyrimidine-related grade III and IV toxicity for the non-synonymous polymorphism c.496A>G (p.Met166Val). We then confirmed our initial results using an independent sample of 53 individuals suffering from drug-adverse-effects. The combined odds ratio calculated for 92 toxicity cases was 4.42 [95% CI 2.12–9.23]; p (trend)<0.001; p (corrected) = 0.001; the attributable risk was 56.9%. Comparing tumor-type matched sets of samples, correlation of c.496A>G with toxicity was particularly present in patients with gastroesophageal and breast cancer, but did not reach significance in patients with colorectal malignancies.

Conclusion

Our results show compelling evidence that, at least in distinct tumor types, a common DPYD polymorphism strongly contributes to the occurrence of fluoropyrimidine-related drug adverse effects. Carriers of this variant could benefit from individual dose adjustment of the fluoropyrimidine drug or alternate therapies.

Utility of Pretreatment Bilirubin Level and UGT1A1 Polymorphisms in Multivariate Predictive Models of Neutropenia Associated with Irinotecan Treatment in Previously Untreated Patients with Colorectal Cancer

PURPOSE: Statistical models for predicting hematologic toxicity were evaluated based on UGT1A1 polymorphisms and baseline serum bilirubin. METHODS: Blood DNA samples were collected from 113 patients with untreated metastatic colorectal cancer receiving irinotecan (FOLFIRI, n = 36; mIFL, n = 41; CapeIRI, n = 36). The primary endpoint was absolute neutrophil count nadir during first treatment cycle. Linear regression models, with increased R(2) implying important additional predictive power, sequentially added age, sex, baseline bilirubin level, and UGT1A1 genotype. RESULTS: All models demonstrated low R(2), suggesting unaccounted variables. UGT1A1 genotype added approximately 8-9% during cycle 1 and from approximately 7% [mIFL regimen] to 26% [CapeIRI regimen] after cycle 1. Correlation between genotype and overall ANC nadir without regard to treatment was low (R = -0.201, P = 0.035). Patients with genotype 7/7 may have increased risk for severe neutropenia, but data are insufficient to characterize this. Contribution of baseline bilirubin level was negligible. CONCLUSIONS: Ability of UGT1A1 or baseline bilirubin to predict neutropenia is low and depends on regimen.

Induction of T cell-mediated immunity using a c-Myb DNA vaccine in a mouse model of colon cancer

Overexpression of the proto-oncogene c-Myb occurs in more than 80% of colorectal cancer (CRC) and is associated with aggressive disease and poor prognosis. To test c-Myb as a therapeutic target in CRC we devised a DNA fusion vaccine to generate an anti-CRC immune response. c-Myb, like many tumor antigens, is weakly immunogenic as it is a "self" antigen and subject to tolerance. To break tolerance, a DNA fusion vaccine was generated comprising wild-type c-Myb cDNA flanked by two potent Th epitopes derived from tetanus toxin. Vaccination was performed targeting a highly aggressive, weakly immunogenic, subcutaneous, syngeneic, colon adenocarcinoma cell line MC38 which highly expresses c-Myb. Prophylactic intravenous vaccination significantly suppressed tumor growth, through the induction of anti-tumor immunity for which the tetanus epitopes were essential. Vaccination generated anti-tumor immunity mediated by both CD4+ and CD8+ T cells and increased infiltration of immune effector cells at the tumor site. Importantly, no evidence of autoimmune pathology in endogenous c-Myb expressing tissues was detected as a consequence of breaking tolerance. In summary, these results establish c-Myb as a potential antigen for immune targeting in CRC and serve to provide proof of principle for the continuing development of DNA vaccines targeting c-Myb to bring this approach to the clinic.

Imaging findings after liver resection by using radiofrequency parenchymal coagulation devices: initial experiences

PURPOSE

To retrospectively evaluate the imaging features and potential pitfalls in interpreting the findings at the site of surgery in patients undergoing hepatic resection by using the InLine and TissueLink radiofrequency devices for parenchymal coagulation prior to transection.

MATERIALS AND METHODS

This HIPAA-compliant study was approved by the Institutional Review Board with waiver of informed consent. Twenty-six patients (14 men, 12 women; mean age, 56 years), in whom intraoperative Inline and TissueLink devices were used for resection of hepatocellular carcinoma or metastatic liver disease or other liver tumors, were identified. Information such as tumor characteristics, diagnostic studies, surgical therapy, and surveillance methods were reviewed. All computed tomographic (CT) and positron emission tomographic (PET) scans and the single magnetic resonance and ultrasonographic images of the abdomen were retrospectively reviewed by a radiologist and compared with the initial interpreting physician's report.

RESULTS

Of 35 CT scans, 33 revealed a hypodense line of demarcation (mean thickness, 13.2 mm) between the surgical resection clips and the normal liver parenchyma. This demarcation was interpreted as "could not exclude site recurrence" in three cases and "recurrence or probable recurrence" in five cases. In two CT scans, the hypodense demarcation was not present. In all seven PET scans, the uniform hypermetabolic activity associated with the demarcation was labeled as a recurrence. At follow-up CT (median, 12.5 months), marginal recurrence was not detected in 25 patients, though in one case there was a recurrence in close proximity to the surgical site.

CONCLUSION

The use of InLine and TissueLink devices during hepatectomy is associated with a linear hypodense demarcation at the surgical margin that also demonstrates a symmetrical rimlike hypermetabolic activity seen on PET scans.

Radiofrequency ablation of colorectal liver metastases: small size favorably predicts technique effectiveness and survival

The objective of this study was to analyze long-term results of radiofrequency thermal ablation (RFA) for colorectal metastases (MTS), in order to evaluate predictors for adverse events, technique effectiveness, and survival. One hundred ninety-nine nonresectable MTS (0.5-8 cm; mean, 2.9 cm) in 122 patients underwent a total of 166 RFA sessions, percutaneously or during surgery. The technique was "simple" or "combined" with vascular occlusion. The mean follow-up time was 24.2 months. Complications, technique effectiveness, and survival rates were statistically analyzed. Adverse events occurred in 8.1% of lesions (major complication rate: 1.1%), 7.1% with simple and 16.7% with combined technique (p = 0.15). Early complete response was obtained in 151 lesions (81.2%), but 49 lesions (26.3%) recurred locally after a mean of 10.4 months. Sustained complete ablation was achieved in 66.7% of lesions < or = 3 cm versus 33.3% of lesions > 3 cm (p < 0.0001). Survival rates at 1, 3, and 5 years were 91%, 54%, and 33%, respectively, from the diagnosis of MTS and 79%, 38%, and 22%, respectively, from RFA. Mean survival time from RFA was 31.5 months, 36.2 in patients with main MTS < or = 3 cm and 23.2 in those with at least one lesion > 3 cm (p = 0.006). We conclude that "simple" RFA is safe and successful for MTS < or = 3 cm, contributing to prolong survival when patients can be completely treated.

Ethnic disparities in Americans of European descent versus Americans of African descent related to polymorphic ERCC1, ERCC2, XRCC1, and PARP1

Nucleotide excision repair (NER) and base excision repair (BER) pathways are DNA repair pathways that are important in carcinogenesis and in response to DNA-damaging chemotherapy. ERCC1 and ERCC2 are important molecular markers for NER; XRCC1 and PARP1 are important molecular markers for BER. Functional polymorphisms have been described that are associated with altered expression levels of these genes and with altered DNA repair capability. We assayed genomic DNA from 156 Americans of European descent and 164 Americans of African descent for the allelic frequencies of specific polymorphisms of ERCC1 N118N (500C>T), ERCC1 C8092A, ERCC2 K751Q (2282A>C), XRCC1 R399Q (1301G>A), XRCC1 R194W (685C>T), and PARP1 V762A (2446T>C). Differences were observed between Americans of European descent and Americans of African descent in the allelic frequencies of the ERCC1 N118N polymorphism (P < 0.000001). Differences were also observed between these two ethnic groups for ERCC2 K751Q (P = < 0.006675), XRCC1 R399Q (P < 0.000001), and PARP1 V762A (P = 0.000001). The ERCC1 N118N polymorphic variant that is seen most commonly in Americans of European descent is associated with a measurable reduction in NER function. ERCC1-mediated reduction in NER functionality affects the repair of cisplatin-DNA lesions.

Current status of antivascular therapy and targeted treatment in the clinic

Antivascular and targeted therapy are now an integrated part of the treatment of myelogenous leukemias, GIST tumours, B-cell lymphomas and breast cancer. In various malignancies improved responses and prolongation of survival for several months is regularly reported. The progress in this field is relevant for hyperthermia. Heat has among other effects documented antivascular effects, and can be considered as one of the established methods in the field based on several randomised phase III studies. Hyperthermia should be considered for combination with other antiangiogenic agents.