Relevance of Ki-67 antigen expression and K-ras mutation in colorectal liver metastases

Reclassification of RAS/BRAF allele mutations predicts the survival benefit of triplet chemotherapy in metastatic colorectal cancer

Background

Different RAS/BRAF allele mutations imply distinct biological properties in various solid tumors. Recently, several studies have focused on the predictive and prognostic roles of various RAS/BRAF allele mutations in colorectal cancer (CRC) but the results remain controversial.

Methods

Between March 2017 and September 2022, the patients diagnosed as stages I-IV CRC with detailed medical records including next-generation sequencing (NGS) data and clinicopathological follow-up information available at our center were enrolled. Survival data were estimated using the Kaplan-Meier method, and the difference was tested in a log-rank test. Multivariate tests were carried out using Cox models.

Results

A total of 1029 CRC patients were included, and the incidence of RAS/BRAF mutation was 58.4%. The hypermutated cohort was defined as patients with microsatellite instability-H or POLE/D mutation. In the non-hypermutational cohort, only KRAS G13D mutation was associated with a higher incidence and inferior disease-free survival in patients with stage I-III CRC. In the cohort of patients with non-hypermutated metastatic colorectal cancer (mCRC), we assessed the risk of various RAS/BRAF allele mutations and subsequently reclassified patients into four groups based on first-line median progression-free survival: wild type (group 1), low-risk RAS/BRAF mutation (group 2, RAS/BRAF mutations other than KRAS G13D/G12V/G12C or BRAF V600E), high-risk RAS mutation (group 3, KRAS G13D/G12V/G12C), and BRAF V600E mutation (group 4). mCRC patients with high-risk RAS mutation could significantly benefit from intensive triplet chemotherapy (hazard ratio, 2.54; 95% confidence interval, 1.36-5.12; p = 0.0091).

Conclusion

In the non-hypermutated CRC cohort, the prognostic risk of various RAS/BRAF allele mutations varied between local and metastatic CRC. KRAS G13D mutation tended to be the only prognostic marker for stages I-III CRC; however, KRAS G13D/G12V/G12C mutations collectively defined a high-risk subgroup of mCRC patients with poor prognosis, who would benefit from intensive triplet chemotherapy.

Prognostic Biomarkers of Cell Proliferation in Colorectal Cancer (CRC): From Immunohistochemistry to Molecular Biology Techniques

Colorectal cancer (CRC) is one of the most common and severe malignancies worldwide. Recent advances in diagnostic methods allow for more accurate identification and detection of several molecular biomarkers associated with this cancer. Nonetheless, non-invasive and effective prognostic and predictive testing in CRC patients remains challenging. Classical prognostic genetic markers comprise mutations in several genes (e.g., APC, KRAS/BRAF, TGF-β, and TP53). Furthermore, CIN and MSI serve as chromosomal markers, while epigenetic markers include CIMP and many other candidates such as SERP, p14, p16, LINE-1, and RASSF1A. The number of proliferation-related long non-coding RNAs (e.g., SNHG1, SNHG6, MALAT-1, CRNDE) and microRNAs (e.g., miR-20a, miR-21, miR-143, miR-145, miR-181a/b) that could serve as potential CRC markers has also steadily increased in recent years. Among the immunohistochemical (IHC) proliferative markers, the prognostic value regarding the patients' overall survival (OS) or disease-free survival (DFS) has been confirmed for thymidylate synthase (TS), cyclin B1, cyclin D1, proliferating cell nuclear antigen (PCNA), and Ki-67. In most cases, the overexpression of these markers in tissues was related to worse OS and DFS. However, slowly proliferating cells should also be considered in CRC therapy (especially radiotherapy) as they could represent a reservoir from which cells are recruited to replenish the rapidly proliferating population in response to cell-damaging factors. Considering the above, the aim of this article is to review the most common proliferative markers assessed using various methods including IHC and selected molecular biology techniques (e.g., qRT-PCR, in situ hybridization, RNA/DNA sequencing, next-generation sequencing) as prognostic and predictive markers in CRC.

Association between Ki67 expression and therapeutic outcome in colon cancer

Ki67 is a commonly used proliferation marker in pathological diagnosis of tumors; however, its prognostic value in colon cancer is controversial. A total of 312 consecutive patients with stage I-III colon cancer who underwent radical surgery with or without adjuvant chemotherapy were included in the present study. Ki67 expression was assessed using immunohistochemistry and was classified according to 25% intervals. The association between Ki67 expression and clinicopathological features was analyzed. Long-term postoperative survival, including disease-free survival (DFS) and overall survival, was calculated, and its association with Ki67 was analyzed. High Ki67 expression (>50%) was associated with improved DFS in patients treated with adjuvant chemotherapy postoperatively, but not in patients who received surgery alone (P=0.138). Ki67 expression was significantly associated with histological differentiation of the tumor (P=0.01), while it was not associated with other clinicopathological factors. Multivariate analysis demonstrated that pathological T and N stage were independent prognostic factors. In conclusion, high Ki67 expression was associated with a good therapeutic outcome in patients receiving adjuvant chemotherapy in colon cancer.

Role of Artificial Intelligence in Radiogenomics for Cancers in the Era of Precision Medicine

Simple Summary

Recently, radiogenomics has played a significant role and offered a new understanding of cancer’s biology and behavior in response to standard therapy. It also provides a more precise prognosis, investigation, and analysis of the patient’s cancer. Over the years, Artificial Intelligence (AI) has provided a significant strength in radiogenomics. In this paper, we offer computational and oncological prospects of the role of AI in radiogenomics, as well as its offers, achievements, opportunities, and limitations in the current clinical practices.

Abstract

Radiogenomics, a combination of “Radiomics” and “Genomics,” using Artificial Intelligence (AI) has recently emerged as the state-of-the-art science in precision medicine, especially in oncology care. Radiogenomics syndicates large-scale quantifiable data extracted from radiological medical images enveloped with personalized genomic phenotypes. It fabricates a prediction model through various AI methods to stratify the risk of patients, monitor therapeutic approaches, and assess clinical outcomes. It has recently shown tremendous achievements in prognosis, treatment planning, survival prediction, heterogeneity analysis, reoccurrence, and progression-free survival for human cancer study. Although AI has shown immense performance in oncology care in various clinical aspects, it has several challenges and limitations. The proposed review provides an overview of radiogenomics with the viewpoints on the role of AI in terms of its promises for computational as well as oncological aspects and offers achievements and opportunities in the era of precision medicine. The review also presents various recommendations to diminish these obstacles.

Implications of RAS Mutations on Oncological Outcomes of Surgical Resection and Thermal Ablation Techniques in the Treatment of Colorectal Liver Metastases

Simple Summary

Modern management of colorectal liver metastases (CRLM) requires a thorough knowledge of tumor biology and oncogenes mutations. RAS mutations are of paramount interest for the indication of targeted therapies and is increasingly considered as a negative prognostic factor for patients undergoing surgical resection or ablation for CRLM. Several studies discussed the results of specific technical considerations according to RAS mutational status on the oncological outcomes after surgical resection/ablation for CRLM. We reviewed the available data on the real impact of RAS mutations on the prognosis with special regard to the need of a tailored surgical (ablation) approach according to tumoral biology.

Abstract

Colorectal cancer (CRC) is the third most common cancer worldwide and the second leading cause of cancer-related death. More than 50% of patients with CRC will develop liver metastases (CRLM) during their disease. In the era of precision surgery for CRLM, several advances have been made in the multimodal management of this disease. Surgical treatment, combined with a modern chemotherapy regimen and targeted therapies, is the only potential curative treatment. Unfortunately, 70% of patients treated for CRLM experience recurrence. RAS mutations are associated with worse overall and recurrence-free survival. Other mutations such as BRAF, associated RAS /TP53 and APC/PIK3CA mutations are important genetic markers to evaluate tumor biology. Somatic mutations are of paramount interest for tailoring preoperative treatment, defining a surgical resection strategy and the indication for ablation techniques. Herein, the most relevant studies dealing with RAS mutations and the management of CRLM were reviewed. Controversies about the implication of this mutation in surgical and ablative treatments were also discussed.

Prognostic Value of Ki-67 Index in Patients With Endometrial Stromal Sarcoma

Objective

The Ki-67 index is used to evaluate cell proliferation activity, which is related to tumor progression, metastasis, and prognosis. We aimed to explore the prognostic value of Ki-67 index in endometrial stromal sarcoma and to explore the optimal cut-off value of Ki-67 index for predicting recurrent endometrial stromal sarcoma.

Methods

A total of 82 patients with endometrial stromal sarcoma who were treated in our hospital were collected. Clinicopathological data of these patients were retrospectively analyzed. Ki-67 index was detected by the immunohistochemical method. Receiver operating characteristic curve and the Youden index were performed to determine the optimal cut-off value of Ki-67 index for predicting recurrent endometrial stromal sarcoma. The Cox regression was performed to analyze risk factors affecting prognosis of endometrial stromal sarcoma. The Kaplan–Meier method and Log-rank test were performed to analyze the survival of patients.

Results

The optimal cut-off value of Ki-67 index for predicting recurrent endometrial stromal sarcoma was 35%. The results of univariate analysis showed that high Ki-67 index (≥35%) was statistically significantly bound up with shorter progress free survival and overall survival. The results of multivariate analysis showed that Ki-67 index (P = 0.001) and ovarian preservation (P = 0.040) were independent prognostic factors of progress free survival.

Conclusions

A Ki-67 index cut-off of 35% was optimal for predicting recurrent endometrial stromal sarcoma. Ki-67 index may be a useful prognostic marker in endometrial stromal sarcoma.

Clinical Significance and Prognostic Value of the Maximum Standardized Uptake Value of 18F-Flurodeoxyglucose Positron Emission Tomography-Computed Tomography in Colorectal Cancer

Background

The role of ¹⁸F-flurodeoxyglucose (¹⁸F-FDG) positron emission tomography–computed tomography (PET/CT) in colorectal cancer (CRC) remains unclear. This study aimed to explore the association of the maximum standardized uptake value (SUVmax), a parameter of ¹⁸F-FDG PET/CT, with KRAS mutation, the Ki-67 index, and survival in patients with CRC.

Methods

Data of 66 patients with CRC who underwent ¹⁸F-FDG PET/CT was retrospectively collected in our center. The clinical significance of the SUVmax in CRC and the association of the SUVmax with KRAS mutation and the Ki-67 index were determined. A meta-analysis was conducted by a systematic search of PubMed, Web of Science, and CNKI databases, and the data from published articles were combined with that of our study. The association of the SUVmax with KRAS mutation and the Ki-67 index was determined using the odds ratio to estimate the pooled results. The hazard ratio was used to quantitatively evaluate the prognosis of the SUVmax in CRC.

Results

By analyzing the data of 66 patients with CRC, the SUVmax was found not to be related to the tumor-node-metastasis stage, clinical stage, sex, and KRAS mutation but was related to the tumor location and nerve invasion. The SUVmax had no significant correlation with the tumor biomarkers and the Ki-67 index. Data of 17 studies indicated that the SUVmax was significantly increased in the mutated type compared with the wild type of KRAS in CRC; four studies showed that there was no remarkable difference between patients with a high and low Ki-67 index score regarding the SUVmax. Twelve studies revealed that the SUVmax had no significant association with overall survival and disease-free survival in CRC patients.

Conclusions

Based on the combined data, this study demonstrated that the SUVmax of ¹⁸F-FDG PET/CT was different between colon and rectal cancers and associated with KRAS mutation but not the Ki-67 index; there was no significant association between the SUVmax and survival of patients with CRC.

Reevaluating the prognostic value of RAS mutation status in patients with resected liver metastases from colorectal cancer: A systematic review and meta-analysis

BACKGROUND

Although the value of Rat Sarcoma Oncogene (RAS) mutation status in predicting long-term outcomes in patients with colorectal liver metastases (CRLM) is widely accepted, the magnitude of its impact has recently been challenged by three large cohort studies. The aim of this meta-analysis is to reevaluate the impact of RAS mutations on overall survival (OS) and disease-free survival (DFS) in patients who underwent curative-intent resection of CRLM.

METHODS

A comprehensive literature search was performed for studies reporting outcomes of patients undergoing curative-intent surgery stratified by RAS mutation status. Exclusion criteria were defined a priori. Subgroup analysis was performed to evaluate the effect of publication date, sample size, and KRAS vs any RAS mutation on overall outcomes.

RESULTS

Ten studies incorporating 3115 patients with known RAS status were identified. Pooled results revealed significantly worse OS (Hazard Ratio 1.5, 95% CI 1.31-1.71) and DFS (Hazard Ratio 1.36, 95% CI 1.22-1.52) in RAS-mutated patients. Subgroup analyses revealed that studies including more than 300 patients or published after 2015 reported lower HR than their counterparts.

CONCLUSION

The results of this meta-analysis suggest that the prognostic value of RAS mutation status in patients with CRLM has been previously overestimated.

Prevalence of proliferating CD8+ cells in normal lymphatic tissues, inflammation and cancer

CD8⁺ cytotoxic T-lymphocytes are essential components of the anti-tumor immunity. To better understand the expansion of CD8⁺ T-cells we used multiplex fluorescence immunohistochemistry to study Ki67⁺CD8⁺ cells in normal lymphoid tissues, selected inflammatory diseases and cancers in 41 large sections/ microenvironment tissue microarrays (TMAs) as well as 765 samples in a conventional TMA format. The evaluation of more than 20 different compartments of normal lymphoid tissues revealed that the percentage of proliferating (ki67⁺) CD8⁺ cells did commonly not exceed 3%. In inflammations, the percentage of Ki67⁺CD8⁺ cells was more variable and higher compared to normal tissues. In cancers, the percentage of Ki67⁺CD8⁺ cells was higher in the tumor center than at the invasive margin. In the tumor center of 765 colorectal cancers, the density of Ki67⁺CD8⁺ cells and the percentage of proliferating CD8⁺ cytotoxic T-cells was significantly associated with microsatellite instability (p<0.0001), pT (p<0.0002) and pN category (p<0.0098). In summary, these data show that the percentage of Ki67⁺CD8⁺ cells is usually at a baseline proliferation rate below 3% in healthy secondary lymphoid organs. This rate is often markedly higher in inflammatory and neoplastic diseases compared to normal tissues. The striking link with unfavorable tumor features in colorectal cancer suggest a potential clinical utility of assessing the percentage of Ki67⁺CD8⁺ cells to predict patients outcome.

Tumor Biomarkers and Interventional Oncology: Impact on Local Outcomes for Liver and Lung Malignancy

PURPOSE OF REVIEW

Interventional oncology (IO) loco-regional treatments are widely utilized in clinical practice. However, local tumor control rates are still widely variable. There is a need to identify and develop novel biomarkers prognosticators following IO therapies. Here, we review the current literature on molecular tumor biomarkers in IO, mainly focusing on patients with liver and lung cancers.

RECENT FINDINGS

RAS mutation is a prognosticator for patients with colorectal liver metastases. Several promising serum metabolites, gene signatures, circulating tumor nucleotides, and peptides are being evaluated for patients with hepatocellular carcinoma. Ki-67 and RAS mutation are independent risk factors for local tumor progression in the ablation of lung cancer. The relevant interplay between specific tumor biomarkers and IO loco-regional therapies outcomes has brought a new vision in the management of cancer. Further evolution of personalized interventional oncology accordingly to tumor biomarkers should improve oncologic outcomes for patients receiving IO therapies.

PBK expression predicts favorable survival in colorectal cancer patients

Colorectal cancer (CRC) is one of the most common gastrointestinal cancers worldwide with high morbidity and mortality rates. The discovery of small molecule anticancer reagents has significantly affected cancer therapy. However, the anticancer effects of these therapies are not sufficient to completely cure CRC. PDZ-binding kinase (PBK) was initially identified as a mitotic kinase for mitogen-activated protein kinase and is involved in cytokinesis and spermatogenesis. Aberrant expression of PBK has been reported to be closely associated with malignant phenotypes of many cancers and/or patient survival. However, the expression of PBK and its association to patient survival in CRC have not been fully elucidated. In the present study, 269 primary CRCs were evaluated immunohistochemically for PBK expression to assess its ability as a prognostic factor. CRC tumor cells variably expressed PBK (range, 0-100%; median, 32%) in the nucleus and cytoplasm. Univariate analyses identified a significant inverse correlation between PBK expression and pT stage (P<0.0001). Furthermore, patients carrying CRC with higher PBK expression showed significantly favorable survival (P=0.0094). Multivariate Cox proportional hazards regression analysis revealed high PBK expression (HR, 0.52; P=0.015) as one of the potential favorable factors for CRC patients. PBK expression showed significant correlation to Ki-67 labeling indices (ρ=0.488, P<0.0001). In vitro, the PBK inhibitor OTS514 suppressed cellular proliferation of CRC cells with PBK expression through downregulation of P-ERK and induction of apoptosis. These results suggest that PBK-targeting therapeutics may be useful for the treatment of PBK-expressing CRC patients.

Adjuvant Hepatic Artery Infusion Chemotherapy is Associated With Improved Survival Regardless of KRAS Mutation Status in Patients With Resected Colorectal Liver Metastases: A Retrospective Analysis of 674 Patients

OBJECTIVE

To investigate the impact of adjuvant hepatic artery infusion (HAI) in relation to KRAS mutational status in patients with resected colorectal cancer liver metastases (CRLM).

BACKGROUND

Patients with KRAS-mutated CRLM have worse outcomes after resection. Adjuvant HAI chemotherapy improves overall survival after liver resection.

METHODS

Patients with resected CRLM treated at MSKCC with and without adjuvant HAI who had available KRAS status (wild-type, WT; mutated, MUT) were reviewed from a prospectively maintained institutional database. Correlations between KRAS status, adjuvant HAI, clinical factors, and outcomes were analyzed. Cox proportional hazard model was used to adjust for confounders.

RESULTS

Between 1993 and 2012, 674 patients (418 KRAS-WT, 256 MUT) with a median follow up of 6.5 years after resection were evaluated. Fifty-four percent received adjuvant HAI. Tumor characteristics (synchronous disease, number of lesions, clinical-risk score, 2-stage hepatectomy) were significantly worse in the HAI group; however, there were more patients with resected extrahepatic metastases in the no-HAI group. In KRAS-WT tumors, 5-year survival was 78% for patients treated with HAI versus 57% for patients without HAI [hazard ratio (HR) 0.51, P < 0.001]. In KRAS-MUT tumors, 5-year survival was 59% for patients treated with HAI versus 40% for patients without HAI (HR 0.56, P < 0.001). On multivariate analysis, HAI remained associated with improved OS (HR 0.53, P < 0.002) independent of KRAS status and other clinicopathologic factors.

CONCLUSION

Adjuvant HAI after resection of CRLM is independently associated with improved outcomes regardless of KRAS mutational status. Adjuvant HAI may mitigate the worse outcomes seen in patients with resectable KRAS-MUT CRLM.

Computed Tomography-Based Radiomic Features Could Potentially Predict Microsatellite Instability Status in Stage II Colorectal Cancer: A Preliminary Study

RATIONALE AND OBJECTIVES

To investigate whether quantitative radiomics features extracted from computed tomography (CT) can predict microsatellite instability (MSI) status in an Asian cohort of patients with stage Ⅱ colorectal cancer (CRC).

MATERIALS AND METHODS

This retrospective study was approved by our institutional review board, and the informed consent requirement was waived. From March 2016 to March 2018, 119 Chinese patients with pathologically confirmed stage Ⅱ CRC, available MSI status, and preoperative contrast-enhanced CT images were included in this study. Clinical and pathological information was obtained from the institutional database. The radiomics features were extracted from portal venous-phase CT images of segmented volumes of each entire primary tumor by using Matrix Laboratory (MATLAB), and radiomics signatures were generated using the least absolute shrinkage and selection operator logistic regression model. The minority group was balanced via synthetic minority over-sampling technique method. The association between the clinicopathologic characteristics and MSI status was assessed using Student's t test, Chi-square, or Fisher's exact test. The predictive efficacy of MSI status using radiomics features, clinical factors (including age, gender, CT-reported tumor location, differentiation degree of tumor, smoking history, hypertension history, family history of cancer, diabetes history, level of the Ki-67 expression, and laboratory analysis) and the combined models were evaluated, respectively. Predictive performance was evaluated by the area under receiver operating characteristic curve, accuracy, sensitivity, and specificity.

RESULTS

MSI status was significantly associated with tumor location (p = 0.043); differentiation degree of tumor (p < 0.0001), hypertension history (p = 0.012), and the level of the Ki-67 expression (p = 0.015). Six radiomics features and 11 clinical characteristics were selected for predicting MSI status. The model that used the combination of clinical factors and radiomics features achieved the overall best performance than using either of the two features alone, yielding the area under the curve, sensitivity, and specificity of 0.752, 0.663, 0.841 for the combined model, 0.598, 0.371, 0.825 for clinical factors alone, and 0.688, 0.517, 0.858 for radiomics features alone, respectively.

CONCLUSION

CT-based radiomic features of stage Ⅱ CRC are associated with MSI status. Combining analysis of clinical features and CT features could improve predictive efficacy and could potentially select the patients for individualized therapy noninvasively.

Thermal Ablation of Metastatic Colon Cancer to the Liver

Colorectal cancer (CRC) is responsible for approximately 10% of cancer-related deaths in the Western world. Liver metastases are frequently seen at the time of diagnosis and throughout the course of the disease. Surgical resection is often considered as it provides long-term survival; however, few patients are candidates for resection. Percutaneous ablative therapies are also used in the management of this patient population. Different thermal ablation (TA) technologies are available including radiofrequency ablation, microwave ablation (MWA), laser, and cryoablation. There is growing evidence about the role of interventional oncology and image-guided percutaneous ablation in the management of metastatic colorectal liver disease. This article aims to outline the technical considerations, outcomes, and rational of TA in the management of patients with CRC liver metastases, focusing on the emerging role of MWA.

Impact of primary colorectal Cancer location on the KRAS status and its prognostic value

BACKGROUND

Colorectal cancer (CRC) originating from the right-sided or left-sided colon is distinct clinicopathological entity. The KRAS status and its prognostic value in CRC remain controversial. This study aimed to investigate the association of KRAS status with clinicopathological features and prognostic value in CRC.

METHODS

178 colon cancer and 145 rectal cancer patients were enrolled. KRAS mutation test was performed on paraffin-embedded tumor samples using PCR methods. The colon cancer was divided into right-sided colon cancer (RCC) and left-sided colon cancer (LCC). Studies that reported the association of KRAS mutation with CRC clinical features and prognosis in databases were searched prior to 2018. The data of the present study was combined with the data of published studies using meta-analysis methods.

RESULTS

No significant difference between colon cancer and rectal cancer regarding the KRAS status. The KRAS mutation was much frequent in RCC than in LCC (p = 0.010). 17 studies with 11,385 colon cancer patients were selected, the pooled results of our data and previous published data showed that KRAS mutation was more frequent in RCC compared with in LCC (p < 0.01); KRAS mutation was not associated with the prognosis in RCC patient; however, KRAS mutation indicated a poor prognosis in LCC patients compared with KRAS wild type (p < 0.01).

CONCLUSION

KRAS status has no difference between colon cancer and rectal cancer. KRAS mutation was more frequent in RCC than in LCC, and associated with a poor prognosis in LCC patients, but not in RCC patients.

Interaction of CD200 Overexpression on Tumor Cells with CD200R1 Overexpression on Stromal Cells: An Escape from the Host Immune Response in Rectal Cancer Patients

CD200 imparts an immunoregulatory signal through its receptor, CD200R1, leading to the suppression of tumor specific immunity. The mechanism of CD200:CD200R1 signaling pathway is still uncertain. Our aim was to investigate the expression and localization of CD200 and its receptor CD200R1 and their clinical significance in rectal cancer patients. We examined the immunohistochemical expressions and localizations of CD200 and CD200R1 in 140 rectal cancer patients. Among the patients, 79 underwent the preoperative radiotherapy and the others were untreated prior to the surgery. In addition, 121 matched normal rectal mucosa samples were evaluated. The results of immunohistochemical analysis showed a strikingly high level of CD200 in tumor cells (p=0.001) and CD200R1 expression in normal mucosal epithelium and stromal cells. Importantly, CD200R1 was overexpressed in stromal cells of the metastatic cancer patients compared to patients without metastases (p=0.002). More than that, 87% of metastatic patients had a phenotype of upregulated CD200 in tumor cells accompanied by overexpressed CD200R1 in stromal cells. In addition, low levels of CD200 were correlated with improved overall survival in untreated patients. We showed that tumor-stroma communication through CD200 and its receptor interaction is selected in patients with high risk of relapse. High levels of these molecules support instigation of the far and local metastatic nest that provides solid ground for metastasis. Our current data also disclose a mechanism by which CD200:CD200R1 affects tumor progression and may strengthen the feasibility of targeting CD200 or CD200R1 as anticancer strategy.

Immunohistochemical investigation of prognostic biomarkers in resected colorectal liver metastases: a systematic review and meta-analysis

Background

Many studies have investigated the prognostic role of biomarkers in colorectal liver metastases (CRLM). However, no biomarker has been established in routine clinical practice. The aim of this study was to scrutinize the current literature for biomarkers evaluated by immunohistochemistry as prognostic markers in patients with resected CRLM.

Methods

A systematic review was performed according to the PRISMA guidelines. Articles were identified in the PubMed database with selected search terms and by cross-references search. The REMARK quality criteria were applied. Markers were included if they reported the prognostic impact of immunohistochemical markers in a multivariable setting in relation to overall survival (OS). A meta-analysis was conducted when more than one original article provided survival data of a marker.

Results

In total, 26 biomarkers were identified as independent significant markers for OS in resected CRLM. These biomarkers were found to be involved in multiple oncogenic signalling pathways that control cell growth, apoptosis, angiogenesis and evasion of immune detection. Among these biomarker candidates were Ki-67, EGFR, p53, hTERT, CD34, TSP-1, KISS1, Aurora kinase A and CDX2. CD34 and TSP-1 were reported as significantly associated with survival by more than one study and where therefore pooled in a meta-analysis.

Conclusion

A number of independent prognostic biomarkers for resected CRLM were identified. However, most markers were evaluated in a retrospective setting with small patient cohorts, without external validation. Large, prospective, multicentre studies with standardised methods are needed before biomarkers can translated into the clinic.

Colorectal Liver Metastases: Does the Future of Precision Medicine Lie in Genetic Testing?

Colorectal liver metastases (CRLM) present an important clinical challenge in both surgical and medical oncology. Despite improvements in management, survival among patients undergoing resection of CRLM is still very variable and there is a paucity of clinical trial data and reliable biomarkers that could guide prognostic forecasts, treatment selection, and follow-up. Fortunately, recent advances in molecular biology and tumor sequencing have identified a number of critical genetic loci and proliferation markers that may hold the key to understanding the biologic behavior of CRLM; specifically, mutations of KRAS, BRAF, TP53, PIK3CA, APC, expression of Ki-67, and the presence of microsatellite instability appear to have a decisive impact on prognosis and response to treatment in patients with CRLM. While the applicability of genetic biomarkers in everyday clinical practice remains conditional on the development of inexpensive bedside sequencing, targeted therapies, and the conduct of appropriate clinical trials, the promise of personalized treatment may be closer to realization than ever before.

The Shifting Paradigm of Prognostic Factors of Colorectal Liver Metastases: From Tumor-Centered to Host Immune-Centered Factors

The determinants of prognosis in patients with colorectal liver metastases (CLM) have been traditionally searched among the tumoral factors, either of the primary colorectal tumor or of the CLM. While many different scoring systems have been developed based on those clinic-pathological factors with disparate results, there has been the introduction of genetic biological markers that added a theranostic perspective. More recently, other important elements, such as those factors related to the host immune system, have been proposed as determinants of prognosis of CLM patients. In the present work, we review the current prognostic factors of CLM patients as well as the burgeoning shifting paradigm of prognostication that relies on the host immune system.

Biomarkers in colorectal liver metastases

BACKGROUND

Despite a 5-year overall survival rate of 58 per cent after liver resection for colorectal liver metastases (CLMs), more than half of patients develop recurrence, highlighting the need for accurate risk stratification and prognostication. Traditional prognostic factors have been superseded by newer outcome predictors, including those defined by the molecular origin of the primary tumour.

METHODS

This review synthesized findings in the literature using the PubMed database of articles in the English language published between 1998 and 2017 on prognostic and predictive biomarkers in patients undergoing resection of CLMs.

RESULTS

Responses to preoperative chemotherapy define prognosis in patients undergoing CLM resection. There are differences by embryological origin too. Somatic mutations in the proto-oncogenes KRAS and NRAS are associated with positive surgical margins and tumour regrowth after ablation. Other mutations (such as BRAF) and co-occurring mutations in RAS/TP53 and APC/PIK3CA have emerged as important biomarkers that determine an individual patient's tumour biology and may be used to predict outcome after CLM resection.

CONCLUSION

Knowledge of somatic mutations can guide the use of preoperative therapy, extent of surgical margin and selection for ablation alone.

Correlations between the iodine concentrations from dual energy computed tomography and molecular markers Ki-67 and HIF-1α in rectal cancer: A preliminary study

PURPOSE

To investigate whether dual energy computed tomography (CT) with iodine quantification is correlated with molecular markers Ki-67and hypoxia-inducible factor 1α (HIF-1α)in rectal cancer (RC).

MATERIALS AND METHODS

Eighty patients (43 males and 37 females) diagnosed with rectal cancer got pelvic contrast-enhanced CT scan with dual energy computed tomography before any anticancer treatment. Analyse the normalized iodine concentration (NIC) values and CT values at each energy level (40-140 keV) from the virtual monochromatic image of the primary lesions. The postoperative specimens of all 80 patients underwent Ki-67 and HIF-1α immunohistochemistry staining. By SPSS17.0 software package, we analyzed the correlations of NIC values and CT values at each energy level (40-140 keV) with Ki-67 and HIF-1α expression. The receiver operating characteristic (ROC) curves of these dual energy computed tomography parameters were calculated and the diagnostic value were assessed.

RESULTS

There was a weak positive correlation between NIC values and carcinoembryonic antigen level (r=0.246, P=0.028) in RC. Both the value and the level of Ki-67 expression were correlated positively with the NIC values (r=0.344, P=0.002 and r=0.248, P=0.026). HIF-1α expression was correlated positively with the NIC values of the RC (r=0.598, P<0.001). The best threshold values of NIC values in diagnosing the expression of HIF-1α was 0.5839. The sensitivity, 78%; specificity, 87%; PPV, 86%; NPV,79%;accuracy, 83%.

CONCLUSION

The NIC values on dual energy computed tomography may be used as a measurement of hypoxia in RC and determining the ability of tumor invasion noninvasively.

Management of patients with colorectal liver metastasis in eleven questions and answers

INTRODUCTION

Colorectal liver metastasis (CRLM) is the most frequent indication for liver resection in many centers. Recent improvements in oncology, surgery, interventional radiology, pathology and anesthesiology allow curative treatment in a larger proportion of patients with CRLM. Areas covered: We illustrate the various aspects of the management of CRLM through 11 questions that summarize the topic, from the current obtained survival to future perspectives such as transplantation. The limits of a curative treatment are also presented from different angles, such as the benefits of pathology, the surgical options for extreme resections, the available chemotherapies and their efficacy, or the non-surgical ablative treatments. Expert commentary: Given the increasing therapeutic possibilities, we strengthen the importance to analyze the situation of each patient with CRLM in a dedicated multidisciplinary team, in order to offer the best individualized treatment combination.

Prognostic Implication of KRAS Status after Hepatectomy for Colorectal Liver Metastases Varies According to Primary Colorectal Tumor Location

BACKGROUND

Right-sided and left-sided colorectal cancer (CRC) is known to differ in their molecular carcinogenic pathways. We sought to investigate the variable prognostic implication of KRAS mutation after hepatectomy for colorectal liver metastases (CRLM) according to the site of primary CRC.

METHODS

A total of 426 patients who underwent a curative-intent hepatic resection and whose KRAS status was available were identified. Clinicopathologic characteristics and long-term outcomes were stratified by KRAS status (wild type vs. mutant type) and primary tumor location (right-sided vs. left-sided). Cecum, right and transverse colon were defined as right-sided, whereas left colon and rectum were defined as left-sided.

RESULTS

Among patients with a right-sided CRC, 5-year recurrence-free survival (RFS) and overall survival (OS) were not correlated with KRAS status (wild type: 30.8 and 47.2 % vs. mutant type: 38.5 and 49.1 %, respectively) (both P > 0.05). Specifically, mutant-type KRAS was not associated with either RFS or OS on multivariable analysis (hazard ratio [HR] 1.51, 95 % confidence interval [CI] 0.73-3.14, P = 0.23 and HR 1.03, 95 % CI 0.51-2.08, P = 0.95, respectively). In contrast, among patients who underwent resection of CRLM from a left-sided primary CRC, 5-year RFS and OS were worse among patients with mutant-type KRAS (wild type: 23.7 and 57.2 % vs. mutant type: 19.6 and 38.2 %, respectively) (both P < 0.05). On multivariable analysis, mutant-type KRAS remained independently associated with worse RFS and OS among patients with a left-sided primary CRC (HR 1.57, 95 % CI 1.01-2.44, P = 0.04 and HR 1.81, 95 % CI 1.11-2.96, P = 0.02, respectively).

CONCLUSIONS

KRAS status has a variable prognostic impact after hepatic resection for CRLM depending on the site of the primary CRC. Future studies examining the impact of KRAS status on prognosis after hepatectomy should take into account the primary CRC tumor site.

Mimicking Metastases Including Tumor Stroma: A New Technique to Generate a Three-Dimensional Colorectal Cancer Model Based on a Biological Decellularized Intestinal Scaffold

Tumor models based on cancer cell lines cultured two-dimensionally (2D) on plastic lack histological complexity and functionality compared to the native microenvironment. Xenogenic mouse tumor models display higher complexity but often do not predict human drug responses accurately due to species-specific differences. We present here a three-dimensional (3D) in vitro colon cancer model based on a biological scaffold derived from decellularized porcine jejunum (small intestine submucosa+mucosa, SISmuc). Two different cell lines were used in monoculture or in coculture with primary fibroblasts. After 14 days of culture, we demonstrated a close contact of human Caco2 colon cancer cells with the preserved basement membrane on an ultrastructural level as well as morphological characteristics of a well-differentiated epithelium. To generate a tissue-engineered tumor model, we chose human SW480 colon cancer cells, a reportedly malignant cell line. Malignant characteristics were confirmed in 2D cell culture: SW480 cells showed higher vimentin and lower E-cadherin expression than Caco2 cells. In contrast to Caco2, SW480 cells displayed cancerous characteristics such as delocalized E-cadherin and nuclear location of β-catenin in a subset of cells. One central drawback of 2D cultures—especially in consideration of drug testing—is their artificially high proliferation. In our 3D tissue-engineered tumor model, both cell lines showed decreased numbers of proliferating cells, thus correlating more precisely with observations of primary colon cancer in all stages (UICC I-IV). Moreover, vimentin decreased in SW480 colon cancer cells, indicating a mesenchymal to epithelial transition process, attributed to metastasis formation. Only SW480 cells cocultured with fibroblasts induced the formation of tumor-like aggregates surrounded by fibroblasts, whereas in Caco2 cocultures, a separate Caco2 cell layer was formed separated from the fibroblast compartment beneath. To foster tissue generation, a bioreactor was constructed for dynamic culture approaches. This induced a close tissue-like association of cultured tumor cells with fibroblasts reflecting tumor biopsies. Therapy with 5-fluorouracil (5-FU) was effective only in 3D coculture. In conclusion, our 3D tumor model reflects human tissue-related tumor characteristics, including lower tumor cell proliferation. It is now available for drug testing in metastatic context—especially for substances targeting tumor–stroma interactions.

Microvessel density and endothelial cell proliferation levels in colorectal liver metastases from patients given neo-adjuvant cytotoxic chemotherapy and bevacizumab

The treatment of patients with colorectal liver metastasis has improved significantly and first line therapy is often combined chemotherapy and bevacizumab, although it is unknown who responds to this regimen. Colorectal liver metastases grow in different histological growth patterns showing differences in angiogenesis. To identify possible response markers, histological markers of angiogenesis were assessed. Patients who underwent resection of colorectal liver metastasis at Rigshospitalet, Copenhagen, Denmark from 2007 to 2011 were included (n = 254) including untreated and patients treated with chemotherapy or chemotherapy plus bevacizumab. The resected liver metastases were characterised with respect to growth pattern, endothelial and tumour cell proliferation as well as microvessel density and tumour regression. Tumour regression grade of liver metastases differed significantly between untreated/chemotherapy treated patients in comparison to chemotherapy plus bevacizumab treated patients (both p < 0.0001). Microvessel density was decreased in liver metastases from patients treated with bevacizumab in comparison to those from untreated/chemotherapy-treated patients (p = 0.006/p = 0.002). Tumour cell proliferation assessed by Ki67 expression correlated to a shorter recurrence free survival in the total patient cohort. In conclusion, liver metastases from patients treated with neo-adjuvant chemotherapy and bevacizumab had significantly lower microvessel densities and tumour regression grades when compared to liver metastases from untreated or chemotherapy treated patients. This may indicate that bevacizumab treatment results in altered vascular biology and tumour viability, with possible tumour reducing effect.

Meta-analysis of KRAS mutations and survival after resection of colorectal liver metastases

BACKGROUND

In patients with advanced colorectal cancer, KRAS mutation status predicts response to treatment with monoclonal antibody targeting the epithelial growth factor receptor (EGFR). Recent reports have provided evidence that KRAS mutation status has prognostic value in patients with resectable colorectal liver metastases (CLM) irrespective of treatment with chemotherapy or anti-EGFR therapy. A meta-analysis was undertaken to clarify the impact of KRAS mutation on outcomes in patients with resectable CLM.

METHODS

PubMed, Embase and Cochrane Library databases were searched systematically to identify full-text articles reporting KRAS-stratified overall (OS) or recurrence-free (RFS) survival after resection of CLM. Hazard ratios (HRs) and 95 per cent c.i. from multivariable analyses were pooled in meta-analyses, and a random-effects model was used to calculate weight and overall results.

RESULTS

The search returned 355 articles, of which 14, including 1809 patients, met the inclusion criteria. Eight studies reported OS after resection of CLM in 1181 patients. The mutation rate was 27.6 per cent, and KRAS mutation was negatively associated with OS (HR 2.24, 95 per cent c.i. 1.76 to 2.85). Seven studies reported RFS after resection of CLM in 906 patients. The mutation rate was 28.0 per cent, and KRAS mutation was negatively associated with RFS (HR 1.89, 1.54 to 2.32).

CONCLUSION

KRAS mutation status is a prognostic factor in patients undergoing resection of colorectal liver metastases and should be considered in the evaluation of patients having liver resection.

Discrepancies between the K-ras mutational status of primary colorectal cancers and corresponding liver metastases are found in codon 13

K-ras mutation status has remained elusive in the metastatic liver tumors of colorectal cancer (CRC) in contrast to the primary CRC tumors. In this study, K-ras mutational status of the primary and corresponding liver metastatic tumors was investigated in the 43 CRC patients. Codons 12 and 13 of K-ras were directly sequenced, and a K-ras mutation was evident in 17 cases (39.5%). In 6 cases, the K-ras mutation was evident only in the liver metastasis, but not in the primary CRC, where the mutation was found in codon 13. This discrepancy between primary and metastatic lesions with regard to codon 13 of the K-ras gene may explain the clinical discrepancy of EGFR antibody therapy. In conclusion, the current data may lead to the development of personalized medicine for recurrent CRC, although further validation study is still required.

KRAS and BRAF mutations are prognostic biomarkers in patients undergoing lung metastasectomy of colorectal cancer

Background:

We evaluated KRAS (mKRAS (mutant KRAS)) and BRAF (mBRAF (mutant BRAF)) mutations to determine their prognostic potential in assessing patients with colorectal cancer (CRC) for lung metastasectomy.

Methods:

Data were reviewed from 180 patients with a diagnosis of CRC who underwent a lung metastasectomy between January 1998 and December 2011.

Results:

Molecular analysis revealed mKRAS in 93 patients (51.7%), mBRAF in 19 patients (10.6%). In univariate analyses, overall survival (OS) was influenced by thoracic nodal status (median OS: 98 months for pN−, 27 months for pN+, P<0.0001), multiple thoracic metastases (75 months vs 101 months, P=0.008) or a history of liver metastases (94 months vs 101 months, P=0.04). mBRAF had a significantly worse OS than mKRAS and wild type (WT) (P<0.0001). The 5-year OS was 0% for mBRAF, 44% for mKRAS and 100% for WT, with corresponding median OS of 15, 55 and 98 months, respectively (P<0.0001). In multivariate analysis, WT BRAF (HR: 0.005 (95% CI: 0.001–0.02), P<0.0001) and WT KRAS (HR: 0.04 (95% CI: 0.02–0.1), P<0.0001) had a significant impact on OS.

Conclusions:

mKRAS and mBRAF seem to be prognostic factors in patients with CRC who undergo lung metastasectomy. Further studies are necessary.

Clinical impact of c-MET expression and genetic mutational status in colorectal cancer patients after liver resection

c-MET is implicated in the pathogenesis and growth of a wide variety of human malignancies, including colorectal cancer (CRC). The aim of the present study was to clarify the association between c-MET expression and tumor recurrence in CRC patients after curative liver resection, and to evaluate concordance in c-MET expression and various mutations of KRAS, BRAF and PIK3CA between primary CRC and paired liver metastases. A cohort of patients was tested for c-MET immunoreactivity (i.e. immunohistochemistry [IHC]) and KRAS, BRAF and PIK3CA mutations. Analyses were performed both on primary tumors and paired liver metastases, and the association between IHC and mutations results were assessed. A total of 108 patients were eligible. A total of 53% of patients underwent simultaneous resection of primary tumors and metastases, and the others underwent metachronous resection. Levels of concordance between primary tumors and metastases were 65.7%, 87.7%, 100% and 95.2% for c-MET, KRAS, BRAF and PIK3CA, respectively. High levels of c-MET expression (c-MET-high) in the primary tumors were observed in 52% of patients. Relapse-free survival was significantly shorter for patients with c-MET-high primary tumors (9.7 months) than for those with c-MET-low primary tumors (21.1 months) (P = 0.013). These results suggest that a high level of genetic concordance in KRAS, BRAF and PIK3CA between primary tumors and liver metastases, and c-MET-high in the primary tumors were associated with shorter relapse-free survival after hepatic metastasectomy.

SMAD4 and TS expression might predict the risk of recurrence after resection of colorectal liver metastases

PURPOSE

Colorectal liver metastases (CLM) have significant molecular heterogeneity, which contributes to the risk of recurrence following surgery. Most of the traditional scores intended to predict recurrence is based on clinicopathological variables and it is unclear whether incorporating molecular biomarkers might improve our assessment of the risk of recurrence. Our aim was to determine if molecular biomarkers might be associated with the risk of recurrence after surgery of CLM.

PATIENTS AND METHODS

A total of 121 patients diagnosed with colorectal cancer (CRC) with resected liver metastases were included. The role of several clinicopathological variables to predict patient's outcome after resection of liver metastases was analyzed. Eighteen genes related to CRC pathogenesis were also included in the analyses. Univariate and multivariate stepwise Cox regression analyses were performed to identify factors associated with recurrence and the risk of death.

RESULTS

Eight prognostic factors for progression-free survival and nine factors for overall survival were identified in the univariate analyses. After adjusting for other risk factors, only the expression of two molecular factors was associated with the risk of recurrence: TS (HR 0.631, 95 % CI 0.422-0.944) and SMAD4 (HR 1.680, 95 % CI 1.047-2.695). None of the variables was significantly associated with the risk of death in the multivariate analyses.

CONCLUSIONS

The prognostic significance of most traditional clinicopathological variables might be insufficient to define patients at risk for recurrence after liver metastases resection. Molecular biomarkers might improve the identification of patients with higher risk of recurrence.

Can we improve the clinical risk score? The prognostic value of p53, Ki-67 and thymidylate synthase in patients undergoing radical resection of colorectal liver metastases

OBJECTIVES

The aim of this study was to assess whether biological markers can provide prognostic information additional to that supplied by the clinical risk score (CRS) in patients with colorectal liver metastases.

METHODS

A retrospective review of a prospectively maintained database was conducted. Patients selected for this study were treated between 1996 and 2011 with potentially curative liver surgery. Expressions of p53, Ki-67 and thymidylate synthase were assayed using immunohistochemical techniques on tissue microarrays.

RESULTS

A total of 98 (24%) of 406 patients met the inclusion criteria. The median follow-up was 103 months. Analysis revealed a correlation between p53 protein overexpression and high CRS (P = 0.058). Following multivariate analysis, only high CRS remained as an independent negative prognostic predictor of survival (P = 0.018), as well as an indicator of early recurrence of disease (P = 0.010). Of the biological markers investigated, only Ki-67 overexpression was identified as a positive predictor of survival on multivariate analysis (P = 0.038).

CONCLUSIONS

Ki-67 overexpression was a positive predictor of survival. Only high CRS remained an independent negative prognostic predictor.

Surgery for colorectal liver metastases: The evolution of determining prognosis

Despite improvements in the multi-modality treatment of colorectal liver metastasis (CRLM), survival after resection remains varied. Determining prognosis after surgical resection has historically been predicated on preoperative clinicopathological factors such as primary tumor stage, carcinoembryonic antigen levels, number of liver metastases, presence of extrahepatic disease, as well as other factors. While scoring systems have been developed by combining certain preoperative factors, these have been inconsistent in accurately determining prognosis. There has been increasing interest in the use of biologic and molecular markers to predict prognosis following CRLM. The role of markers such as KRAS, BRAF, p53, human telomerase reverse transcriptase, thymidylate synthase, Ki-67, and hypoxia inducible factor-1α and their correlation with accurately predicting survival after surgical resection have been supported by several studies. Furthermore, other elements such as pathological response to chemotherapy and the presence of circulating tumor cells have shown promise in accurately determining prognosis after resection for colorectal liver metastasis. We herein review past, present, and possible future markers of prognosis among colorectal cancer patients with liver metastasis undergoing resection with curative intent.

Incidence and prognostic impact of KRAS and BRAF mutation in patients undergoing liver surgery for colorectal metastases

BACKGROUND

Molecular biomarkers offer the potential for refining prognostic determinants in patients undergoing cancer surgery. Among patients with colorectal cancer, KRAS and BRAF are important biomarkers, but their role in patients undergoing surgical therapy for liver metastases is unknown. In this study, the incidence and prognostic significance of KRAS and BRAF mutations were determined in patients undergoing surgical therapy of colorectal liver metastases (CRLM).

METHODS

KRAS and BRAF analysis was performed on 202 patients undergoing surgery for CRLM between 2003 and 2008. Tumor samples were analyzed for somatic mutations using sequencing analysis (KRAS, codon12/13, BRAF, V600E). The frequency of mutations was ascertained, and their impact on outcome was determined relative to other clinicopathologic factors.

RESULTS

KRAS gene mutations were detected in 58/202 patients (29%). In contrast, mutation in the BRAF gene was identified in very low frequency in this surgical cohort, found in only 4/202 (2%) patients. On multivariate analysis, KRAS mutation was associated with worse survival (hazard ratio [HR], 1.99; 95% confidence interval [CI], 1.21-3.26), as well as recurrence risk (HR, 1.68; 95% CI, 1.04-2.70). Although other clinicopathologic features, including tumor number, carcinoembryonic antigen, and primary stage were also associated with survival, KRAS status remained independently predictive of outcome. The low incidence of BRAF mutation limited assessment of its prognostic impact.

CONCLUSION

Whereas KRAS mutations were found in approximately one third of patients, BFAF mutations were found in only 2% of patients undergoing surgery for CRLM. KRAS status was an independent predictor of overall and recurrence-free survival. Molecular biomarkers such as KRAS may help to refine our prognostic assessment of patients undergoing surgical therapy for CRLM.

Is availability of anti-EGFR therapy for the colorectal adenocarcinomas showing fascin expression limited?

Colorectal adenocarcinoma (CRC) is a major cause of death. Fascin expression in CRCs was proved to be related with higher metastatic rates and poor prognosis, while metastatic patients with only wild type K-RAS gene are the candidates of recent molecularly targeted anti-epidermal growth factor receptor (EGFR) therapies. This study is designed to investigate the correlation between the fascin expression status and the K-RAS mutational status of CRCs in order to assess the availability rate of anti-EGFR therapies for patients with fascin-expressing CRCs. Immunohistochemical expression of fascin and mutational status of K-RAS were investigated in the archival materials of randomly selected 50 metastatic colorectal carcinoma patients. Strength of fascin expression and tumor percentage stained with fascin were scored semi quantitatively. c.34 > C (p.G12R), c.35 g > C (p.G12C), c.34G > A (p.G12S), c.35G > A (p.G12D), c.35G > T (p.G12V), c.35G > C (p.G12A), and c.38G > A (p.G13.D) mutations in K-RAS gene were studied by using RT-PCR. In immunohistochemical evaluation, 32 of the 50 cases stained positive with fascin, while 21 were positive for K-RAS mutations in codon 12 (10 patients) or in codon 13 (3 patients). The correlation between the positivity of fascin and the presence of K-RAS mutations, the strength of fascin staining and the presence of K-RAS mutations, and the tumor cell percentage stained with fascin and the presence of K-RAS mutations were found statistically significant. The results of this study suggest that patients with fascin-expressing CRCs have a greater tendency to carry an activating K-RAS mutation which will prevent them from taking targeted anti-EGFR therapies. Larger series are needed to confirm these results.

The tumour biology of synchronous and metachronous colorectal liver metastases: a systematic review

Forty to fifty percent of colorectal cancer (CRC) patients develop colorectal liver metastases (CLM) that are either synchronous or metachronous in presentation. Clarifying whether there is a biological difference between the two groups of liver metastases or their primaries could have important clinical implications. A systematic review was performed using the following resources: MEDLINE from PubMed (1950 to present), Embase, Cochrane and the Web of Knowledge. Thirty-one articles met the inclusion criteria. The review demonstrated that the majority of studies found differences in molecular marker expression between colorectal liver metastases and their respective primaries in both the synchronous and metachronous groups. Studies investigating genetic aberrations demonstrated that the majority of changes in the primary tumour were 'maintained' in the colorectal liver metastases. A limited number of studies compared the primary tumours of the synchronous and metachronous groups and generally demonstrated no differences in marker expression. Although there were conflicting results, the colorectal liver metastases in the synchronous and metachronous groups demonstrated some differences in keeping with a more aggressive tumour subtype in the synchronous group. This review suggests that biological differences may exist between the liver metastases of the synchronous and metachronous groups. Whether there are biological differences between the primaries of the synchronous and metachronous groups remains undetermined due to the limited number of studies available. Future research is required to determine whether differences exist between the two groups and should include comparisons of the primary tumours.

Survival after liver resection in metastatic colorectal cancer: review and meta-analysis of prognostic factors

Background

Hepatic metastases develop in approximately 50% of colorectal cancer (CRC) cases. We performed a review and meta-analysis to evaluate survival after resection of CRC liver metastases (CLMs) and estimated the summary effect for seven prognostic factors.

Methods

Studies published between 1999 and 2010, indexed on Medline, that reported survival after resection of CLMs, were reviewed. Meta-relative risks for survival by prognostic factor were calculated, stratified by study size and annual clinic volume. Cumulative meta-analysis results by annual clinic volume were plotted.

Results

Five- and 10-year survival ranged from 16% to 74% (median 38%) and 9% to 69% (median 26%), respectively, based on 60 studies. The overall summary median survival time was 3.6 (range: 1.7–7.3) years. Meta-relative risks (95% confidence intervals) by prognostic factor were: node positive primary, 1.6 (1.5–1.7); carcinoembryonic antigen level, 1.9 (1.1–3.2); extrahepatic disease, 1.9 (1.5–2.4); poor tumor grade, 1.9 (1.3–2.7); positive margin, 2.0 (1.7–2.5); >1 liver metastases, 1.6 (1.4–1.8); and >3 cm tumor diameter, 1.5 (1.3–1.8). Cumulative meta-analyses by annual clinic volume suggested improved survival with increasing volume.

Conclusion

The overall median survival following CLM liver resection was 3.6 years. All seven investigated prognostic factors showed a modest but significant predictive relationship with survival, and certain prognostic factors may prove useful in determining optimal therapeutic options. Due to the increasing complexity of surgical interventions for CLM and the inclusion of patients with higher disease burdens, future studies should consider the potential for selection and referral bias on survival.

KRAS status and outcome of liver resection after neoadjuvant chemotherapy including bevacizumab

Background

The prognostic value of KRAS mutation in patients with colorectal cancer liver metastases (CLM) receiving neoadjuvant chemotherapy including bevacizumab before liver resection is unclear.

Methods

The KRAS and BRAF status of resected CLM was assessed in prospectively studied patients. Mutations were correlated with recurrence-free and overall survival. Only patients with remaining vital tumour cells in the resected specimen and those without disease progression were analysed; those with progressive disease did not undergo resection.

Results

A total of 60 patients were enrolled. Fifteen (25 per cent) had a KRAS mutation, but none of the 60 patients had a BRAF mutation. The radiological response to neoadjuvant chemotherapy including bevacizumab, assessed according to the Response Evaluation Criteria In Solid Tumours, was partial in 52 patients (87 per cent) and the remaining eight had stable disease. The partial response rate was similar in patients with a KRAS mutation and those with the wild-type gene (12 of 15 versus 40 of 45 patients; P = 0·400). KRAS mutation had a negative prognostic effect on recurrence-free survival (hazard ratio (HR) 2·48, 95 per cent confidence interval 1·26 to 4·89; P = 0·009) and overall survival (HR 3·51, 1·30 to 9·45; P = 0·013).

Conclusion

This study provided further evidence for the prognostic importance of KRAS status in terms of recurrence-free and overall survival. Neoadjuvant chemotherapy including bevacizumab elicited a response, irrespective of KRAS status, in this selected group of patients with CLM.

Management of colorectal cancer patients after resection of liver metastases: can we offer a tailored treatment?

Surgical resection remains the only option of cure for patients with colorectal liver metastases, and no patient should be precluded from surgery. There is much controversy not only regarding the most appropriate therapeutic approach in the neoadjuvant setting but also after surgery is performed. Many patients will experience early relapses but others will be long survivors. We need to establish reliable prognostic and predictive factors to offer a tailored treatment. Several prognostic factors after metastasectomy have been identified: high C-reactive protein levels, a high neutrophil-lymphocyte ratio, elevated neutrophil count and low serum albumin are related to a worst outcome. Elevated CEA and Ki 67 levels, intrahepatic and perihepatic lymph node invasion are also some of the markers related to a worst outcome. In contrast, the administration of preoperative chemotherapy has been associated with a better prognosis after hepatectomy. The administration of adjuvant chemotherapy should be done taking in consideration these factors. Regarding predictive factors, determination of ERCC1, TS, TP and DPD and UGT1 polymorphisms assessment could be considered prior to chemotherapy administration. This would avoid treatment related toxicities and increase this population quality of life.

Is K-ras gene mutation a prognostic factor for colorectal cancer: a systematic review and meta-analysis

BACKGROUND

: The K-ras gene is one of the commonly mutated oncogenes associated with colorectal cancer. However, its prognostic significance for patients with colorectal cancer remains inconclusive.

OBJECTIVE

: To derive a more precise estimation of the prognostic significance of K-ras gene mutations, a systematic review and meta-analysis were performed.

DATA SOURCES

: We searched PubMed, Embase, and the Cochrane databases from January 1992 to November 2011.

STUDY SELECTION

: The prognostic value of K-ras gene mutations was examined in patients with colorectal cancer who did not receive preoperative chemotherapy or radiation.

MAIN OUTCOME MEASURES

: The effect of K-ras gene mutations on the overall survival was measured by the HR and 95% CIs.

RESULTS

: The pooled HR for the association between K-ras gene mutations and overall survival in patients with colorectal cancer was 1.04 (95% CI: 0.99-1.10, p = 0.11). Subgroup analysis showed significant reductions in the overall survival associated with mutations at K-ras codon 12, the articles that reported HR directly, and the studies published before and after 2005, although publication bias was present. All the associations disappeared after adjustment with the trim-and-fill method. The pooled HR of 3 studies examining mutations at K-ras codon 13 was 1.47 (95% CI: 1.09-1.97, p = 0.02), and no publication bias was observed. No significant association was observed in different study regions.

LIMITATIONS

: The heterogeneity in the study populations is a potential problem, the use of different staging systems or small groups of different stages may contribute to heterogeneity, and residual confounding may have influenced the results in those studies that did not completely adjust for other factors.

CONCLUSIONS

: Overall K-ras gene mutations seem not to correlate with the prognosis of patients with colorectal cancer. The association remains to be confirmed with a more precise analysis of a large sample.

A high proliferative index of recurrent melanoma is associated with worse survival

OBJECTIVE

Previous melanoma studies evaluating prognostic factors of survival at recurrence have focused on primary tumor characteristics and clinical variables at first recurrence. We examined the prognostic relevance of recurrent tumor proliferation.

METHODS

114 melanoma patients with available recurrent tissues who were prospectively enrolled at New York University Medical Center were studied. Standard of care prognostic variables (e.g. stage at initial diagnosis and lactate dehydrogenase level) and recurrent tissue expression of proliferative marker Ki-67 were evaluated for their association with overall survival.

RESULTS

High Ki-67 expression was observed in 57 (50%) of the 114 recurrent melanomas. On univariate analysis, the median overall survival of patients whose recurrent tumors overexpressed Ki-67 was significantly shorter than that of patients whose recurrent tumors had low Ki-67 expression (3.6 vs. 9.5 years, p = 0.03). On multivariate analysis, a high proliferative index of the recurrent melanoma remained an independent predictor of worse overall survival, controlling for stage at initial diagnosis, disease-free survival, and stage at first recurrence [HR = 2.09 (95% CI 1.24-3.54), p = 0.006].

CONCLUSIONS

Our results demonstrate the prognostic relevance of tumor proliferation in recurrent melanoma patients. Data also support restratification of risk assessment upon recurrence that considers tumor biology in addition to clinical variables evaluated as part of the standard of care.

A review of the most promising biomarkers in colorectal cancer: one step closer to targeted therapy

Rapidly growing insights into the molecular biology of colorectal cancer (CRC) and recent developments in gene sequencing and molecular diagnostics have led to high expectations for the identification of molecular markers to be used in optimized and tailored treatment regimens. However, many of the published data on molecular biomarkers are contradictory in their findings and the current reality is that no molecular marker, other than the KRAS gene in the case of epidermal growth factor receptor (EGFR)- targeted therapy for metastatic disease, has made it into clinical practice. Many markers investigated suffer from technical shortcomings, resulting from lack of quantitative techniques to capture the impact of the molecular alteration. This understanding has recently led to the more comprehensive approaches of global gene expression profiling or genome-wide analysis to determine prognostic and predictive signatures in tumors. In this review, an update of the most recent data on promising biological prognostic and/or predictive markers, including microsatellite instability, epidermal growth factor receptor, KRAS, BRAF, CpG island methylator phenotype, cytotoxic T lymphocytes, forkhead box P3-positive T cells, receptor for hyaluronic acid-mediated motility, phosphatase and tensin homolog, and T-cell originated protein kinase, in patients with CRC is provided.