Detection of tumor-derived cell-free DNA from colorectal cancer peritoneal metastases in plasma and peritoneal fluid.

Tumor-derived cell-free DNA (cfDNA) is an emerging biomarker for guiding the personalized treatment of patients with metastatic colorectal cancer (CRC). While patients with CRC liver metastases (CRC-LM) have relatively high levels of plasma cfDNA, little is known about patients with CRC peritoneal metastases (CRC-PM). This study evaluated the presence of tumor-derived cfDNA in plasma and peritoneal fluid (i.e. ascites or peritoneal washing) in 20 patients with isolated CRC-PM and in the plasma of 100 patients with isolated CRC-LM. Among tumor tissue KRAS/BRAF mutation carriers, tumor-derived cfDNA was detected by droplet digital polymerase chain reaction (ddPCR) in plasma of 93% of CRC-LM and 20% of CRC-PM patients and in peritoneal fluid in all CRC-PM patients. Mutant allele fraction (MAF) and mutant copies per ml (MTc/ml) were lower in CRC-PM plasma than in CRC-LM plasma (median MAF = 0.28 versus 18.9%, p < 0.0001; median MTc/ml = 21 versus 1,758, p < 0.0001). Within patients with CRC-PM, higher cfDNA levels were observed in peritoneal fluid than in plasma (median MAF = 16.4 versus 0.28%, p = 0.0019; median MTc/ml = 305 versus 21, p = 0.0034). These data imply that tumor-derived cfDNA in plasma is a poor biomarker to monitor CRC-PM. Instead, cfDNA detection in peritoneal fluid may offer an alternative to guide CRC-PM treatment decisions.

Outcomes of Resectability Assessment of the Dutch Colorectal Cancer Group Liver Metastases Expert Panel.

BACKGROUND: Decision making on optimal treatment strategy in patients with initially unresectable colorectal cancer liver metastases (CRLM) remains complex because uniform criteria for (un)resectability are lacking. This study reports on the feasibility and short-term outcomes of The Dutch Colorectal Cancer Group Liver Expert Panel. STUDY DESIGN: The Expert Panel consists of 13 hepatobiliary surgeons and 4 radiologists. Resectability assessment is performed independently by 3 randomly assigned surgeons, and CRLM are scored as resectable, potentially resectable, or permanently unresectable. In absence of consensus, 2 additional surgeons are invited for a majority consensus. Patients with potentially resectable or unresectable CRLM at baseline are evaluated every 2 months of systemic therapy. Once CRLM are considered resectable, a treatment strategy is proposed. RESULTS: Overall, 398 panel evaluations in 183 patients were analyzed. The median time to panel conclusion was 7 days (interquartile range [IQR] 5-11 days). Intersurgeon disagreement was observed in 205 (52%) evaluations, with major disagreement (resectable vs permanently unresectable) in 42 (11%) evaluations. After systemic treatment, 106 patients were considered to have resectable CRLM, 84 of whom (79%) underwent a curative procedure. R0 resection (n = 41), R0 resection in combination with ablative treatment (n = 26), or ablative treatment only (n = 4) was achieved in 67 of 84 (80%) patients. CONCLUSIONS: This study analyzed prospective resectability evaluation of patients with CRLM by a panel of radiologists and liver surgeons. The high rate of disagreement among experienced liver surgeons reflects the complexity in defining treatment strategies for CRLM and supports the use of a panel rather than a single-surgeon decision.

Laparoscopic surgery facilitates administration of adjuvant chemotherapy in locally advanced colon cancer: propensity score analyses.

PURPOSE: The aim of this study was to evaluate the impact of a laparoscopic approach on long-term oncological outcomes in curative intent surgery for pT4 colon cancer, in both overall and stratified subgroups with distinct clinical entities. PATIENTS AND METHODS: Patients with a pT4N0-2M0 colon cancer from four centers between 2000 and 2014 were included. Laparoscopic and open approaches were compared according to the intention-to-treat principle. Propensity scores were used to adjust for baseline differences between the groups in three manners: i) as a linear predictor in a Cox regression model, ii) to create a 1:1 matched cohort, and iii) to stratify patients into four groups with an increasing chance of receiving laparoscopy. RESULTS: In total, 424 patients were included. After 1:1 matching, a laparoscopic approach correlated with higher rates of radical resection, lower morbidity, and a higher percentage of patients receiving adjuvant chemotherapy. This translated into better 5-year disease-free survival (52% vs 40%, HR 0.70; 95% CI 0.50-0.96) and 5-year overall survival (68% vs 57%, HR 0.66; 95% CI 0.43-0.99). These results were confirmed in the other two propensity score analyses. In the multivariable models, adjuvant chemotherapy remained independently associated with better survival, whereas surgical approach lost significance. CONCLUSIONS: In locally advanced colon cancer, an intentional laparoscopic approach in experienced hands seems to decrease morbidity and to increase the proportion of patients receiving adjuvant chemotherapy. Receiving adjuvant chemotherapy was independently associated with improved survival.

The impact of data errors on the outcome of randomized clinical trials.

Background/aims Considerable human and financial resources are typically spent to ensure that data collected for clinical trials are free from errors. We investigated the impact of random and systematic errors on the outcome of randomized clinical trials. Methods We used individual patient data relating to response endpoints of interest in two published randomized clinical trials, one in ophthalmology and one in oncology. These randomized clinical trials enrolled 1186 patients with age-related macular degeneration and 736 patients with metastatic colorectal cancer. The ophthalmology trial tested the benefit of pegaptanib for the treatment of age-related macular degeneration and identified a statistically significant treatment benefit, whereas the oncology trial assessed the benefit of adding cetuximab to a regimen of capecitabine, oxaliplatin, and bevacizumab for the treatment of metastatic colorectal cancer and failed to identify a statistically significant treatment difference. We simulated trial results by adding errors that were independent of the treatment group (random errors) and errors that favored one of the treatment groups (systematic errors). We added such errors to the data for the response endpoint of interest for increasing proportions of randomly selected patients. Results Random errors added to up to 50% of the cases produced only slightly inflated variance in the estimated treatment effect of both trials, with no qualitative change in the p-value. In contrast, systematic errors produced bias even for very small proportions of patients with added errors. Conclusion A substantial amount of random errors is required before appreciable effects on the outcome of randomized clinical trials are noted. In contrast, even a small amount of systematic errors can severely bias the estimated treatment effects. Therefore, resources devoted to randomized clinical trials should be spent primarily on minimizing sources of systematic errors which can bias the analyses, rather than on random errors which result only in a small loss in power.

Update on optimal treatment for metastatic colorectal cancer from the ACTG/AGITG expert meeting: ECCO 2015.

The treatment of metastatic CRC (mCRC) has evolved over the last 20 years, from fluoropyrimidines alone to combination chemotherapy and new biologic agents. Median overall survival is now over 24 months for RAS mutated (MT) patients and over 30 months for RAS wild-type (WT) patients. However, there are subgroups of patients with BRAF V600E MT CRC who have a significantly poorer outlook. Newer treatment options are also being explored in select subgroups of patients (anti-HER 2 in HER2 positive mCRC and immunotherapy in patients with defective mismatch repair (dMMR)). The best use of these systemic treatment options, as well as surgery in well-selected patients requires careful consideration of predictive biomarkers and importantly, the optimal sequence in which therapies should be given to derive maximal benefit. A group of colorectal subspecialty medical oncologists from Australia, USA, The Netherlands and Germany met during ECCO 2015 in Vienna to review current practice.

Intranodal vaccination with mRNA-optimized dendritic cells in metastatic melanoma patients.

Autologous dendritic cell (DC) therapy is an experimental cellular immunotherapy that is safe and immunogenic in patients with advanced melanoma. In an attempt to further improve the therapeutic responses, we treated 15 patients with melanoma, with autologous monocyte-derived immature DC electroporated with mRNA encoding CD40 ligand (CD40L), CD70 and a constitutively active TLR4 (caTLR4) together with mRNA encoding a tumor-associated antigen (TAA; respectively gp100 or tyrosinase). In addition, DC were pulsed with keyhole limpet hemocyanin (KLH) that served as a control antigen. Production of this DC vaccine with high cellular viability, high expression of co-stimulatory molecules and MHC class I and II and production of IL-12p70, was feasible in all patients. A vaccination cycle consisting of three vaccinations with up to 15×106 DC per vaccination at a biweekly interval, was repeated after 6 and 12 months in the absence of disease progression. mRNA-optimized DC were injected intranodally, because of low CCR7 expression on the DC, and induced de novo immune responses against control antigen. T cell responses against tyrosinase were detected in the skin-test infiltrating lymphocytes (SKIL) of two patients. One mixed tumor response and two durable tumor stabilizations were observed among 8 patients with evaluable disease at baseline. In conclusion, autologous mRNA-optimized DC can be safely administered intranodally to patients with metastatic melanoma but showed limited immunological responses against tyrosinase and gp100.

Highlights from the seventh European Multidisciplinary Colorectal Cancer Congress (EMCCC) 2014.

It is widely recognised that colorectal cancer has become a complex disease and involves many medical disciplines. The mission of the European Multidisciplinary Colorectal Cancer Congress (EMCCC), which is an initiative of the Dutch Colorectal Cancer Group (DCCG), is to facilitate the interaction between relevant disciplines on current issues of research. The three-day meeting in Amsterdam in November 2014 assembled approximately 450 participants with nine different disciplines from 38 countries worldwide. On day one, workshops on imaging, surgery, medical oncology/pathology, radiotherapy, and genetics were followed by the keynote lecture of the congress. On day two and three, a total of 35 established international opinion leaders presented lectures in plenary sessions on prevention and screening of early colorectal cancer, genetics, translational research, biomarkers, organ-saving treatment in rectal cancer, current controversies, and multidisciplinary management. Posters from submitted abstracts were displayed, with selected abstracts being orally presented.

Importance of helper T-cell activation in dendritic cell-based anticancer immunotherapy.

Dendritic cell-based anticancer immunotherapy is feasible, safe and results in the induction of tumor-specific immune responses, at least in a fraction of vaccinated patients. The concomitant activation of cytotoxic and helper T cells, by loading DCs with peptides or electroporating them with the corresponding mRNAs, may further enhance vaccine-induced antitumor responses.

Adjuvant therapy with pegylated interferon alfa-2b versus observation alone in resected stage III melanoma: final results of EORTC 18991, a randomised phase III trial.

BACKGROUND: Any benefit of adjuvant interferon alfa-2b for melanoma could depend on dose and duration of treatment. Our aim was to determine whether pegylated interferon alfa-2b can facilitate prolonged exposure while maintaining tolerability. METHODS: 1256 patients with resected stage III melanoma were randomly assigned to observation (n=629) or pegylated interferon alfa-2b (n=627) 6 mug/kg per week for 8 weeks (induction) then 3 mug/kg per week (maintenance) for an intended duration of 5 years. Randomisation was stratified for microscopic (N1) versus macroscopic (N2) nodal involvement, number of positive nodes, ulceration and tumour thickness, sex, and centre. Randomisation was done with a minimisation technique. The primary endpoint was recurrence-free survival. Analyses were done by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00006249. FINDINGS: All randomised patients were included in the primary efficacy analysis. 608 patients in the interferon group and 613 patients in the observation group were included in safety analyses. The median length of treatment with pegylated interferon alfa-2b was 12 (IQR 3.8-33.4) months. At 3.8 (3.2-4.2) years median follow-up, 328 recurrence events had occurred in the interferon group compared with 368 in the observation group (hazard ratio 0.82, 95% CI 0.71-0.96; p=0.01); the 4-year rate of recurrence-free survival was 45.6% (SE 2.2) in the interferon group and 38.9% (2.2) in the observation group. There was no difference in overall survival between the groups. Grade 3 adverse events occurred in 246 (40%) patients in the interferon group and 60 (10%) in the observation group; grade 4 adverse events occurred in 32 (5%) patients in the interferon group and 14 (2%) in the observation group. In the interferon group, the most common grade 3 or 4 adverse events were fatigue (97 patients, 16%), hepatotoxicity (66, 11%), and depression (39, 6%). Treatment with pegylated interferon alfa-2b was discontinued because of toxicity in 191 (31%) patients. INTERPRETATION: Adjuvant pegylated interferon alfa-2b for stage III melanoma has a significant, sustained effect on recurrence-free survival.

Sequential versus combination chemotherapy with capecitabine, irinotecan, and oxaliplatin in advanced colorectal cancer (CAIRO): a phase III randomised controlled trial.

BACKGROUND: The optimum use of cytotoxic drugs for advanced colorectal cancer has not been defined. Our aim was to investigate whether combination treatment is better than sequential administration of the same drugs in patients with advanced colorectal cancer. METHODS: We randomly assigned 820 patients with advanced colorectal cancer to receive either first-line treatment with capecitabine, second-line irinotecan, and third-line capecitabine plus oxaliplatin (sequential treatment; n=410) or first-line treatment capecitabine plus irinotecan and second-line capecitabine plus oxaliplatin (combination treatment; n=410). The primary endpoint was overall survival. Analyses were done by intention to treat. This trial is registered with ClinicalTrials.gov with the number NCT00312000. FINDINGS: 17 patients (nine in the sequential treatment group, eight in the combination group) were found to be ineligible and were excluded from the analysis. 675 (84%) patients died during the study: 336 in the sequential group and 339 in the combination group. Median overall survival was 16.3 (95% CI 14.3-18.1) months for sequential treatment and 17.4 (15.2-19.2) months for combination treatment (p=0.3281). The hazard ratio for combination versus sequential treatment was 0.92 (95% CI 0.79-1.08; p=0.3281). The frequency of grade 3-4 toxicity over all lines of treatment did not differ significantly between the two groups, except for grade 3 hand-foot syndrome, which occurred more often with sequential treatment than with combination treatment (13%vs 7%; p=0.004). INTERPRETATION: Combination treatment does not significantly improve overall survival compared with the sequential use of cytotoxic drugs in advanced colorectal cancer. Thus sequential treatment remains a valid option for patients with advanced colorectal cancer.