Hubert Piessevaux

Effects of KRAS, BRAF, NRAS, and PIK3CA mutations on the efficacy of cetuximab plus chemotherapy in chemotherapy-refractory metastatic colorectal cancer: a retrospective consortium analysis

BACKGROUND Following the discovery that mutant KRAS is associated with resistance to anti-epidermal growth factor receptor (EGFR) antibodies, the tumours of patients with metastatic colorectal cancer are now profiled for seven KRAS mutations before receiving cetuximab or panitumumab. However, most patients with KRAS wild-type tumours still do not respond. We studied the effect of other downstream mutations on the efficacy of cetuximab in, to our knowledge, the largest cohort to date of patients with chemotherapy-refractory metastatic colorectal cancer treated with cetuximab plus chemotherapy in the pre-KRAS selection era. METHODS 1022 tumour DNA samples (73 from fresh-frozen and 949 from formalin-fixed, paraffin-embedded tissue) from patients treated with cetuximab between 2001 and 2008 were gathered from 11 centres in seven European countries. 773 primary tumour samples had sufficient quality DNA and were included in mutation frequency analyses; mass spectrometry genotyping of tumour samples for KRAS, BRAF, NRAS, and PIK3CA was done centrally. We analysed objective response, progression-free survival (PFS), and overall survival in molecularly defined subgroups of the 649 chemotherapy-refractory patients treated with cetuximab plus chemotherapy. FINDINGS 40.0% (299/747) of the tumours harboured a KRAS mutation, 14.5% (108/743) harboured a PIK3CA mutation (of which 68.5% [74/108] were located in exon 9 and 20.4% [22/108] in exon 20), 4.7% (36/761) harboured a BRAF mutation, and 2.6% (17/644) harboured an NRAS mutation. KRAS mutants did not derive benefit compared with wild types, with a response rate of 6.7% (17/253) versus 35.8% (126/352; odds ratio [OR] 0.13, 95% CI 0.07-0.22; p<0.0001), a median PFS of 12 weeks versus 24 weeks (hazard ratio [HR] 1.98, 1.66-2.36; p<0.0001), and a median overall survival of 32 weeks versus 50 weeks (1.75, 1.47-2.09; p<0.0001). In KRAS wild types, carriers of BRAF and NRAS mutations had a significantly lower response rate than did BRAF and NRAS wild types, with a response rate of 8.3% (2/24) in carriers of BRAF mutations versus 38.0% in BRAF wild types (124/326; OR 0.15, 95% CI 0.02-0.51; p=0.0012); and 7.7% (1/13) in carriers of NRAS mutations versus 38.1% in NRAS wild types (110/289; OR 0.14, 0.007-0.70; p=0.013). PIK3CA exon 9 mutations had no effect, whereas exon 20 mutations were associated with a worse outcome compared with wild types, with a response rate of 0.0% (0/9) versus 36.8% (121/329; OR 0.00, 0.00-0.89; p=0.029), a median PFS of 11.5 weeks versus 24 weeks (HR 2.52, 1.33-4.78; p=0.013), and a median overall survival of 34 weeks versus 51 weeks (3.29, 1.60-6.74; p=0.0057). Multivariate analysis and conditional inference trees confirmed that, if KRAS is not mutated, assessing BRAF, NRAS, and PIK3CA exon 20 mutations (in that order) gives additional information about outcome. Objective response rates in our series were 24.4% in the unselected population, 36.3% in the KRAS wild-type selected population, and 41.2% in the KRAS, BRAF, NRAS, and PIK3CA exon 20 wild-type population. INTERPRETATION While confirming the negative effect of KRAS mutations on outcome after cetuximab, we show that BRAF, NRAS, and PIK3CA exon 20 mutations are significantly associated with a low response rate. Objective response rates could be improved by additional genotyping of BRAF, NRAS, and PIK3CA exon 20 mutations in a KRAS wild-type population. FUNDING Belgian Federation against Cancer (Stichting tegen Kanker).

Association of KRAS p.G13D Mutation With Outcome in Patients With Chemotherapy-Refractory Metastatic Colorectal Cancer Treated With Cetuximab

CONTEXT Patients with metastatic colorectal cancer who have KRAS codon 12- or KRAS codon 13-mutated tumors are presently excluded from treatment with the anti-epidermal growth factor receptor monoclonal antibody cetuximab. OBJECTIVE To test the hypothesis that KRAS codon 13 mutations are associated with a better outcome after treatment with cetuximab than observed with other KRAS mutations. DESIGN, SETTING, AND PATIENTS We studied the association between KRAS mutation status (p.G13D vs other KRAS mutations) and response and survival in a pooled data set of 579 patients with chemotherapy-refractory colorectal cancer treated with cetuximab between 2001 and 2008. Patients were included in the CO.17, BOND, MABEL, EMR202600, EVEREST, BABEL, or SALVAGE clinical trials or received off-study treatment. Univariate and multivariate analyses, adjusting for possible prognostic factors and data set, were performed. The effect of the different mutations was studied in vitro by constructing isogenic cell lines with wild-type KRAS, p.G12V, or p.G13D mutant alleles and treating them with cetuximab. MAIN OUTCOME MEASURES The main efficacy end point was overall survival. Secondary efficacy end points were response rate and progression-free survival. RESULTS In comparison with patients with other KRAS-mutated tumors, patients with p.G13D-mutated tumors (n = 32) treated with cetuximab had longer overall survival (median, 7.6 [95% confidence interval {CI}, 5.7-20.5] months vs 5.7 [95% CI, 4.9-6.8] months; adjusted hazard ratio [HR], 0.50; 95% CI, 0.31-0.81; P = .005) and longer progression-free survival (median, 4.0 [95% CI, 1.9-6.2] months vs 1.9 [95% CI, 1.8-2.8] months; adjusted HR, 0.51; 95% CI, 0.32-0.81; P = .004). There was a significant interaction between KRAS mutation status (p.G13D vs other KRAS mutations) and overall survival benefit with cetuximab treatment (adjusted HR, 0.30; 95% CI, 0.14-0.67; P = .003). In vitro and mouse model analysis showed that although p.G12V-mutated colorectal cells were insensitive to cetuximab, p.G13D-mutated cells were sensitive, as were KRAS wild-type cells. CONCLUSIONS In this analysis, use of cetuximab was associated with longer overall and progression-free survival among patients with chemotherapy-refractory colorectal cancer with p.G13D-mutated tumors than with other KRAS-mutated tumors. Evaluation of cetuximab therapy in these tumors in prospective randomized trials may be warranted.

Endoscopic submucosal dissection: European Society of Gastrointestinal Endoscopy (ESGE) Guideline

UNLABELLED This Guideline is an official statement of the European Society of Gastrointestinal Endoscopy (ESGE). The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system 1 2 was adopted to define the strength of recommendations and the quality of evidence. MAIN RECOMMENDATIONS 1 ESGE recommends endoscopic en bloc resection for superficial esophageal squamous cell cancers (SCCs), excluding those with obvious submucosal involvement (strong recommendation, moderate quality evidence). Endoscopic mucosal resection (EMR) may be considered in such lesions when they are smaller than 10 mm if en bloc resection can be assured. However, ESGE recommends endoscopic submucosal dissection (ESD) as the first option, mainly to provide an en bloc resection with accurate pathology staging and to avoid missing important histological features (strong recommendation, moderate quality evidence). 2 ESGE recommends endoscopic resection with a curative intent for visible lesions in Barretts esophagus (strong recommendation, moderate quality evidence). ESD has not been shown to be superior to EMR for excision of mucosal cancer, and for that reason EMR should be preferred. ESD may be considered in selected cases, such as lesions larger than 15 mm, poorly lifting tumors, and lesions at risk for submucosal invasion (strong recommendation, moderate quality evidence). 3 ESGE recommends endoscopic resection for the treatment of gastric superficial neoplastic lesions that possess a very low risk of lymph node metastasis (strong recommendation, high quality evidence). EMR is an acceptable option for lesions smaller than 10 - 15 mm with a very low probability of advanced histology (Paris 0-IIa). However, ESGE recommends ESD as treatment of choice for most gastric superficial neoplastic lesions (strong recommendation, moderate quality evidence). 4 ESGE states that the majority of colonic and rectal superficial lesions can be effectively removed in a curative way by standard polypectomy and/or by EMR (strong recommendation, moderate quality evidence). ESD can be considered for removal of colonic and rectal lesions with high suspicion of limited submucosal invasion that is based on two main criteria of depressed morphology and irregular or nongranular surface pattern, particularly if the lesions are larger than 20 mm; or ESD can be considered for colorectal lesions that otherwise cannot be optimally and radically removed by snare-based techniques (strong recommendation, moderate quality evidence).

Clinical Usefulness of EGFR Gene Copy Number as a Predictive Marker in Colorectal Cancer Patients Treated with Cetuximab: A Fluorescent In situ Hybridization Study

Purpose: To evaluate the usefulness and the pitfalls inherent to the assessment of the epidermal growth factor receptor (EGFR) gene copy number (GCN) by fluorescence in situ hybridization (FISH) for outcome prediction to cetuximab in metastatic colorectal cancer. The value of testing KRAS mutation status, in addition to EGFR GCN, was also explored. Experimental Design: FISH analysis of 87 metastatic colorectal cancer patients treated with cetuximab was done, recording individual GCN per cell and using different samples per tumor. Performances of published cutoff points and different summaries of EGFR GCN distribution were assessed for response prediction. Results: In our data set, two published cutoff points performed less well than in their training set, yielding positive predictive values and negative predictive values between 40.0% and 48.3% and between 81.0% and 86.5%, respectively. Among summaries of GCN distribution explored, mean and right-tailed distribution of GCN yielded the highest performances. A mean EGFR GCN ≥2.83 provided an area under the curve of 0.71. Important heterogeneity of repeated measures of mean EGFR GCN was observed within tumors (intraclass correlation, 0.61; within-class SD, 0.40), leading to potential misclassifications of FISH status in 7 of 18 (38.8%) patients if a cutoff point were used. In multivariable analysis, EGFR GCN testing provided significant information independent of the KRAS status to predict response (P = 0.016) and overall survival (P = 0.005). Conclusions: We confirm the association between increased EGFR GCN and outcome after cetuximab. However, because of reproducibility concerns, any decision making based on published cutoff points is not warranted.

Stepwise radical endoscopic resection for eradication of Barrett's oesophagus with early neoplasia in a cohort of 169 patients

Background and Aims Endoscopic resection is safe and effective to remove early neoplasia (ie,high-grade intra-epithelial neoplasia/early cancer) in Barretts oesophagus. To prevent metachronous lesions during follow-up, the remaining Barretts oesophagus can be removed by stepwise radical endoscopic resection (SRER). The aim was to evaluate the combined experience in four tertiary referral centres with SRER to eradicate Barretts oesophagus with early neoplasia. Methods Design: Retrospective cohort study. Setting: Four tertiary referral centres. Participants: 169 patients (151 males, age 64 years (IQR 57–71), Barretts oesophagus 3 cm (IQR 2–5)) with early neoplasia in Barretts oesophagus ≤5 cm, without deep submucosal infiltration or lymph node metastases, treated by SRER between January 2000 and September 2006. Intervention: Endoscopic resection every 4–8 weeks, until complete endoscopic and histological eradication of Barretts oesophagus and neoplasia. Results According to intention-to-treat analysis complete eradication of all neoplasia and all intestinal metaplasia by the end of the treatment phase was reached in 97.6% (165/169) and 85.2% (144/169) of patients, respectively. One patient had progression of neoplasia during treatment and died of metastasised adenocarcinoma (0.6%). After median follow-up of 32 months (IQR 19–49), complete eradication of neoplasia and intestinal metaplasia was sustained in 95.3% (161/169) and 80.5% (136/169) of patients, respectively. Acute, severe complications occurred in 1.2% of patients, and 49.7% of patients developed symptomatic stenosis. Conclusions SRER of Barretts oesophagus ≤5 cm containing early neoplasia appears to be an effective treatment modality with a low rate of recurrent lesions during follow-up. The procedure, however, is technically demanding and is associated with oesophageal stenosis in half of the patients.

Magnesium wasting associated with epidermal-growth-factor receptor-targeting antibodies in colorectal cancer: a prospective study

BACKGROUND Preliminary evidence suggests that magnesium wasting occurs in patients who are treated with epidermal-growth-factor receptor (EGFR)-targeting antibodies for colorectal cancer. The mechanism of this side-effect is unknown, and if all or a subset of patients are affected is also unclear. We aimed to assess the incidence, characteristics, and predictive factors of magnesium wasting during treatment with EGFR-targeting antibodies, and to study the pathophysiology of this phenomenon. METHODS We measured prospectively magnesium concentrations in a cohort of 98 patients with colorectal cancer treated with EGFR-targeting antibodies with or without combined chemotherapy. The primary outcome measure was the slope of the serum magnesium concentrations over time. In 35 patients, 24-h urinary magnesium excretion was measured. In a subset of patients (n=5), an intravenous magnesium load test was done. 16 patients who had chemotherapy alone acted as controls. A clinical protocol was written before initiation of the study, but because this was a non-interventional study, the protocol was not formally registered. FINDINGS 95 (97%) patients had decreasing serum magnesium concentrations during EGFR-targeting treatment compared with baseline measurements. The mean serum magnesium slope during EGFR-targeting treatment (with or without combined chemotherapy) was significantly lower compared with chemotherapy alone (-0.00157 mmol/L/day, SD 0.00162 [95% CI -0.00191 to -0.00123] vs 0.00014 mmol/L/day, SD -00076 [-0.00026 to 0.00055]; (t test, p < 0.0001). 24-h urine analysis and intravenous magnesium load tests showed a defect in renal magnesium reabsorption. INTERPRETATION EGFR-inhibiting antibodies compromised the renal magnesium retention capacity, leading to hypomagnesaemia in most patients. Future studies should address the effects of exposure and target affinity. Our study suggests a pivotal role of the EGFR-signalling pathway in regulating magnesium homoeostasis.

Use of Early Tumor Shrinkage to Predict Long-Term Outcome in Metastatic Colorectal Cancer Treated With Cetuximab

PURPOSE Early tumor shrinkage (ETS) is associated with long-term outcome in patients with chemorefractory metastatic colorectal cancer (mCRC) receiving cetuximab. This association was investigated in the first-line setting in the randomized CRYSTAL and OPUS mCRC trials, after controlling for KRAS tumor mutation status. METHODS Radiologic assessments at week 8 were used to calculate the relative change in the sum of the longest diameters of the target lesions. Time-dependent receiver operating characteristics provided Cτ-indices (time-dependent c-index). Cox regression models and subpopulation treatment effect pattern plot analysis investigated associations between ETS (radiologic tumor size decrease at week 8) and survival and progression-free survival (PFS). RESULTS In both trials, in patients with KRAS wild-type mCRC, Cτ values for PFS and survival were higher (P < .001) in those receiving chemotherapy plus cetuximab versus chemotherapy alone, indicating a stronger predictive value of ETS for long-term outcome in these patients. In the CRYSTAL and OPUS trials, respectively, the cutoff value of ETS ≥ 20% (v < 20%) identified patients with KRAS wild-type mCRC receiving chemotherapy plus cetuximab with longer PFS (medians 14.1 v 7.3 months, hazard ratio [HR] = 0.32; P < .001, and medians 11.9 v 5.7 months, HR = 0.22; P < .001) and survival (medians 30.0 v 18.6 months, HR = 0.53; P < .001 and medians 26.0 v 15.7 months, HR = 0.43; P = .006). CONCLUSION ETS was significantly associated with long-term outcome in patients with KRAS wild-type mCRC treated first-line with chemotherapy plus cetuximab. Validation in prospective trials is required to assess the value of this on-treatment marker in the clinical decision-making process.

Intragastric distribution of a standardized meal in health and functional dyspepsia: correlation with specific symptoms.

Abstract  In functional dyspepsia, abnormal intragastric distribution of a test meal has been identified but has never been correlated to any symptom pattern. The aim of this study was to compare the intragastric distribution of a meal between functional dyspepsia patients and controls, and to correlate distribution with symptom patterns, using scintigraphic gastric emptying studies. In forty patients with functional dyspepsia and 29 healthy volunteers, scintigraphic planar images were obtained immediately after ingestion of a mixed radiolabelled test meal and every 20 min for 2 h. The images of the stomach were divided into proximal and distal compartments. The mean intragastric distribution was similar in patients and controls. Over the whole test, 18 (45%) and 20 (50%) patients had a distal redistribution of the solid and liquid phase of the meal, respectively, while proximal retention of these phases was found in 13 (33%) and 9 (23%) patients. Early satiety was associated with early distal redistribution of the liquid phase and fullness was associated with late proximal retention. This study shows similar intragastric distribution of a test meal in health and functional dyspepsia. Within the patient group, an association between abnormal intragastric distribution patterns and symptom profiles was found, which might be related to different pathophysiological mechanisms.

Dyspeptic symptoms in the general population: a factor and cluster analysis of symptom groupings.

Abstract  Both dyspeptic and gastro‐oesophageal reflux‐like symptoms are frequent in the general population, but their degree of overlap is unknown. In severe functional dyspepsia (FD), symptoms are organized in factors associated with pathophysiological mechanisms. The aims of this study were: (i) to assess the prevalence of dyspeptic symptoms with and without overlapping reflux symptoms in the general population and their impact on daily life and on healthcare utilization; and (ii) to compare symptom groupings in the general population to FD patients. A total of 2025 subjects, representative of the Belgian general population, were used in this study. The subjects were submitted to a questionnaire with validated questions on their dyspeptic and reflux symptoms and with evaluators of impact on daily life and use of healthcare resources. Significant dyspeptic symptoms were found in 417 (20.6%). Overlapping reflux symptoms were present in 141 (33.8%). In this group, symptoms were more frequent and more severe. Dyspeptic symptoms induced weight loss (12.7%) and absenteeism (12.4%), affected daily life (61.2%) and generated use of healthcare resources, such as medical consultations (61.4%) and medication (70.9%). Factor analysis revealed a three‐component structure with factor 1 including fullness, bloating and early satiety, factor 2 including nausea and vomiting and factor 3 including discomfort, pain, belching and reflux. If forced in a four‐factor model, the analysis separates belching as independent factor. Dyspeptic symptoms are frequent in the general population, with overlapping reflux symptoms and increased symptom burden in about a third.

Is early enteral nutrition in acute pancreatitis dangerous? About 20 patients fed by an endoscopically placed nasogastrojejunal tube.

Bowel rest during treatment of acute pancreatitis deprives the gut of nutrients and affects its structure and function. Enteral feeding is usually performed late in the course of acute pancreatitis and therefore cannot prevent intestinal barrier dysfunction and possible bacterial translocation. To assess the effect of early enteral nutrition we performed a prospective study on 21 patients (11 males/10 females) presenting with severe acute pancreatitis (13 biliary, 6 alcoholic, and 2 miscellaneous). Severity was established by a mean Ranson score of 3.57. All but one patient could be fed through a double-lumen nasogastrojejunal tube within 60 h after admission. No significant complication of the technique was observed. We conclude that early jejunal feeding can be used safely in severe acute pancreatitis. Further comparative studies are necessary to demonstrate any superiority to total parenteral nutrition.