Treatment of colorectal cancer. Current guidelines and future prospects for drug therapy

DMF-Net: a deep multi-level semantic fusion network for high-resolution chest CT and X-ray image de-noising

Medical images such as CT and X-ray have been widely used for the detection of several chest infections and lung diseases. However, these images are susceptible to different types of noise, and it is hard to remove these noises due to their complex distribution. The presence of such noise significantly deteriorates the quality of the images and significantly affects the diagnosis performance. Hence, the design of an effective de-noising technique is highly essential to remove the noise from chest CT and X-ray images prior to further processing. Deep learning methods, mainly, CNN have shown tremendous progress on de-noising tasks. However, existing CNN based models estimate the noise from the final layers, which may not carry adequate details of the image. To tackle this issue, in this paper a deep multi-level semantic fusion network is proposed, called DMF-Net for the removal of noise from chest CT and X-ray images. The DMF-Net mainly comprises of a dilated convolutional feature extraction block, a cascaded feature learning block (CFLB) and a noise fusion block (NFB) followed by a prominent feature extraction block. The CFLB cascades the features from different levels (convolutional layers) which are later fed to NFB to attain correct noise prediction. Finally, the Prominent Feature Extraction Block(PFEB) produces the clean image. To validate the proposed de-noising technique, a separate and a mixed dataset containing high-resolution CT and X-ray images with specific and blind noise are used. Experimental results indicate the effectiveness of the DMF-Net compared to other state-of-the-art methods in the context of peak signal-to-noise ratio (PSNR) and structural similarity measurement (SSIM) while drastically cutting down on the processing power needed.

Personalized Medicine-Current and Emerging Predictive and Prognostic Biomarkers in Colorectal Cancer

Colorectal cancer (CRC) is the third most common cancer diagnosed worldwide and is heterogeneous both morphologically and molecularly. In an era of personalized medicine, the greatest challenge is to predict individual response to therapy and distinguish patients likely to be cured with surgical resection of tumors and systemic therapy from those resistant or non-responsive to treatment. Patients would avoid futile treatments, including clinical trial regimes and ultimately this would prevent under- and over-treatment and reduce unnecessary adverse side effects. In this review, the potential of specific biomarkers will be explored to address two key questions—1) Can the prognosis of patients that will fare well or poorly be determined beyond currently recognized prognostic indicators? and 2) Can an individual patient’s response to therapy be predicted and those who will most likely benefit from treatment/s be identified? Identifying and validating key prognostic and predictive biomarkers and an understanding of the underlying mechanisms of drug resistance and toxicity in CRC are important steps in order to personalize treatment. This review addresses recent data on biological prognostic and predictive biomarkers in CRC. In addition, patient cohorts most likely to benefit from currently available systemic treatments and/or targeted therapies are discussed in this review.

Irinotecan toxicity during treatment of metastatic colorectal cancer: focus on pharmacogenomics and personalized medicine

Colorectal cancer, one of the most frequent types of cancer worldwide, has a high mortality rate. Irinotecan (CPT-11) has been approved for the treatment of advanced or metastatic disease either as a single agent or, more commonly, as part of combined chemotherapeutic regimens. Treatment with irinotecan is often accompanied by severe toxicity (e.g. neutropenia and diarrhea) that can result in treatment interruption or cessation, thus jeopardizing the patient's prognosis and quality of life. Irinotecan is bioactivated into its metabolite SN-38, which is subsequently detoxified by uridine diphosphate-glucuronosyl transferases (mainly UGT1A1). Further, ABC transporters (i.e. ABCB1, ABCC1-ABCC6, and ABCG2) are responsible for drug efflux into bile and urine whereas OATP transporters (SLCO1B1) enable its influx from blood into hepatocytes. Genetic polymorphisms in these enzymes/pumps may result in increased systemic SN-38 level, directly correlating with toxicity. Contemporary research is focused on the clinical implementation of genetic screenings for validated gene variations prior to treatment onset, allowing tailored individual doses or treatment regimens.

Alpha- and Beta-Cyclodextrin Inclusion Complexes with 5-Fluorouracil: Characterization and Cytotoxic Activity Evaluation

Cyclodextrins are natural macrocyclic oligosaccharides able to form inclusion complexes with a wide variety of guests, affecting their physicochemical and pharmaceutical properties. In order to obtain an improvement of the bioavailability and solubility of 5-fluorouracil, a pyrimidine analogue used as chemotherapeutic agent in the treatment of the colon, liver, and stomac cancers, the drug was complexed with alpha- and beta-cyclodextrin. The inclusion complexes were prepared in the solid state by kneading method and characterized by Fourier transform-infrared (FT-IR) spectroscopy and X-ray powder diffractometry. In solution, the 1:1 stoichiometry for all the inclusion complexes was established by the Job plot method and the binding constants were determined at different pHs by UV-VIS titration. Furthermore, the cytotoxic activity of 5-fluorouracil and its complexation products were evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay on MCF-7 (breast cancer cell line), Hep G2 (hepatocyte carcinoma cell line), Caco-2 (colon adenocarcinoma cell line), and A-549 (alveolar basal epithelial carcinoma cell line). The results showed that both inclusion complexes increased the 5-fluorouracil capability of inhibiting cell growth. In particular, 5-fluorouracil complexed with beta-cyclodextrin had the highest cytotoxic activity on MCF-7; with alpha-cyclodextrin the highest cytotoxic activity was observed on A-549. The IC₅₀ values were equal to 31 and 73 µM at 72 h, respectively. Our results underline the possibility of using these inclusion complexes in pharmaceutical formulations for improving 5-fluorouracil therapeutic efficacy.

Population pharmacokinetics of 5-fluorouracil in colorectal cancer patients

Aims. The pharmacokinetics of 5-fluorouracil (5-FU) after intravenous administration in color- ectal cancer patients were examined using population analysis. The relevant covariates and the extent of inter- and intraindividual variability were evaluated.

Methods. Data from 27 patients with diagnosis of nonmetastatic colorectal adenocarcinoma receiving weekly 5-FU (450 mg/m2), plus levamisol 50 mg/8 hours by oral route for 3 days every 15 days, were pooled with data from 17 patients with diagnosis of metastatic colorectal adenocarcinoma, receiving daily 5-FU (425 mg/m2) and intravenous folinic acid (20 mg/m2) over five consecutive days (daily times five), every four weeks. In both groups 5-FU was administered as a 60-minute infusion and blood samples were collected at 10, 30 and 60 minutes from the end of the infusion, and analysed using a validated high-performance liquid chromatography assay. An open two-compartmental pharmacokinetic model with first-order elimination from central compartment was fitted to the plasma concentration data using nonlinear mixed effect modelling (NONMEM). The potential effect of patient covariates was evaluated using a stepwise method. Model evaluation was performed using bootstrap method.

Results. The pharmacokinetic model was successfully fitted to the data. None of the covariates tested were significantly correlated to the pharmacokinetic parameters. The mean parameters’ estimates (%CV) and the percent coefficient of variation of the central tendency parameters, interindividual (IIV), interoccasion (IOV) and residual variability (s) for the final model were: CL (L/h), 65.3 (13.2); Vc (L), 14.7 (11.8); Vp (L), 334.0 (31.4); Q (L/h), 19.6 (25.5); IIVCL (%), 76.5 (34.6); IIVVc (%), 82.3 (31.0); IIVVp (%), 137.5 (35.1); IIVQ (%), 117.5 (38.5); IOVCL (%), 66.1 (45.3); IOVVc (%), 70.8 (39.5); IOVQ (%), 81.1 (27.8) and s (%), 3.0 (25.4). The bootstrap resampling method confirmed the stability of the final model. The estimates of the central tendency parameters, IIV, IOV and residual variability were essentially equal to those generated with the original dataset (0% to 18% deviation) and the 95% confidence intervals included the mean parameters’ estimates obtained from the former set.

Conclusions. The two-compartmental model accurately described the pharmacokinetics of 5-FU administered by short-term infusion. A population pharmacokinetic approach is a useful tool to integrate the knowledge gathered in the clinical setting. The model developed may help in dose adaptation and will further be used in PK/PD modelling of therapeutic outcomes and adverse events.

The efficacy and safety of panitumumab in the treatment of patients with metastatic colorectal cancer: a meta-analysis from five randomized controlled trials

Background

The efficacy of adding panitumumab to chemotherapy remains controversial in the treatment of metastatic colorectal cancer (mCRC). Thus, we conducted this meta-analysis to assess the efficacy and safety of this combination regimen in patients with mCRC.

Methods

The PubMed, Embase, and Web of Science databases were comprehensively searched. Eligible studies included randomized controlled trials (RCTs) that estimated the efficacy of panitumumab with or without chemotherapy in the treatment of patients with mCRC. Hazard ratio (HR), risk ratio (RR), and 95% confidence intervals (CIs) were calculated, and heterogeneity was tested using I² statistics.

Results

Four studies involving a total of 3,066 patients were included in this meta-analysis. The addition of panitumumab to chemotherapy significantly improved progression-free survival (PFS) (HR =0.84, 95% CI =0.78–0.91, P=0.000) and the objective response rate (ORR) (RR =2.18, 95% CI =1.13–4.22, P=0.021) compared to chemotherapy alone, but no effect was noted on overall survival (OS) (HR =0.97, 95% CI =0.89–1.05, P=0.402). Subgroup analysis based on KRAS gene status revealed that the combined therapy significantly improved PFS (HR =0.71, 95% CI =0.57–0.88, P=0.002) and ORR (RR =2.43, 95% CI =1.21–4.90, P=0.013) in patients with wild-type KRAS tumors. Irinotecan-based chemotherapy plus panitumumab significantly prolonged PFS in patients with mCRC (HR =0.84, 95% CI =0.76–0.94, P=0.002). The combined treatment also increased the incidence of grade 3/4 adverse events.

Conclusion

This meta-analysis indicates that the combination of panitumumab and chemotherapy effectively improved PFS and ORR, but it did not prolong OS. However, as the number of studies in the meta-analysis was limited, more large-scale, better-designed RCTs are needed to assess the combination of panitumumab and chemotherapy.

Efficacy and toxicity of adding cetuximab to chemotherapy in the treatment of metastatic colorectal cancer: a meta-analysis from 12 randomized controlled trials

Cetuxiamb, a monoclonal antibody against epidermal growth factor receptor (EGFR), has been used in combination with chemotherapy for patients with metastatic colorectal cancer (mCRC). However, the efficacy of combined therapies of cetuximab and different chemotherapy regimens remains controversial. Therefore, we conducted a meta-analysis to evaluate the efficacy and toxicity of adding cetuximab to oxaliplatin-based or irinotecan-based chemotherapeutic regimens for the treatment of patients with mCRC with wild-type/mutated KRAS tumors. Randomized controlled trials (RCTs), published in Pubmed and Embase were systematically reviewed to assess the survival benefits and toxicity profile mCRC patients treated with cetuximab plus chemotherapy. Outcomes included overall survival (OS), progression-free survival (PFS), overall response rate (ORR), and toxicities. Results were expressed as the hazard ratio (HR) with 95 % confidence intervals (CI). Pooled estimates were generated by using a fixed-effects model or a randomized-effects model, depending on the heterogeneity among studies. A total of 12 trials involving 6,297 patients met the inclusion criteria and were included in this meta-analysis. All patients were administered oxaliplatin-based or irinotecan-based chemotherapy with or without cetuximab. Pooled results showed that the addition of cetuximab did not significantly improve the OS (HR = 0.99, 95 % CI = 0.89-1.09; Z = 0.28, P = 0.78) or PFS (HR = 0.94, 95 % CI = 0.81-1.10; Z = 0.76, P = 0.49), but did improve ORR (RR = 1.34, 95 % CI = 1.08-1.65; Z = 2.72, P = 0.00), when compared with chemotherapy alone. Subgroup analysis showed the highest PFS benefit in patients with wild-type KRAS tumors (HR = 0.80, 95 % CI = 0.65-0.99; Z = 2.1, P = 0.04) or wild-type KRAS/BRAF tumors (HR = 0.64, 95 % CI = 0.52-0.79; Z = 4.15, P = 0.00). When combined with cetuximab, irinotecan-based chemotherapy was significantly associated with prolonged PFS (HR = 0.79, 95 % CI = 0.66-0.96; Z = 2.36, P = 0.02) for all patients with differing gene-status. The incidence of grade 3/4 adverse events, including skin toxicity, diarrhea, hypertension, anorexia, and mucositis/stomatitis, was slightly higher in the combined therapy group than in the chemotherapy-only group. Based on the current evidence, the addition of cetuximab to chemotherapy significantly improves the PFS in patients with wild-type KRAS or wild-type KRAS/BRAF tumors as well as the ORR in all patients. In addition, irinotecan-based combination therapy showed a beneficial effect on the PFS in all patients. These findings confirm the use of cetuximab in combination with chemotherapy for the treatment of patients with mCRC with wild-type KRAS tumors. Further multi-center RCTs are needed to indentify these findings.

Predictors of irinotecan toxicity and efficacy in treatment of metastatic colorectal cancer

The colorectal cancer ranks high among the malignant tumours in incidence and mortality and irinotecan is standardly used in palliative treatment of metastatic disease in every therapeutic line. Unfortunately, the treatment with irinotecan is often associated with severe toxicities, especially neutropenia and diarrhea. The majority of the toxic manifestation is caused by the insufficient deactivation (glucuronidation) of irinotecan active metabolite SN-38 by UGT1A enzyme. The elevated SN-38 plasma concentration is responsible for the hematological and gastrointestinal toxicity that can become life-threatening. The patients carrying the mutation of the gene encoding UGT1A enzyme lack the ability of bilirubin glucuronidation, and suffer from the inherited un-conjugated hyperbilirubinemia (Gilbert syndrome, Crigler-Najjar type 1 and 2 syndrome). The mutations in other enzyme systems also play role in the etiopathogenesis of the irinotecan toxicity: CYP3A (cytochrome P-450), ABC family of transmembrane transporters (adenosine-triphosphate binding cassette). The goal of the contemporary research is to determine the predictive factors that will enable the individual adjustment of the individual drug dosage while minimising the adverse effects and maintaining the treatment benefit.

Chemotherapy for the biliary tract cancers: moving toward improved survival time

BACKGROUND

The biliary tract carcinomas rank fifth in incidence among all gastrointestinal tumours. This group of tumours includes both cholangiocarcinoma and gallbladder carcinoma. Although surgery represents the main therapeutic option for these patients, both radiotherapy and chemotherapy could be used in a multidisciplinary approach. Several studies are currently available on the use of chemotherapy, including 5-fluorouracil, mitomycin C, methotrexate, doxorubicin and cisplatin or newer anticancer molecules, such as gemcitabine, capecitabine, oxaliplatin and irinotecan. However, the small sample size of most of these studies prevents generalization.

DISCUSSION

We reviewed the available data on both chemotherapy and targeted therapies for biliary carcinoma. By using conventional chemotherapy, a response rate ranging from 10% to 40% has been reported. Although encouraging data emerged with the use of targeted therapies, further efforts are needed to improve treatment options for patients with biliary tract cancer.

A novel polypeptide extracted from Ciona savignyi induces apoptosis through a mitochondrial-mediated pathway in human colorectal carcinoma cells

BACKGROUND

Sessile marine animals such as sponges, ascidians, and bryozoans are a rich source of bioactive natural products, many of which exhibit potent anticancer activity.

MATERIALS AND METHODS

We extracted and purified a polypeptide with potent antitumor activity from Ciona savignyi by acetone fractionation, ultrafiltration, ion exchange chromatography, gel chromatography, and high-performance liquid chromatography. An MTT assay was used to study the cytotoxicity of the isolated fraction and the purified polypeptide. Cell cycle and Western blot analysis were performed to study the mode of action of the purified polypeptide.

RESULTS

A novel polypeptide with potent antitumor activity was purified. The molecular weight of the polypeptide, designated CS5931, was 5931 Da, and use of the genome basic local alignment search tool (BLAST) revealed that the N-terminal sequence of CS5931 is identical to that of granulin A from C savignyi. CS5931 exhibited significant cytotoxicity for several cancer cell types and induced apoptotic death in HCT-8 cells in a dose- and time-dependent manner. Cell cycle analysis demonstrated that CS5931 caused cell cycle arrest at the G(2)/M phase, and a sub-G(1) peak appeared after treating the cells with CS5931 for 12 hours. The mitochondrial-mediated pathway was implicated in CS5931-induced apoptosis.

CONCLUSION

Our observations clearly demonstrate the antiproliferative and proapoptotic activities of the polypeptide CS5931 from C savignyi and the mitochondrial-mediated pathway involved in the polypeptide-induced cell death.

Cetuximab-based therapy vs noncetuximab therapy in advanced or metastatic colorectal cancer: a meta-analysis of seven randomized controlled trials

PURPOSE

A meta-analysis was performed to assess the efficacy and safety of cetuximab-based therapy vs noncetuximab therapy in advanced or metastatic colorectal cancer.

METHOD

A total of 4617 patients from seven randomized controlled trials were available for analysis, with 2305 patients in the cetuximab group and 2312 patients in the noncetuximab group. The efficacy data included progression-free survival (PFS), overall survival (OS) and overall response rate (ORR). The safety data that contained overall grade 3 and 4 adverse events (AEs), specific grade 3 and 4 toxicity such as acneiform rash, cetuximab-related skin toxicity, diarrhoea, fatigue, neutropenia, hypertension, nausea and hand-foot skin reaction are evaluated.

RESULT

There was a significant PFS benefit in favour of cetuximab-based therapy (HR = 0.68, 95%CI: 0.63 to 0.73) and OS benefit (HR = 0.90, 95%CI: 0.81 to 1.00). The ORR was significantly higher in the cetuximab-based arm (OR = 2.19, 95% CI: 1.30 to 3.68). The incidence of overall grade 3-4 toxicity was significantly higher in the cetuximab arm compared with the noncetuximab arm (61.2%vs 43.0%, OR = 2.32, 95%CI: 1.59-3.39). This difference was mainly attributed to cetuximab-related skin toxicity (OR = 5.86, 95%CI: 1.38-24.88), especially acneiform rash (OR = 51.37, 95%CI: 22.75-116.02). In addition, cetuximab resulted in a significant increase in grade 3 and 4 diarrhoea, fatigue and neutropenia, except for hypertension, nausea and hand-foot skin reaction.

CONCLUSION

Cetuximab-based therapy improves PFS and OS resulting in better ORR vs noncetuximab therapy. Its most common and severe AE is skin toxicity that should be predictable and manageable.

IGF-I activates caspases 3/7, 8 and 9 but does not induce cell death in colorectal cancer cells

BACKGROUND

Colorectal cancer is the third most common cancer in the western world. Chemotherapy is often ineffective to treat the advanced colorectal cancers due to the chemo-resistance. A major contributor to chemo-resistance is tumour-derived inhibition or avoidance of apoptosis. Insulin-like growth factor I (IGF-I) has been known to play a prominent role in colorectal cancer development and progression. The role of IGF-I in cancer cell apoptosis is not completely understood.

METHODS

Using three colorectal cancer cell lines and one muscle cell line, associations between IGF-I and activities of caspase 3/7, 8 and 9 have been examined; the role of insulin-like growth factor I receptor (IGF-IR) in the caspase activation has been investigated.

RESULTS

The results show that exogenous IGF-I significantly increases activity of caspases 3/7, 8 and 9 in all cell lines used; blocking IGF-I receptor reduce IGF-I-induced caspase activation. Further studies demonstrate that IGF-I induced caspase activation does not result in cell death. This is the first report to show that while IGF-I activates caspases 3/7, 8 and 9 it does not cause colorectal cancer cell death.

CONCLUSION

The study suggests that caspase activation is not synonymous with apoptosis and that activation of caspases may not necessarily induce cell death.

Transcription factor PDX-1 in human colorectal adenocarcinoma: A potential tumor marker?

AIM: To examine the expression of pancreatic duodenal homeobox-1 (PDX-1) transcription factor in human colorectal cancer.

METHODS: RT-PCR, Western blotting, and immuno-histochemistry were performed to determine the expression pattern of transcription factor PDX-1 in primary colorectal tumor, hepatic metastasis, and benign colon tissue from a single patient.

RESULTS: The highest PDX-1 transcription levels were detected in the metastasis material. Lower levels of PDX-1 were found to be present in the primary tumor, while normal colon tissue failed to express detectable levels of PDX-1. Western blot data revealed a PDX-1 expression pattern identical to that of mRNA expression. Immunohistochemistry confirmed high metastasis PDX-1 expression, lower levels in the primary tumor, and the presence of only traces of PDX-1 in normal colon tissue.

CONCLUSION: These data argue for further evaluation of PDX-1 as a biomarker for colorectal cancer.

Pharmacokinetic and pharmacogenetic determinants of the activity and toxicity of irinotecan in metastatic colorectal cancer patients

This study aims at establishing relationships between genetic and non-genetic factors of variation of the pharmacokinetics of irinotecan and its metabolites; and also at establishing relationships between the pharmacokinetic or metabolic parameters and the efficacy and toxicity of irinotecan. We included 49 patients treated for metastatic colorectal cancer with a combination of 5-fluorouracil and irinotecan; a polymorphism in the UGT1A1 gene (TA repeat in the TATA box) and one in the CES2 gene promoter (830C>G) were studied as potential markers for SN-38 glucuronidation and irinotecan activation, respectively; and the potential activity of CYP3A4 was estimated from cortisol biotransformation into 6β-hydroxycortisol. No pharmacokinetic parameter was directly predictive of clinical outcome or toxicity. The AUCs of three important metabolites of irinotecan, SN-38, SN-38 glucuronide and APC, were tentatively correlated with patients' pretreatment biological parameters related to drug metabolism (plasma creatinine, bilirubin and liver enzymes, and blood leukocytes). SN-38 AUC was significantly correlated with blood leukocytes number and SN-38G AUC was significantly correlated with plasma creatinine, whereas APC AUC was significantly correlated with plasma liver enzymes. The relative extent of irinotecan activation was inversely correlated with SN-38 glucuronidation. The TATA box polymorphism of UGT1A1 was significantly associated with plasma bilirubin levels and behaved as a significant predictor for neutropoenia. The level of cortisol 6β-hydroxylation predicted for the occurrence of diarrhoea. All these observations may improve the routine use of irinotecan in colorectal cancer patients. UGT1A1 genotyping plus cortisol 6β-hydroxylation determination could help to determine the optimal dose of irinotecan.

Determination of ERCC2 Lys751Gln and GSTP1 Ile105Val gene polymorphisms in colorectal cancer patients: relationships with treatment outcome

INTRODUCTION

Glutathione S-transferase P1 (GSTP1) and excision-repair cross-complementing repair deficiency group 2 protein (ERCC2 or XPD) may modulate the activity of platinum derivatives. The SNPs, Ile105Val for GSTP1 and Lys751Gln for ERCC2, may affect the efficiency of oxaliplatin in patients treated with an oxaliplatin-based regimen for metastatic colorectal carcinoma.

PATIENTS & METHODS

A total of 107 patients treated with first-line chemotherapy, 59 with an oxaliplatin-based regimen and 48 with an irinotecan-based regimen, were included retrospectively. GSTP1 and ERCC2 genotypes were identified on DNA samples extracted from paraffin blocks containing either normal tissue (nodes) or tumor tissue. We analyzed treatment response, event-free and overall survival.

RESULTS

GSTP1 genotype distribution was Ile/Ile 58%, Ile/Val 35% and Val/Val 7%. ERCC2 genotype distribution was Lys/Lys 49%, Lys/Gln 44%, Gln/Gln 7%. Event-free and overall survivals were not significantly different as a function of the GSTP1 genotype, whatever the treatment received. Event-free survival was significantly different as a function of the ERCC2 genotype only in patients receiving oxaliplatin: patients having at least one variant allele had a shorter median event-free survival (6 months) than those having no variant allele (11.6 months, p = 0.008). This difference was maintained for median overall survival (15.6 vs 25.3 months, p = 0.016). Using univariate analysis, ERCC2 genotype, hemoglobinemia and carbohydrate antigen 19.9 plasma levels were significantly related to overall and event-free survival in patients receiving oxaliplatin.

CONCLUSION

The ERCC2 genotype appears as an important predictive factor of the survival of patients treated with oxaliplatin in first-line therapy for metastatic colorectal cancer.

Inducing apoptosis of human colon cancer cells by an IGF-I D domain analogue peptide

Background

The resistance of tumour cells to apoptosis is a major contributor to the limited effectiveness of chemotherapies. Insulin-like growth factor I (IGF-I) has potential to protect cancer cells from variety of apoptotic challenges. This study was carried out to investigate the effect of a novel IGF-I receptor antagonist on apoptosis in colon cancer cells.

Results

We have designed and synthesised a novel antagonist of IGF-I receptor. The effect of this antagonist on human colon cancer cell proliferation was examined by a non-radioactive assay; the apoptosis was revealed by determining the activities of cellular caspases3/7, 8 and 9. The apoptosis pathways were investigated by examining the levels of pro-apoptosis proteins with Western blotting. Following 40 hours treatment with the novel antagonist peptide, colon cancer cell Caspase 3/7 activities increased 2–7 times; Caspase 8 activities increased 2–5 times and Caspase 9 increased 1.2–1.6 times. The proliferation of cancer cell was inhibited by 14–15%. The data showed that the antagonist induced colon cancer cell apoptosis and inhibited cancer cell proliferation. The different changes of Caspase 3/7, 8 and 9 activities suggested that the extrinsic pathways may play a major role in the antagonist peptide-induced apoptosis.

Conclusion

This is the first report on this novel antagonist to induce human colon cancer cell apoptosis and inhibit cancer cell proliferation. These results suggest that IGF-I receptor antagonists may have the potential to be developed as a novel therapy for colon cancers in the future.

Effect of thalidomide on colorectal cancer liver metastases in CBA mice

BACKGROUND AND AIMS

Thalidomide has undergone resurgence in the treatment of specific malignancies. One of the possible actions of thalidomide may be an antiangiogenic effect. This study investigates the effects of thalidomide on tumor growth and long-term survival in a murine model of colorectal liver metastases.

METHODS

Liver metastases were produced in male CBA mice by intrasplenic injection of a dimethyl hydrazine induced MoCR colon cancer murine cell line. Thalidomide was administered daily at doses ranging from 50 to 300 mg/kg by intraperitoneal injection. Tumor growth was assessed using quantitative stereological analysis. The effect on long-term survival was determined at the maximum tolerated dose using Kaplan-Meier analysis. The microvascular effects of thalidomide were assessed by laser Doppler flowmetry (LDF) and microvascular resin casting. Immunohistochemistry was used to determine vascular endothelial growth factor (VGEF) and basic fibroblast growth factor (bFGF) expression.

RESULTS

Thalidomide, (50-300 mg/kg) caused no significant reduction in tumor growth by day 21 following induction of liver metastases and caused systemic toxicity at a dose of 300 mg/kg. At a dose of 200 mg/kg given beyond 35 days, thalidomide significantly reduced tumor growth compared to control, (P = 0.029). No significant impact on survival was however observed (P = 0.93). LDF and microvascular resin casting showed no differences in blood flow or tumor microvascular architecture. VGEF and FGF were expressed in tumors, but remained unaltered by thalidomide administration compared to matched controls.

CONCLUSIONS

Thalidomide caused a significant reduction in the volume of colorectal liver metastases during the late phase of tumor growth. There was however no improvement in survival. Tumor growth reduction in this model did not appear to be due to microvascular changes or altered expression of VGEF or basic FGF. Further investigation into potential mechanisms of action of thalidomide and its synergistic use with other therapies is required.

Chinese medical herbs for chemotherapy side effects in colorectal cancer patients

BACKGROUND

Side effects, including nausea and vomiting, sore mouth , diarrhoea, hepatotoxicity, myelosuppression, and immunosuppression , are commonly encountered in patients with colorectal cancer who are treated with chemotherapy. A variety of Chinese herbal medicines have been used for managing these adverse effects.

OBJECTIVES

To assess the effect of herbal medicines plus chemotherapy, compared with chemotherapy alone, on the side effects of chemotherapy on the quality of life, and on adverse events in patients with colorectal cancer.

SEARCH STRATEGY

We searched the Cochrane Library, MEDLINE, EMBASE, CBM, and handsearched the relevant Chinese journals.

SELECTION CRITERIA

Randomised trials comparing either chemotherapy only or chemotherapy plus anti-emetics (tropisetron, sulpiride etc) with chemotherapy plus Chinese herbs.

DATA COLLECTION AND ANALYSIS

Trial quality was assessed independently by two reviewers. Data were extracted by one reviewer and checked by the second reviewer. Since the four included studies differed significantly in design, we could only perform limited meta-analyses. We have therefore presented the majority of the data in narrative form.

MAIN RESULTS

We included four relevant trials. All of them were of low quality. All of studies used a decoction containing Huangqi compounds as the intervention with chemotherapy. The intervention groups of three studies were compared to a chemotherapy alone control group, the fourth study compared the decoction of Huangqi compounds with two other Chinese herbal interventions. None of the studies reported on primary outcome using Common Toxicity Criteria (CTC). There was a significant reduction in the proportion of patients who experienced nausea & vomiting when decoctions of Huangqi compounds were given in addition to chemotherapy. There was also a decrease in the rate of leucopenia (WBC <3 x 10(9) per L). Huangqi compounds were also associated with increases in the proportions of T-lymphocyte subsets: CD3; CD4 and CD8. Huangqi decoctions had no significant effects on Immunoglobulins G, A or M.

AUTHORS' CONCLUSIONS

Despite the included studies being of low quality, the results suggest that decoctions of Huangqi compounds may stimulate immunocompetent cells and decrease side effects in patients treated with chemotherapy. Due to the methodological limitations of the studies, there is no robust demonstration of benefit. We found no evidence of harm arising from the use of Chinese herbs. We need high quality randomised controlled studies investigating the effects of decoctions of Chinese herbs, particularly Astragalus spp.(as in Huangqi), upon chemotherapy-related side effects.

Validated liquid chromatographic determination of 5-fluorouracil in human plasma

A sensitive, reproducible, selective and accurate high performance liquid chromatographic (HPLC) method for the quantitative determination of 5-flurorouracil in plasma has been developed and validated using isocratic elution and UV detection. The method provides a selective quantifications of 5-flurorouracil without any interference of the endogenous uracil. The assay is performed after a double extraction of 5-flurorouracil and thymine (internal standard) from human plasma using ethyl acetate. The drug and the internal standard were eluted from a Genesis C(18) analytical column at ambient temperature with mobile phase consisting of methanol:water (10:90, v/v) adjusted to pH 3.2 with perchloric acid at a flow rate of 1.0 ml/min. The effluent was monitored with an ultraviolet detector at 260 nm. Quantification was achieved by the measurement of the peak-height ratios and the limit of quantification for 5-flurorouracil in plasma was 30 ng/ml. The retention times for 5-flurorouracil, uracil, and thymine were 4.5, 6.0, and 9.0, respectively. The intra-day coefficient of variation (CV) ranged from 1.35 to 4.53% at three different concentrations and the inter-day CVs varied from 1.29 to 4.98%. The relative and absolute recoveries varied from 96 to 101%. Stability tests showed that 5-flurorouracil is stable for at least 72 h in plasma after freezing. The simple method may permit the assessment of 5-flurorouracil plasma concentrations for pharmacokinetic studies in combination with clinical trials.

Cetuximab

Cetuximab is a chimeric monoclonal antibody highly selective for the epidermal growth factor receptor (EGFR), which is over-expressed by 25-80% of colorectal cancer tumours and associated with advanced disease. Cetuximab induces a broad range of cellular responses in tumours expressing EGFR, enhancing sensitivity to radiotherapy and chemotherapeutic agents. In a large, randomised, open-label, multicentre study in adult patients with irinotecan-refractory, metastatic colorectal cancer expressing EGFR, cetuximab 400 mg/m2 initial dose followed by 250 mg/m2 weekly plus irinotecan (various doses) produced a greater rate of partial response and disease control (partial response plus stable disease), and increased time to disease progression, compared with cetuximab monotherapy; survival was similar in both groups. The same dosage of cetuximab combined with irinotecan, fluorouracil and folinic acid (various regimens) produced partial responses in 43-58% of patients, a complete response in 5% of patients (one study only) and stable disease in 32-52% of patients with treatment-naive metastatic colorectal cancer expressing EGFR in three small, open-label trials. The most common grade 3/4 adverse events associated with cetuximab monotherapy were acne-like rash, asthenia, abdominal pain and nausea/vomiting. In patients receiving cetuximab plus irinotecan, these were diarrhoea, asthenia, leucopenia and neutropenia.

A Phase II Study with CPT-11 Plus Leucovorin and Bolus IV 5-Fluorouracil in Patients with Advanced Colorectal Carcinoma

Standard chemotherapy in advanced colorectal carcinoma (CRC) has not yet been established. The present study was conducted to assess the efficacy and toxicity profile of CPT-11, leucovorin (LV), and bolus 5-fluorouracil (5-FU) in a weekly schedule. Fifty-five patients were entered with no prior chemotherapy for advanced disease or adjuvant treatment ended at least 6 months preceding study entry, and 45 were assessable for response. Patients were treated with CPT-11 80 mg/m2 (7 patients) or 70 mg/m2 (48 patients). After completion of CPT-11 infusion, LV 200 mg/m2 was administered over 2 hr followed immediately by 5-FU 450 mg/m2, IV bolus, weekly for 6 weeks followed by a 2-week rest period. Treatment was continued for four cycles. Because of grade 3 and 4 diarrhea in four of the first seven patients, the study was amended to reduce the starting dose of CPT-11 from 80 to 70 mg/m2 weekly. Four complete and 10 partial responses were observed (response rate: 25.5%), the median time to progression (TTP) was 7.7 months, 1-year survival rate was 62.3%, and the median overall survival was 15.0 months. Grade 3 and 4 diarrhea occurred in seven patients (12.7%), four of them treated with CPT-11 80 mg/m2. Grade 3 myelotoxicity occurred in five patients (9.0%). Toxic death because of diarrhea, neutropenia, bacteremia, and sepsis occurred in a patient treated with CPT-11 80 mg/m2. Our results confirm the efficacy of CPT-11, LV, and 5-FU in a weekly schedule in patients with advanced CRC. Further studies are needed to compare the present regimen with higher doses of CPT-11 with LV plus different schedules of 5-FU administration in the treatment of metastatic CRC.

IGF-1R, IGF-1 and IGF-2 expression as potential prognostic and predictive markers in colorectal-cancer

Insulin-like growth factors (IGF-1 and IGF-2) and the IGF-1 membrane receptor (IGF-1R) have been found to play a critical role in the carcinogenesis of several tumors, among them colorectal cancer (CRC). To study the prognostic impact of these molecules, a total number of 713 cases of CRC were examined for the expression of IGF-1, IGF-2, and IGF-1R. The results were correlated with other clinicopathological data and clinical follow-up. IGF-1 expression was noted in 53 (7.5%), IGF-2 in 88 (12.6%), and IGF-1R in 698 (99.6%) of the cases. There were significant associations between the two growth factors ( P<0.00001), between IGF-1 and Ki-67 proliferation activity ( P<0.05), and between IGF-2 and tumor stage ( P<0.005). IGF-2 positivity was significantly correlated to a worse clinical outcome ( P<0.005) only in univariate, but not in multivariate, survival analysis. A similar trend was obtained for patients with IGF-1-positive CRC, but reached statistical significance only in limited tumor stages (pT1/pT2; P<0.01). Although the synchronous expression of IGF-1, IGF-2, and IGF-1R in a subset of CRC is consistent with an auto-/paracrine loop of cancer cell autostimulation, the prognostic effect of IGF-1 and IGF-2 expression seems to be of limited value. However, the identification of IGF-positive CRC might be beneficial for predictive reasons, as new molecular therapeutic approaches are aimed at the IGF system and related pathways.

Microsphere design for the colonic delivery of 5-fluorouracil

The treatment of colon cancer has been aimed by approaches of oral drug administration. 5-Fluorouracil is the standard treatment still nowadays and would be a candidate to be delivered orally to the colon. A pH-sensitive polymer Eudragit P-4135F was used to prepare microspheres by a simple oil/water emulsification process. Process parameters were analyzed in order to optimize the drug loading and release profiles. In further attempts mixtures with Eudragit RS100 were prepared to prolong drug release. Scanning electron microscopy and confocal laser scanning microscopy permitted a structural analysis. The solvent extraction was preferable over solvent evaporation with a view to the encapsulation rate (extraction: 37%; evaporation: 19%) due to the hydrophilic character of the drug while release pattern were nearly unchanged. Eudragit P-4135F, pure or in mixture, was found to retain drug release at pH 6.8 lower than 35% within 6 h. At pH 7.4, nearly immediate release (within 30 min) was observed for pure P-4135F, while mixtures enabled to prolong the release slightly. Analysis of the morphology led to an inhomogeneous polymer distribution of P-4135F and RS100 throughout the particle core. A capsule-like structure was concluded which allowed only slight changes of the release kinetics by the addition of RS100. However, the formulation proved its applicability in-vitro as a promising device for pH-dependent colon delivery of 5-fluorouracil.

A Bayesian method for predicting 5-fluorouracil pharmacokinetic parameters following short-term infusion in patients with colorectal cancer

The objective of this study was to develop a population pharmacokinetic model and validate it using a Bayesian approach for predicting, a priori and a posteriori, the individual volume of distribution (V(d)) and clearance (Cl) of 5-fluorouracil (5-FU) given as short-term intravenous infusion in weekly and multiple doses. Forty-four patients were divided in group A (5-FU weekly doses) including 27 patients with nonmetastatic colorectal adenocarcinoma treated with 450 mg/m(2) of 5-FU, 1 day per week for 48 doses, plus oral levamisol (50 mg/8 h) for 3 days, every 15 days and group B (5-FU multiple doses) including 17 patients with metastatic colorectal adenocarcinoma, receiving 5-FU (425 mg/m(2)) plus intravenous folinic acid (20 mg/m(2)) over 5 consecutive days, every 4 weeks for six cycles. In both groups 5-FU was administered as a 30-60-min infusion. A total of 176 plasma concentrations were analyzed using a NONMEM program according to a linear one-compartment model. In group A, 5-FU population pharmacokinetic parameters were obtained and the covariables studied were age, gender, weight, ideal body weight, height, body surface area, creatinine clearance, and hepatic function tests. A priori and a posteriori validation of this model was carried out with plasma concentrations obtained in day 1 in group B. In group B, population pharmacokinetic parameters of 5-FU following multiple doses were estimated using scale factors to identify differences in 5-FU V(d) and Cl between days 1 and 4, and the interindividual, interoccasion, and residual variabilities studied. V(d) was 0.266 L/kg of ideal body weight and Cl was 1.21 L/h. kg of total weight following weekly doses. The plasma sample obtained at 10 min gave the best accuracy and precision predictions. When 5-FU was administered in multiple doses, the Cl of the drug in day 4 is reduced by 30.14% compared to day 1. The interoccasion variability was lower than interindividual variability for both V(d) and Cl, suggesting that it could be feasible to individualise dosage of 5-FU for subsequent cycles from data obtained in a previous one in an attempt to improve the therapeutic index of colorectal cancer treatment.

A phase II trial of farnesyl protein transferase inhibitor SCH 66336, given by twice-daily oral administration, in patients with metastatic colorectal cancer refractory to 5-fluorouracil and irinotecan

BACKGROUND

ras genes encode Ras proteins that are important for signal transduction in cancer cells. Farnesyl protein transferase (FPTase) is an enzyme that is responsible for a critical post-translational modification of Ras.

PATIENTS AND METHODS

We report the results of a phase II trial of SCH 66336, an FPTase inhibitor, in patients with metastatic colorectal cancer. This is the first reported experience of an FPTase inhibitor in this disease. All patients were considered refractory to first- and second-line therapy. A total of 21 evaluable patients were treated with a starting dose of 200 mg b.i.d. given continuously.

RESULTS

The major side-effects were fatigue (grade 1 in 42%, grade 2 in 42% and grade 3 in 14%), diarrhea (grade 1 in 23% and grade 3 in 42%) and nausea (grade 2 in 16%). Elevations in serum creatinine (grade 2 or 3) were observed in 19% of patients and appeared to be related to dehydration induced by diarrhea. Significant hematological toxicity was not observed (only grade 1 thrombocytopenia in 19% and grade 2 or 3 anemia in 28%). Pharmacological studies revealed adequate mean pre-dose plasma concentrations in this group of patients on day 15 of therapy. No objective responses were observed, although stable disease was seen in three patients for several months. Administration of SCH 66336 was accompanied by gastrointestinal toxicity.

CONCLUSIONS

Future development of this compound cannot be recommended as monotherapy in this disease.

[Preoperative serum levels of the carcinoembryonic antigen (CEA) and prognosis in colorectal cancer]

OBJECTIVE

To analyze the prognostic value of the preoperative serum levels of the carcinoembryonic antigen (CEA) in primary colorectal carcinoma.

MATERIAL AND METHODS

Preoperative serum levels of CEA were analyzed in 275 colorectal cancer patients, who were followed up for a minimum of 5 years, or until death.

RESULTS

The percentage of positivities for the preoperative serum levels of CEA (> 6 ng/ml) was positively and significantly associated with the tumoral stage (A: 10,5%; B: 38,8%; C: 32,2%; y D: 72%; p < 0,0001). In addition, the elevated serum values of the antigen were significantly associated, in the univariate analysis, with short survival in the overall group of patients (p < 0,0001). However, the multivariate analysis only showed an independent prognosis value of the CEA in the subgroup of patients with stage C tumors.

CONCLUSIONS

Preoperative serum levels of CEA may be useful to predict tumoral extension, and also for the prognosis regarding stage C colorectal cancer patients.

Risk factors determining chemotherapeutic toxicity in patients with advanced colorectal cancer

Antitumour therapy in advanced colorectal cancer has limited efficacy. For decades, fluorouracil has been the main anticancer drug for the treatment of colorectal cancer. Recently, however, new agents have been introduced: raltitrexed, irinotecan and oxaliplatin. Currently, the dosage for an individual patient is calculated from the estimated body surface area of the patient. Toxicity, however, frequently necessitates decreasing the dosage, extending the dose interval or even discontinuing treatment. Risk factors with predictive value for toxicity have been identified in several studies. These risk factors are often determined by the pharmacokinetic and pharmacodynamic properties of the drug. In this review, the risk factors for toxicity of the cytotoxic agents used in the treatment of advanced colorectal cancer are considered. For fluorouracil, age, gender, performance status, genetic polymorphism of dihydropyridine dehydrogenase, drug administration schedule, circadian rhythm of plasma concentrations, history of previous chemotherapy-related diarrhoea, xerostomia, low neutrophil levels, and drug-drug interactions have been identified as affecting chemotherapeutic toxicity. For raltitrexed, gender and renal and hepatic impairment, and for oxaliplatin, renal impairment and circadian rhythm of plasma concentrations, respectively, can be considered as risk factors for toxicity. In addition, age, performance status, bilirubinaemia, genetic polymorphism of uridine 5'-diphosphate-glucuronyltransferase-1A1 and drug administration schedule have been shown to be related to irinotecan toxicity. The available literature suggests that dose adjustment based on these risk factors can be used to individualise the dose in order to decrease toxicity and to improve the therapeutic index. This also applies to therapeutic drug monitoring, which has been shown to be effective controlling the toxicity of fluorouracil in some studies. Future research is warranted to assess the potential advantage of dose individualisation of chemotherapy founded on risk factors, over direct dose calculation from the estimated body surface area, with regard to toxicity, therapeutic index, and quality of life, in patients with advanced colorectal cancer.

Improved results in rectal cancer surgery-an effect of specialization?

OBJECTIVE

The surgeon- and hospital-related variability in outcome after surgery for rectal cancer has been much debated. This study comprises a 6-year period of rectal cancer treatment at a single surgical Institution, where substantial changes in the treatment strategy of rectal cancer were implemented.

PATIENTS AND METHODS

Prospective and retrospective analysis of complications, stoma frequency, local recurrence rate and survival in 252 patients operated on for rectal cancer before (1990-1992) and after (1994-1996) the creation of a specialized rectal cancer team.

RESULTS

Specialization led to a significant decrease both in the need of permanent stomas (52% before vs 33% after specialization; P=0.02) and in the frequency of local recurrence (18% vs 3%; P=0.002). No increase in the frequency of post-operative complications, re-operations or, specifically, pelvic sepsis could be detected in the later period, although more extensive surgery was used and the anastomotic level decreased from 8 to 4 cm (P < 0.001). Cancer-specific survival at 2 years after operation was significantly higher in patients operated in 1994-1996 than in those operated 1990-1992 (P=0.006).

CONCLUSION

Concentrating the care of patients with rectal cancer to a specialized team seems to improve quality and outcome.

Antagonists of growth hormone-releasing hormone (GH-RH) inhibit IGF-II production and growth of HT-29 human colon cancers

Insulin-like growth factors (IGFs) I and II are implicated in progression of various tumours including colorectal carcinomas. To interfere with the production of IGFs, we treated male nude mice bearing xenografts of HT-29 human colon cancer with various potent growth hormone-releasing hormone (GH-RH) antagonists. Twice daily injections of antagonist MZ-4-71, 10 microg intraperitoneally or 5 microg subcutaneously (s.c.) resulted in a significant 43-45% inhibition of tumour growth. Longer acting GH-RH antagonists, MZ-5-156 and JV-1-36 given once daily at doses of 20 microg s.c. produced a 43-58% decrease in volume and weight of cancers. Histological analyses of HT-29 cancers demonstrated that both a decreased cell proliferation and an increased apoptosis contributed to tumour inhibition. GH-RH antagonists did not change serum IGF-I or IGF-II levels, but significantly decreased IGF-II concentration and reduced mRNA expression for IGF-II in tumours. In vitro studies showed that HT-29 cells produced and secreted IGF-II into the medium, and addition of MZ-5-156 dose-dependently decreased IGF-II production by about 40% as well as proliferation of HT-29 cells. Our studies demonstrate that GH-RH antagonists inhibit growth of HT-29 human colon cancers in vivo and in vitro. The effect of GH-RH antagonists may be mediated through a reduced production and secretion of IGF-II by cancer cells.

Granulocyte apheresis as a possible new approach in cancer therapy: A pilot study involving two cases

Patients with advanced cancer often develop immunodeficiency which may be associated with granulocytosis. The granulocytes have the potential to deplete cytotoxic T cells, resulting in accelerated tumor growth and metastasis. To study the elimination of excess granulocytes using granulocyte apheresis in patients with elevated granulocyte to lymphocyte ratios, 2 patients with recurrent metastatic tumors, were selected. Granulocyte apheresis was performed by extracorporeal vein-to-vein circulation with the G-1 granulocyte and monocyte/macrophage apheresis column filled with cellulose acetate beads, each 2 mm in diameter to adsorb granulocytes and monocytes/macrophages. The patients received 1 or 2 apheresis of 30 to 50 min duration per week, at a flow rate of 30-50 ml/min, with 15 sessions constituting one therapeutic course. Apheresis markedly reduced tumor size and prolonged patient survival time without causing any serious adverse events. The results of the present study suggest that granulocyte and monocyte/macrophage apheresis may be beneficial in patients with metastasizing tumors.