C. J. A. Punt

KRAS mutation analysis: a comparison between primary tumours and matched liver metastases in 305 colorectal cancer patients

Background:KRAS mutation is a negative predictive factor for treatment with anti-epidermal growth factor receptor antibody in metastatic colorectal cancer (CRC). KRAS mutation analysis is usually performed on primary tumour tissue because metastatic tissue is often not available. However, controversial data are available on the concordance of test results between primary tumours and corresponding metastases. We assessed the concordance of KRAS mutation status in a study of 305 primary colorectal tumours and their corresponding liver metastases.Methods:Patients with histologically confirmed CRC who underwent surgical resection of the primary tumour and biopsy or surgical resection of the corresponding liver metastasis were included. KRAS mutation analysis was performed for codons 12 and 13.Results:KRAS mutation was detected in 108 out of 305 primary tumours (35.4%). In 11 cases (3.6%), we found a discordance between primary tumour and metastasis: 5 primary tumours had a KRAS mutation with a wild-type metastasis, 1 primary tumour was wild type with a KRAS mutation in the metastasis, and in 5 cases the primary tumour and the metastasis had a different KRAS mutation.Conclusion:We observed a high concordance of KRAS mutation status of 96.4% (95% CI 93.6–98.2%) between primary colorectal tumours and their corresponding liver metastases. In only six patients (2.0%; 95% CI 0.7–4.2%), the discordance was clinically relevant. In this largest and most homogenous study to date, we conclude that both primary tumours and liver metastases can be used for KRAS mutation analysis.

A randomised phase III study on capecitabine, oxaliplatin and bevacizumab with or without cetuximab in first-line advanced colorectal cancer, the CAIRO2 study of the Dutch Colorectal Cancer Group (DCCG). An interim analysis of toxicity

BACKGROUND Targeting the vascular endothelial growth factor or the epidermal growth factor receptor (EGFR) has shown efficacy in advanced colorectal cancer (ACC), but no data are available on the combination of these strategies with chemotherapy in the first-line treatment. The CAIRO2 study evaluates the effect of adding cetuximab, a chimeric mAb against EGFR, to capecitabine, oxaliplatin and bevacizumab in the first-line treatment of ACC. PATIENTS AND METHODS In all, 755 patients were randomly assigned between treatment with capecitabine, oxaliplatin and bevacizumab with or without cetuximab. The primary end point is progression-free survival. We here present the toxicity results in the first 400 patients that entered the study. RESULTS The incidence of overall grade 3-4 toxicity was significantly higher in arm B compared with arm A (81% versus 72%, P = 0.03). This difference is fully attributed to cetuximab-related skin toxicity. The addition of cetuximab did not result in an increase of gastrointestinal toxicity or treatment-related mortality. CONCLUSIONS The addition of cetuximab to capecitabine, oxaliplatin and bevacizumab in the first-line treatment of ACC appears to be safe and feasible. No excessive or unexpected toxicity in the cetuximab-containing treatment arm was observed.

Circulating tumour cells early predict progression-free and overall survival in advanced colorectal cancer patients treated with chemotherapy and targeted agents

BACKGROUND Early predictive markers for response are needed for advanced colorectal cancer (ACC) patients. We assessed the value of circulating tumour cells (CTC) in ACC patients treated with chemotherapy plus targeted agents (CAIRO2 phase III trial) and compared the results with computed tomography (CT) imaging. MATERIALS AND METHODS CTC were determined at baseline and at different time points during treatment. Patients were stratified into low (less than three CTC per 7.5 ml of blood) or high CTC (three or more CTC per 7.5 ml of blood). RESULTS A total of 467 patients were assessable for CTC analysis. Among them, 129 patients (29%) with high baseline CTC had a significantly decreased progression-free survival [PFS; hazard ratio (HR) 1.5] and overall survival (OS; HR 2.2) compared with 322 patients with low baseline CTC. This difference remained statistically significant during treatment. The sensitivity and specificity of high CTC at baseline for the prediction of progressive disease on CT imaging were 16.7% and 70.1%, respectively, and of high CTC at 1-2 weeks after the start of treatment 20.0% and 95.1%, respectively. The combined analysis of CTC and CT imaging provided a more accurate outcome assessment than either modality alone. CONCLUSIONS The CTC count before and during treatment independently predicts PFS and OS in ACC patients treated with chemotherapy plus targeted agents and provides additional information to CT imaging.

Clinicopathological features and outcome in advanced colorectal cancer patients with synchronous vs metachronous metastases

Background:Synchronous metastases of colorectal cancer (CRC) are considered to be of worse prognostic value compared with metachronous metastases, but only few and conflicting data have been reported on this issue.Methods:We retrospectively investigated patient demographics, primary tumour characteristics and overall survival (OS) in 550 advanced CRC patients with metachronous vs synchronous metastases, who participated in the phase III CAIRO study. For this purpose only patients with a prior resection of the primary tumour were considered.Results:The clinical and pathological characteristics associated with poor prognosis that we observed more often in patients with synchronous metastases (n=280) concerned an abnormal serum lactate dehydrogenase (LDH) concentration (P=0.01), a worse WHO performance status (P=0.02), primary tumour localisation in the colon (P=0.002) and a higher T stage (P=0.0006). No significant difference in median OS was observed between patients with synchronous metastases and metachronous metastases (17.6 vs 18.5 months, respectively, P=0.24).Conclusion:Despite unfavourable clinicopathological features in patients with synchronous metastases with a resected primary tumour compared to patients with metachronous metastases, no difference in the median OS was observed. Possible explanations include a (partial) chemoresistance in patients with metachronous disease because of previous adjuvant treatment, whereas differences between the two groups in screening procedures resulting in a lead time bias to diagnosis or in prognostic molecular markers remain speculative.

The predictive and prognostic value of circulating endothelial cells in advanced colorectal cancer patients receiving first-line chemotherapy and bevacizumab

Currently, the use of bevacizumab in combination with fluoropyrimidine-containing chemotherapy is the standard first-line treatment for patients with advanced colorectal cancer (ACC). However, only a subset of ACC patients will respond to treatment, and to date, there is no biological marker that may predict the benefit of this treatment. Recently, Ronzoni et al. reported on the correlation between the baseline levels of both total circulating endothelial cells (CECs) and their subsets and the response to bevacizumab-based first-line treatment in ACC patients. They suggested significant correlations between the CEC baseline levels and the antitumor efficacy [1]. We assessed the prognostic and predictive value of CECs in 473 ACC patients treated in a randomized phase III trial with first-line chemotherapy and targeted therapy including bevacizumab (CAIRO2 trial of the Dutch Colorectal Cancer Group) [2]. Peripheral blood was collected at baseline and at three time points after the start of treatment (1–2, 3–5, and 6–12 weeks). Samples were collected in 10-ml evacuated tubes (CellSave tubes; Veridex LLC, Raritan, NJ) and processed in a central laboratory within 72 hours. The CellSearch System (Veridex LLC) was used for CEC enumeration [3]. The criteria for CEC included round-to-oval morphology, a visible nucleus [4#-6-diamidino-2-phenylindole (DAPI) positive], expression of CD146 as well as CD105, and absence of CD45. The median number of CECs at baseline was 6.8 CEC/ml, which is comparable with that found in other studies using the automated immunomagnetic separation system [3, 4]. In our study population, 17% had a CEC count at baseline above the upper reference limit of 24 CECs/ml, which is comparable with that of Rowand et al. [3]. To define the prognostic value of CECs, the correlation of baseline CEC count and progressionfree survival (PFS) and overall survival (OS) was analyzed. In univariate Cox regression analysis, the hazard ratio (95% confidence interval) of progression was 0.99 (0.90–1.08) and of death 0.95 (0.87–1.05). A significant increase in CECs was observed after 1–2 weeks of treatment compared with baseline (P £ 0.001). Hereafter, no further increase in CEC count was observed. However, we could not predict PFS or OS by changes in CEC levels at any time point during therapy (Table 1). Our results are in contrast to the findings of Ronzoni et al., which are based on a considerable smaller number of patients. Ronzoni et al. [1] only observed a correlation between baseline ‘total’ and ‘resting’ CEC counts and PFS, and no correlation was found regarding activated CECs or circulating progenitor cells and outcome. The lack of correlation of CECs with outcome in our study may be due to the different technique used for CEC enumeration. So far, there is no consensus on the phenotypic characterization of CECs and technique for CEC enumeration, and conflicting results concerning the role of CECs as a marker for prognosis and/or response to treatment have been reported. The most commonly used techniques for CEC evaluation are flow cytometry or microscopic evaluation after immunomagnetic separation. We used the CellSearch System, which is an automated system based on immunomagnetic enrichment targeting the CD146 antigen and detection by fluorescent microscopy of DAPI+, CD105+, CD452 cells, that has shown to be a reproducible and accurate method [3]. Our technique also included morphology in classification of CECs, which allows to discriminate CECs from endothelial microparticles, conglomerates, and/or anuclear cells. In the study by Ronzoni [1], staining with a nucleic acid dye was not included in the definition, which may lead to the inclusion of large platelets rather than endothelial cells into the CEC definition [5]. In conclusion, our study demonstrated that CEC counts at baseline were not prognostic for PFS or OS in a subset of ACC patients. Neither was change in CEC counts at baseline and during treatment predictive for outcome. To our knowledge, this is the first study that investigates the correlation between CECs and bevacizumab-based treatment in a large number of ACC patients. However, different subsets of CECs exist and consensus on phenotypic characterization and enumeration technique is the first step to make comparison of different studies concerning CEC evaluation possible.

A prospective monitoring of fatal serious adverse events (SAEs) in a Dutch Colorectal Cancer Group (DCCG) phase III trial (CAIRO) in patients with advanced colorectal cancer

BACKGROUND Early and correct assessment of treatment-related mortality is highly important in clinical cancer trials. However, no data are available on the quality of safety monitoring. PATIENTS AND METHODS An on-site review was carried out by the study coordinators of the individual charts of all patients participating in the Capecitabine-Irinotecan-Oxaliplatin (CAIRO) study who had died within 30 days of the last administration of study drugs when death was accompanied by any other event than disease progression. The relationship between treatment and death was categorized as unrelated, remote, possible, or probable and submitted to an independent data monitoring committee (IDMC). These results were then compared with the initial assessment of the local investigator. RESULTS Forty of 820 patients qualified for review. The relationship between cause of death and study drugs was changed in 26 patients (65%). A major protocol violation (MPV) was identified in 12 of 14 patients with a probable relationship between cause of death and study treatment. CONCLUSIONS There was little agreement between the relation as assessed by the local investigator compared with the IDMC. A quality control improves the assessment of safety results and the observed MPVs underscore the importance of educating medical staff and patients.