Monitoring the effect of first line treatment in RAS/RAF mutated metastatic colorectal cancer by serial analysis of tumor specific DNA in plasma

BACKGROUND

Precision medicine calls for an early indicator of treatment efficiency. Circulating tumor DNA (ctDNA) is a promising marker in this setting. Our prospective study explored the association between disease development and change of ctDNA during first line chemotherapy in patients with RAS/RAF mutated metastatic colorectal cancer (mCRC).

METHODS

The study included 138 patients with mCRC receiving standard first line treatment. In patients with RAS/RAF mutated tumor DNA the same mutation was quantified in the plasma using droplet digital PCR. The fractional abundance of ctDNA was assessed in plasma before treatment start and at every treatment cycle until radiologically defined progressive disease.

RESULTS

RAS/RAF mutations were detected in the plasma from 77 patients. Twenty patients progressed on treatment and 57 stopped treatment without progression. The presence of mutated DNA in plasma was correlated with poor overall survival. A low level of ctDNA after the first cycle of chemotherapy was associated with a low risk of progression. On the other hand, a significant increase of ctDNA at any time during the treatment course was associated with a high risk of progression on continuous treatment. The first increase in ctDNA level occurred at a median of 51 days before radiologically confirmed progression.

CONCLUSIONS

The results indicate that the ctDNA level holds potential as a clinically valuable marker in first line treatment of mCRC. A rapid decrease was associated with a prolonged progression free interval, whereas a significant increase gave notice of early progression with a relevant lead time.

Report of mecC-carrying MRSA in domestic swine

Objectives

We unexpectedly identified MRSA isolates carrying mecC (mecC-MRSA) from a Danish swine farm located in eastern Zealand. The objective of the present study was to investigate the origin of these isolates and their genetic relatedness to other mecC-MRSA isolates from Zealand.

Methods

WGS was used to infer the phylogenetic relationship between 19 identified mecC-MRSA isolates from the swine farm and 34 additional epidemiologically unrelated human isolates from the same geographical region of Denmark. Variations in the accessory genome were investigated by bioinformatics tools, and antibiotic susceptibility profiles were assessed by MIC determination.

Results

mecC-MRSA was isolated from a domestic swine farm, but not from cattle reared at the same farm. Phylogenetic analysis revealed that all mecC-MRSA isolates from both farm animals and workers formed a separate cluster, whereas human isolates from the same municipality belonged to a closely related cluster. Analysis of the accessory genome supported this relationship.

Conclusions

To the best of our knowledge, this is the first report of mecC-MRSA isolated from domestic swine. The investigation strongly indicates that transmission of mecC-MRSA has taken place on the swine farm between the farmers and swine. The close clustering of farm isolates and isolates from the same municipality suggests a local transmission of mecC-MRSA.

Changes in circulating microRNA-126 during treatment with chemotherapy and bevacizumab predicts treatment response in patients with metastatic colorectal cancer

Background:

This study investigated the predictive value of circulating microRNA-126 (cir-miRNA-126) in patients with metastatic colorectal cancer (mCRC) treated with first-line chemotherapy combined with bevacizumab.

Methods:

The study included 68 patients. Blood samples (plasma) were collected before the treatment initiation, at the first clinical evaluation after 3 weeks and at progression. Levels of cir-miRNA-126 were determined by qRT–PCR after purification of total RNA from plasma. Primary clinical end points were response rates evaluated according to the Response Evaluation Criteria In Solid Tumours (RECIST) and progression-free survival (PFS).

Results:

Changes in circulating miRNA-126 during treatment were predictive of tumour response. Non-responding patients had a median increase in cir-miRNA-126 of 0.244 (95% confidence interval (CI), 0.050–0.565) compared with a median decrease of −0.374 (95% CI, −0.472 to −0.111) in the responding patients, P=0.002. A significant positive correlation was demonstrated by comparing the changes in tumour size with the changes in cir-miRNA-126, r=0.48, P=0.0001. Grouping the patients according to the changes in cir-miRNA-126 disclosed a borderline significant separation of the groups in the PFS analysis favouring patients with decreasing miRNA-126 levels, hazard ratio (HR) 0.60 (95% CI, 0.33–1.09), P=0.07.

Conclusions:

The present results indicate that changes in cir-miRNA-126 during treatment are related to the response to chemotherapy and bevacizumab in patients with mCRC, thus representing a possible biomarker for the resistance to anti-angiogenic containing treatments.

Redefining high-risk patients with stage II colon cancer by risk index and microRNA-21: results from a population-based cohort

Background:

The aim of the present study was to analyse the prognostic value of microRNA-21 (miRNA-21) in patients with stage II colon cancer aiming at a risk index for this group of patients.

Methods:

A population-based cohort of 554 patients was included. MicroRNA-21 was analysed by qPCR based on tumour tissue. An index was created using the coefficients obtained from a collective multiple Cox regression. The entire procedure was cross-validated (10-fold). The performance of the index was quantified by time-dependent receiver operating characteristics curves.

Results:

High miRNA-21 expression was associated with an unfavourable recurrence-free cancer-specific survival (RF-CSS), hazard ratio 1.35 (95% confidence interval, 1.03–1.76) (P=0.028). The generated RF-CSS index divided the traditional high-risk patients into subgroups with 5-year RF-CSS rates of 87% and 73%, respectively (P<0.001). The overall survival (OS) index identified three different subgroups (P<0.001). Cross-validated 5-year OS rates were 88%, 68%, and 50%, respectively.

Conclusions:

This population-based study supports miRNA-21 as an additional prognostic biomarker in patients with stage II colon cancer. Furthermore, the introduction of a risk index may guide the use of postoperative adjuvant treatment in a more appropriate way compared with current practice.

A randomized phase III trial on maintenance treatment with bevacizumab alone or in combination with erlotinib after chemotherapy and bevacizumab in metastatic colorectal cancer: the Nordic ACT Trial

BACKGROUND

The main objective was to study the effect on progression-free survival (PFS) of adding erlotinib to bevacizumab as maintenance treatment following chemotherapy and bevacizumab as first-line treatment of metastatic colorectal cancer (mCRC).

PATIENTS AND METHODS

Patients with untreated mCRC received doublet chemotherapy + bevacizumab during 18 weeks and those without tumor progression were eligible for randomization to bevacizumab + erlotinib (arm A) or bevacizumab alone (arm B), until progression or unacceptable toxic effect.

RESULTS

Of the 249 patients enrolled, 80 started maintenance treatment in arm A and 79 in arm B. The rate of any grade 3/4 toxic effect was 53% in arm A and 13% in arm B. Median PFS was 5.7 months in arm A and 4.2 months in arm B (HR = 0.79; 95% confidence interval 0.55-1.12; P = 0.19). Overall survival (OS) from start of induction chemotherapy was 26.7 months in the randomized population, with no difference between the two arms.

CONCLUSIONS

The addition of erlotinib to bevacizumab as maintenance treatment after first-line chemotherapy in mCRC did not improve PFS significantly. On-going clinical and translational studies focus on identifying subgroups of patients that may benefit from erlotinib in the maintenance setting.

CLINICAL TRIALS NUMBER

NCT00598156.

Ultrasound elastography in patients with rectal cancer treated with chemoradiation

OBJECTIVE

The current literature has described several predictive markers in rectal cancer patients treated with chemoradiation, but so far none of them have been validated for clinical use. The purpose of the present study was to compare quantitative elastography based on ultrasound measurements in the course of chemoradiation with tumor response based on T stage classification and the Mandard tumor regression grading (TRG).

MATERIALS AND METHODS

We prospectively examined 31 patients with rectal cancer planned for high dose radiochemotherapy. The tumor and the mesorectal fat elasticity were measured using the Acoustic Radiation Force Impulse to generate information on the mechanical properties of the tissue. The objective quantitative elastography shear wave velocity was compared to the T stage classification and TRG.

RESULTS

The baseline mean tumor elasticity was 3.13 m/s. Two and six weeks after the start of chemoradiation the velocities were 2.17 m/s and 2.11 m/s, respectively. The difference between baseline velocity and velocities during the treatment course was statistically significant, (p<0.0001). Patients with tumor confined to the rectal wall at histopathology (ypT1-2) had a mean elasticity measurement after two weeks of treatment of 1.95 m/s, whereas tumors invading the mesorectal fat (ypT3-4) had a velocity of 2.47 m/s, (p<0.05). The mean elasticity tended to be lower (1.99m/s) after two weeks in patients with TRG 1-2 responses in contrast to 2.24 m/s in those with TRG 3-4.

CONCLUSION

Ultrasound elastography after two weeks of chemoradiation seems to hold early predictive information to the pathological T stage.

Phase II marker-driven trial of panitumumab and chemotherapy in KRAS wild-type biliary tract cancer

BACKGROUND

Combination chemotherapy has proven beneficial in biliary tract cancer and further improvements may be achieved by individualizing treatment based on biomarkers and by adding biological agents. We report the effect of chemotherapy with panitumumab as first-line therapy for KRAS wild-type irresectable biliary tract cancer.

PATIENTS AND METHODS

Patients were treated with gemcitabine 1000 mg/m(2), oxaliplatin 60 mg/m(2), and panitumumab 6 mg/kg i.v. every 2 weeks followed by two daily administrations of capecitabine 1000 mg/m(2) in 7 days.

RESULTS

During 22 months, 46 patients were included in a single institution. The primary end point, fraction of progression-free survival (PFS) at 6 months, was 31/42 [74%; 95% confidence interval (CI) 58% to 84%]. Forty-two patients had measurable disease. Response rate was 33% and disease control rate 86%. Median PFS was 8.3 months (95% CI 6.7-8.7 months) and median overall survival was 10.0 months (95% CI 7.4-12.7 months). Toxicity was manageable including eight cases of epidermal growth factor receptor-related skin adverse events of grade 2 or more.

CONCLUSIONS

Marker-driven patient selection is feasible in the systemic treatment of biliary tract cancer. Combination chemotherapy with panitumumab in patients with KRAS wild-type tumors met the efficacy criteria for future testing in a randomized trial.

The relationship between serum vascular endothelial growth factor A and microsatellite instability in colorectal cancer

AIM

It has been suggested that colorectal neoplasms with or without microsatellite instability (MSI) can stimulate angiogenesis in different ways. The vascular endothelial growth factor (VEGF) system is essential for the angiogenetic process and the growth of malignant tumours. The aim of this study was to analyse the relationship between serum VEGF-A and the MSI status of patients with colorectal cancer (CRC).

METHOD

In the study, 249 patients with CRC were divided into a test cohort of 83 patients and a validation cohort of 166. MSI was determined using immunohistochemistry. Tumours lacking protein expression of any of the four mismatch repair genes (MLH1, PMS2, MSH2 or MSH6) were labelled as high MSI. The rest were considered to be microsatellite stable (MSS). The serum VEGF-A analyses were performed by ELISA.

RESULTS

The tumours of 15 patients in the test cohort and 27 in the validation cohort were classified as MSI. In the test cohort, patients with an MSI tumour had a significantly higher median serum VEGF-A concentration [617 pg/ml (95% CI 445-863)], compared with patients with an MSS tumour, [317 pg/ml (95% CI 224-386)], P = 0.01. A similar relationship was confirmed in the validation cohort, P = 0.04.

CONCLUSION

This study provides some evidence to suggest that patients with an MSI tumour have higher serum VEGF-A levels than patients with an MSS tumour. If further validated, these findings could be of importance when considering the effects of anti-VEGF-A treatment.

Scandiatransplant report 2009

Scandiatransplant is the Nordic organ exchange organization that has existed for 41 years by a close collaboration between transplant centers. It has been valuable to ensure the optimal usage of available organs for transplantation. Analyzing the database for the past 15 years (1995-2009) revealed that the fraction of organ donors in the age category 60 to 90 years has increased considerably. The number of retrieved organs from deceased donors increased for kidney, liver, and lungs but only slightly for hearts. In the last time period, the mean number of organs retrieved per deceased donor counting only those having a recipient increased to 3.7 for younger donors and to 2.6 from the older group. In 2009, the STAMP (Scandiatransplant acceptable mismatch program) was launched to help highly immunized kidney patients. In 2009, kidney transplantations exhibited for Norway, 60 per million people (pmp); more than 40 pmp for Sweden and for Denmark; approximately 35 pmp for Finland; and more than 20 pmp for the living donor kidney transplantations in Iceland. The best year ever within Scandiatransplant with respect to total number of organ transplantations from deceased and living donors was 2009.

Contrast-enhanced ultrasound vs multidetector-computed tomography for detecting liver metastases in colorectal cancer: a prospective, blinded, patient-by-patient analysis

AIM

This study compared the sensitivity and specificity of contrast-enhanced ultrasound (CEUS) and multidetector-computed tomography (MDCT) in the detection of liver metastases in patients with colorectal cancer.

METHOD

Between September 2004 and December 2008, 271 consecutive patients (146 men and 125 women; median age 68 years, range: 34-91 years) with primary colorectal cancer were evaluated. All underwent combined liver ultrasound and CEUS following intravenous injection of 2.4 ml of SonoVue(TM). The interval from injection to arrival time in the hepatic vein (ATHV) was noted. Contrast-enhanced MDCT in the portal phase was performed and interpreted blindly. In all patients, intra-operative ultrasound was used as the reference point. In addition, magnetic resonance imaging (MRI) or biopsy was performed on all suspicious lesions or if there was inconsistency in the results.

RESULTS

Liver metastases were detected in 21 (8%) patients. Both CEUS and MDCT had a sensitivity of 85.7%, with respective specificities of 97.6% and 95.6%, and positive predictive values of 75%vs 62%. The negative predictive value of both methods was 99%. In patients with and without liver metastases, ATHV was 18 and 22 s, respectively (P < 0.05).

CONCLUSION

CEUS has potential as a diagnostic alternative to MDCT in the detection of liver metastases. ATHV was shorter in patients with liver metastases.

The predictive value of genetic variations in the vascular endothelial growth factor A gene in metastatic colorectal cancer

Single-nucleotide polymorphisms (SNPs) in the vascular endothelial growth factor A (VEGF-A) gene may have clinical implications. The aim of this study was to investigate the possible predictive value of the VEGF-A SNPs, in patients with metastatic colorectal cancer (mCRC) treated with first-line capecitabine and oxaliplatin (XELOX). The study included 72 patients with mCRC. Genomic DNA was isolated from whole blood, and SNPs were analyzed by PCR. SNPs were correlated with response and progression-free survival (PFS). Haplotypes were estimated using the PHASE program. Response was observed in 21% of the patients with the -2578 CA genotype compared with 59% of the patients with CC+AA, P=0.002, in 26% of the patients with the -460 CT genotype compared with 57% with CC+TT, P=0.01, and in 27% of the patients with the +405 GC genotype compared with 54% with GG+CC, P=0.02. Two SNPs were significantly related to PFS. A haplotype with a significant relationship to response was identified. The results demonstrated obvious relationships between genetic variations in the VEGF-A gene and response to first-line XELOX in patients with mCRC, which translated to a significant difference in PFS. The results call for validation in a larger cohort of patients.

The relationship of VEGF polymorphisms with serum VEGF levels and progression-free survival in patients with epithelial ovarian cancer

OBJECTIVE

The vascular endothelial growth factor (VEGF) is an important regulator of angiogenesis and vascular permeability of tumors. In the present study we evaluated the relation of five single nucleotide polymorphisms (SNPs) in the VEGF gene with progression-free survival. Furthermore, we evaluated the functional significance of the SNPs as determined by the influence on serum VEGF levels in ovarian cancer.

METHODS

Serum from 143 consecutive ovarian cancer patients referred for first line platinum/paclitaxel treatment were analyzed for serum VEGF levels using commercially available enzyme-linked immunosorbent assay (ELISA). VEGF gene polymorphisms (-2578 C/A, -1154 G/A, -460 T/C, +405 G/C and +936C/T) were determined by real time PCR using genomic DNA extracted from whole blood samples.

RESULTS

VEGF serum levels were significantly higher in carriers of the 2578C, 460T and 405C, alleles compared to non-carriers (p=0.003, p=0.003 and p=0.001, respectively). There was no significant correlation between VEGF SNP genotypes and progression-free survival. In haplotype analysis, the multivariate survival analysis showed that progression-free survival (PFS) for the patients with the AGCGC haplotype was significantly improved compared to patients with other haplotypes (HR 1.9, p=0.036).

CONCLUSIONS

VEGF polymorphisms were found to be significantly related with serum VEGF levels. The AGCGC haplotype was found to be independently associated with improved PFS.

Clinical outcome in 520 consecutive Danish rectal cancer patients treated with short course preoperative radiotherapy

AIM

The purpose of this study was to analyse the results of preoperative short course radiotherapy in a consecutive, national cohort of patients with rectal cancer.

METHODS

Through a validated, prospective national database we identified 520 Danish patients who presented with high-risk mobile tumours in the lower two thirds of the rectum and were referred for preoperative radiotherapy with 5 x 5 Gy. The inclusion period was 56 months. Radiotherapy data was retrospectively collected.

RESULTS

Of the 520 patients, 514 completed radiotherapy and 506 had surgery. Surgery was considered curative in 439 patients. The 3-year local recurrence rate was 4.0% (95% CI 2.5-6.5%) and the distant recurrence rate at 3 years was 18.7% (95% CI 15.4-22.5%). The 5-year disease free survival rate was 40.2% (95% CI 27.0-53.1%) and overall survival 50.4% (95% CI 36.1-63.1%). Most tumours (61%) were classified as T3 or T4 and 41% of the local recurrences occurred in patients with a fixed tumour at surgery.

CONCLUSION

This study confirms data from randomised studies that the short course 5 x 5 Gy regime is a feasible treatment for locally advanced rectal cancer even when applied in a population outside clinical trials.