Performance and cost efficiency of KRAS mutation testing for metastatic colorectal cancer in routine diagnosis: the MOKAECM study, a nationwide experience

Outcome of Patients With Resected Early-Stage Non-small Cell Lung Cancer and EGFR Mutations: Results From the IFCT Biomarkers France Study

INTRODUCTION

Molecular profile of resected stage I-II non-small cell lung cancer (NSCLC) would help refine prognosis and personalize induction or adjuvant strategies. We sought to report the molecular profile of resected stage I-II NSCLC and analyzed the impact of epidermal growth factor receptor (EGFR) mutations on outcomes in a Western population.

PATIENTS AND METHODS

Surgical cases were identified from Biomarkers France study, a nationwide prospective study including NSCLC patients screened for EGFR, HER2, KRAS, BRAF, PIK3CA, ALK alterations from 2012 to 2013. Among surgical patients, clinical charts of the largest centers were reviewed in order to analyze the prognostic impact of EGFR mutations.

RESULTS

In the BMF database (n = 17.636), surgical patients (n = 854) were characterized by a higher proportion of EGFR mutations than nonsurgical patients (12.9% vs. 10.2%, P = .025), while the other molecular alterations did not differ. The proportion of EGFR mutations was 27% in women undergoing surgery. In the study group (n = 293; EGFR wild type, n = 235; usual mutation, n = 50; rare mutation, n = 8), after a median follow-up of 67 months, 215 patients (74.4%) had not relapsed. No difference was found between EGFR-mutant and EGFR-wt tumors regarding recurrence site, disease-free survival, and overall survival. The 5-year disease-free survival and overall survival after surgical resection of stage I-II EGFR-mutated tumors were 65% and 75%, respectively.

CONCLUSION

In resected stage I to II NSCLC, EGFR mutations were found in 12.9% of cases, associated with a 5-year overall survival of 75%, with no impact on recurrence site, disease-free survival, and overall survival.

Deep Neural Network for the Prediction of KRAS Genotype in Rectal Cancer

BACKGROUND

KRAS mutation can alter the treatment plan after resection of colorectal cancer. Despite its importance, the KRAS status of several patients remains unchecked because of the high cost and limited resources. This study developed a deep neural network (DNN) to predict the KRAS genotype using hematoxylin and eosin (H&E)-stained histopathological images.

STUDY DESIGN

Three DNNs were created (KRAS_Mob, KRAS_Shuff, and KRAS_Ince) using the structural backbone of the MobileNet, ShuffleNet, and Inception networks, respectively. The Cancer Genome Atlas was screened to extract 49,684 image tiles that were used for deep learning and internal validation. An independent cohort of 43,032 image tiles was used for external validation. The performance was compared with humans, and a virtual cost-saving analysis was done.

RESULTS

The KRAS_Mob network (area under the receiver operating curve [AUC] 0.8, 95% CI 0.71 to 0.89) was the best-performing model for predicting the KRAS genotype, followed by the KRAS_Shuff (AUC 0.73, 95% CI 0.62 to 0.84) and KRAS_Ince (AUC 0.71, 95% CI 0.6 to 0.82) networks. Combing the KRAS_Mob and KRAS_Shuff networks as a double prediction approach showed improved performance. KRAS_Mob network accuracy surpassed that of two independent pathologists (AUC 0.79 [95% CI 0.64 to 0.93], 0.51 [95% CI 0.34 to 0.69], and 0.51 (95% CI 0.34 to 0.69]; p < 0.001 for all comparisons).

CONCLUSION

The DNN has the potential to predict the KRAS genotype directly from H&E-stained histopathological slide images. As an algorithmic screening method to prioritize patients for laboratory confirmation, such a model might possibly reduce the number of patients screened, resulting in significant test-related time and economic savings.

Next-Generation Sequencing Targeted Panel in Routine Care for Metastatic Colon Cancers

Simple Summary

The place of Next-Generation-Sequencing (NGS) targeted panel in routine practice in digestive oncology should be addressed. The aim of our retrospective study was to assess the results and impact of NGS panel for metastatic colorectal cancer (mCRC) patients. In total, 210 patients with mCRC were included. Based on our findings, a major advantage of the NGS panel over single gene techniques is that, beyond the classical hotspots, it allows for an exhaustive search for molecular abnormalities in routinely recommended genes. In addition, routine NGS is a way to detect amplifications associated with resistance to anti-EGFR therapies and low-prevalence mutations in actionable genes, providing patients with the opportunity to access innovative targeted therapies. In conclusion, NGS targeted panel in mCRC is feasible in routine practice. Nevertheless, panels need to be regularly updated and in-depth studies are needed to better analyse the prognostic factors.

Abstract

In digestive oncology, the clinical impact of targeted next-generation sequencing (NGS) in routine practice should be addressed. In this work, we studied the impact of a 22-gene NGS amplicon-based panel with Ion Torrent Proton Sequencing, prospectively performed in routine practice. We analyzed the results of extended molecular testing, beyond RAS and BRAF, in metastatic colorectal cancer (mCRC) patients in a single-center, retrospective, observational study of consecutive mCRC patients followed up at the Georges Pompidou European Hospital between January 2016 and December 2018. Overall, 210 patients with mCRC were included. Median follow-up was 25.4 months (IQR: 14.9–39.5). The three most frequently mutated genes were: TP53 (63%), KRAS (41%) and PIK3CA (19%). A positive association was found between overall survival and performance status (PS) ≥ 2 (HR: 4.91 (1.84–13.1); p = 0.001) and differentiation (HR: 4.70 (1.51–14.6); p = 0.007) in multivariate analysis. The NGS panel enabled five patients to access a targeted therapy not currently registered for CRC. In conclusion, targeted NGS panels in mCRC are feasible in routine practice, but need to be regularly updated and in-depth studies are needed to better analyze the prognostic factors.

RAS mutation analysis in circulating tumor DNA from patients with metastatic colorectal cancer: the AGEO RASANC prospective multicenter study

Background

RAS mutations are currently sought for in tumor samples, which takes a median of almost 3 weeks in western European countries. This creates problems in clinical situations that require urgent treatment and for inclusion in therapeutic trials that need RAS status for randomization. Analysis of circulating tumor DNA might help to shorten the time required to determine RAS mutational status before anti-epidermal growth factor receptor antibody therapy for metastatic colorectal cancer. Here we compared plasma with tissue RAS analysis in a large prospective multicenter cohort.

Patients and methods

Plasma samples were collected prospectively from chemotherapy-naive patients and analyzed centrally by next-generation sequencing (NGS) with the colon lung cancer V2 Ampliseq panel and by methylation digital PCR (WIF1 and NPY genes). Tumoral RAS status was determined locally, in parallel, according to routine practice. For a minimal κ coefficient of 0.7, reflecting acceptable concordance (precision ± 0.07), with an estimated 5% of non-exploitable data, 425 subjects were necessary.

Results

From July 2015 to December 2016, 425 patients were enrolled. For the 412 patients with available paired plasma and tumor samples, the κ coefficient was 0.71 [95% confidence interval (CI), 0.64-0.77] and accuracy was 85.2% (95% CI, 81.4% to 88.5%). In the 329 patients with detectable ctDNA (at least one mutation or one methylated biomarker), the κ coefficient was 0.89 (95% CI, 0.84-0.94) and accuracy was 94.8% (95% CI, 91.9% to 97.0%). The absence of liver metastases was the main clinical factor associated with inconclusive circulating tumor DNA results [odds ratio = 0.11 (95% CI, 0.06-0.21)]. In patients with liver metastases, accuracy was 93.5% with NGS alone and 97% with NGS plus the methylated biomarkers.

Conclusion

This prospective trial demonstrates excellent concordance between RAS status in plasma and tumor tissue from patients with colorectal cancer and liver metastases, thus validating plasma testing for routine RAS mutation analysis in these patients.

Clinical Trial registration

Clinicaltrials.gov, NCT02502656.

Validity of Targeted Next-Generation Sequencing in Routine Care for Identifying Clinically Relevant Molecular Profiles in Non-Small-Cell Lung Cancer: Results of a 2-Year Experience on 1343 Samples

Theranostic assays are based on single-gene testing, but the ability of next-generation sequencing (NGS) to interrogate numerous genetic alterations will progressively replace single-gene assays. Although NGS was evaluated to screen for theranostic mutations, its usefulness in clinical practice on large series of samples remains to be demonstrated. NGS performance was assessed following guidelines. TaqMan probes and NGS were compared for their ability to detect EGFR and KRAS mutations, and NGS mutation profiles were analyzed on a large series of non-small-cell lung cancers (n = 1343). The R² correlation between expected and measured allelic ratio, using commercial samples, was >0.96. Mutation detection threshold was 2% for 10 ng of DNA input. κ Scores for TaqMan versus NGS were 0.99 (95% CI, 0.97-1.00) for EGFR and 0.98 (95% CI, 0.97-1.00) for KRAS after exclusion of rare EGFR (n = 40) and KRAS (n = 60) mutations. NGS identified 693 and 292 mutations in validated and potential oncogenic drivers, respectively. Significant associations were found between EGFR and PI3KCA or CTNNB1 and between KRAS and STK11. Potential oncogenic driver mutations or gene amplifications were more frequent in validated oncogenic driver nonmutated samples. This work is a proof of concept that targeted NGS is accessible in routine screening, including large screening, at reasonable cost. Clinical data should be collected and implemented in specific databases to make molecular data meaningful for direct patients' benefit.

The clinical effectiveness and cost-effectiveness of cetuximab (review of technology appraisal no. 176) and panitumumab (partial review of technology appraisal no. 240) for previously untreated metastatic colorectal cancer: a systematic review and economic evaluation

BACKGROUND

Colorectal cancer is the fourth most commonly diagnosed cancer in the UK after breast, lung and prostate cancer. People with metastatic disease who are sufficiently fit are usually treated with active chemotherapy as first- or second-line therapy. Targeted agents are available, including the antiepidermal growth factor receptor (EGFR) agents cetuximab (Erbitux^®, Merck Serono UK Ltd, Feltham, UK) and panitumumab (Vecitibix^®, Amgen UK Ltd, Cambridge, UK).

OBJECTIVE

To investigate the clinical effectiveness and cost-effectiveness of panitumumab in combination with chemotherapy and cetuximab in combination with chemotherapy for rat sarcoma (RAS) wild-type (WT) patients for the first-line treatment of metastatic colorectal cancer.

DATA SOURCES

The assessment included a systematic review of clinical effectiveness and cost-effectiveness studies, a review and critique of manufacturer submissions, and a de novo cohort-based economic analysis. For the assessment of effectiveness, a literature search was conducted up to 27 April 2015 in a range of electronic databases, including MEDLINE, EMBASE and The Cochrane Library.

REVIEW METHODS

Studies were included if they were randomised controlled trials (RCTs) or systematic reviews of RCTs of cetuximab or panitumumab in participants with previously untreated metastatic colorectal cancer with RAS WT status. All steps in the review were performed by one reviewer and checked independently by a second. Narrative synthesis and network meta-analyses (NMAs) were conducted for outcomes of interest. An economic model was developed focusing on first-line treatment and using a 30-year time horizon to capture costs and benefits. Costs and benefits were discounted at 3.5% per annum. Scenario analyses and probabilistic and univariate deterministic sensitivity analyses were performed.

RESULTS

The searches identified 2811 titles and abstracts, of which five clinical trials were included. Additional data from these trials were provided by the manufacturers. No data were available for panitumumab plus irinotecan-based chemotherapy (folinic acid + 5-fluorouracil + irinotecan) (FOLFIRI) in previously untreated patients. Studies reported results for RAS WT subgroups. First-line treatment with anti-EGFR therapies in combination with chemotherapy appeared to have statistically significant benefits for patients who are RAS WT. For the independent economic evaluation, the base-case incremental cost-effectiveness ratio (ICER) for RAS WT patients for cetuximab plus oxaliplatin-based chemotherapy (folinic acid + 5-fluorouracil + oxaliplatin) (FOLFOX) compared with FOLFOX was £104,205 per quality-adjusted life-year (QALY) gained; for panitumumab plus FOLFOX compared with FOLFOX was £204,103 per QALY gained; and for cetuximab plus FOLFIRI compared with FOLFIRI was £122,554 per QALY gained. The ICERs were sensitive to treatment duration, progression-free survival, overall survival (resected patients only) and resection rates.

LIMITATIONS

The trials included RAS WT populations only as subgroups. No evidence was available for panitumumab plus FOLFIRI. Two networks were used for the NMA and model, based on the different chemotherapies (FOLFOX and FOLFIRI), as insufficient evidence was available to the assessment group to connect these networks.

CONCLUSIONS

Although cetuximab and panitumumab in combination with chemotherapy appear to be clinically beneficial for RAS WT patients compared with chemotherapy alone, they are likely to represent poor value for money when judged by cost-effectiveness criteria currently used in the UK. It would be useful to conduct a RCT in patients with RAS WT.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42015016111.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Cost-effectiveness of KRAS, EGFR and ALK testing for decision making in advanced nonsmall cell lung carcinoma: the French IFCT-PREDICT.amm study

ALK rearrangement and EGFR/KRAS mutations constitute the primary biomarkers tested to provide targeted or nontargeted therapies in advanced nonsmall cell lung cancer (NSCLC) patients. Our objective was to assess the cost-effectiveness of biomarker testing for NSCLC.

Between 2013 and 2014, 843 treatment-naive patients were prospectively recruited at 19 French hospitals into a longitudinal observational cohort study. Two testing strategies were compared, i.e. with “at least one biomarker status known” and “at least KRAS status known”, in addition to “no biomarker testing” as the reference strategy. The Kaplan–Meier approach was employed to assess restricted mean survival time. Direct medical costs incurred by hospitals were estimated with regard to treatment, inpatient care and biomarker testing.

Compared with “no biomarker testing”, the “at least one biomarker status known” strategy yielded an incremental cost-effectiveness ratio of EUR13 230 per life-year saved, which decreased to EUR7444 per life-year saved with the “at least KRAS status known” testing strategy. In sensitivity analyses, biomarker testing strategies were less costly and more effective in 41% of iterations.

In summary, molecular testing prior to treatment initiation proves to be cost-effective in advanced NSCLC management and may assist decision makers in defining conditions for further implementation of these innovations in general practice.

[Detection of RAS genes mutation using the Cobas® method in a private laboratory of pathology: Medical and economical study in comparison to a public platform of molecular biology of cancer]

In France, determination of the mutation status of RAS genes for predictive response to anti-EGFR targeted treatments is carried out by public platforms of molecular biology of cancer created by the French National Cancer Institute. This study aims to demonstrate the feasibility of these analyses by a private pathology laboratory (MEDIPATH) as per the requirements of accreditation. We retrospectively studied the mutation status of KRAS and NRAS genes in 163 cases of colorectal metastatic cancer using the Cobas^® technique. We compared our results to those prospectively obtained through pyrosequencing and allelic discrimination by the genetic laboratory of solid tumors at the Nice University Hospital (PACA-EST regional platform). The results of both series were identical: 98.7% positive correlation; negative correlation of 93.1%; overall correlation of 95.7% (Kappa=0.92). This study demonstrates the feasibility of molecular analysis in a private pathology laboratory. As this practice requires a high level of guarantee, its accreditation, according to the NF-EN-ISO15189 quality compliance French standard, is essential. Conducting molecular analysis in this context avoids the steps of routing the sample and the result between the pathology laboratory and the platform, which reduces the overall time of rendering the result. In conclusion, the transfer of some analysis from these platforms to private pathology laboratories would allow the platforms to be discharged from a part of routine testing and therefore concentrate their efforts to the development of new analyses constantly required to access personalized medicine.

Clinical Outcomes of Patients with Rare and Heavily Pretreated Solid Tumors Treated according to the Results of Tumor Molecular Profiling

Patients with heavily pretreated advanced cancer or with rare tumors are difficult to treat. Molecular profiling (MP) of tumors to identify biomarkers that predict potential outcomes with individual therapies is an emerging strategy to guide treatment decisions. Patients with rare tumors for which standard-of-care therapy was unavailable or more common tumors for which standard-of-care options had been exhausted underwent MP at a single Australian center. Data regarding treating physicians' choice of therapy, MP results and recommendations, and patient outcomes were collected. Seven patients had received prior standard first-line therapy (PST), 16 had rare tumors, and 31 had been heavily pretreated (HPT; ≥2 prior lines). Most treatments suggested by MP (541/594; 91.1%) were common chemotherapy drugs available in generic formulations. MP-guided therapy recommendations differed from physician's recommendations in 48 patients (88.9%). MP-guided therapy produced clinical benefit (improved QOL and/or performance status, symptoms, bodyweight, or RECIST) in 19/31 (61.3%), 11/16 (68.8%), and 3/7 (42.9%) patients with HPTs, rare tumors, and PSTs, respectively, and had a PFS ratio ≥1.3 in 22/37 evaluable patients (59.5%; 95% confidence interval 44–76%). The null hypothesis that ≤15% of these patients would have a PFS ratio ≥1.3 was rejected (one-sided p < 0.0001). In conclusion, using MP to guide therapy selection is feasible in clinical practice and may improve patient outcomes.

Enabling Equal Access to Molecular Diagnostics: What Are the Implications for Policy and Health Technology Assessment?

Molecular diagnostics can offer important benefits to patients and are a key enabler of the integration of personalised medicine into health care systems. However, despite their promise, few molecular diagnostics are embedded into clinical practice (especially in Europe) and access to these technologies remains unequal across countries and sometimes even within individual countries. If research translation and the regulatory environments have proven to be more challenging than expected, reimbursement and value assessment remain the main barriers to providing patients with equal access to molecular diagnostics. Unclear or non-existent reimbursement pathways, together with the lack of clear evidence requirements, have led to significant delays in the assessment of molecular diagnostics technologies in certain countries. Additionally, the lack of dedicated diagnostics budgets and the siloed nature of resource allocation within certain health care systems have significantly delayed diagnostics commissioning. This article will consider the perspectives of different stakeholders (patients, health care payers, health care professionals, and manufacturers) on the provision of a research-enabled, patient-focused molecular diagnostics platform that supports optimal patient care. Through the discussion of specific case studies, and building on the experience from countries that have successfully integrated molecular diagnostics into clinical practice, this article will discuss the necessary evolutions in policy and health technology assessment to ensure that patients can have equal access to appropriate molecular diagnostics.

Routine molecular profiling of patients with advanced non-small-cell lung cancer: results of a 1-year nationwide programme of the French Cooperative Thoracic Intergroup (IFCT)

BACKGROUND

The molecular profiling of patients with advanced non-small-cell lung cancer (NSCLC) for known oncogenic drivers is recommended during routine care. Nationally, however, the feasibility and effects on outcomes of this policy are unknown. We aimed to assess the characteristics, molecular profiles, and clinical outcomes of patients who were screened during a 1-year period by a nationwide programme funded by the French National Cancer Institute.

METHODS

This study included patients with advanced NSCLC, who were routinely screened for EGFR mutations, ALK rearrangements, as well as HER2 (ERBB2), KRAS, BRAF, and PIK3CA mutations by 28 certified regional genetics centres in France. Patients were assessed consecutively during a 1-year period from April, 2012, to April, 2013. We measured the frequency of molecular alterations in the six routinely screened genes, the turnaround time in obtaining molecular results, and patients' clinical outcomes. This study is registered with ClinicalTrials.gov, number NCT01700582.

FINDINGS

18,679 molecular analyses of 17,664 patients with NSCLC were done (of patients with known data, median age was 64·5 years [range 18-98], 65% were men, 81% were smokers or former smokers, and 76% had adenocarcinoma). The median interval between the initiation of analysis and provision of the written report was 11 days (IQR 7-16). A genetic alteration was recorded in about 50% of the analyses; EGFR mutations were reported in 1947 (11%) of 17,706 analyses for which data were available, HER2 mutations in 98 (1%) of 11,723, KRAS mutations in 4894 (29%) of 17,001, BRAF mutations in 262 (2%) of 13,906, and PIK3CA mutations in 252 (2%) of 10,678; ALK rearrangements were reported in 388 (5%) of 8134 analyses. The median duration of follow-up at the time of analysis was 24·9 months (95% CI 24·8-25·0). The presence of a genetic alteration affected first-line treatment for 4176 (51%) of 8147 patients and was associated with a significant improvement in the proportion of patients achieving an overall response in first-line treatment (37% [95% CI 34·7-38·2] for presence of a genetic alteration vs 33% [29·5-35·6] for absence of a genetic alteration; p=0·03) and in second-line treatment (17% [15·0-18·8] vs 9% [6·7-11·9]; p<0·0001). Presence of a genetic alteration was also associated with improved first-line progression-free survival (10·0 months [95% CI 9·2-10·7] vs 7·1 months [6·1-7·9]; p<0·0001) and overall survival (16·5 months [15·0-18·3] vs 11·8 months [10·1-13·5]; p<0·0001) compared with absence of a genetic alteration.

INTERPRETATION

Routine nationwide molecular profiling of patients with advanced NSCLC is feasible. The frequency of genetic alterations, acceptable turnaround times in obtaining analysis results, and the clinical advantage provided by detection of a genetic alteration suggest that this policy provides a clinical benefit.

FUNDING

French National Cancer Institute (INCa).

RAS testing in metastatic colorectal cancer: advances in Europe

Personalized medicine shows promise for maximizing efficacy and minimizing toxicity of anti-cancer treatment. KRAS exon 2 mutations are predictive of resistance to epidermal growth factor receptor-directed monoclonal antibodies in patients with metastatic colorectal cancer. Recent studies have shown that broader RAS testing (KRAS and NRAS) is needed to select patients for treatment. While Sanger sequencing is still used, approaches based on various methodologies are available. Few CE-approved kits, however, detect the full spectrum of RAS mutations. More recently, "next-generation" sequencing has been developed for research use, including parallel semiconductor sequencing and reversible termination. These techniques have high technical sensitivities for detecting mutations, although the ideal threshold is currently unknown. Finally, liquid biopsy has the potential to become an additional tool to assess tumor-derived DNA. For accurate and timely RAS testing, appropriate sampling and prompt delivery of material is critical. Processes to ensure efficient turnaround from sample request to RAS evaluation must be implemented so that patients receive the most appropriate treatment. Given the variety of methodologies, external quality assurance programs are important to ensure a high standard of RAS testing. Here, we review technical and practical aspects of RAS testing for pathologists working with metastatic colorectal cancer tumor samples. The extension of markers from KRAS to RAS testing is the new paradigm for biomarker testing in colorectal cancer.

Eprobe-mediated screening system for somatic mutations in the KRAS locus

Activating mutations in the Kirsten rat sarcoma viral oncogene homolog (KRAS) loci are largely predictive of resistance to epidermal growth factor receptor (EGFR) therapy in colorectal cancer (CRC). A highly sensitive detection system for the KRAS gene mutations is urgently needed; however, conventional methods have issues with feasibility and cost performance. Here, we describe a novel detection system using a fluorescence ‘Eprobe’ capable of detecting low level KRAS gene mutations, via real-time PCR, with high sensitivity and simple usability. We designed our Eprobes to be complementary to wild-type (WT) KRAS or to the commonly mutated codons 12 and 13. The WT Eprobe binds strongly to the WT DNA template and suppresses amplification by blocking annealing of the primer during PCR. Eprobe-PCR with WT Eprobe shows high sensitivity (0.05–0.1% of plasmid DNA, 1% of genomic DNA) for the KRAS mutation by enrichment of the mutant type (MT) amplicon. Assay performance was compared to Sanger sequencing using 92 CRC samples. Discrepancies were analyzed by mutation genotyping via Eprobe-PCR with full match Eprobes for 7 prevalent mutations and the next generation sequencing (NGS). Significantly, the Eprobe system had a higher sensitivity for detecting KRAS mutations in CRC patient samples; these mutations could not be identified by Sanger sequencing. Thus, the Eprobe approach provides for highly sensitive and convenient mutation detection and should be useful for diagnostic applications.

Prognostic value of KRAS mutations in stage III colon cancer: post hoc analysis of the PETACC8 phase III trial dataset

BACKGROUND

The prognostic value of KRAS mutations in colon adenocarcinoma is controversial. We examined this question as an ancillary study of the PETACC8 phase III trial.

PATIENTS AND METHODS

We analyzed the prognostic impact of KRAS exon 2 mutations in stage III colon cancer patients (n = 1657) receiving adjuvant FOLFOX ± cetuximab therapy included in the PETACC8 trial. Patients with BRAF-mutated cancers were excluded and, as no difference was found for time to recurrence (TTR) and disease-free survival (DFS) between treatment arms, both were pooled for analysis. Associations with TTR and DFS were analyzed using a Cox proportional hazards model.

RESULTS

KRAS mutations were found in 638 of 1657 tumors and linked to shorter TTR (P < 0.001). However, when specific mutations were compared with wild-type, codon 12 mutations [hazard ratio (HR) 1.67, 95% confidence interval (CI) 1.35-2.04; P < 0.001] but not codon 13 (HR 1.23, 95% CI 0.85-1.79; P = 0.26) were significantly associated with shorter TTR, independently of other covariates. The interaction test showed that, regarding tumor location (distal versus proximal), KRAS genotype affects differently on recurrence (P = 0.02) and DFS (P = 0.042). Subgroup analysis showed that KRAS only affected TTR and DFS in distal tumors (n = 1043; 692 wild type; 351 mutated), with an increased risk of relapse (HR 1.96, 95% CI 1.51-2.56; P < 0.0001) for KRAS codon 12 mutations and a borderline significance for codon 13 mutations (HR 1.59, 95% CI 1.00-2.56; P = 0.051).

CONCLUSION

KRAS exon 2 mutations are independent predictors of shorter TTR in patients with resected stage III distal colon cancers receiving adjuvant therapy. Future clinical trials in the adjuvant setting should consider both the tumor location and KRAS mutations as important stratification factors.

CLINICAL TRIAL NUMBER

This is an ancillary study of the PETACC8 trial: EUDRACT 2005-003463-23.

Improvement of the quality of BRAF testing in melanomas with nationwide external quality assessment, for the BRAF EQA group

Background

Knowledge about tumour gene mutation status is essential for the treatment of increasing numbers of cancer patients, and testing quality has a major impact on treatment response and cost. In 2012, 4,629 tests for BRAF p.V600 were performed in France, in patients with melanomas.

Methods

Two batches of unstained melanoma sections were sent, in May and November 2012, to the 46 laboratories supported by the French National Institute of Cancer (INCa). An external quality assessment (EQA) evaluated mutation status, response times and compliance with INCa recommendations.

Results

All the French laboratories involved in testing participated in the EQA. Fourteen different methods were used to detect BRAF mutations, most consisting of combinations of in-house techniques. False responses were noted in 25/520 cases (4.8%), 11 of which concerned confusion between p.V600E and p.V600K. Thus, 2.7% of responses would have led to inappropriate treatment. Within six months, mean response times decreased from 22 to 12 days (P<0.001), and the percentage of samples evaluated by a pathologist for tumour cell content increased, from 75.2% to 96.9% (P<0.001).

Conclusion

Despite the use of non-certified methods, the false response rate was low. Nationwide EQA can improve the quality of molecular pathology tests on tumours.