Codon 13 KRAS mutation predicts patterns of recurrence in patients undergoing hepatectomy for 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.

KRAS status predicted by pretreatment MRI radiomics was associated with lung metastasis in locally advanced rectal cancer patients

BACKGROUND

Mutated KRAS may indicate an invasive nature and predict prognosis in locally advanced rectal cancer (LARC). We aimed to establish a radiomic model using pretreatment T2W MRIs to predict KRAS status and explore the association between the KRAS status or model predictions and lung metastasis.

METHODS

In this retrospective multicentre study, LARC patients from two institutions between January 2012 and January 2019 were randomly divided into training and testing cohorts. Least absolute shrinkage and selection operator (LASSO) regression and the support vector machine (SVM) classifier were utilized to select significant radiomic features and establish a prediction model, which was validated by radiomic score distribution and decision curve analysis. The association between the model stratification and lung metastasis was investigated by Cox regression and Kaplan‒Meier survival analysis; the results were compared by the log-rank test.

RESULTS

Overall, 103 patients were enrolled (73 and 30 in the training and testing cohorts, respectively). The median follow-up was 38.1 months (interquartile range: 26.9, 49.4). The radiomic model had an area under the curve (AUC) of 0.983 in the training cohort and 0.814 in the testing cohort. Using a cut-off of 0.679 defined by the receiver operating characteristic (ROC) curve, patients with a high radiomic score (RS) had a higher risk for lung metastasis (HR 3.565, 95% CI 1.337, 9.505, p = 0.011), showing similar predictive performances for the mutant and wild-type KRAS groups (HR 3.225, 95% CI 1.249, 8.323, p = 0.016, IDI: 1.08%, p = 0.687; NRI 2.23%, p = 0.766).

CONCLUSIONS

We established and validated a radiomic model for predicting KRAS status in LARC. Patients with high RS experienced more lung metastases. The model could noninvasively detect KRAS status and may help individualize clinical decision-making.

Impact of Molecular Status on Metastasectomy of Colorectal Cancer Liver Metastases

Although surgical resection could provide better survival for patients with colorectal cancer liver metastases (CRLM), the recurrence rate after resection of CRLM remains high. The progress of genome sequencing technologies has greatly improved the molecular understanding of colorectal cancer. In the era of genomics and targeted therapy, genetic mutation analysis is of great significance to guide systemic treatment and identify patients who can benefit from resection of CRLM. RAS and BRAF mutations and microsatellite instability/deficient deoxyribonucleic acid (DNA) mismatch repair status have been incorporated into current clinical practice. Other promising molecular biomarkers such as coexisting gene mutations and circulating tumor DNA are under active investigation. This study aimed to review the prognostic significance of molecular biomarkers in patients with CRLM undergoing metastasectomy based on the current evidence.

KRAS Mutation Status in Bulgarian Patients with Advanced and Metastatic Colorectal Cancer

RAS somatic variants are predictors of resistance to anti-EGFR therapy for colorectal cancer (CRC) and affect the outcome of the disease. Our study aimed to evaluate the frequency of RAS, with a focus on KRAS variants, and their association with tumor location and some clinicopathological characteristics in Bulgarian CRC patients. We prospectively investigated 236 patients with advanced and metastatic CRC. Genomic DNA was extracted from FFPE tumor tissue samples, and commercially available kits were used to detect RAS gene somatic mutations via real-time PCR. A total of 115 (48.73%) patients tested positive for RAS mutations, with 106 (44.92%) testing positive for KRAS mutations. The most common mutation in exon 2 was c.35G>T p.Gly12Val (32.56%). We did not find a significant difference in KRAS mutation frequency according to tumor location. However, patients with a mutation in exon 4 of KRAS were 3.23 times more likely to have a tumor in the rectum than in other locations (95% CI: 1.19-8.72, p = 0.021). Studying the link between tumor location and KRAS mutations in exon 4 is crucial for better characterizing CRC patients. Further research with larger cohorts, especially in rectal cancer patients, could provide valuable insights for patient follow-up and treatment selection.

Precision Surgery of Colorectal Liver Metastases in the Current Era: A Systematic Review

Liver resection for colorectal liver metastases (CRLM) is widely considered the treatment with the highest curative potential. However, not all patients derive the same oncological benefit, underlining the need for better patient stratification and treatment allocation. In this context, we performed a systematic review of the literature to determine the role of RAS status in selecting the optimal surgical strategy. Evidence comparing anatomical with non-anatomical resections depending on RAS mutational status was scarce and conflicting, with two studies reporting superiority in mutated RAS (mutRAS) patients and two studies reporting equivalent outcomes. The rate of incomplete microscopic resection (R1) was found to be increased among mutRAS patients, possibly due to higher micrometastatic spread lateral to the primary lesion. The impact of R1 resection margins was evaluated separately for mutRAS and wild-type patients in three studies, of which, two indicated an additive detriment to long-term survival in the former group. In the current era of precision surgery, RAS status can be utilized to predict the efficacy of liver resection in the treatment of CRLM, avoiding a potentially morbid operation in patients with adverse tumor profiles.

Genomic Predictors of Recurrence Patterns After Complete Resection of Colorectal Liver Metastases and Adjuvant Hepatic Artery Infusion Chemotherapy

BACKGROUND

Despite curative hepatectomy, most colorectal liver metastasis (CRLM) patients relapse locally within 2 years. Genomic predictors for hepatic recurrence are poorly understood. This study was designed to identify genomic signatures for recurrence in resected CRLM patients treated with adjuvant hepatic artery infusion (HAI) and/or systemic (SYS) chemotherapy.

METHODS

Patients undergoing curative hepatectomy and adjuvant HAI+SYS or SYS between January 2000 and October 2017 with next-generation sequencing data were catalogued. Gene and signaling-level alterations were checked for association with time to any (AR), liver (LR), and extrahepatic recurrence (ER) by using Kaplan-Meier analysis.

RESULTS

Of 172 receiving HAI+SYS, 100 patients recurred, with 69 LR and 83 ER. Five- and ten-year LR-free rates were 57% (95% confidence interval [CI] 48-65%) and 51% (95% CI 41-60%), respectively. Five- and 10-year ER-free, rates were 51% (95% CI 43-58%) and 45% (95% CI 36-54%), respectively. More ER was observed with tumors harboring altered KRAS (38% [95% CI 25-50%] vs. 63% [95% CI 53-71%], p-adj = 0.003) and RAS/RAF (36% [95% CI 25-48%] vs. 66% [95% CI 56-74%], p-adj < 0.001) than wild-type. Co-altered RAS/RAF-TP53 was associated with worse AR (26% [95% CI 14-40%] vs. 48% [95% CI 39-57%], p-unadj < 0.001), ER (30% [95% CI 17-45%] vs. 62% [95% CI 53-70%], p-unadj < 0.001), and LR rate (40% [95% CI 24-57%] vs. 70% [95% CI 60-77%], p-unadj = 0.002). On multivariable analysis, controlling for clinical risk score, ablation, margin status, and primary T-stage, co-altered RAS/RAF-TP53 was associated with increased risk for AR (HR = 2.14, 95% CI 1.38-3.31, p-unadj < 0.001), LR (HR = 1.79, 95% CI 1.06-3.02, p-unadj = 0.029), and ER (HR = 2.81, 95% CI 1.78-4.44, p-unadj < 0.001).

CONCLUSIONS

Altered KRAS, RAS/RAF, and RAS/RAF-TP53 associated with earlier local and distant recurrence in resected CRLM patients receiving adjuvant HAI+SYS. Co-altered RAS/RAF-TP53 was a novel predictor of LR warranting investigation of whether genomic cooperativity is associated with this relapsing phenotype. Systemic therapies tailored to high-risk tumor biology are needed to reduce distant relapse after hepatectomy.

Impact of anatomical liver resection on patient survival in KRAS-wild-type colorectal liver metastasis: A multicenter retrospective study

BACKGROUND

Liver resection is a standard therapy for colorectal liver metastasis. However, the impact of anatomical resection and nonanatomical resection on the survival in patients with Kirsten rat sarcoma-wild-type and Kirsten rat sarcoma-mutated colorectal liver metastasis remain unclear. We investigated whether anatomical resection versus nonanatomical resection improves survival in colorectal liver metastasis stratified by Kirsten rat sarcoma mutational status.

METHODS

Among 639 consecutive patients with colorectal liver metastasis who underwent primary liver resection between January 2008 and December 2017, 349 patients were excluded due to their unknown Kirsten rat sarcoma mutational status, or due to receiving anatomical resection with concomitant non-anatomical resection, radiofrequency, or R2 resection. Accordingly, 290 patients with colorectal liver metastasis were retrospectively assessed. The relationships between resection types and survival were investigated in Kirsten rat sarcoma-wild-type and -mutated groups.

RESULTS

Anatomical resection was performed in 77/186 (41%) and 44/104 (42%) patients with Kirsten rat sarcoma-wild-type and Kirsten rat sarcoma-mutated genetic statuses, respectively. For both, the clinical-pathologic factors were comparable, except a larger maximum tumor size and surgical margin were observed in anatomical resection cases. Anatomical resection patients had significantly longer recurrence-free survival and overall survival than nonanatomical resection cases in the Kirsten rat sarcoma-wild-type group (recurrence-free survival, P < .001; overall survival, P = .005). No significant recurrence-free survival or overall survival differences were observed between Kirsten rat sarcoma-mutated anatomical resection and non-anatomical resection (recurrence-free survival, P = .132; overall survival, P = .563). Although, intrahepatic recurrence in Kirsten rat sarcoma-wild-type and -mutated colorectal liver metastasis was comparable (P = .973), extrahepatic recurrence was increased in Kirsten rat sarcoma-mutated versus -wild-type colorectal liver metastasis (P < .001).

CONCLUSION

In contrast to Kirsten rat sarcoma-mutated colorectal liver metastasis with higher extrahepatic recurrence after liver resection, local liver control via anatomical resection improved the postoperative survival in patients with Kirsten rat sarcoma-wild-type colorectal liver metastasis.

Prognostic Models Incorporating RAS Mutation to Predict Survival in Patients with Colorectal Liver Metastases: A Narrative Review

Recurrence and survival vary widely among patients who undergo curative-intent resection of colorectal liver metastases (CRLM). Prognostic models provide estimated probabilities of these outcomes and allow the effects of multiple potentially interacting variables to be adjusted and assessed simultaneously. Although many prognostic models based on clinicopathologic factors have been developed since the 1990s to predict survival after resection of CRLM, these models vary in their predictive performance when applied to contemporary cohorts. Rat sarcoma viral oncogene homolog (RAS) mutation status is routinely tested in patients with metastatic colorectal cancer to predict response to anti-epidermal growth factor therapy. In addition, mutations in RAS predict survival and recurrence in patients undergoing hepatectomy for CRLM. Several recent prognostic models have incorporated RAS mutation status as a surrogate of tumor biology and combined revised clinicopathologic variables to improve the prediction of recurrence and survival. This narrative review aims to evaluate the differences between contemporary prognostic models incorporating RAS mutation status and their clinical applicability in patients considered for curative-intent resection of CRLM.

The management of colorectal liver metastases amenable of surgical resection: How to shape treatment strategies according to clinical, radiological, pathological and molecular features

Metastatic colorectal cancer (mCRC) patients have poor chances of long term survival, being < 15% of them still alive after 5 years from diagnosis. Nonetheless, patients with colorectal liver metastases (CRLM) may be eligible for metastases resection thus being able to achieve long-term disease remission and survival. The likelihood for patients with CRLM of being or becoming eligible for liver metastasectomy is increasing, thanks to the evolution of surgical techniques, the availability of active systemic treatments and the widespread diffusion of experienced multidisciplinary boards to manage these patients. However, disease relapse after liver surgery is common and occurs in two-thirds of resected patients. Therefore, adequate radiological staging and risk stratification is crucial for the optimal selection of patients candidate to surgery in order to maximize the benefit-risk ratio of liver metastasectomy and to individualize the treatment strategy. Based on the multidimensional assessment, three possible approaches are available: upfront liver surgery followed by adjuvant chemotherapy, perioperative chemotherapy preceding and following liver surgery, and an upfront systemic treatment including chemotherapy plus a targeted agent, both chosen according to patients' and tumours' characteristics, then followed by liver surgery if indicated. In this review, we describe the most important factors impacting the therapeutic choices in patients with resectable and potentially resectable CRLM, and we discuss the most promising factors that may reshape the future decision-making process of these patients.

Assessment of Primary Colorectal Cancer CT Radiomics to Predict Metachronous Liver Metastasis

Objectives

To establish and validate a machine learning-based CT radiomics model to predict metachronous liver metastasis (MLM) in patients with colorectal cancer.

Methods

In total, 323 patients were retrospectively recruited from two independent institutions to develop and evaluate the CT radiomics model. Then, 1288 radiomics features were extracted to decode the imaging phenotypes of colorectal cancer on CT images. The optimal radiomics features were selected using a recursive feature elimination selector configured by a support vector machine. To reduce the bias caused by an unbalanced dataset, the synthetic minority oversampling technique was applied to resample the minority samples in the datasets. Then, both radiomics and clinical features were used to train the multilayer perceptron classifier to develop two classification models. Finally, a score-level fusion model was developed to further improve the model performance.

Results

The area under the curve (AUC) was 0.78 ± 0.07 for the tumour feature model and 0.79 ± 0.08 for the clinical feature model. The fusion model achieved the best performance, with AUCs of 0.79 ± 0.08 and 0.72 ± 0.07 in the internal and external validation cohorts.

Conclusions

Radiomics models based on baseline colorectal contrast-enhanced CT have high potential for MLM prediction. The fusion model combining radiomics and clinical features can provide valuable biomarkers to identify patients with a high risk of colorectal liver metastases.

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.

4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone provokes progression from chronic pancreatitis to pancreatic intraepithelial neoplasia

The risk of pancreatic cancer is higher among people who are cigarette smokers than among non-smokers; however, the action mechanisms of cigarette metabolites are not yet fully understood. In this study, we investigated the effect of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) in cigarette smoking on chronic pancreatitis and pancreatic cancer as well as the biological mechanism of NNK causing malignant transformation. We show that smoking may promote Kras mutation and P16 promoter methylation from clinical samples and NNK markedly facilitates the growth and migration of pancreatic cancer cells via the activation of Sonic Hedgehog signaling. We demonstrate that NNK promotes acinar-to-ductal metastasis and pancreatic intraepithelial neoplasia in rats with chronic pancreatitis, accompanied by desmoplastic reaction and Gli1 overexpression. Together, we here present evidence that NNK provokes the progression of chronic pancreatitis toward pancreatic cancer and highlight potential strategies and targets for early prevention of pancreatic cancer and its therapeutics.

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Smoking is positively correlated with Kras mutation and P16 hypermethylation

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NNK promotes acinar-to-ductal metastasis and preneoplasia lesions in rats

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NNK promotes desmoplastic reaction and Gli1 expression in chronic pancreatitis

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NNK facilitates the growth and migration of cancer via Sonic Hedgehog signaling

Shifting concepts in the management of colorectal liver metastases

Management of patients with colorectal liver metastases has evolved considerably due to a better understanding of the biology of the disease with concurrent improvements in surgical techniques, oncological strategies and radiological interventions. This review article examines the factors that have contributed to this radical change. Management will be discussed in relation to chemotherapy, surgery and interventional radiology. The addition of chemotherapy and biological agents has greatly extended the reach and scope of surgery. Parenchymal sparing resections, repeat resections, two stage hepatectomy and Associating Liver Partition and Portal Vein ligation are all available to the hepatobiliary surgeon who deals with colorectal liver metastases. Interventional radiology techniques like liver venous deprivation may also replace established surgical practice. Whilst traditionally it was thought that only a few liver metastases could be treated effectively, nowadays tumour number is no longer a limiting factor provided enough functioning liver can be spared and the patient can tolerate the operation.

Prognostic and Therapeutic Implications of Tumor Biology in Colorectal Liver Metastases

Prognostic models allow clinicians to predict survival outcomes, facilitate patient-physician discussions, and identify subgroups with potentially distinct prognoses [...].

Not All Kirsten Rat Sarcoma Viral Oncogene Homolog Mutations Predict Poor Survival in Patients With Unresectable Colorectal Liver Metastasis

Objective: To assess the characteristics of Kirsten rat sarcoma viral oncogene homolog (KRAS) mutations and investigated whether all KRAS mutations predict poor prognosis in patients with unresectable colorectal liver metastasis (CRLM). Methods: Correlations between KRAS-mutation status and clinicopathological characteristics of 93 patients with unresectable CRLM at our institution between 2010 and 2018 were retrospectively analyzed. Kaplan–Meier and Cox proportional hazard models were used to evaluate the prognostic significance of KRAS mutations. Results:KRAS were primarily single-point mutations, identified in 41.9% of patients. There were no significant differences in clinicopathological characteristics between wild-type KRAS and mutant KRAS. Patients with mutant KRAS had significantly worse overall survival (OS) and progression-free survival (PFS) than those with wild-type KRAS. Moreover, patients with codon 12 mutations had worse OS and PFS than those with wild-type KRAS, whereas mutations in codon 13 were not associated with a worse prognosis. Among the 5 most common mutations in codons 12, G12V, and G12D were associated with worse OS, furthermore, G12C mutation seemed to associated with worse PFS than patients with wild-type KRAS. Conclusion:KRAS codon 12 mutations were predictive for a poor prognosis in patients with unresectable CRLM. G12D and G12V mutations were associated with worse OS, whereas G12C mutation seemed to be associated with decreased PFS.

Genetic mutations associated with sensitivity to neoadjuvant chemotherapy in metastatic colon cancer: A case report and review of literature

BACKGROUND

Colorectal liver metastases (CLM) occur in 15%-30% of patients with colorectal cancer (CRC). Advancements in next generation sequencing (NGS) can provide more precise prognoses for cancer patients and help guide clinical treatment. However, the genetic variants that predict high sensitivity to neoadjuvant chemotherapy remain unclear, especially in patients with CLM. The aim of this study was to identify the relevant genetic variants in a single CLM patient and to summarize the current evidence on mutations and single nucleotide polymorphisms (SNPs) that objectively predict sensitivity to neoadjuvant chemotherapy.

CASE SUMMARY

A 76-year-old male patient, who was diagnosed as stage IV colon cancer with liver metastases, was found to have APC/TP53/KRAS mutations. He showed a good therapeutic response to 12 courses of oxaliplatin regimens combined with Bevacizumab. Genetic analysis of the patient identified 5 genes with 7 detected SNPs that may be related to a better response to chemotherapy drugs. In addition, a critical literature review was performed based on a standardized appraisal form after selecting the articles. Ultimately, 21 eligible studies were appraised to assess the association between gene mutations and good prognosis. Mutations in KRAS, TP53, SMAD4, and APC were identified as being associated with a poor response to chemotherapy drugs, whereas mutations of CREBBP and POLD1 were associated with longer overall survival.

CONCLUSION

NGS can identify precise predictors of response to neoadjuvant chemotherapy, leading to improved outcomes for CRC patients.

Predictive factors for distant recurrence of colorectal cancer in patients after curative resection for stage I-III colorectal cancer in Australia

PURPOSE

Distant recurrence is a devastating occurrence after colorectal cancer resection. This study aimed to identify the risk factors for distant recurrence following surgery.

METHODS

All consecutive colorectal cancer resections with curative intent were included from a prospectively maintained colorectal cancer database. The primary outcome was to identify predictive factors for distant recurrence of colorectal cancer.

RESULTS

A total of 670 eligible cases were identified with 88 (13.1%) developing distant recurrence during the follow-up period. The median time to distant recurrence was 1.2 years with the most common sites of distant recurrence being the lung (44.3%) and liver (44.3%). Predictive factors for distant recurrence in colon cancer included a high tumor, nodal, and overall stage of the primary cancer (p < 0.001 for all). Surgical complications (p = 0.007), including anastomotic leak (p = 0.023), were associated with a higher risk of developing distant recurrence in rectal cancer patients. Independent variables associated with distant recurrence included tumor stage (OR 1.61, p = 0.011), nodal stage (OR 2.18, p < 0.001), and both KRAS (OR 11.04, p < 0.001) and MLH/PMS2 (OR 0.20, p = 0.035) genetic mutations. Among patients with distant recurrence, treatment with surgery conferred the best survival, with patients < 50 years of age having the best overall 5-year survival.

CONCLUSION

Predictive factors for distant recurrence include advanced tumor and nodal stages, and the presence of KRAS and MLH/PSM2 mutations. Clinicians should be cognizant of these risk factors, and instate close surveillance plans for patients exhibiting these features.

Prognostic Value of KRAS Exon 3 and Exon 4 Mutations in Colorectal Cancer Patients

Background: The clinical significance of KRAS exon 3/4 mutations in colorectal cancer (CRC) remains unclear. We aimed to assess the prognostic value of KRAS exons 3 and 4 mutations to determine the necessity for their testing.

Methods:KRAS mutations in exon 2/3/4 were evaluated in 1816 stage I-IV patients with colorectal adenocarcinoma.

Results: The mutation rates of KRAS and KRAS exons 2, 3, and 4 were 49.0%, 43.0%, 1.9%, and 4.1%, respectively. Univariate survival analysis showed that patients with exon 3 mutation had worse overall survival (OS) compared to those with KRAS exon 2 mutation or wild-type KRAS (P = 0.044, and P = 0.001). Meanwhile, there was no difference in survival between patients with wild-type KRAS and with exon 4 mutation (P = 0.128). In multivariate analysis, KRAS mutations in exon 3 and 2 were both independent factors for worse OS (Exon 3, P = 0.032, HR = 1.861, 95% CI: 1.021-3.391; Exon 2, P = 0.049, HR = 1.298, 95% CI: 1.002-1.682). Among the patients with KRAS exon 2 mutations, those that had mutations in codon 13 had significantly worse prognosis than those with wild-type KRAS (P = 0.001) or KRAS codon 12 mutations (P = 0.003).

Conclusions: In KRAS-mutated CRC, exon 3 mutations predict the worst prognosis, while exon 4 mutations predict the best prognosis. Among KRAS exon 2 mutated patients, codon 13 mutations predict worse prognosis than codon 12 mutations. Mutations of different KRAS exons should be analyzed separately.

The current understanding on the impact of KRAS on colorectal cancer

KRAS (kirsten rat sarcoma viral oncogene) is a member of the RAS family. KRAS mutations are one of most dominant mutations in colorectal cancer (CRC). The impact of KRAS mutations on the prognosis and survival of CRC patients drives many research studies to explore potential therapeutics or target therapy for the KRAS mutant CRC. This review summarizes the current understanding of the pathological consequences of the KRAS mutations in the development of CRC; and the impact of the mutations on the response and the sensitivity to the current front-line chemotherapy. The current therapeutic strategies for treating KRAS mutant CRC, the difficulties and challenges will also be discussed.

Liver metastases

Liver metastases are commonly detected in a range of malignancies including colorectal cancer (CRC), pancreatic cancer, melanoma, lung cancer and breast cancer, although CRC is the most common primary cancer that metastasizes to the liver. Interactions between tumour cells and the tumour microenvironment play an important part in the engraftment, survival and progression of the metastases. Various cells including liver sinusoidal endothelial cells, Kupffer cells, hepatic stellate cells, parenchymal hepatocytes, dendritic cells, resident natural killer cells as well as other immune cells such as monocytes, macrophages and neutrophils are implicated in promoting and sustaining metastases in the liver. Four key phases (microvascular, pre-angiogenic, angiogenic and growth phases) have been identified in the process of liver metastasis. Imaging modalities such as ultrasonography, CT, MRI and PET scans are typically used for the diagnosis of liver metastases. Surgical resection remains the main potentially curative treatment among patients with resectable liver metastases. The role of liver transplantation in the management of liver metastasis remains controversial. Systemic therapies, newer biologic agents (for example, bevacizumab and cetuximab) and immunotherapeutic agents have revolutionized the treatment options for liver metastases. Moving forward, incorporation of genetic tests can provide more accurate information to guide clinical decision-making and predict prognosis among patients with liver metastases.

Recurrence Patterns After Resection of Colorectal Liver Metastasis are Modified by Perioperative Systemic Chemotherapy

BACKGROUND

This study investigated the impact of perioperative systemic chemotherapy on the recurrence rate and pattern following resection of colorectal liver metastases.

METHODS

A retrospective cohort study was conducted in two centers. Rates and patterns of recurrence and overall survival (OS) were compared between patients treated with and without perioperative systemic chemotherapy. The clinical risk score (CRS) was used to stratify patients in low risk (CRS 0-2) and high risk (CRS 3-5) of recurrence.

RESULTS

A total of 2020 patients were included, of whom 1442 (71%) received perioperative systemic chemotherapy. The median follow-up was 88 months, and 1289 patients (64%) developed a recurrence. The recurrence pattern was independent of chemotherapy in low-risk patients: intrahepatic recurrences (30% vs. 30%, p = 0.97) and extrahepatic recurrences (38% vs. 39%, p = 0.52). In high-risk patients, no difference in intrahepatic recurrences was found (48% vs. 50%, p = 0.59). However, a lower rate of extrahepatic recurrences (43% vs. 55%, p = 0.007) was observed with perioperative systemic chemotherapy, mainly due to a reduction in pulmonary recurrences (25% vs. 35%, p = 0.007). In competing risk analysis, the cumulative incidence of extrahepatic recurrence was significantly lower with perioperative systemic chemotherapy in high-risk patients only (5-year cumulative incidence 44% vs. 59%, p < 0.001). Perioperative chemotherapy was associated with improved OS in high-risk patients (adjusted HR 0.73, 95% CI 0.57-0.94, p = 0.02), but not in low-risk patients (adjusted HR 0.99, 95% CI 0.82-1.19, p = 0.90).

CONCLUSIONS

Perioperative systemic chemotherapy had no association with intrahepatic recurrence, but was associated with fewer pulmonary recurrences and superior OS in high-risk patients only.

Impact and clinical usefulness of genetic data in the surgical management of colorectal cancer liver metastasis: a narrative review

Importance

In patients who undergo surgery for colorectal cancer liver metastases (CRLM), a number of somatic mutations have been associated with worse overall (OS) and recurrence-free survival (RFS). Although useful, an association with prognosis does not necessarily equate to an impact on surgical management.

Objective

The aim of this review was to investigate whether the best-studied somatic mutations impact surgical management of CRLM by informing: (I) post-hepatectomy surveillance; (II) selection of surgical technique; (III) selection of optimal margin width; and (IV) selection of patients for surgery. Lastly, we discuss the refinement of genetic data from overall mutation status to specific variants, as well as lesser studied somatic mutations.

Evidence Review

We conducted a computerized search using PubMed and Google Scholar for reports published so far, using mesh headings and keywords related to genetic data and CRLM.

Findings

Genetic data may impact surgical management of CRLM in three ways. Firstly, KRAS mutations can predict lung recurrences. Secondly, KRAS mutations may help tailor margin width. Thirdly, KRAS mutations may help tailor surgical technique.

Conclusions

Although genetic data may impact post-hepatectomy surveillance, selection of surgical technique and optimal margin width, their use to guide surgical selection remains elusive, as the data cannot support denying surgery to patients according to their somatic mutation profile.

BRAF Mutation in Colorectal Cancers: From Prognostic Marker to Targetable Mutation

Simple Summary

Colorectal cancer with a mutation in an oncogene BRAF has paid much attention, as it comprises a population with dismal prognosis since two decades ago. A series of research since then has successfully changed this malignancy to be treatable with specific treatment. Here we thoroughly overviewed the basic, translational and clinical studies on colorectal cancer with BRAF mutation from a physician’s viewpoint. Accumulating lines of evidence suggest that intervention of the trunk cellular growth signal transduction pathway, namely EGFR-RAS-RAF-MEK-ERK pathway, is a clue to controlling this disease. However, it is not so straightforward. Recent studies unveil the diverse and plastic nature of this signal transduction pathway. We will introduce our endeavor to conquer this condition, based on newly arriving datasets, and discuss how we could open the door to future development of CRC treatment.

Abstract

The Raf murine sarcoma viral oncogene homolog B (BRAF) mutation is detected in 8–12% of metastatic colorectal cancers (mCRCs) and is strongly correlated with poor prognosis. The recent success of the BEACON CRC study and the development of targeted therapy have led to the determination of BRAF-mutated mCRCs as an independent category. For nearly two decades, a growing body of evidence has established the significance of the BRAF mutation in the development of CRC. Herein, we overview both basic and clinical data relevant to BRAF-mutated CRC, mainly focusing on the development of treatment strategies. This review is organized into eight sections, including clinicopathological features, molecular features, prognosis, the predictive value of anti-epidermal growth factor receptor (EGFR) therapy, resistant mechanisms for BRAF-targeting treatment, the heterogeneity of the BRAF mutation, future perspectives, and conclusions. A characterization of the canonical mitogen-activated protein kinase (MAPK) pathway is essential for controlling this malignancy, and the optimal combination of multiple interventions for treatments remains a point of debate.

Colorectal liver metastases: Current management and future perspectives

The liver is the commonest site of metastatic disease for patients with colorectal cancer, with at least 25% developing colorectal liver metastases (CRLM) during the course of their illness. The management of CRLM has evolved into a complex field requiring input from experienced members of a multi-disciplinary team involving radiology (cross sectional, nuclear medicine and interventional), Oncology, Liver surgery, Colorectal surgery, and Histopathology. Patient management is based on assessment of sophisticated clinical, radiological and biomarker information. Despite incomplete evidence in this very heterogeneous patient group, maximising resection of CRLM using all available techniques remains a key objective and provides the best chance of long-term survival and cure. To this end, liver resection is maximised by the use of downsizing chemotherapy, optimisation of liver remnant by portal vein embolization, associating liver partition and portal vein ligation for staged hepatectomy, and combining resection with ablation, in the context of improvements in the functional assessment of the future remnant liver. Liver resection may safely be carried out laparoscopically or open, and synchronously with, or before, colorectal surgery in selected patients. For unresectable patients, treatment options including systemic chemotherapy, targeted biological agents, intra-arterial infusion or bead delivered chemotherapy, tumour ablation, stereotactic radiotherapy, and selective internal radiotherapy contribute to improve survival and may convert initially unresectable patients to operability. Currently evolving areas include biomarker characterisation of tumours, the development of novel systemic agents targeting specific oncogenic pathways, and the potential re-emergence of radical surgical options such as liver transplantation.

Intestinal adenosquamous carcinoma with a synchronous skin metastasis: a immunohistochemical and molecular analysis

INTRODUCTION

Intestinal adenosquamous carcinoma (ASC) is a rare colorectal neoplasm frequently occurring at onset as a locally advanced disease with distant metastases. The liver is the most common site of metastasis, followed by the peritoneum and the lung. Cutaneous metastases from usual colorectal adenocarcinoma occur in about 3% of cases, both at the time of diagnosis in advanced disease and during the follow-up. To the best of our knowledge, skin metastasis from ASC has never been described, and no biological landscape of ASC has ever been investigated.

METHODS

We report a case of synchronous intestinal ASC and cutaneous single facial metastasis in a 70-year-old man with morphological, immunohistochemical, and molecular analysis of primary and metastatic lesions.

RESULTS

Primary and metastatic ASC showed the same morphological and immunohistochemical features. Target sequencing analysis revealed, both in primary tumor and metastasis, a pathogenic KRAS gene missense mutation c.38G > A p.(Gly13Asp) and a likely pathogenic CTNNB1 gene missense mutation c.94G > A p.(Asp32Asn). A nuclear localization of β-catenin protein in adenocarcinomatous component of primary and metastatic lesions was observed on immunohistochemistry.

CONCLUSION

We describe a case of single synchronous facial cutaneous metastasis from intestinal ASC showing KRAS and CTNN1B mutations both on primary and metastatic lesions.

Biomarker-guided therapy for colorectal cancer: strength in complexity

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

Gene mutation and surgical technique: Suggestion or more?

Advancements in chemotherapy and molecular targeted therapy have improved long-term outcomes for patients with resectable colorectal liver metastases (CLM). RAS mutation status was an original focus as a molecular biomarker as it predicted treatments response to anti-epidermal growth factor receptor agents. More recently, studies have incorporated somatic mutation data in analyses pertaining to surgical outcomes and prognosis. This evidenced-based review covers the implications of somatic mutations in patients undergoing resection of CLM.

Nomogram predicted disease free survival for colorectal liver metastasis patients with preoperative chemotherapy followed by hepatic resection

BACKGROUND

Hepatic resection is regarded to as a potentially curative option for colorectal cancer liver metastases (CRLM), but it is associated with a high rate of recurrence. The present study intended to establish an effective nomogram to predict disease free survival (DFS) and select candidates of hepatic resection.

METHODS

The nomogram was based on a retrospective study on 447 CRLM patients treated with preoperative chemotherapy followed by hepatic resection using a multicentric database between January 1st, 2010 and December 31st, 2017. Results were validated using bootstrap resampling on 117 patients. The predictive accuracy and discriminative ability of the nomogram were determined by concordance index (C-index) and calibration curve. Overall survival, disease free survival, and local recurrence rate for patients with colorectal cancer were measured.

RESULTS

Based on multivariate analysis of the primary cohort, independent factors for DFS included tumor size larger than 5 cm, multiple liver metastases(>1), RAS mutation, primary lymph node metastasis and tumor size increase after preoperative chemotherapy. These five factors were all considered in the nomogram. The C-index of the nomogram for predicting survival was 0.675. With external validation, the C-index of the nomogram for the prediction of the DFS was 0.77, which demonstrated that this model has a good level of discriminative ability. For the 382 patients (66.7%) who developed recurrence, the optimal cutoff point for early recurrence was determined to be 12 months after hepatic resection.

CONCLUSIONS

The proposed nomogram demonstrated accurate prognostic prediction of DFS for CRLM patients with preoperative chemotherapy followed by hepatic resection.

Association between KRAS G13D mutations and anastomotic recurrence in colorectal cancer: Two case reports

RATIONALE

The prevalence of anastomotic recurrence (AR) in colorectal cancer (CRC) after resection of the primary tumor (PT) is 5% to 14%. However, no association has been observed between specific somatic genetic alterations and AR. Such associations may shed light on the mechanism of AR.

PATIENT CONCERNS

We experienced 2 patients with AR of CRC. The first patient was a 42-year-old woman who underwent resection of an AR of rectal cancer 2 times within 19 months after resection of the PT. The second patient was a 77-year-old woman who underwent resection of an AR of ascending colon cancer twice within 38 months after resection of the PT.

DIAGNOSIS

Both cases were diagnosed as repetitive AR.

INTERVENTIONS

Loss of heterozygosity analysis, microsatellite instability (MSI) study of 9 microsatellite loci, and mutational analysis of KRAS, BRAF, APC, TP53, and SMAD4 were performed.

OUTCOMES

All the lesions, except 1, harbored mutations in APC, KRAS, and TP53, without MSI, after neoadjuvant chemoradiotherapy. The APC, KRAS, and TP53 mutations were pathogenic or likely pathogenic in the PTs and ARs. Both women harbored the same KRAS G13D mutation, which accounts for 8% of all KRAS mutations in sporadic CRC s. The probability of the incidental occurrence of KRAS G13D mutations in both cases is 0.64%, provided that the mutations were independent of AR.

LESSONS

Our findings may shed light on the mechanism of AR in CRC, namely, that the PT harbored the same mutations as the AR and the lesions in both cases harbored the KRAS G13D mutation.

Mutation status and surgical selection

Current evidence cannot support denying metastasectomy in otherwise resectable patients solely based on their overall KRAS or BRAF mutational status. The combination of KRAS or BRAF mutational status with certain clinicopathologic characteristics has defined groups of patients who may not derive benefit from metastasectomy, but external validation is needed. The effect of certain KRAS or BRAF variants on survival may be more pronounced and therefore future studies should consider them for surgical selection.

The value of KRAS gene status in predicting local tumor progression of colorectal liver metastases following radiofrequency ablation

PURPOSE

We investigated the relationships between KRAS gene status and local tumor progression (LTP) of colorectal liver metastases (CLMs) after treatment with percutaneous ultrasound-guided radiofrequency ablation (RFA).

MATERIALS AND METHODS

Clinical and imaging data from 76 patients (154 lesions) with CLM who underwent percutaneous ultrasound-guided RFA and had KRAS gene test results between January 2012 and June 2016 were analyzed. The average lesion size was 2.3 ± 1.0 cm (range 0.9-5.7 cm); 38 cases (82 lesions) had wild-type KRAS, and 38 cases (72 lesions) had KRAS mutations.

RESULTS

The technique effectiveness was 98.1% (151/154), and the LTP rate was 18.2% (28/154) after RFA, which was performed between January 2012 and November 2017. The mean and median follow-up were 32.7 ± 2.5 and 32.0 ± 2.6 months (range 1-70 months), respectively. Cumulative LTP rates at 6 months and 1, 2 and 3 years post-RFA for all patients were 7.4, 14.5, 17.8 and 19.2%, respectively. The LTP rate for patients with mutant KRAS (27.8% [20/72]) was significantly higher than that in patients with wild-type KRAS (9.8% [8/82]; p = .004). The cumulative LTP rates at 6 months and 1, 2 and 3 years post-RFA were 4.0, 11.1, 11.1 and 11.1%, respectively, for patients with wild-type KRAS and 11.2, 18.4, 25.2 and 36.2%, respectively, for patient with mutant KRAS (p = .011). Univariate (p = .011) and multivariate analyses (p = .005) showed that KRAS genotype in liver metastases was predictive of LTP. Multivariate analysis also showed that ablation margin size (p< .001) and modified clinical risk score (CRS; p = .033) were independent prognostic factors for LTP.

CONCLUSIONS

KRAS gene status of liver metastatic lesions was associated with LTP rates after RFA of CLM. Ablation margin size and modified CRS were also independent prognostic factors for LTP.

The prognosis of colorectal cancer liver metastases associated with inflammatory bowel disease: An exploratory analysis

BACKGROUND AND OBJECTIVES

In contrast with sporadic colorectal cancer liver metastases (CRLM), inflammatory bowel disease (IBD)-related CRLM have not been studied to date.

METHODS

Patients who underwent resection for IBD-related and sporadic CRLM from 2000 to 2015 were identified from an international registry and matched for pertinent prognostic variables. Overall survival (OS) and recurrence-free survival (RFS) were subsequently assessed.

RESULTS

Twenty-eight patients had IBD-related CRLM. Synchronous extrahepatic disease was more common in IBD-related CRLM patients than patients with sporadic CRLM (28.6% vs 8.3%; P < 0.001), most commonly located in the lungs. In multivariable analysis, IBD did not have a significant influence on OS ( P = 0.835), and had a hazard ratio (HR) close to 1 (HR, 0.95; 95% confidence interval [CI], 0.57-1.57). IBD was also not associated with inferior RFS (HR, 1.07; 95%CI, 0.68-1.68; P = 0.780). Among patients with IBD-related CRLM, 9(50%) had isolated intrahepatic recurrence and 8(44.4%) isolated extrahepatic recurrence, while only 1(5.6%) developed combined recurrence. Of those who experienced recurrence after resection of IBD-related CRLM, 10 had their recurrence treated with curative intent.

CONCLUSIONS

Patients with IBD-related CRLM had similar survival compared with patients with sporadic CRLM, even though they more often present with extrahepatic disease. In addition, patients with IBD-related CRLM may experience patterns of recurrence different from patients with sporadic CRLM.

Associations between primary tumor RAS, BRAF and PIK3CA mutation status and metastatic site in patients with chemo-resistant metastatic colorectal cancer

BACKGROUND

Several studies have investigated correlations between metastatic pattern and mutation status in patients with colorectal cancer (CRC). However, most of the studies were small and heterogeneously designed and further research is needed to confirm previous results. In this study, we investigated the association between RAS (KRAS or NRAS), BRAF, PIK3CA mutations and metastatic pattern in patients with metastatic (m) CRC.

MATERIAL AND METHODS

This study reviewed Danish biobank and database of patients with mCRC who received cetuximab and irinotecan, independent of RAS mutation status, after fluoropyrimidine, oxaliplatin and irinotecan treatment failure. The database contained information regarding tumor mutation status of KRAS, NRAS, BRAF and PIK3CA genes.

RESULTS

Totally, 448 patients were included. On multivariate analyses, RAS mutations were significantly associated with increased odds of having lung metastases at diagnosis of mCRC (odds ratio (OR) = 2.04; 95% confidence interval (CI) = 1.32-3.17), and PIK3CA mutations with decreased odds of peritoneal metastases at diagnosis of mCRC (OR = 0.10; 95%CI = 0.01-0.79). On multivariate analyses of the hazard of developing metastases at any time during follow-up, RAS mutations were significantly associated with increased hazard of lung (hazard ratio (HR) = 1.34; 95%CI = 1.04-1.72) and ovarian metastases (HR = 3.12; 95%CI = 1.05-9.24), BRAF V600E mutation was associated with increased hazard of skin metastases (HR = 6.82; 95%CI = 1.86-25.02) and PIK3CA mutations with decreased hazard of peritoneal metastases (HR = 0.31; 95%CI = 0.11-0.86).

CONCLUSIONS

This study indicated that in patients with mCRC, RAS mutations are associated with increased risk of lung and ovary metastases. BRAF V600E is associated with increased risk of skin metastases, and PIK3CA mutation with decreased risk of peritoneal metastases.

Association of BRAF Mutations With Survival and Recurrence in Surgically Treated Patients With Metastatic Colorectal Liver Cancer

Importance

BRAF mutations are reportedly associated with aggressive tumor biology. However, in contrast with primary colorectal cancer, the association of V600E and non-V600E BRAF mutations with survival and recurrence after resection of colorectal liver metastases (CRLM) has not been well studied.

Objective

To investigate the prognostic association of BRAF mutations with survival and recurrence independently and compared with other prognostic determinants, such as KRAS mutations.

Design, Setting, and Participants

In this cohort study, all patients who underwent resection for CRLM with curative intent from January 1, 2000, through December 31, 2016, at the institutions participating in the International Genetic Consortium for Colorectal Liver Metastasis and had data on BRAF and KRAS mutational status were retrospectively identified. Multivariate Cox proportional hazards regression models were used to assess long-term outcomes.

Interventions

Hepatectomy in patients with CRLM.

Main Outcomes and Measures

The association of V600E and non-V600E BRAF mutations with disease-free survival (DFS) and overall survival (OS).

Results

Of 853 patients who met inclusion criteria (510 men [59.8%] and 343 women [40.2%]; mean [SD] age, 60.2 [12.4] years), 849 were included in the study analyses. Forty-three (5.1%) had a mutated (mut) BRAF/wild-type (wt) KRAS (V600E and non-V600E) genotype; 480 (56.5%), a wtBRAF/wtKRAS genotype; and 326 (38.4%), a wtBRAF/mutKRAS genotype. Compared with the wtBRAF/wtKRAS genotype group, patients with a mutBRAF/wtKRAS genotype more frequently were female (27 [62.8%] vs 169 [35.2%]) and 65 years or older (22 [51.2%] vs 176 [36.9%]), had right-sided primary tumors (27 [62.8%] vs 83 [17.4%]), and presented with a metachronous liver metastasis (28 [64.3%] vs 229 [46.8%]). On multivariable analysis, V600E but not non-V600E BRAF mutation was associated with worse OS (hazard ratio [HR], 2.76; 95% CI, 1.74-4.37; P < .001) and DFS (HR, 2.04; 95% CI, 1.30-3.20; P = .002). The V600E BRAF mutation had a stronger association with OS and DFS than the KRAS mutations (β for OS, 10.15 vs 2.94; β for DFS, 7.14 vs 2.27).

Conclusions and Relevance

The presence of the V600E BRAF mutation was associated with worse prognosis and increased risk of recurrence. The V600E mutation was not only a stronger prognostic factor than KRAS but also was the strongest prognostic determinant in the overall cohort.

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.

Common KRAS and NRAS gene mutations in sporadic colorectal cancer in Northeastern Iranian patients

OBJECTIVES

Mutation analysis of the Epidermal Growth Factor Receptor downstream has been a main part of colorectal carcinoma evaluation. Large prospective clinical trials have shown only colorectal cancer (CRC) with wild-type KRAS and NRAS responds to anti-Epidermal Growth Factor Receptor treatment. Hence, mutation analysis is necessary prior to treatment. It is essential to conduct studies to learn about the mutation signature of such tumors. The aim of this study was to evaluate the frequency of hotspot mutations in KRAS and NRAS genes in Iranian CRC patients and to explore their correlations with clinicopathologic parameters.

METHODS

We detected mutations in exon 2 (codons 12 and 13) of the KRAS and NRAS genes using high resolution melting analysis, Intplex design and Sanger sequencing in 87 Iranian CRC patients. Genomic DNA was isolated from fresh tissue samples of CRC patients.

RESULTS

From 87 eligible cases, 51 were male and 36 were females. KRAS mutations in codons 12 and 13 were present in 28.7% of all analyzed CRCs. Our findings suggested that the tumors with KRAS mutations are not with well- and moderately differentiated tumors compared to poorly differentiated tumors (P value = 0.32). The most frequent types of mutations were glycine to aspartate on codon 12 (p.G12D), and glycine to aspartate on codon 13 (p.G13D). No mutation was found in the NRAS gene in our patients.

CONCLUSIONS

Based on this study, the frequency of KRAS mutations seems to be in the spectrum of frequencies of other countries such as China, Japan, India, USA, France, and Germany and NRAS was similar to the West of Iran.

Genetic And Morphological Evaluation (GAME) score for patients with colorectal liver metastases

BACKGROUND

This study sought to develop a clinical risk score for resectable colorectal liver metastasis (CRLM) by combining clinicopathological and clinically available biological indicators, including KRAS.

METHODS

A cohort of patients who underwent resection for CRLM at the Johns Hopkins Hospital (JHH) was analysed to identify independent predictors of overall survival (OS) that can be assessed before operation; these factors were combined into the Genetic And Morphological Evaluation (GAME) score. The score was compared with the current standard (Fong score) and validated in an external cohort of patients from the Memorial Sloan Kettering Cancer Center (MSKCC).

RESULTS

Six preoperative predictors of worse OS were identified on multivariable Cox regression analysis in the JHH cohort (502 patients). The GAME score was calculated by allocating points to each patient according to the presence of these predictive factors: KRAS-mutated tumours (1 point); carcinoembryonic antigen level 20 ng/ml or more (1 point), primary tumour lymph node metastasis (1 point); Tumour Burden Score between 3 and 8 (1 point) or 9 and over (2 points); and extrahepatic disease (2 points). The high-risk group in the JHH cohort (GAME score at least 4 points) had a 5-year OS rate of 11 per cent, compared with 73·4 per cent for those in the low-risk group (score 0-1 point). Importantly, in cohorts from both the JHH and MSKCC (747 patients), the discriminatory capacity of the GAME score was superior to that of the Fong score, as demonstrated by the C-index and the Akaike information criterion.

CONCLUSION

The GAME score is a preoperative prognostic tool that can be used to inform treatment selection.

Mutations in KRAS codon 12 predict poor survival in Chinese patients with metastatic colorectal cancer

KRAS mutations serve a function in tumorigenesis of colorectal cancer (CRC) and guide the use of targeted drugs. However, the prognostic value of KRAS mutations and their subtypes remain controversial. The present study aimed to investigate the correlations between KRAS mutations and clinicopathological characteristics, and their prognostic significance in Chinese patients with metastatic CRC (mCRC). A total of 135 patients with mCRC were analyzed for KRAS mutations. Mutations in codon 12 and 13 were identified in 45 (33.3%) patients. Only 3 patients harbored a mutation of V600E. Compared with male patients, KRAS codon 12 mutations were more common in female patients (P<0.05). KRAS codon 13 mutations tended to arise in right-sided compared with left-sided colon cancer (P<0.05). Survival analysis was performed in 101 patients receiving primary tumor resection. Compared with KRAS codon 12 wild-type, codon 12 mutations were markedly correlated with a poorer survival (log-rank P=0.002). No prognostic significance was revealed in codon 13 mutations. In univariate analysis, mortality risk was significantly increased by subtypes of G12D and G12V [hazard ratio (HR) =2.313, 95% confidence interval (CI) =1.069-5.004, P=0.03; HR=2.621, 95% CI=1.057-6.497, P=0.04, respectively]. The results of the present study suggested that codon 12 mutations, in particular G12D and G12V, predicted a negative prognosis in Chinese patients with mCRC. These findings require further confirmation via prospective studies with larger samples.

Impact of RAS Mutations in Metastatic Colorectal Cancer After Potentially Curative Resection: Does Site of Metastases Matter?

BACKGROUND

RAS mutation status is an important prognostic factor after resection of liver metastases (LiM) from colorectal cancer (CRC). The prognostic significance of RAS after resection of lung (LuM) and peritoneal (PM) metastases from CRC is unknown.

METHODS

Between 2005 and 2014, all consecutive patients with known RAS status who underwent potentially curative resection for LiM, LuM, or PM were evaluated.

RESULTS

A total of 720 patients with known RAS status underwent resection of LiM (n = 468), LuM (n = 102), and PM (n = 150). RAS mutations were identified in 63 and 58% of patients with LuM and PM, respectively, compared with 41% of patients with LiM (p < 0.001). Five-year overall survival (OS) after resection of PM was 45%, compared with 52% after resection of LiM (p = 0.018) and 64% after resection of LuM (p = 0.005). RAS mutations were associated with significantly worse OS after resection of LiM (p < 0.001), but did not affect OS among patients undergoing resection of LuM (p = 0.41) and PM (p = 0.65).

CONCLUSIONS

RAS mutations are more prevalent among patients undergoing resection of LuM and PM than LiM but do not affect survival after lung and peritoneal metastasectomy, as they do after hepatectomy. These results suggest that the prognostic significance of RAS mutations after resection of metastatic CRC depends on the specific site of metastases.

Anatomical Resections Improve Disease-free Survival in Patients With KRAS-mutated Colorectal Liver Metastases

OBJECTIVE

To investigate the potential clinical advantage of anatomical resection versus nonanatomical resection for colorectal liver metastases, according to KRAS mutational status.

BACKGROUND

KRAS-mutated colorectal liver metastases (CRLM) are known to be more aggressive than KRAS wild-type tumors. Although nonanatomical liver resections have been demonstrated as a viable approach for CRLM patients with similar oncologic outcomes to anatomical resections, this may not be the case for the subset of KRAS-mutated CRLM.

METHODS

389 patients who underwent hepatic resection of CRLM with known KRAS mutational status were identified. Survival estimates were calculated using the Kaplan-Meier method, and multivariable analysis was conducted using the Cox proportional hazards regression model.

RESULTS

In this study, 165 patients (42.4%) underwent nonanatomical resections and 140 (36.0%) presented with KRAS-mutated CRLM. Median disease-free survival (DFS) in the entire cohort was 21.3 months, whereas 1-, 3-, and 5-year DFS was 67.3%, 34.9%, and 31.5% respectively. Although there was no difference in DFS between anatomical and nonanatomical resections in patients with KRAS wild-type tumors (P = 0.142), a significant difference in favor of anatomical resection was observed in patients with a KRAS mutation (10.5 vs. 33.8 months; P < 0.001). Five-year DFS was only 14.4% in the nonanatomically resected group, versus 46.4% in the anatomically resected group. This observation persisted in multivariable analysis (hazard ratio: 0.45; 95% confidence interval: 0.27-0.74; P = 0.002), when corrected for number of tumors, bilobar disease, and intraoperative ablations.

CONCLUSIONS

Nonanatomical tissue-sparing hepatectomies are associated with worse DFS in patients with KRAS-mutated tumors. Because of the aggressive nature of KRAS-mutated CRLM, more extensive anatomical hepatectomies may be warranted.

Can molecular biomarkers replace a clinical risk score for resectable colorectal liver metastasis?

In resectable colorectal liver metastasis (CRLM) the role and use of molecular biomarkers is still controversial. Several biomarkers have been linked to clinical outcomes in CRLM, but none have so far become routine for clinical decision making. For several reasons, the clinical risk score appears to no longer hold the same predictive value. Some of the reasons include the ever expanding indications for liver resection, which now increasingly tend to involve extrahepatic disease, such as lung metastases (both resectable and non-resectable) and the shift in indication from “what is taken out” (e.g., how much liver has to be resected) to “what is left behind” (that is, how much functional liver tissue the patient has after resection). The latter is amenable to modifications by using adjunct techniques of portal vein embolization and the associating liver partition and portal vein ligation for staged hepatectomy techniques to expand indications for liver resection. Added to this complexity is the increasing number of molecular markers, which appear to hold important prognostic and predictive information, for which some will be discussed here. Beyond characteristics of tissue-based genomic profiles will be liquid biopsies derived from circulating tumor cells and cell-free circulating tumor DNA in the blood. These markers are present in the peripheral circulation in the majority of patients with metastatic cancer disease. Circulating biomarkers may represent more readily available methods to monitor, characterize and predict cancer biology with future implications for cancer care.

The prognostic implications of primary colorectal tumor location on recurrence and overall survival in patients undergoing resection for colorectal liver metastasis

BACKGROUND AND OBJECTIVES

The prognostic impact of primary colorectal cancer (CRC) location following resection of colorectal liver metastasis (CRLM) remains largely unknown. We sought to characterize the prognostic implications of primary tumor location among patients who underwent curative-intent hepatectomy for CRLM.

METHODS

Tumors of the cecum, ascending, and transverse colon were defined as right-sided; tumors of the sigmoid flexure, descending, and sigmoid colon were defined as left-sided. Clinicopathologic and long-term survival data were collected and assessed using univariable and multivariable analyses.

RESULTS

About 475 patients who underwent CRLM resection at a single institution were included; most patients had left-sided tumors (n = 284). Median and 5-year RFS was 20.2 months and 28.0%, respectively. Patients who had a left-sided primary tumor had a shorter RFS compared with patients who had a right-sided tumor (P = 0.01). Although site of and time to recurrence did not differ between the two groups (P > 0.05), patients with right-sided primary tumors were more likely to recur with advanced disease (i.e., ≥4 recurrent lesions) (P < 0.01). In turn, patients with right-sided tumors had both worse OS (P = 0.03) and worse survival after recurrence (P = 0.01).

CONCLUSION

While patients with right-sided tumors experienced longer RFS, when these patients did recur following CRLM resection, disease extent was more advanced. In turn, OS following recurrence was shorter among patients with right-sided CRC. J. Surg. Oncol. 2016;114:803-809. © 2016 2016 Wiley Periodicals, Inc.