Indocyanine green fluorescence imaging in the surgical management of liver cancers: current facts and future implications

Imaging detection of liver cancers and identification of the bile ducts during surgery, based on the fluorescence properties of indocyanine green, has recently been developed in liver surgery. The principle of this imaging technique relies on the intravenous administration of indocyanine green before surgery and the illumination of the surface of the liver by an infrared camera that simultaneously induces and collects the fluorescence. Detection by fluorescence is based on the contrast between the (fluorescent) tumoral or peri-tumoral tissues and the healthy (non-fluorescent) liver. Results suggest that indocyanine green fluorescence imaging is capable of identification of new liver cancers and enables the characterization of known hepatic lesions in real time during liver resection. The purpose of this paper is to present the fundamental principles of fluorescence imaging detection, to describe successively the practical and technical aspects of its use and the appearance of hepatic lesions in fluorescence, and to expose the diagnostic and therapeutic perspectives of this innovative imaging technique in liver surgery.

Predictors of early mortality and validation of novel prognostic models in Asian patients on phase I trials (PIT): A single-center experience

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Background: Despite the growing number of clinical trials conducted in Asia and the unique pt demographic and molecular profile of endemic cancers, there is still lacking of studies examining the outcomes of pts on PIT. We examined the characteristics and outcomes of pts enrolled in phase I trials in National Cancer Center Singapore (NCCS). Methods: We reviewed 296 pts enrolled in PIT from 2004-2012 to identify factors that predicted for 90-day mortality and OS. Logistic regression model and Cox proportional hazard model assessed factors associated with 90DM and OS, respectively. The discriminative ability of the RMH prognostic score (LDH, no of met sites, albumin) and the final multivariate Cox model derived in Asian pts was evaluated using Harrell’s concordance index (c-index), and that for the logistic model was based on area under ROC curve (AUC). Internal validation was performed based on simulated data via bootstrapping. Results: Median age 60 (23-85), M:F (65/35%). The commonest cancer type thoracic (56%), GI (24%), head and neck (12%). 57% pt had comorbidities, commonest diabetes (16.6%) and hepatitis B (11.1%). Median no of lines of treatment 2. 20% of pts had known mut status. 15% pts survived less than 90 days from start of trial. Median OS was 9.6 m (95CI 7.8-11.2 m). Based on the RMH prognostic model, pts with score of 0 to 1 had a superior OS (median OS = 12.9 m) compared to those with score of 2 to 3 (OS = 5.7 m) (p < 0.001). The c-index for the RMH prognostic score was 0.64. On univariate analysis, alb<35,LDH>ULN, ≥3 met sites, low BMI, ECOG>0, Na<135,plt>440, Hb<12 and ≥3 lines of chemo were negative prognostic factors. On multivariate analysis, reduced model selection techniques identified alb<35, LDH>ULN, ≥3 met sites, and ≥ 3 prior lines of chemo as independent negative predictors of OS with a bias-corrected of 0.69. For 90DM, we developed a risk normogram based on ECOG, WBC, Na and Hb as continuous predictors with bias-corrected AUC 0.78. Conclusions: We have developed a novel NCCS normogram to predict for 90DM for PIT. The RMH prognostic score can be improved upon with the addition of number of prior lines of chemotherapy, underscoring the importance of early access to phase I trials.

Do elderly patients benefit from enrollment in phase I clinical trials?

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Background: Despite the significant burden of cancer in the older population, their outcomes in the context of phase I studies have been poorly studied. We evaluated the clinical characteristics and outcomes of elderly pts enrolled in phase 1 clinical trials in our centre and evaluate the performance of Royal Marsden Hospital (RMH) prognostic score (albumin, LDH, no of met sites) in this pt population. Methods: 296 consecutive pts who were treated in 20 phase 1 trials from 2005-2012 in our unit were analysed. Clinical characteristics and outcomes between young pts (<65, n=202) and older pts (≥65, n=94) were compared. Results: The median age of the older pts was 69 (65-84), 71% were males. 51% of the pts received chemotherapy based treatment with or w/out biological agents. 61% of the pts had lung cancers and 32% had gastrointestinal cancers. 52% of pts had ≥2 co-morbidities. After median follow up of 7.5 mths (0.36-50.6 mths), the median progression free survival (PFS) and overall survival (OS) were 5.8 and 8.8 mths respectively. Although elderly pts had more co-morbidities and lower albumin levels at baseline, there was no significant difference in survival (8.8 vs 9.9 mths), p=0.68) compared to younger pts. The prognostic factors for OS identified in multivariate analysis were prior lines of chemotherapy (0-2 vs ≥3), baseline sodium levels (≥135 vs <135mmol/L) and platelet levels (≤400 vs >400×10⁹). We developed a risk nomogram based on the factors identified prognostic of OS with concordance(c)-index of 0.65. RMH score (2-3 vs 0-1) predicted for OS with hazard ratio of 2.1, p=0.03 and c- index of 0.63. 26% of elderly pts experienced grade 3/4 toxicities in the first cycle of treatment. Common grade 3/4 toxicities were dermatological (25%), haematological (17%) and gastrointestinal (13%). Both age of pts (p=0.70) and dose levels (p=0.18) did not have any bearing on occurrence of grade 3/4 toxicities. Conclusions: Elderly pts (≥65) enrolled into phase 1 clinical trials had similar survival outcomes and toxicity profiles compared to younger pts. Risk scoring models to aid patient selection need further clarification in this population.

Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy in Asian patients: 100 consecutive patients in a single institution

BACKGROUND

Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) have been shown to improve survival in selected patients with peritoneal carcinomatosis. We review our institutional experience with the procedure and evaluate the overall survival (OS) and disease-free survival (DFS) rates in 100 consecutive patients.

METHODS

Data were prospectively collected from 100 consecutive patients with peritoneal carcinomatosis treated by CRS and HIPEC at the National Cancer Centre Singapore between April 2001 and May 2012. Our primary end points were OS and DFS.

RESULTS

Of the 100 patients, 84 were of Chinese ethnicity, 3 were Malay, 6 were Indian, and 7 were of other ethnicities. Primary tumors were ovarian cancer (n=39), colorectal cancer (n=28), primary peritoneal (n=6), appendiceal cancer (n=20), and mesothelioma (n=7). Median follow-up duration was 21 months. At 5 years, the DFS was 26.3% and OS was 50.9%. Factors influencing OS and DFS were cytoreductive score, primary cancer, and disease-free interval of more than 12 months on univariate analysis. The only factors that remained significant for prognosis after multivariate analysis were primary cancer and cytoreductive score. Thirty-day morbidity was 56%, and there were no 30-day mortalities.

CONCLUSIONS

CRS and HIPEC can be safely carried out in Asian patients with peritoneal carcinomatosis from ovarian, colorectal, appendiceal, mesothelioma, and primary peritoneal origins. Overall, the ovarian, appendiceal, mesothelioma, and primary peritoneal cancer patients tended to do better than the colorectal patients, but careful patient selection ensuring that optimal cytoreduction can be achieved is essential for the success of this procedure.

A Phase 1 dose-finding and pharmacodynamic study of rapamycin in combination with bevacizumab in patients with unresectable hepatocellular carcinoma

BACKGROUND & AIMS

Preclinical studies have demonstrated the additive effect of rapamycin with bevacizumab for hepatocellular carcinoma treatment. We conducted a Phase 1 study to evaluate the safety and pharmacokinetics of the combination in patients with hepatocellular carcinoma.

METHODS

Adult participants with advanced hepatocellular carcinoma received intravenous bevacizumab (5mg/kg every 14 days) and oral rapamycin (1-6 mg/day; 3+3 dose escalation design). Computed tomography assessed tumour response and treatment safety. Pharmacokinetics assessment established rapamycin blood concentrations pre- and post-dose. Dynamic contrast-enhanced computed tomography analysed the tumour region for blood flow, permeability surface area product, fractional intravascular blood volume and extracellular-extravascular volume.

RESULTS

Twenty-four participants were treated. There were two dose limiting toxicities with rapamycin 5mg: grade 3 thrombocytopenia and grade 3 mucositis. The maximally tolerated dose of rapamycin was 4 mg. Adverse events (grade 1-2) included hyperglycaemia (83%), thrombocytopenia (75%), fatigue (46%), mucositis (46%), anorexia (42%), diarrhoea (33%) and proteinuria (12.5%). Of 20 evaluable participants, one reached complete response that lasted 4.5 months, two reached partial response, 14 reached stable disease and three had progressive disease. Median overall survival was 9.4 months; progression-free survival was 5.5 months. Dose level and steady state area under the concentration time curve for hour zero to infinity of rapamycin correlated inversely with blood flow rate and change in permeability-surface area. After 22 days of treatment, there were significant reductions from baseline in blood flow rate, permeability-surface area and fractional intracellular blood volume.

CONCLUSIONS

The recommended Phase 2 dose of rapamycin is 4 mg in combination with bevacizumab. Evidence of anti-vascular activity was observed together with promising clinical activity.

Analytic treatment of tipping points for social consensus in large random networks

We introduce a homogeneous pair approximation to the naming game (NG) model by deriving a six-dimensional Open Dynamics Engine (ODE) for the two-word naming game. Our ODE reveals the change in dynamical behavior of the naming game as a function of the average degree {k} of an uncorrelated network. This result is in good agreement with the numerical results. We also analyze the extended NG model that allows for presence of committed nodes and show that there is a shift of the tipping point for social consensus in sparse networks.

Asymmetric division of Drosophila male germline stem cell shows asymmetric histone distribution

Stem cells can self-renew and generate differentiating daughter cells. It is not known whether these cells maintain their epigenetic information during asymmetric division. Using a dual-color method to differentially label "old" versus "new" histones in Drosophila male germline stem cells (GSCs), we show that preexisting canonical H3, but not variant H3.3, histones are selectively segregated to the GSC, whereas newly synthesized histones incorporated during DNA replication are enriched in the differentiating daughter cell. The asymmetric histone distribution occurs in GSCs but not in symmetrically dividing progenitor cells. Furthermore, if GSCs are genetically manipulated to divide symmetrically, this asymmetric mode is lost. This work suggests that stem cells retain preexisting canonical histones during asymmetric cell divisions, probably as a mechanism to maintain their unique molecular properties.

MicroRNAs downregulate Bag of marbles to ensure proper terminal differentiation in the Drosophila male germline

In many adult stem cell lineages, the continuous production of functional differentiated cells depends on the maintenance of progenitor cells in an undifferentiated and proliferative state, as well as the subsequent commitment to proper terminal differentiation. In the Drosophila male germline stem cell (GSC) lineage, a key differentiation factor, Bag of marbles (Bam), is required for the transition from proliferative spermatogonia to differentiating spermatocytes. We show that bam mRNA, but not Bam, is present in spermatocytes, suggesting that bam is regulated post-transcriptionally. Consistent with this, repression of Bam accumulation is achieved by microRNAs via the bam 3'UTR. When the bam 3'UTR was substituted with the 3'UTR of a constitutively expressed α-Tubulin, Bam became stabilized in spermatocytes. Moreover, such a persistent expression of Bam in spermatocytes was recapitulated by specifically mutating the putative miR-275/miR-306 recognition site at the bam 3'UTR. In addition, overexpression of miR-275 or miR-306 in spermatogonial cells resulted in a delay of the proliferation-to-differentiation transition and resembled the bam loss-of-function phenotype, suggesting that these microRNAs are sufficient to downregulate Bam. Finally, the failure of Bam downregulation in spermatocytes affected spermatid terminal differentiation and resulted in increased male sterility. Our results demonstrate that microRNAs control the stem cell differentiation pathway through regulating Bam, the downregulation of which is crucial for proper spermatid terminal differentiation.

Outcome of extensive descending aorta repair adopting present concepts of spinal cord preservatio

AIM: Preoperative radiological identification of the Adamkiewicz artery and intraoperative neurologic monitoring are known to be helpful for preventing paraplegia after thoracoabdominal aorta replacement. To answer whether they should be used routinely, we investigated the incidence of spinal cord ischemia after extensive descending aortic repair without using such modalities. METHODS: We retrospectively reviewed the outcome of 95 patients who underwent extensive descending thoracic (DTA) or thoracoabdominal aorta (TAA) repair without the Adamkiewicz artery identification or neurologic monitoring from 2006 through 2010. Spinal cord protection strategy consisted of distal aortic perfusion, cerebrospinal fluid drainage, mild hypothermia, and maintenance of hypertension (systolic≥120mmHg) through the second postoperative day. A few segmental arteries were empirically selected for reimplantation based on the size and the amount of backbleeding; overall 1.4 per patient, 0.3 for DTA, 1.4 for type I, 2.4 for type II, 0.9 for type III, and 0 for type IV TAA. RESULTS: Two patients died early after surgery. All the remaining patients awoke without paraplegia or paraparesis. Delayed deficit occurred in 7 patients (7.4%) after hypotensive events caused by sedation, bleeding, respiratory distress, or cardiac dysfunction. Three patients (3.2%) became permanently paraplegic and the other four recovered completely within 48 hours after cerebrospinal fluid drainage and elevation of systemic blood pressure. CONCLUSION: Even without the Adamkiewicz artery identification and neuromonitoring, the incidence of immediate paraplegia could be kept low by applying the strategy based on the modern concept of cord perfusion. The relatively high incidence of delayed deficit suggests the importance of postoperative hemodynamic management and prevention of cardiopulmonary complications.

Microfluidic approach to genotyping human platelet antigens

Centralised laboratories routinely determine blood types by serological and molecular methods. Current practices have limitations in terms of cost, time and accessibility. Miniaturised microfluidic platforms offer an alternative to conventional genotyping methods, since they consume fewer reagents, provide faster analysis and allow for complete integration and automation. As these 'lab-on-a-chip' devices have been used for bacterial and viral detection, the authors investigated blood group genotyping as a novel application of microfluidic technology. To demonstrate the feasibility of microfluidic chip-based genotyping, the authors compared human platelet antigen 1 (HPA-1) genotype results from conventional and chip-based analysis for 19 blood donor specimens. DNA purification was performed with ChargeSwitch™ magnetic beads, DNA amplification (PCR), restriction length polymorphism (RFLP) and capillary electrophoresis (CE) for identification of the DNA on microfluidic chips. It was found that nine donors were HPA-1a/1a and ten were HPA-1a/1b. Concordance between the conventional and on-chip methods was achieved for all but one sample. All the steps were demonstrated for complete blood group genotyping analysis of patient whole blood specimens on separate microfluidic chips. Future work will focus on integration of all the genotyping protocols on a single microfluidic chip.

Portal vein occlusion before major hepatectomy in patients with colorectal liver metastases: rationale, indications, technical aspects, complications and outcome

Surgery is the only curative treatment for colorectal liver metastases (CRLM), but resection should be total with tumor-free margins and the remaining parenchyma, functionally evaluated. The rationale behind portal vein embolization (PVE) to reduce the risk of these hepatic resections is threefold: (i) surgery for CRLM has become more and more aggressive, and hepatocellular insufficiency represents the leading cause of mortality after major hepatectomy for hepatic metastasis (HM), (ii) underlying hepatic disease occurs more frequently than previously thought in these patients having undergone neoadjuvant chemotherapy, and can alter hepatic function and/or hinder postoperative regeneration, and (iii) the operative risk is increased if major hepatectomy is associated with resection of the primary tumor. The goal of this update is to review the reasons behind and the indications for PVE, to analyze the literature pertaining to whether PVE should be routine or selective, and to tackle certain technical aspects, all within the framework of the treatment of CRLM.

[A modified Gritti-Stokes amputation for vascular indications in the elderly: futility or utility?]

AIM

Major lower limb amputation in elderly patients is a dreaded event with high mortality and morbidity. Peripheral arterial disease is the nearly exclusive etiology. The aim of this retrospective study was to assess the feasibility of through-knee amputation, and the morbidity and mortality risk in the elderly (>65 years).

PATIENTS AND METHODS

From January 2000 to October 2010, 65 Gritti-Stokes through-knee amputations were performed in 58 patients (30 women, 28 men; mean age 79 years). Acute limb ischemia was the most common cause (40%). The others indications were: severe peripheral arterial disease with extensive necrotic lesions (19%), diabetic foot ulcers (15%), non-healing below-knee amputation (10%) and vascular graft infection after prosthetic lower extremity bypass surgery (6%).

RESULTS

Overall 30-day mortality was 24% (n=14/58). Vascular morbidity was 9% (n=6/65). The mean hospital stay was 31 days (range 3 to 96). The overall healing rate was 78% (n=51/65). Conversion to above-knee amputation for failed Gritti-Stokes amputation was performed in one patient.

CONCLUSION

Gritti-Stokes amputation is feasible in the elderly with an acceptable one-month mortality and a satisfactory overall healing rate. Most amputations are necessitated by complications of acute limb ischemia. For this subpopulation, Gritti-Stokes amputation should be the standard amputation level. The data collected in this study provide important information that can be useful before amputation for this population, their families and primary care physicians. Ambulation is an important postoperative goal and a multidisciplinary approach in specialized centers is required to achieve good wound healing rates.

Social consensus through the influence of committed minorities

We show how the prevailing majority opinion in a population can be rapidly reversed by a small fraction p of randomly distributed committed agents who consistently proselytize the opposing opinion and are immune to influence. Specifically, we show that when the committed fraction grows beyond a critical value p(c) ≈ 10%, there is a dramatic decrease in the time T(c) taken for the entire population to adopt the committed opinion. In particular, for complete graphs we show that when p < pc, T(c) ~ exp [α(p)N], whereas for p>p(c), T(c) ~ ln N. We conclude with simulation results for Erdős-Rényi random graphs and scale-free networks which show qualitatively similar behavior.

Social influencing and associated random walk models: Asymptotic consensus times on the complete graph

We investigate consensus formation and the asymptotic consensus times in stylized individual- or agent-based models, in which global agreement is achieved through pairwise negotiations with or without a bias. Considering a class of individual-based models on finite complete graphs, we introduce a coarse-graining approach (lumping microscopic variables into macrostates) to analyze the ordering dynamics in an associated random-walk framework. Within this framework, yielding a linear system, we derive general equations for the expected consensus time and the expected time spent in each macro-state. Further, we present the asymptotic solutions of the 2-word naming game and separately discuss its behavior under the influence of an external field and with the introduction of committed agents.