KRAS mutation in patients undergoing hepatic resection for colorectal liver metastasis: a biomarker of cancer biology or a byproduct of patient selection?

Histopathological Growth Pattern in Colorectal Liver Metastasis and The Tumor Immune Microenvironment

Almost half of all patients with colorectal cancer present with or eventually develop metastasis, most frequently in the liver. Understanding the histopathological growth patterns and tumor immune microenvironment of colorectal liver metastases may help determine treatment strategies and assess prognosis. A literature search was conducted to gather information on cancer biology, histopathological growth patterns, and the tumor immune microenvironment in colorectal liver metastases, including their mechanisms and their impact on clinical outcomes. A first consensus on histopathological growth patterns emerged in 2017, identifying five growth patterns. Later studies found benefits from a two-tier system, desmoplastic and non-desmoplastic, incorporated into the updated 2022 consensus. Furthermore, the tumor immune microenvironment shows additional characteristic features with relevance to cancer biology. This includes density of T-cells (CD8+), expression of claudin-2, presence of vessel co-option versus angiogenesis, as well as several other factors. The relation between histopathological growth patterns and the tumor immune microenvironment delineates distinct subtypes of cancer biology. The distinct subtypes are found to correlate with risk of metastasis or relapse, and hence to clinical outcome and long-term survival in each patient. In order to optimize personalized and precision therapy for patients with colorectal liver metastases, further investigation into the mechanisms of cancer biology and their translational aspects to novel treatment targets is warranted.

Limited Prognostic Value of KRAS in Patients Undergoing Hepatectomy for Colorectal Liver Metastases

BACKGROUND

RAS mutation status is considered a powerful prognostic factor in patients undergoing hepatectomy for colorectal liver metastases (CLM). However, whether its prognostic power is robust regardless of administration of preoperative chemotherapy or tumor burden remains unclear.

METHODS

Consecutive patients who underwent initial hepatectomy for CLM from April 2010 through March 2017 in two hospitals were included. The prognostic value of KRAS was compared based on whether patients received preoperative chemotherapy and their tumor burden score (TBS).

RESULTS

We included 409 patients (median follow-up 38 months). In the preoperative chemotherapy group, patients with mutant KRAS (mt-KRAS) CLM had poorer overall survival (OS) than those with wild KRAS (wt-KRAS; 5-year OS: 37.7% vs 53.8%, p = 0.024), although their OS was not different from patients undergoing upfront surgery. Similarly, patients with mt-KRAS had poorer OS than those with wt-KRAS in TBS of 3-9 (5-year OS: 33.1% vs 63.2%, p = 0.001), although their OS was not different from patients with TBS < 3 or ≥ 9. In multivariate analysis, mt-KRAS was an independent prognostic factor of OS among patients receiving preoperative chemotherapy (hazard ratio [HR] 1.61, 95% confidence interval [CI]: 1.034-2.491; p = 0.035) and patients with TBS of 3-9 (HR 1.836, 95% CI 1.176-2.866; p = 0.008). However, it was not a prognostic factor in patients who underwent upfront surgery or with TBS > 3 or ≥ 9.

CONCLUSIONS

In patients undergoing hepatectomy for CLM, the prognostic value of KRAS depends on their history of preoperative chemotherapy or tumor burden.

Preoperative nomogram to predict survival following colorectal cancer liver metastasis simultaneous resection

Background

Simultaneous resection for patients with synchronous colorectal cancer liver metastases (CRLM) remains an optimal option for the sake of curability. However, few studies so far focus on outcome of this subgroup of patients (who receive simultaneous resection for CRLM). Substantial heterogeneity exists among such patients and more precise categorization is needed preoperatively to identify those who may benefit more from surgery. In this study, we formulated this internally validated scoring system as an option.

Methods

Clinicopathological and follow-up data of 234 eligible CRLM patients undergoing simultaneous resection from January 2010 to March 2019 in our center were included for analysis. Patients were randomized to either a training or validation cohort. We performed multivariable Cox regression analysis to determine preoperative factors with prognostic significance using data in training cohort, and a nomogram scoring system was thus established. Time-dependent receiver operating characteristic (ROC) curve and calibration plot were adopted to evaluate the predictive power of our risk model.

Results

In the multivariable Cox regression analysis, five factors including presence of node-positive primary defined by enhanced CT/MR, preoperative CEA level, primary tumor location, tumor grade and number of liver metastases were identified as independent prognostic indicators of overall survival (OS) and adopted to formulate the nomogram. In the training cohort, calibration plot graphically showed good fitness between estimated and actual 1- and 3-year OS. Time-dependent ROC curve by Kaplan-Meier method showed that our nomogram model was superior to widely used Fong's score in prediction of 1- and 3-year OS (AUC 0.702 vs. 0.591 and 0.848 vs. 0.801 for 1- and 3-year prediction in validation cohort, respectively). Kaplan-Meier curves for patients stratified by the assessment of nomogram showed great discriminability (P<0.001).

Conclusions

In this retrospective analysis we identified several preoperative factors affecting survival of synchronous CRLM patients undergoing simultaneous resection. We also constructed and validated a risk model which showed high accuracy in predicting 1- and 3-year survival after surgery. Our risk model is expected to serve as a predictive tool for CRLM patients receiving simultaneous resection and assist physicians to make treatment decision.

Genomic stratification beyond Ras/B-Raf in colorectal liver metastasis patients treated with hepatic arterial infusion

Background

Resection of colorectal liver metastases (CLM) can cure disease, but many patients with extensive disease cannot be fully resected and others recur following surgery. Hepatic arterial infusion (HAI) chemotherapy can convert extensive liver disease to a resectable state or decrease recurrence risk, but response varies and no biomarkers currently exist to identify patients most likely to benefit.

Methods

We performed a retrospective cohort study of CLM patients receiving HAI chemotherapy whose tumors underwent MSK‐IMPACT sequencing. The frequency of oncogenic alterations and their association with overall survival (OS) and objective response rate were analyzed at the individual gene and signaling pathway levels.

Results

Three hundred and seventy patients met inclusion criteria: 189 (51.1%) who underwent colorectal liver metastasectomy followed by HAI + systemic therapy (Adjuvant cohort), and 181 (48.9%) with unresectable CLM (Metastatic cohort) who received HAI + systemic therapy, consisting of 63 (34.8%) with extrahepatic disease and 118 (65.2%) with liver‐restricted disease. Genomic alterations were similar in each cohort, and no individual gene or pathway was significantly associated with objective response. Patients in the adjuvant cohort with concurrent Ras/B‐Raf alteration and SMAD4 inactivation had worse prognosis while in the metastatic cohort patients with co‐alteration of Ras/B‐Raf and TP53 had worse OS. Similar findings were observed in a validation cohort.

Conclusions

Concurrently altered Ras/B‐Raf and SMAD4 mutations were associated with worse survival in resectable patients, while concurrent Ras/B‐Raf and TP53 alterations were associated with worse survival in unresectable patients. The mutual exclusivity of Ras/B‐Raf, SMAD4, and TP53 may have prognostic value for CLM patients receiving HAI.

Multimodality Treatment of a Colorectal Cancer Stage IV Patient with FOLFOX-4, Bevacizumab, Rigvir Oncolytic Virus, and Surgery

Colorectal cancer is one of the most commonly diagnosed cancers worldwide. The treatment consists of surgical resection, systemic chemotherapy, and new biological agents. One more recently emerging treatment option is oncolytic virotherapy. Although the use of the new treatment methods shows improved overall and progression-free survival, in general, even with the new treatments, mortality remains high and combinations of treatments should be sought to treat patients with colorectal cancer. Here we report a stage IV colorectal cancer patient who received multimodality treatment including bevacizumab, FOLFOX-4, surgery, and the oncolytic virus Rigvir. The patient shows complete pathological remission and remains stable 7.7 years after initial diagnosis. The possible benefits of combining Rigvir oncolytic virus and bevacizumab should be investigated since in vitro research suggests that anti-angiogenesis agents improve viral distribution by altering the microenvironment of the tumor.

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.

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.

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.

Assessment of clinically related outcomes and biomarker analysis for translational integration in colorectal cancer (ACROBATICC): study protocol for a population-based, consecutive cohort of surgically treated colorectal cancers and resected colorectal liver metastasis

Background

More accurate predictive and prognostic biomarkers for patients with colorectal cancer (CRC) primaries or colorectal liver metastasis (CLM) are needed. Outside clinical trials, the translational integration of emerging pathways and novel techniques should facilitate exploration of biomarkers for improved staging and prognosis.

Methods

An observational study exploring predictive and prognostic biomarkers in a population-based, consecutive cohort of surgically treated colorectal cancers and resected colorectal liver metastases. Long-term outcomes will be cancer-specific survival, recurrence-free survival and overall survival at 5 years from diagnosis. Beyond routine clinicopathological and anthropometric characteristics and laboratory and biochemistry results, the project allows for additional blood samples and fresh-frozen tumour and normal tissue for investigation of circulating tumour cells (CTCs) and novel biomarkers (e.g. immune cells, microRNAs etc.). Tumour specimens will be investigated by immunohistochemistry in full slides. Extracted DNA/RNA will be analysed for genomic markers using specific PCR techniques and next-generation sequencing (NGS) panels. Flow cytometry will be used to characterise biomarkers in blood. Collaboration is open and welcomed, with particular interest in mutual opportunities for validation studies.

Status and perspectives

The project is ongoing and recruiting at an expected rate of 120–150 patients per year, since January 2013. A project on circulating tumour cells (CTCs) has commenced, with analysis being prepared. Investigating molecular classes beyond the TNM staging is under way, including characteristics of microsatellite instability (MSI) and elevated microsatellite alterations in selected tetranucleotides (EMAST). Hot spot panels for known mutations in CRC are being investigated using NGS. Immune-cell characteristics are being performed by IHC and flow cytometry in tumour and peripheral blood samples. The project has ethical approval (REK Helse Vest, #2012/742), is financially supported with a Ph.D.-Grant (EMAST project; Folke Hermansen Cancer Fund) and a CTC-project (Norwegian Research Council; O. Nordgård). The ACROBATICC clinical and molecular biobank repository will serve as a long-term source for novel exploratory analysis and invite collaborators for mutual validation of promising biomarker results. The project aims to generate results that can help better discern prognostic groups in stage II/III cancers; explore prognostic and predictive biomarkers, and help detail the biology of colorectal liver metastasis for better patient selection and tailored treatment. The project is registered at http://www.ClinicalTrials.gov NCT01762813.

The prognostic yield of biomarkers harvested in chemotherapy-naive stage II colon cancer: can we separate the wheat from the chaff?

The TNM-system fails to accurately predict disease recurrence in a considerate number of patients. While node-negative (stage II) colon cancer is considered to have an overall good prognosis, the 5-year cancer-specific survival is reported at 81-83% in patients who did not have adjuvant chemotherapy. Thus, reliance on node-status alone has lead to under-treatment in a subgroup of stage II patients with an unfavorable prognosis. The search for new and better prognosticators in stage II colon cancer has suggested several proposed biomarkers of better prognostication and prediction. However, few such biomarkers have reached widespread clinical utility. For the clinician swimming in the sea of emerging biomarkers, it may be hard to recognize the true floating aid from the surrounding debris in the search for more precise decision-making. Proposed markers include microsatellite instability (MSI), KRAS mutations and BRAF mutations, but a number of gene panels and consensus molecular subtypes are proposed for clinical prediction and prognostication as well. While several studies suggest such biomarkers or panels to have a prognostic role in subgroups of patients, a number of studies are reported in heterogeneous groups with in part discordant findings, which again distorts the predictive and prognostic ability of each marker. Lack of homogeneous cohorts, underpowered studies in strict subgroups and challenges in analytical and clinical validity may hamper the progress towards widespread clinical utility. The harvest of prognostic biomarkers in colon cancer has yielded a huge number of candidates for which it is now time to separate the wheat from the chaff.

Codon 13 KRAS mutation predicts patterns of recurrence in patients undergoing hepatectomy for colorectal liver metastases

BACKGROUND

Investigations regarding the impact of tumor biology after surgical management of colorectal liver metastasis have focused largely on overall survival. We investigated the impact of codon-specific KRAS mutations on the rates and patterns of recurrence in patients after surgery for colorectal liver metastasis (CRLM).

METHODS

All patients who underwent curative-intent surgery for CRLM between 2002 and 2015 at Johns Hopkins who had available data on KRAS mutation status were identified. Clinico-pathologic data, recurrence patterns, and recurrence-free survival (RFS) were assessed using univariable and multivariable analyses.

RESULTS

A total of 512 patients underwent resection only (83.2%) or resection plus radiofrequency ablation (16.8%). Although 5-year overall survival was 64.6%, 284 (55.5%) patients recurred with a median RFS time of 18.1 months. The liver was the initial recurrence site for 181 patients, whereas extrahepatic recurrence was observed in 162 patients. Among patients with an extrahepatic recurrence, 102 (63%) had a lung recurrence. Although overall KRAS mutation was not associated with overall RFS (P = 0.186), it was independently associated with a worse extrahepatic (P = 0.004) and lung RFS (P = 0.007). Among patients with known KRAS codon-specific mutations, patients with codon 13 KRAS mutation had a worse 5-year extrahepatic RFS (P = 0.01), whereas codon 12 mutations were not associated with extrahepatic (P = 0.11) or lung-specific recurrence rate (P = 0.24). On multivariable analysis, only codon 13 mutation independently predicted worse overall extrahepatic RFS (P = 0.004) and lung-specific RFS (P = 0.023).

CONCLUSIONS

Among patients undergoing resection of CRLM, overall KRAS mutation was not associated with RFS. KRAS codon 13 mutations, but not codon 12 mutations, were associated with a higher risk for overall extrahepatic recurrence and lung-specific recurrence. Cancer 2016. © 2016 American Cancer Society. Cancer 2016;122:2698-2707. © 2016 American Cancer Society.

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.