Review article: current management of metastatic colorectal cancer - the evolving impact of targeted drug therapies

BACKGROUND

The field of colorectal cancer chemotherapy has been transformed by the advent of molecule-specific drugs. Combined use of such drugs enhances tumour response rates, but controlled data quantifying the relative efficacy and cost-effectiveness of different drug combinations on overall survival remain scarce.

AIM

To conduct an overview of published clinical trials in advanced colorectal cancer, with the objective of framing provisional approaches to current management.

METHODS

An NCBI/PubMed search was performed using the strings, 'colorectal cancer' ('metastatic' or 'advanced' or 'palliative') and ('chemotherapy' or 'drug therapy' or 'targeted' or 'target-specific' or 'molecularly-targeted').

RESULTS

Combinations of target-specific drugs (with or without the DNA-alkylating agent oxaliplatin) have substantially enhanced colorectal cancer time to progression over the last decade and have also expedited surgical resection of liver metastases. Disease-free survival, overall survival and quality of life are favourably influenced.

CONCLUSIONS

Target-specific drugs improve palliative efficacy in the setting of advanced colorectal cancer. However, key issues persist as to the cost-effectiveness of these newer drug treatments, and further controlled trials are needed to resolve this important debate.

Characterization of sperm chromatin quality in testicular cancer and Hodgkin's lymphoma patients prior to chemotherapy

BACKGROUND

Although the incidences of testicular cancer and Hodgkin's lymphoma have increased in young men over the past decade, combination chemotherapy has improved survival. As fertility is of importance to these patients, characterization of sperm chromatin structure is needed. We assessed sperm chromatin in testicular cancer and Hodgkin's lymphoma patients prior to chemotherapy, in comparison with control community and idiopathic infertile volunteers.

METHODS

DNA damage was assessed with the sperm chromatin structure assay (SCSA), terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) and comet assays; reactive thiols (SH) and DNA compaction were determined with the monobromobimane (mBBr) and chromomycin A3 (CMA3) assays, respectively.

RESULTS

Both testicular cancer (37%) and Hodgkin's lymphoma (81%) patients had normospermic samples with increased DNA damage, compared with controls. Cancer patients also had higher reactive thiols and CMA3 staining, indicating low DNA compaction.

CONCLUSIONS

Sperm DNA integrity and compaction were affected in testicular cancer and Hodgkin's lymphoma patients prior to chemotherapy. Although SCSA, TUNEL and comet assays all detected DNA damage, the latter was optimal for use in cancer patients. A combination of the comet assay with tests that evaluate sperm DNA compaction, such as flow cytometry-based CMA3 and mBBr assays, is a reliable strategy to characterize sperm chromatin quality in cancer patients at the time of sperm banking.

Telemedical retinopathy of prematurity diagnosis: accuracy, reliability, and image quality

OBJECTIVE

To prospectively measure accuracy, reliability, and image quality of telemedical retinopathy of prematurity (ROP) diagnosis.

METHODS

Two-hundred forty-eight eyes from 67 consecutive infants underwent wide-angle retinal imaging by a trained neonatal nurse at 31 to 33 weeks' and/or 35 to 37 weeks' postmenstrual age (PMA) using a standard protocol. Data were uploaded to a Web-based telemedicine system and interpreted by 3 expert retinal specialist graders who provided a diagnosis (no ROP, mild ROP, type 2 prethreshold ROP, treatment-requiring ROP) and an evaluation of image quality for each eye. Findings were compared with a reference standard of indirect ophthalmoscopy by an experienced pediatric ophthalmologist.

RESULTS

At 35 to 37 weeks' PMA, sensitivity and specificity for diagnosis of mild or worse ROP were 0.908 and 1.000 for grader A, 0.971 and 1.000 for grader B, and 0.908 and 0.977 for grader C. Sensitivity and specificity for diagnosis of type 2 prethreshold or worse ROP were 1.000 and 0.943 for grader A, 1.000 and 0.930 for grader B, and 1.000 and 0.851 for grader C. At 35 to 37 weeks' PMA, weighted kappa for intergrader reliability was 0.791 to 0.889, and kappa for intragrader reliability for detection of type 2 prethreshold or worse ROP was 0.769 to 1.000. Image technical quality was rated as "adequate" or "possibly adequate" for diagnosis in 93.3% to 100% of eyes.

CONCLUSION

A telemedicine system using nurse-captured retinal images has the potential to improve existing shortcomings of ROP management, particularly at later PMAs.

Clinical trial: levofloxacin-based quadruple therapy was inferior to traditional quadruple therapy in the treatment of resistant Helicobacter pylori infection

BACKGROUND

The efficacy of levofloxacin-based quadruple therapy in resistant Helicobacter pylori infection is not known.

AIM

To test the efficacy of levofloxacin-based quadruple therapy and traditional quadruple therapy in resistant H. pylori infection.

METHODS

One hundred and two patients with resistant H. pylori infection were randomized to 1 week of either EBAL (esomeprazole 40 mg b.d., bismuth subcitrate 240 mg b.d., amoxicillin 1 g b.d. and levofloxacin 500 mg b.d.) or EBMT (esomeprazole 40 mg b.d., bismuth subcitrate 240 mg b.d., metronidazole 400 mg t.d.s. and tetracycline 500 mg q.d.s.). (13)C-urea breath test was performed at week 12 to assess post-treatment H. pylori status.

RESULTS

In intention-to-treat analysis H. pylori eradication was achieved in 37 of 51 (73%) subjects in EBAL and 45 of 51 (88%) subjects in EBMT groups, respectively (P = 0.046). Per-protocol eradication rates of EBAL and EMBT groups were 78% and 94%, respectively (P = 0.030). The intention-to-treat eradication rate was statistically lower for EBAL than EMBT (56% vs. 90%, P = 0.013) among those who had failed more than one course of eradication therapy. Previous levofloxacin triple therapy did not affect the efficacy of either protocol significantly.

CONCLUSIONS

Levofloxacin-based quadruple therapy was inferior to traditional quadruple therapy for resistant H. pylori infection.

XELOX causes less disabling peripheral neuropathy than FOLFOX 4 for Chinese colorectal cancer patients

14592

Background: Infusional 5-FU plus leucovorin and oxaliplatin (FOLFOX4) is an efficacious treatment for colorectal cancer patients in both the adjuvant and metastatic settings. However, around 10% of FOLFOX4 patients will develop with disabling grade 3–4 neuropathy. Recent phase II studies have demonstrated that oral capecitabine in combination with oxaliplatin (XELOX) is as least as effective as FOLFOX4 for colorectal cancer. In this study, we assessed the toxicities of XELOX in Chinese colorectal cancer patients. Methods: Patients who received XELOX at Queen Mary Hospital, Hong Kong between November 2004 and November, 2006 were analyzed. Toxicities were graded by the National Cancer Institute common toxicity system. Results: Thirty-five patients received XELOX on an outpatient basis during the study period: Twenty-four as adjuvant therapy and 11 as treatment for metastatic disease. The most common side effect was grade 1–2 peripheral neuropathy which occurred in 77% of patients. No grade 3–4 neuropathy was reported. Grade 1–2 diarrhea and palmar-plantar erythrodysesthesia (PPE) also occurred in 40 % and 37 % of patients, respectively. The commonest grade 3 toxicities was diarrhea which occurred in 17% of the patients followed by 9% of patients experienced grade 3 PPE. No grade 4 toxicities were reported in our patient’s cohort. Overall, only one (3%) patient had neutropenic sepsis and 36% of patients required 20% reduction in drug dosage. No treatment related death was reported. Conclusions: Our study suggests that XELOX is a well-tolerated and convenient treatment regime. Although mild neuropathy is common in patients receiving XELOX, it causes far less disabling neuropathy than FOLFOX4 in Chinese metastatic colorectal cancer patients.

No significant financial relationships to disclose.

Treatment outcomes in anaplastic thyroid carcinoma from 1966–2006: Failure of overall survival enhancement despite four decades of progress in surgery, radiotherapy and chemoradiation

16537

Introduction: Anaplastic thyroid carcinoma (ATC) is a notoriously aggressive malignancy associated with a highly lethal clinical course despite therapeutic intervention. To identify factors that could suggest improved therapeutic strategies, we have analysed the clinicopathological features, treatment and outcome of all patients with ATC treated over the past four decades in our institution. Methods: Fifty patients presenting with biopsy-proven ATC to our centre between 1966 and 2006 were studied. All patients were managed with surgery, radiotherapy, chemotherapy, and/or chemoradiation. Survival was calculated using the Kaplan-Meier method. Potential factors affecting survival were compared using the log-rank test. Results: Most patients (88%) presented with a neck mass, while 17 (34%) patients also had cervical lymphadenopathy. Distant metastases at diagnosis were present in 9 (18%) of patients. Median survival was 97 days, while the 1- and 3-year survival was 14 % and 8% respectively. On univariate analysis, patients aged ≤65 years (p=0.04), undergoing surgical resection (p<0.01), receiving RT to the neck (p<0.01) and without metastatic disease on presentation (p<0.01) enjoyed longer survival. Cytotoxic chemotherapy was not associated with survival enhancement (p = 0.4). Moreover, no change in survival was evident as a function of treatment era (p = 0.5). Conclusions: ATC remains a uniformly lethal disease despite numerous technical advances in surgery, radiotherapy and chemotherapy over the last forty years. Nonetheless, our results indicate that younger patients with localized ATC be treated aggressively in a multimodality manner. Identification of signalling pathways that can be medically blocked to reduce ATC metastatic/invasive potential and enhance apoptotic sensitivity should now be the main priority for multicentre collaborative clinical research.

No significant financial relationships to disclose.

Cervix cancer regression measured using weekly MR imaging during fractionated radiotherapy: Radiobiologic modeling and correlation with tumor hypoxia

5547

Background: To utilize cervix cancer volumetry, as measured with MR imaging during definitive chemoirradiation (RT-CT), to derive radiobiological parameters using a mathematical model of tumor regression, and compare them to pre-treatment measurements of tumor hypoxia. Methods: Twenty-eight patients receiving RT-CT for cervix cancer underwent weekly magnetic resonance imaging (MRI) scans. Tumor volume was assessed on each of these scans and the rate of regression plotted. A mathematical model of tumor regression was formulated to simulate the relationship between three independent radiobiological parameters, 1) surviving fraction of cells after 2 Gy, SF2, 2) the cell clearance constant Tc, and 3) the cellular proliferation constant Tp. Non-linear regression analysis was applied to fit the MR-derived tumor volumes to the mathematical model and to derive SF2 and Tc values for each patient. These were compared to pre-treatment hypoxia measurements. Results: Initial tumor volume ranged between 8 and 209 cm3. Relative reduction in volume during treatment was 0.02 to 0.79. Simulations using representative values of the independent biologic variables derived from the literature showed SF2 and Tc to strongly influence the shape of the volume response curves. Non-linear regression analysis yielded a median SF2 of 0.71 and median Tc of 10 days. Radioresistant tumors (SF2 >0.71) were significantly more hypoxic at diagnosis (p=0.02). Conclusion: Based on serial MR imaging during treatment, a marked variation in cervix tumor regression is seen from patient to patient. Through our radiobiological model, tumors can be classified as radioresistant or radiosensitive, which correlates with hypoxia

[Table: see text]

No significant financial relationships to disclose.

Diffusion tensor tractography-based group mapping of the pyramidal tract in relapsing-remitting multiple sclerosis patients

BACKGROUND AND PURPOSE

Many studies have reported abnormal changes in relapsing-remitting multiple sclerosis (RRMS) by histogram and region-of-interest-based methods by using diffusion tenor imaging. However, there are few studies on specific white matter fiber tracts of RRMS. Our study sought to use diffusion tensor tractography-based group mapping to investigate the presence of abnormal diffusion in the normal-appearing pyramidal tract (PYT) of RRMS and its possible mechanism.

METHODS

A PYT probability map was first constructed from data on 20 healthy patients based on the deterministic-based tractography method. The PYT probability map was then applied to 29 RRMS patients to calculate diffusion indices of the PYT. In this study, 4 quantitative indices-fractional anisotropy (FA), directionally averaged diffusion coefficient (D(av)), axial diffusion coefficient (lambda(1)), and radial diffusion coefficient (lambda(23))-were used to characterize the abnormal diffusion.

RESULTS

Compared with healthy controls, RRMS patients had a significantly higher D(av) and lambda(23) but a lower FA and a trend toward a lower lambda(1) in the normal-appearing PYT. In RRMS patients, PYT lesions had a significantly higher lambda(23) and a lower FA, but there were no differences for D(av) and lambda(1) when compared with the normal-appearing PYT. Moreover, the diffusion indices derived from the normal-appearing PYT were significantly correlated with PYT lesion volumes by using the Spearman correlation analysis.

CONCLUSION

Our findings confirm the presence of abnormal diffusion in the normal-appearing PYT of RRMS patients and suggest that wallerian degeneration might be its mechanism.

Extensive nuclear localization of alpha-synuclein in normal rat brain neurons revealed by a novel monoclonal antibody

Synuclein was initially named for its localization in both presynaptic nerve terminals and portions of nuclear envelope. However, subsequent studies only confirmed the presynaptic localization of this protein in the brain; its nuclear localization in the neurons remained elusive. Here, two new monoclonal antibodies against alpha-synuclein (alpha-SYN) were produced. Epitope mapping using phage peptide display showed that the epitopes of the two antibodies were localized in two distinct specific sequences of the C-terminal domain of alpha-SYN. One antibody named 3D5 recognized amino acids 115-121 of alpha-SYN and the other antibody named 2E3 identified the amino acids 134-138 of the protein. Western blot analysis demonstrated that both 2E3 and 3D5 detected a 19 kD protein from rat and human brain homogenates, which was identical to the molecular size of recombinant alpha-SYN. However, immunohistochemical staining on normal adult rat brain sections showed that the two antibodies revealed distinct patterns of subcellular localization of alpha-SYN immunoreactivity. Both 3D5 and 2E3 detected the presynaptic alpha-SYN but only 3D5 detected the nuclear alpha-SYN. The nuclear localization of alpha-SYN was further confirmed by Western blot analysis in isolated nuclear fraction where the same size of alpha-SYN was detected, and by immunoelectron microscopy using colloidal gold probes where gold particles were specifically localized in portions of peri- and intra-nucleus. The nuclear positive neurons were distributed extensively in almost all the brain regions. This is the first report well characterizing the extensive localization of alpha-SYN in the neuronal nuclei throughout the brain in normal conditions. This finding indicates an important physiological function of this molecule in the nuclei of brain neurons, which deserves further investigations.

Mechanism for blockade of angiotensin subtype 1 receptors to lower plasma glucose in streptozotocin-induced diabetic rats

AIMS

We investigated the mechanism(s) by which valsartan, a selective antagonist of angiotensin subtype 1 (AT(1)) receptor, decreased plasma glucose in streptozotocin (STZ)-induced diabetic rats.

METHODS

The plasma glucose concentration was assessed by the glucose oxidase method. The concentration of beta-endorphin in plasma or medium incubating adrenal medulla was measured using an enzyme-linked immunosorbent assay. The mRNA levels of the subtype 4 form of glucose transporter (GLUT4) in soleus muscle and phosphoenolpyruvate carboxykinase (PEPCK) in the liver were detected by Northern blotting analysis, while the protein levels of GLUT4 in isolated soleus muscle and hepatic PEPCK were investigated using Western blotting analysis.

RESULTS

A single intravenous injection of valsartan dose-dependently increased plasma beta-endorphin-like immunoreactivity (BER) in parallel with the lowering of plasma glucose concentration in STZ-induced diabetic rats. Naloxone and naloxonazine inhibited the plasma glucose-lowering action of valsartan at doses sufficient to block opioid micro-receptors. In contrast to its action in wild-type diabetic mice, valsartan failed to modify plasma glucose in opioid micro-receptor knockout diabetic mice. Bilateral adrenalectomy in STZ-induced diabetic rats eliminated both the plasma glucose-lowering action and the plasma BER-elevating action of valsartan. In the isolated adrenal medulla of STZ-induced diabetic rats, angiotensin II (Ang II) or valsartan did not affect spontaneous BER secretion. Activation of cholinergic receptors by 1.0 micromol/l acetylcholine (ACh) enhanced BER secretion from the isolated adrenal medulla of STZ-induced diabetic rats, but not in the presence of 1.0 nmol/l Ang II, while valsartan reversed this inhibition by Ang II in a concentration-dependent manner. Treatment of STZ-induced diabetic rats with valsartan (0.2 mg/kg) three times daily for 3 days resulted in an increase in gene expression of GLUT4 in soleus muscle and impeded the reduction of elevated mRNA or protein level of hepatic PEPCK. Both of these effects were blocked by opioid micro-receptor antagonist.

CONCLUSIONS

The results suggest that blockade of AT(1) receptor by valsartan may enhance the adrenal beta-endorphin secretion induced by ACh, activating the opioid micro-receptors to increase glucose utilization and/or to decrease hepatic gluconeogenesis, resulting in the reduction of plasma glucose in STZ-induced diabetic rats.

Diffusion tensor imaging in the assessment of normal-appearing brain tissue damage in relapsing neuromyelitis optica

BACKGROUND AND PURPOSE

Normal-appearing brain tissue (NABT) damage was established in multiple sclerosis by histology, MR spectroscopy, magnetization transfer imaging and diffusion tensor imaging (DTI). However, whether this phenomenon can be detected in relapsing neuromyelitis optica (RNMO) remains unclear. The aim of this study was to use DTI to investigate the presence of NABT damage in RNMO patients and its possible mechanism.

METHODS

Conventional MR imaging and DTI scans were performed in 16 patients with RNMO without visible lesions on brain MR imaging and in 16 sex- and age-matched healthy control subjects. Histogram analysis of mean diffusivity (MD) and fractional anisotropy (FA) was performed in the entire brain tissue (BT), white matter (WM), and gray matter (GM). Region of interest (ROI) analysis of MD and FA was also performed in WM regions connected with the spinal white matter tracts or optic nerve (including medulla oblongata, cerebral peduncle, internal capsule, and optic radiation), in corpus callosum without direct connection with them, and in some GM regions.

RESULTS

From histogram analysis, we found the RNMO group had a higher average MD of the BT, WM, and GM, a lower average MD peak height and a higher average MD peak location of the GM, and a higher average FA peak height of the WM than did the control group. From ROI analysis, compared with control subjects, RNMO patients had a higher average MD and a lower average FA in ROIs of WM connected with the spinal white matter tracts or optic nerve and a normal average MD and FA in corpus callosum without direct connection with them. In addition, a high average MD was found in parietal GM in these patients.

CONCLUSIONS

Our findings confirm the presence of abnormal diffusion in brain tissue in patients with RNMO and suggest that secondary degeneration caused by lesions in the spinal cord and optic nerve might be an important mechanism for this abnormality.

Comparison of Adjunctive Use of Rofecoxib versus Ibuprofen in the Management of Postoperative Pain after Uterine Artery Embolization

PURPOSE

The primary purpose of the present study was to compare the antiinflammatory effectiveness of rofecoxib with that of ibuprofen in the first 5 days after uterine artery embolization (UAE). The secondary aim was to compare pain levels and narcotic use among patients treated with different embolic agents.

MATERIALS AND METHODS

From July 2003 to June 2004, 68 UAE procedures were performed by one of the authors (D.M.H.). Of this group, 50 women agreed to participate in this study. Exclusion criteria were limited to contraindication to either drug or current steroid or nonsteroidal antiinflammatory drug use. In a randomized, double-blinded fashion, patients received a numbered pill box that contained one of the two agents and its placebo counterpart. Four times per day for 5 days, patients recorded their level of pain on a visual analog scale and the amount of narcotic analgesic drug needed at that time. Score sheets were returned by mail after completion. During the course of the study, three embolic agents (Gold Embospheres, Contour SE particles, and Embospheres) were used in succession, with similar numbers of patients in each group.

RESULTS

Four patients were excluded from analysis: two who were readmitted to the hospital for treatment of pain (one treated with each antiinflammatory medication) and two who failed to complete their score sheets. Subject demographics were very similar with respect to antiinflammatory drug treatment and embolic agent, except that the average age of patients in the Embosphere group was 6 years older than in the Embosphere Gold and Contour SE groups (P= .02). There was no difference in the pain level and narcotic drug intake between the two drug arms, but among embolic agents, the Embosphere Gold group tended to have a higher overall average pain score (P = .12), and the two patients readmitted were in this group. Patients in the Contour SE group tended to use a lower amount of narcotic drug than those in the other two embolic agent groups (P = .09).

CONCLUSIONS

There was no difference between rofecoxib and ibuprofen with respect to postprocedural pain or narcotic use after UAE. Embolic agent appeared to have a greater impact, with patients in the Embosphere Gold group reporting higher pain scores and those in the Contour SE group requiring a lower amount of narcotic drug than those in the Embosphere Gold or Embosphere groups.