J. Maroun

Bevacizumab combined with chemotherapy for patients with advanced colorectal cancer: a systematic review

BACKGROUNDnFluoropyrimidine-based chemotherapy is considered standard treatment of advanced colorectal cancer. Recent studies indicate benefit to the addition of bevacizumab, a recombinant monoclonal antibody targeting vascular endothelial growth factor.nnnMETHODSnMedline, EMBASE, Cochrane Library, and conference proceedings were searched to identify randomized trials in advanced colorectal cancer comparing chemotherapy plus bevacizumab with chemotherapy alone. A meta-analysis of published data was carried out.nnnRESULTSnFive trials comparing chemotherapy plus bevacizumab with chemotherapy alone as first- or second-line treatment were identified. Our meta-analysis indicates an advantage in favor of the addition of bevacizumab to chemotherapy in terms of overall survival (OS) [hazard ratio (HR) 0.79; 95% confidence interval (CI) 0.69-0.90; P = 0.0005], progression-free survival (PFS) (HR 0.63; 95% CI 0.49-0.81, P = 0.0004), and response rate (RR 1.50; 95% CI 1.06-2.10, P = 0.02). The most commonly observed adverse effects related to bevacizumab included hypertension, proteinuria, bleeding, and thrombosis. Gastrointestinal perforation and poor wound healing were also observed; however, their incidence was rare.nnnCONCLUSIONSnFor patients with advanced colorectal cancer receiving first- or second-line fluoropyrimidine-based chemotherapy, the addition of bevacizumab improves PFS and OS at the expense of increased incidence of toxicity. The magnitude of benefit may differ based on the chemotherapy regimen with which bevacizumab is partnered.

Adjuvant Systemic Chemotherapy for Stage II and III Colon Cancer after Complete Resection: An Updated Practice Guideline

AIMSnThe standard adjuvant therapy for resected stage III colon cancer has been intravenous 5-fluorouracil. However, newer chemotherapy agents, such as capecitabine, oxaliplatin and irinotecan, have been investigated in clinical trials since the publication of the original guidelines. The Gastrointestinal Cancer Disease Site Group (DSG) conducted a systematic review of the evidence for the use of adjuvant systemic chemotherapy for patients with resected stage II and III colon cancer and developed an updated practice guideline based on that evidence and expert consensus. The following research questions were addressed: Should patients with stage II or III colon cancer receive adjuvant systemic chemotherapy? What are the preferred adjuvant systemic chemotherapy options for patients with completely resected stage II or III colon cancer? Outcomes of interest were disease-free survival, overall survival, adverse effects and quality of life.nnnMATERIALS AND METHODSnA systematic search of published studies was conducted for the time period following the publication of the original guidelines to identify relevant randomised trials and syntheses of evidence in the form of meta-analyses. Recommendations were based on that evidence, evidence contained in the original guidelines and consensus of the Gastrointestinal Cancer DSG. The systematic review and practice guideline were externally reviewed through a mailed survey of practitioners in Ontario, Canada.nnnRESULTSnRecommendations were drafted based on the available evidence and expert consensus.nnnCONCLUSIONSnThe routine use of adjuvant chemotherapy for all patients with stage II colon cancer is not recommended. However, a subset of patients with high-risk stage II disease should be considered for adjuvant therapy. Patients with completely resected stage III colon cancer should be offered adjuvant chemotherapy. Treatment should depend on factors such as patient suitability and preference, and patients and clinicians must work together to determine the optimal course of treatment.

AmpFlSTR Profiler Plus and AmpFlSTR COfiler analysis of tissues stored in GenoFix, a new tissue preservation solution for mass disaster DNA identification.

A preliminary study was conducted to assess the capability of a new alcohol-based tissue fixative, GenoFix, to preserve DNA from biopsy tissues stored at room temperature and/or -20 degrees C in a freezer, for subsequent short tandem repeat (STR) DNA typing analysis. Fresh human smooth muscle samples were stored at room temperature in GenoFix for one month and up to one year and seven months before being processed using the megaplex STR systems, AmpFlSTR Profiler Plus and AmpFlSTR COfiler. Alternatively, muscle tissues in GenoFix were placed at -20 degrees C in a freezer for up to 3 1/2 years following two to three months in the fixative at room temperature. DNA analysis was also carried out on tissues stored in GenoFix for one month at room temperature and subsequently paraffin-embedded and stored at room temperature for four years. The AmpFlSTR Profiler Plus and AmpFlSTR COfiler STR profiles produced, using DNA extracted from all fixed tissue samples, were of very good quality. The fluorescent signals were well balanced across the nine STR loci or six loci comprised in the megaplexes surveyed and profiles showed no differences with those observed for the control blood of the respective donor patients. Continuous exposure to GenoFix at room temperature (up to one year and seven months) did not compromise the STR typing analysis of the fixed tissues. No adverse effects were noted on the STR typeability of tissues fixed with GenoFix and stored at -20 degrees C in a freezer for up to 3 1/2 years. STR profiles generated from the paraffin-embedded tissues fixed in GenoFix were of excellent quality. This preliminary study suggests that GenoFix can be used to store tissue samples at room temperature for up to one year and seven months or at -20 degrees C in a freezer for longer storage (up to 3 1/2 years). This new and odorless tissue fixative promotes tissue and DNA preservation in a very effective manner and as such may prove useful in criminal investigations or mass disaster identifications carried out in remote locations and in which a small or large number of tissue samples are collected for further analyses.

Consensus Recommendations for the Diagnosis and Management of Pancreatic Neuroendocrine Tumors: Guidelines from a Canadian National Expert Group

Pancreatic neuroendocrine tumors (pNETs) are rare heterogeneous tumors that have been steadily increasing in both incidence and prevalence during the past few decades. Pancreatic NETs are categorized as functional (F) or nonfunctional (NF) based on their ability to secrete hormones that elicit clinically relevant symptoms. Specialized diagnostic tests are required for diagnosis. Treatment options are diverse and include surgical resection, intraarterial hepatic therapy, and peptide receptor radionuclide therapy (PRRT). Systemic therapy options include targeted agents as well as chemotherapy when indicated. Diagnosis and management should occur through a collaborative team of health care practitioners well-experienced in managing pNETs. Recent advances in pNET treatment options have led to the development of the Canadian consensus document described in this report. The discussion includes the epidemiology, classification, pathology, clinical presentation and prognosis, imaging and laboratory testing, medical and surgical management, and recommended treatment algorithms for pancreatic neuroendocrine cancers.

Nuclear Expression of Thymidylate Synthase in Colorectal Cancer Cell Lines and Clinical Samples

Thymidylate synthase (TS) [TYMS; OMIM reference number (188, 350)] is normally considered to be a cytoplasmic enzyme. However, a few reports have suggested it may also be present in the nucleus. To explore this in more detail, we used a highly specific polyclonal antibody to TS and a combination of techniques, including immunocytochemistry, confocal microscopy, cell fractionation, and Western blotting. We developed cell line HeLa-55, a HeLa derivative that grossly overexpresses TS. Although the vast majority of TS was in the cytoplasm, some TS also was seen in the nucleus. TS in parental HeLa cells and in normal human fibroblasts was seen exclusively in the cytoplasm. HeLa-55 cells exposed to 5-fluorodeoxyuridine were fractionated and examined by Western blotting. Interestingly, both free TS and the ternary complex of TS were seen in the cytoplasmic fraction but only free TS was detected in the nuclear fraction. Amongst different cell lines examined, HCT-15 and normal fibroblasts showed no nuclear TS, HCC-2998 and SW-620 showed a small amount of nuclear TS, and HT-29, RKO, and HCT-116 showed a strong nuclear TS signal. Nuclear staining was clearly evident in some clinical colorectal specimens, both normal and malignant. This staining was definitively shown to be TS by competition with recombinant TS protein. A putative leucine-rich nuclear export sequence was identified but its function could not be confirmed. We conclude that small amounts of TS protein is present in the nucleus of some cell types but further work is needed to determine the significance of this observation.

Expression of thymidylate synthase in human cells is an early G(1) event regulated by CDK4 and p16INK4A but not E2F.

Thymidylate synthase (TS) is the enzyme that catalyses the last step in de novo thymidylate synthesis. It is of interest clinically because it is an effective target for drugs such as 5-fluorouracil, often used in combination therapy. Despite a number of earlier reports indicating that TS is a cell cycle-dependent enzyme, this remains equivocal. Here, we show that in HCT116 cells synchronised by serum starvation, there is a clear dissociation between the expression of cyclin E (a well-characterised cell-cycle protein) and TS. Although both cyclin E and TS mRNA and protein increased during G1, TS upregulation was delayed. Moreover, TS levels did not decrease following S-phase completion while cyclin E decreased sharply. Similarly, clear differences were seen between cyclin E and TS as asynchronously growing HCT116 cells were growth-inhibited by low-serum treatment. In contrast to previous reports using rodent cells, adenovirus-mediated over-expression of E2F1 and cyclin E in three human cell lines had no effect on TS. Cell-cycle progression was blocked by treatment of cells with pharmacological inhibitors of CDK2 and CDK4 and by ectopic expression of p16INK4A. Whereas CDK2 inhibition had no effect on TS levels, inhibition of CDK4 was associated with decreased TS protein levels. These results provide the first evidence that drugs targeting CDK4 may be useful with anti-TS drugs as combination therapy for cancer.

Characterization of a Polyclonal Antibody to Human Thymidylate Synthase Suitable for the Study of Colorectal Cancer Specimens

Measurement of thymidylate synthase (hTS) using immunohistochemical techniques has been reported in several clinical studies. However, its value as a prognostic indicator is still not clear. To pursue this, we have developed a new rabbit polyclonal antibody, hTS7.4. The antigen was recombinant hTS containing an N-terminal His6-tag. Antiserum hTS7.4 detected recombinant hTS by ELISA at a titer of 1:100,000. Western blot analysis of several human cell lines showed a single band of the expected 36-kD molecular size. HeLa cells treated with the TS inhibitor 5-FUdR showed the expected additional band corresponding to the ternary complex of hTS-dFUMP-reduced folate. hTS7.4 detected TS in bacterial, rat, mouse, and monkey cell extracts, and hTS8.3 (a closely related antiserum) immunoprecipitated a 36-kD [35 S]-methionine-labeled protein from HeLa extracts. TS was detectable by indirect immunofluorescence in HeLa cells. Proliferating normal human fibroblasts in culture showed staining, but nonproliferating cells did not. Lymphocytes in the germinal center of human tonsil tissue, which are known to be proliferating, stained with hTS7.4 and also with monoclonal antibody TS106. TS may therefore be useful as an immunohistochemical marker of cell proliferation. Normal colon mucosa showed weak staining, whereas some colorectal cancer specimens stained very strongly with hTS7.4. A clinical study of colorectal cancer using this antibody is in progress.

Eastern Canadian Colorectal Cancer Consensus Conference: standards of care for the treatment of patients with rectal, pancreatic, and gastrointestinal stromal tumours and pancreatic neuroendocrine tumours

The annual Eastern Canadian Colorectal Cancer Consensus Conference was held in Halifax, Nova Scotia, October 20-22, 2011. Health care professionals involved in the care of patients with colorectal cancer participated in presentation and discussion sessions for the purposes of developing the recommendations presented here. This consensus statement addresses current issues in the management of rectal cancer, including pathology reporting, neoadjuvant systemic and radiation therapy, surgical techniques, and palliative care of rectal cancer patients. Other topics discussed include multidisciplinary cancer conferences, treatment of gastrointestinal stromal tumours and pancreatic neuroendocrine tumours, the use of folfirinox in pancreatic cancer, and treatment of stage ii colon cancer.

A multicentre, open-label phase II study of I rinotecan, capecitabine ( X eloda®), and O xaliplatin (IXO) as first-line treatment in patients with metastatic gastric or gastroesophageal junction (GEJ) adenocarcinoma

SummaryPurpose Chemotherapy remains the primary treatment for metastatic gastric/GEJ cancer but optimal agents and schedule remain controversial. This study examined the safety and efficacy of first-line Irinotecan, capecitabine (Xeloda®), and Oxaliplatin (IXO). Patients and Methods Eligible patients with HER2-unamplified/unknown, metastatic gastric/GEJ adenocarcinoma were treated with 21-dayxa0cycle IXO at dose level 1 (DL1: Day 1 O-100xa0mg/m2 & I-160xa0mg/m2 IV, Day 2–15 X-1900xa0mg/m2/day PO divided doses) or modified IXO (mIXO): Day 1 O-85xa0mg/m2 & I-120xa0mg/m2 IV, Day 2–15 X-1425xa0mg/m2/day PO divided doses). This Bryant and Day two-stage designed study had dual primary endpoints of objective response rate (ORR) and toxicity. Secondary endpoints were overall survival (OS) and progression-free survival (PFS). Results Fifty patients were enrolled and received a median of 7xa0cycles. After accrual of 9 patients at DL1, evaluable RR was 88% however dose limiting toxicity (DLT) rate was 56% thus doses were adjusted to mIXO. Fifteen patients accrued at mIXO had a RR of 60% and DLT rate of 13% allowing continuation to stage 2. Overall, 48 and 49 patients were evaluable for efficacy and safety, respectively, with ORR of 54% and DLTs in 24% of patients (DL1u2009=u200956%; mIXOu2009=u200918%). Disease control rate was 85%. The most frequent grade 3/4 adverse events were diarrhea, neutropenia, fatigue, hypokalemia, and nausea. Median PFS and OS were 7.5 and 13.0xa0months, respectively, with a median follow-up of 9.7xa0months. Conclusion mIXO demonstrates promising ORR, PFS, OS, and acceptable toxicity compared to standard triplet regimens. IXO should be evaluated in phase III trials.

Corrigendum: Eastern Canadian Gastrointestinal Cancer Consensus Conference 2014

[This corrects the article DOI: 10.3747/co.22.2603.].