High accuracy of a blood ctDNA-based multimodal test to detect colorectal cancer

BACKGROUND

Detection of circulating tumor DNA (ctDNA) is a minimally invasive and convenient blood-based screening strategy that may increase effectiveness of colorectal cancer (CRC) screening.

PATIENTS AND METHODS

A novel multimodal ctDNA-based blood assay that integrates genomics, epigenomics and fragmentomics, as well as proteomics in a refined version, was tested in blood samples from two cohorts: (i) consecutive fecal immunochemical test (FIT)-positive individuals from the CRC Barcelona stool-based screening program; (ii) patients diagnosed with CRC. Primary endpoint was the performance of the test to detect CRC at different tumor-node-metastasis (TNM) stages. Secondary endpoint was the ability of the test to detect advanced precancerous lesions (advanced adenoma or advanced serrated lesion).

RESULTS

A total of 623 blood samples were analyzed in the primary analysis. Sensitivity and specificity of the assay to detect CRC was 93% and 90%, respectively. The sensitivity of CRC detection according to TNM stages was 84% for stage I, 94% for stage II and 96% for stage III (70/73) (P< 0.024). Sensitivity to detect advanced precancerous lesions was 23% with a refined version of the test (including protein and updating bioinformatic thresholding).

CONCLUSION

A blood-based multimodal ctDNA assay detected CRC with high accuracy. This minimally invasive, accessible and convenient assay may help to increase the effectiveness of CRC screening.

Ultra-selection of metastatic colorectal cancer patients using next-generation sequencing to improve clinical efficacy of anti-EGFR therapy

BACKGROUND

Extended RAS analysis is mandatory in metastatic colorectal cancer (mCRC) patients. The optimal threshold of RAS mutated subclones to identify patients most likely to benefit from antiepidermal growth factor receptor (EGFR) therapy is controversial. Our aim was to assess the clinical impact of detecting mutations in RAS, BRAF, PIK3CA and EGFRS492R in basal tissue tumour samples by using a highly sensitive next-generation sequencing (NGS) technology in mCRC patients treated with chemotherapy plus anti-EGFR or anti-vascular endothelial growth factor.

PATIENTS AND METHODS

Five hundred and eighty-one tumour samples from untreated mCRC patients from 7 clinical studies were collected. Mutational analysis was carried out by standard-of-care (therascreen pyro) with a sensitivity detection of 5% mutant allele fraction (MAF), and compared with NGS technology using 454GS Junior platform (Roche Applied Science, Germany) with a sensitivity of 1%. Molecular results were correlated with clinical outcomes.

RESULTS

After quality assessment, 380 samples were evaluable for molecular analysis. Standard-of-care mutational analysis detected RAS, BRAFV600E or PIK3CA mutations in 56.05% of samples compared with 69.21% by NGS (P = 0.00018). NGS identified coexistence of multiple low-frequency mutant alleles in 96 of the 263 mutated cases (36.5%; range 2-7). Response rate (RR), progression-free survival (PFS) and overall survival (OS) were increasingly improved in patients with RAS wild-type, RAS/BRAF wild-type or quadruple (KRAS/NRAS/BRAF/PIK3CA) wild-type tumours treated with anti-EGFR, assessed by standard-of-care. No additional benefit in RR, PFS or OS was observed by increasing the detection threshold to 1% by NGS. An inverse correlation between the MAF of the most prevalent mutation detected by NGS and anti-EGFR response was observed (P = 0.039). EGFRS492Rmutation was not detected in untreated samples.

CONCLUSIONS

No improvement in the selection of patients for anti-EGFR therapy was obtained by adjusting the mutation detection threshold in tissue samples from 5% to 1% MAF. Response to anti-EGFR was significantly better in patients with quadruple wild-type tumours.

Concordance of blood- and tumor-based detection of RAS mutations to guide anti-EGFR therapy in metastatic colorectal cancer

Background

Circulating tumor DNA (ctDNA) is a potential source for tumor genome analysis. We explored the concordance between the mutational status of RAS in tumor tissue and ctDNA in metastatic colorectal cancer (mCRC) patients to establish eligibility for anti-epidermal growth factor receptor (EGFR) therapy.

Patients and methods

A prospective-retrospective cohort study was carried out. Tumor tissue from 146 mCRC patients was tested for RAS status with standard of care (SoC) PCR techniques, and Digital PCR (BEAMing) was used both in plasma and tumor tissue.

Results

ctDNA BEAMing RAS testing showed 89.7% agreement with SoC (Kappa index 0.80; 95% CI 0.71 − 0.90) and BEAMing in tissue showed 90.9% agreement with SoC (Kappa index 0.83; 95% CI 0.74 − 0.92). Fifteen cases (10.3%) showed discordant tissue-plasma results. ctDNA analysis identified nine cases of low frequency RAS mutations that were not detected in tissue, possibly due to technical sensitivity or heterogeneity. In six cases, RAS mutations were not detected in plasma, potentially explained by low tumor burden or ctDNA shedding. Prediction of treatment benefit in patients receiving anti-EGFR plus irinotecan in second- or third-line was equivalent if tested with SoC PCR and ctDNA. Forty-eight percent of the patients showed mutant allele fractions in plasma below 1%.

Conclusions

Plasma RAS determination showed high overall agreement and captured a mCRC population responsive to anti-EGFR therapy with the same predictive level as SoC tissue testing. The feasibility and practicality of ctDNA analysis may translate into an alternative tool for anti-EGFR treatment selection.

Plasma ctDNA RAS mutation analysis for the diagnosis and treatment monitoring of metastatic colorectal cancer patients

Background

RAS assessment is mandatory for therapy decision in metastatic colorectal cancer (mCRC) patients. This determination is based on tumor tissue, however, genotyping of circulating tumor (ct)DNA offers clear advantages as a minimally invasive method that represents tumor heterogeneity. Our study aims to evaluate the use of ctDNA as an alternative for determining baseline RAS status and subsequent monitoring of RAS mutations during therapy as a component of routine clinical practice.

Patients and methods

RAS mutational status in plasma was evaluated in mCRC patients by OncoBEAM™ RAS CRC assay. Concordance of results in plasma and tissue was retrospectively evaluated. RAS mutations were also prospectively monitored in longitudinal plasma samples from selected patients.

Results

Analysis of RAS in tissue and plasma samples from 115 mCRC patients showed a 93% overall agreement. Plasma/tissue RAS discrepancies were mainly explained by spatial and temporal tumor heterogeneity. Analysis of clinico-pathological features showed that the site of metastasis (i.e. peritoneal, lung), the histology of the tumor (i.e. mucinous) and administration of treatment previous to blood collection negatively impacted the detection of RAS in ctDNA. In patients with baseline mutant RAS tumors treated with chemotherapy/antiangiogenic, longitudinal analysis of RAS ctDNA mirrored response to treatment, being an early predictor of response. In patients RAS wt, longitudinal monitoring of RAS ctDNA revealed that OncoBEAM was useful to detect emergence of RAS mutations during anti-EGFR treatment.

Conclusion

The high overall agreement in RAS mutational assessment between plasma and tissue supports blood-based testing with OncoBEAM™ as a viable alternative for genotyping RAS of mCRC patients in routine clinical practice. Our study describes practical clinico-pathological specifications to optimize RAS ctDNA determination. Moreover, OncoBEAM™ is useful to monitor RAS in patients undergoing systemic therapy to detect resistance and evaluate the efficacy of particular treatments.

MRI assessment and outcomes in patients receiving neoadjuvant chemotherapy only for primary rectal cancer: long-term results from the GEMCAD 0801 trial

Background

Primary chemotherapy has been tested as a possible approach for patients with high risk features but predicted clear mesorectal margins on preoperative MRI assessment. This study investigates the prognostic relevance of baseline and post-treatment MRI and pathology staging in rectal cancer patients undergoing primary chemotherapy.

Patients and methods

Forty-six patients with T3 tumour > =2 mm from the mesorectal fascia were prospectively treated with Neoadjuvant Capecitabine, Oxaliplatin and Bevacizumab prior to surgery between 2009 and 2011. The baseline and post-treatment MRI: T, Nodal and Extra-mural venous invasion (EMVI) status were recorded as well as post-treatment MRI Tumour regression grade (TRG) and modified-RECIST assessment of tumour length. The post-treatment pathology (yp) assessments of T3 substage, N, EMVI and TRG status were also recorded. Three-year disease-free survival (DFS) and cumulative incidence of recurrence were estimated by using the Kaplan-Meier product-limit method, and Cox proportional hazards models were used to determine associations between staging and response on MRI and pathology with survival outcomes.

Results

About 46 patients underwent neoadjuvant chemotherapy alone for high risk margin safe primary rectal cancer. The median follow-up was 41 months, 5 patients died and 11 patients experienced relapse (2 local, 8 distant and 1 both). In total 23/46 patients were identified with MRI features of EMVI at baseline. mrEMVI positive status carried independent prognostic significance for DFS (P = 0.0097) with a hazard ratio of 31.33 (95% CI: 2.3-425.4). The histopathologic factor that was of independent prognostic importance was a final ypT downstage of ypT3a or less, hazard ratio: 14.0 (95% CI: 1.5-132.5).

Conclusions

mrEMVI is an independent prognostic factor at baseline for poor outcomes in rectal cancer treated with neoadjuvant chemotherapy while ≤ypT3a is associated with an improvement in DFS. Future preoperative therapy evaluation in rectal cancer patients will need to stratify treatment according to baseline EMVI status as a crucial risk factor for recurrence in patients with predicted CRM clear rectal cancer.

Phase II trial of preoperative chemoradiotherapy with oxaliplatin, cisplatin, and 5-FU in locally advanced esophageal and gastric cancer

BACKGROUND

Based on a phase I study showing the feasibility of combining of oxaliplatin, cisplatin, and 5-fluorouracil (5-FU) (OCF) with radiation therapy (RT) in esophageal cancer, the efficacy of this regimen in esophageal, gastroesophageal (GE), and gastric (G) cancer was assessed in this phase II multicenter study.

PATIENTS AND METHODS

Patients with resectable tumors were eligible. Treatment included two cycles of oxaliplatin 85 mg/m(2), cisplatin 55 mg/m(2), and continuously infused 5-FU 3 g/m(2) in 96 h and concurrent RT (45 Gy), followed by surgery after 6-8 weeks. Primary end point was complete pathologic response (pCR).

RESULTS

Forty-one patients were enrolled. Tumor location was esophagus 39% (squamous 10/adenocarcinoma 6), GE junction 32%, and stomach 29%. G3-G4 adverse events included asthenia (27%) and neutropenia (14%). One toxic death occurred. Thirty-one patients (75.6%) underwent surgery (R0 in 94%). Pathologic response was achieved in 58% of patients, with pCR in 50% and 16% of esophageal and GE/G cancer, respectively. pCR was achieved in 67% of squamous cell carcinoma. Survival: median follow-up, 50.4 months; median progression-free survival and overall survival were 23.2 and 28.4 months, respectively.

CONCLUSION

Preoperative OCF plus RT showed an acceptable toxicity and promising activity especially in squamous cell esophageal cancer.

Phase II study with preoperative oxaliplatin (O), cisplatin (P), 5-fluorouracil (F) (OPF) and radiation (XRT) in patients with esophageal (ES), gastroesophageal (GE), and gastric (G) cancer

e15612

Background: A phase I study showed the feasibility of the triplet combination (OPF) with XRT in ES and GE cancer (Maurel et al, IJRBOP, 2005). We conducted a phase II study to evaluate the efficacy of the regimen. Methods: Enrolled pts had resectable, high-risk (HR) based on endoscopic ultrasonography (EUS) (uT3, uN1 or uT4 if deemed resectable) ES, GE and G cancer. The primary objective was to determine the pathologic complete response (pCR). If 2 or more pCR were reported in the first 18 pts treated, enrollment continues with 23 additional pts. Eligibility criteria: squamous cell or adenocarcinoma of the ES, GE or G cancer and ECOG Performance status (PS) 0–1. Staging was done with EUS and computed spiral tomography. Laparoscopic staging was mandatory for pts with ES, GE and G adenocarcinoma. Pts received 2 cycles of O 85 mg/m2, P 55 mg/m2, F (3 g/m2 in 96h CI) q4w, with concomitant 45 Gy XRT in 25 fractions; surgery was planned 5–8 weeks after XRT. All pathological specimens were reviewed by a unique pathologist and regression analysis was recorded using Cologne (C) and M.D.Anderson (MDA) classification for ES and European Journal of Surgical Oncology (EJSO) for GE and G. Results: Between 5/04 to 12/07, 41 pts were enrolled in 5 Spanish Institutions. Median age 62 yrs (39–75 yrs); Male/female 83%/17%; PS 0/1 27%/73%; ES/GE/G 39%/32%/29%; EUS stageT3N0 (20%), T2–3N1 (65%) and T4 (10%). G3/4 adverse events included asthenia (27%), infection (7%), diarrhea (7%) and stomatitis (5%). There were 2 toxic deaths. Of the 31 pts who underwent surgery, there were R0=94%/R1=3%/R2= 3%. 7/41 pts (17%) achieved pCR. Using C and MDA classification, 9/14 (61%) and 12/14 (85%) ES achieved grade IV/III and P0/P1 regression, respectively. With EJSO classification 3/17 (18%) GE and G tumors achieved pCR. Median time to progression or death (PFS) was 16.2 (CI:12.2-NR) months (mo). Median overall survival (OS) was 28.9 mo. (CI: 22.5-NR). Conclusions: Although in the whole group pCR, PFS and OS does not appear superior to results achieved in other trials with preoperative P/F/XRT in HR pts, the OPF regimen seems specially active in ES cancer.

No significant financial relationships to disclose.

Prostate cancer. Multidisciplinary approach: a key to success

Diagnosis and treatment of prostate cancer has improved in the last few years, in part due to a multidisciplinary approach between urologists, oncologists, radiotherapists, radiologists, pathologists, basic and translational researchers for a successful management. The TAX 327 study is the paradigm of a smooth communication between expert physicians that led to the approval of docetaxel in metastatic hormone-resistant prostate cancer (HRPC). Survival benefit with docetaxel in HRPC was confirmed in an updated survival analysis reported this year. A nomogram to predict survival in metastatic HRPC treated with chemotherapy was established based on the TAX 327 study. Unfortunately in early prostate cancer, some of the phase III clinical trials with chemotherapy had to be closed due to lack of sufficient accrual, due to, at least in part, an unsuccessful collaboration between urologists, medical oncologists and radiotherapists. In earlier phases of prostate cancer, a successful multidisciplinary approach has led to important advances in genomics, biomarkers and imaging techniques that have created big excitement for future improvements in the management of prostate cancer. An example is the validation of novel molecular diagnosis tests such as PCA3 or TMPRSS2 - ETS in urinary samples. Importantly, we should not forget that the key for a successful future development in the management of prostate cancer will require the expertise of all disciplines to provide optimal care.

The proteasome: a novel target for anticancer therapy

The proteasome is an ubiquituous enzyme complex that plays a critical role in the degradation of many proteins involved in cell cycle regulation, apoptosis and angiogenesis. Since these pathways are fundamental for cell survival and proliferation, particularly in cancer cells, the inhibition of proteasome is an attractive potential anticancer therapy. Bortezomib (Velcade, formerly PS-341) is an extremely potent and selective proteasome inhibitor that shows strong activity in in vitro and in vivo laboratory studies against many solid and hematologic tumor types. Moreover, bortezomib, mainly by inhibition of the NF-kappaB pathway, has a chemosensitizing effect when administered together with other antitumoral drugs. Clinical phase I trials, showed good tolerance of bortezomib at doses that achieved a desired degree of proteasome inhibition. Phase II studies showed high response rates in refractory multiple myeloma patients, which led to the accelerated approval of bortezomib by the Food and Drug Administration (FDA) and the European Medicines Agency (EMEA) for this indication. A phase III trial comparing bortezomib to dexamethasone in refractory/relapsed multiple myeloma patients had to be halted due to a survival advantage in the bortezomib arm. Additional studies are focusing in the potential benefit of bortezomib in newly diagnosed multiple myeloma patients. In other solid and hematological malignancies, phase II studies with bortezomib alone or in combination are ongoing with encouraging results, particularly in lung cancer and lymphoma.

Activation of nuclear factor-kappa B is linked to resistance to neoadjuvant chemotherapy in breast cancer patients

The nuclear factor (NF)-kappaB system is a promising anticancer target due to its role in oncogenesis and chemoresistance in preclinical models. To provide evidence in a clinical setting on the role of NF-kappaB in breast cancer, we aimed to study the value of basal NF-kappaB/p65 in predicting resistance to neoadjuvant chemotherapy, and to characterise the pharmacodynamic changes in NF-kappaB/p65 expression following chemotherapy in patients with locally advanced breast cancer. Pre- and post-chemotherapy tumour specimens from 51 breast cancer patients treated with anthracycline- and/or taxane-containing neoadjuvant chemotherapy were assayed by immunohistochemistry for NF-kappaB/p65 subcellular expression. We studied NF-kappaB/p65, a well-characterised member of the NF-kappaB family that undergoes nuclear translocation when NF-kappaB is activated. Activation of NF-kappaB (i.e. nuclear NF-kappaB/p65 staining in pre-therapy specimens) was linked to chemoresistance. Patients with NF-kappaB/p65 nuclear staining in pre-treatment samples had a 20% clinical response rate, while patients with undetected nuclear staining had a 91% response rate to chemotherapy (P = 0.002). Notably, four patients achieved a complete histological response and none of them had pre-treatment NF-kappaB/p65 nuclear staining. Moreover, the number of patients with NF-kappaB/p65 activation increased after chemotherapy exposure. It is concluded that NF-kappaB/p65 activation assayed by immunohistochemistry is a predictive factor of resistance to neoadjuvant chemotherapy in breast cancer patients. Moreover, NF-kappaB activation was inducible following chemotherapy in a proportion of breast cancer patients. These novel clinical findings strengthen the rationale for the use of NF-kappaB inhibitors to prevent or overcome chemoresistance in breast cancer.

Serum Protein S-100 Predicts Clinical Outcome in Patients with Melanoma Treated with Adjuvant Interferon – Comparison with Tyrosinase RT-PCR

OBJECTIVE

To study the clinical value of the determination of serum S-100 protein as a single tumor marker or in combination with tyrosinase RT-PCR in patients with melanoma receiving adjuvant interferon.

PATIENTS AND METHODS

Patients were tested for serum S-100 protein luminoimmunometric assay and for blood tyrosinase mRNA (RT-PCR), before starting interferon and every 2-3 months thereafter.

RESULTS

One hundred and six patients (stage IIA, 27; IIB, 19; III, 49; and IV, 11) were included in the study. Median follow-up was 51 months (range 2-76). In the univariate analysis, under treatment S-100 > or =0.15 microg/l and a positive RT-PCR correlated with a lower disease-free survival and overall survival (OS). In the multivariate analysis, clinical stage, under therapy positive RT-PCR and S-100 levels > or =0.15 mug/ml, were independent prognostic factors for OS. The hazard ratio for OS was 3.9 (95% CI, 1.67-9.15; p = 0.004) and 2.2 (95% CI, 1.05-4.6; p = 0.016) for S-100 > or =0.15 microg/l and positive RT-PCR, respectively. When both techniques where combined, a positive RT-PCR indicated a poorer clinical outcome only in patients with S-100 <0.15 microg/l.

CONCLUSIONS

S-100 > or =0.15 microg/l and a positive RT-PCR during adjuvant interferon therapy indicate a high risk of death in resected melanoma patients. S-100 determination has a higher positive predictive value than RT-PCR, while tyrosinase RT-PCR adds prognostic information in patients with S-100 <0.15 microg/l.

Preclinical and clinical development of the proteasome inhibitor bortezomib in cancer treatment

The proteasome is a ubiquitous enzyme complex that plays a critical role in the degradation of many proteins involved in cell cycle regulation, apoptosis and angiogenesis. Since these pathways are fundamental for cell survival and proliferation, particularly in cancer cells, the inhibition of proteasome is an attractive potential anticancer therapy. The present review will focus on the proteasome inhibitor bortezomib (Velcade, formerly PS-341; Millennium Pharmaceuticals, Inc., Cambridge, MA, USA). Bortezomib is an extremely potent and selective proteasome inhibitor that shows strong activity in in vitro and in vivo laboratory studies against many solid and hematologic tumor types. Moreover, bortezomib, mainly by inhibition of the NF-kappaB pathway, has a chemosensitizing effect when administered together with other antitumoral drugs. Based on these results, bortezomib entered clinical phase I trials, alone or in combination with chemotherapy, that showed good tolerance at doses that achieved a desired degree of proteasome inhibition. Phase II studies showed high response rates in refractory multiple myeloma patients, which led to the accelerated approval of bortezomib by the U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMEA) for this indication. A phase III trial comparing bortezomib with dexamethasone in refractory/ relapsed multiple myeloma patients had to be halted due to a survival advantage in the bortezomib arm. Additional studies are focusing on the potential benefit of bortezomib in newly diagnosed multiple myeloma patients. In other solid and hematological malignancies, phase II studies with bortezomib alone or in combination with other agents are ongoing. Encouraging results, particularly in lung cancer and lymphoma, have been observed. The critical molecules or genes responsible for tumor sensitivity to bortezomib continue to be evaluated using novel technologies.