Critical evaluation of contemporary management in a new Pelvic Exenteration Unit: The first 25 consecutive cases

AIM

To critically appraise short-term outcomes in patients treated in a new Pelvic Exenteration (PE) Unit.

METHODS

This retrospective observational study was conducted by analysing prospectively collected data for the first 25 patients (16 males, 9 females) who underwent PE for advanced pelvic tumours in our PE Unit between January 2012 and October 2016. Data evaluated included age, co-morbidities, American Society of Anesthesiologists (ASA) score, Eastern Cooperative Oncology Group (ECOG) status, preoperative adjuvant treatment, intra-operative blood loss, procedural duration, perioperative adverse event, lengths of intensive care unit (ICU) stay and hospital stay, and oncological outcome. Quantitative data were summarized as percentage or median and range, and statistically assessed by the χ² test or Fisher’s exact test, as applicable.

RESULTS

All 25 patients received comprehensive preoperative assessment via our dedicated multidisciplinary team approach. Long-course neoadjuvant chemoradiotherapy was provided, if indicated. The median age of the patients was 61.9-year-old. The median ASA and ECOG scores were 2 and 0, respectively. The indications for PE were locally invasive rectal adenocarcinoma (n = 13), advanced colonic adenocarcinoma (n = 5), recurrent cervical carcinoma (n = 3) and malignant sacral chordoma (n = 3). The procedures comprised 10 total PEs, 4 anterior PEs, 7 posterior PEs and 4 isolated lateral PEs. The median follow-up period was 17.6 mo. The median operative time was 11.5 h. The median volume of blood loss was 3306 mL, and the median volume of red cell transfusion was 1475 mL. The median lengths of ICU stay and of hospital stay were 1 d and 21 d, respectively. There was no case of mortality related to surgery. There were a total of 20 surgical morbidities, which occurred in 12 patients. The majority of the complications were grade 2 Clavien-Dindo. Only 2 patients experienced grade 3 Clavien-Dindo complications, and both required procedural interventions. One patient experienced grade 4a Clavien-Dindo complication, requiring temporary renal dialysis without long-term disability. The R0 resection rate was 64%. There were 7 post-exenteration recurrences during the follow-up period. No statistically significant relationship was found among histological origin of tumour, microscopic resection margin status and postoperative recurrence (P = 0.67). Four patients died from sequelae of recurrent disease during follow-up.

CONCLUSION

By utilizing modern assessment and surgical techniques, our PE Unit can manage complex pelvic cancers with acceptable morbidities, zero-rate mortality and equivalent oncologic outcomes.

Chromosome 19q13 disruption alters expressions of CYP2A7, MIA and MIA-RAB4B lncRNA and contributes to FAP-like phenotype in APC mutation-negative familial colorectal cancer patients

Familial adenomatous polyposis (FAP) is an autosomal-dominantly inherited form of colorectal cancer (CRC) caused by mutation in the adenomatous polyposis coli (APC) gene. Our ability to exhaustively screen for APC mutations identify microsatellite-stable and APC-mutation negative familial CRC patients, enabling us to search for novel genes. We performed genome-wide scan on two affected siblings of one family and 88 ethnicity- and gender-matched healthy controls to identify deletions shared by the siblings. Combined loss of heterozygosity, copy number and allelic-specific copy number analysis uncovered 5 shared deletions. Long-range polymerase chain reaction (PCR) confirmed chromosome 19q13 deletion, which was subsequently found in one other family. The 32 kb deleted region harbors the CYP2A7 gene and was enriched with enhancer, repressor and insulator sites. The wildtype allele was lost in the polyps of the proband. Further, real-time RT-PCR assays showed that expressions of MIA and MIA-RAB4B located 35 kb upstream of the deletion, were up-regulated in the polyps compared to the matched mucosa of the proband. MIA-RAB4B, the read-through long non-coding RNA (lncRNA), RAB4B, PIM2 and TAOK1 share common binding site of a microRNA, miR-24, in their 3'UTRs. PIM2 and TAOK1, two target oncogenes of miR-24, were co-ordinately up-regulated with MIA-RAB4B in the polyps, suggesting that MIA-RAB4B could function as competitive endogenous RNA to titrate miR-24 away from its other targets. The data suggest that the 19.13 deletion disrupted chromatin boundary, leading to altered expression of several genes and lncRNA, could contribute to colorectal cancer via novel genetic and epigenetic mechanisms.

[Features and advances of Morse taper connection in oral implant]

Dental implants have been widely accepted as a predictable and reliable tool for dental reconstruction with the development of the economy. The design of implant-abutment connections has influence on mechanical properties and biological characteristics of implants. There are two types of implant-abutment connections, the external and the internal connections. Morse taper connection is one of the internal connections and its conical shape creates significant friction via the high propensity of parallelism between the two structures within the joint space. Several studies showed that Morse taper connection performed well in terms of survival rate, stability, bacterial seal and marginal bone loss. Recently, clinical studies indicate implants combining Morse taper connection with platform switching are helpful in reducing marginal bone absorption. This review aims at analyzing the features and advantages of Morse taper connection.

Efficient biosynthesis of d-ribose using a novel co-feeding strategy in Bacillus subtilis without acid formation

Normally, low d-ribose production was identified as responsible for plenty of acid formation by Bacillus subtilis due to its carbon overflow. An approach of co-feeding glucose and sodium citrate is developed here and had been proved to be useful in d-ribose production. This strategy is critical because it affects the cell concentration, the productivity of d-ribose and, especially, the formation of by-products such as acetoin, lactate and acetate. d-ribose production was increased by 59·6% from 71·06 to 113·41 g l^-1 without acid formation by co-feeding 2·22 g l^-1  h^-1 glucose and 0·036 g l^-1  h^-1 sodium citrate to a 60 g l^-1 glucose reaction system. Actually, the cell density was also enhanced from 11·51 to 13·84 g l^-1 . These parameters revealed the importance of optimization and modelling of the d-ribose production process. Not only could zero acid formation was achieved over a wide range of co-feeding rate by reducing glycolytic flux drastically but also the cell density and d-ribose yield were elevated by increasing the hexose monophosphate pathway flux.

SIGNIFICANCE AND IMPACT OF THE STUDY

Bacillus subtilis usually produce d-ribose accompanied by plenty of organic acids when glucose is used as a carbon source, which is considered to be a consequence of mismatched glycolytic and tricarboxylic acid cycle capacities. This is the first study to provide high-efficiency biosynthesis of d-ribose without organic acid formation in B. subtilis, which would be lower than the cost of separation and purification. The strain transketolase-deficient B. subtilis CGMCC 3720 can be potentially applied to the production of d-ribose in industry.

Factors Affecting the Enhancement Patterns of Intrahepatic Cholangiocarcinoma (ICC) on Contrast-Enhanced Ultrasound (CEUS) and their Pathological Correlations in Patients with a Single Lesion

Purpose: To investigate the factors that influence the enhancement patterns of intrahepatic cholangiocarcinomas (ICC) on contrast-enhanced ultrasound (CEUS) and analyze the correlations between the enhancement patterns on CEUS and pathological findings. Materials and Methods: Ninety-six patients with 96 pathologically confirmed ICCs underwent CEUS. CEUS images were retrospectively evaluated for tumor enhancement patterns in the arterial, portal and late phases. The arterial enhancement patterns were correlated with clinicopathological factors. The possible influencing factors were correlated with pathologic findings. Results: Thirty-six patients with ICC demonstrated rim-like enhancement, and 60 exhibited non-rim-like enhancement in the arterial phase on CEUS. The incidence of non-rim-like-enhancing ICCs was higher in patients with cirrhosis and chronic viral hepatitis than patients with no chronic liver disease (p = 0.001). The sizes of the ICCs with homogeneous hyper-enhancement were significantly smaller than those with inhomogeneous hyper-enhancement (p = 0.007). Arterial non-rim-like-enhancing ICCs showed higher microvessel density (MVD) and arterial density (AD) and less fibrous stroma and necrosis than rim-like-enhancing ICCs. Arterial inhomogeneous-enhancing ICCs had lower MVD and AD and much more fibrous stroma and necrosis than homogeneous-enhancing ICCs. Conclusion: The enhancement pattern of ICCs in the arterial phase on CEUS was affected by a liver cirrhosis and chronic viral hepatitis and tumor size. The amount of MVD, AD, fibrous stroma and necrosis in ICC tumors may be responsible for the difference in the enhancement patterns.

[Nicotine alleviates the liver inflammation of non-alcoholic steatohepatitis induced by high-fat and high-fructose in mice]

OBJECTIVE

To investigate the anti-inflammation effects by activation of the cholinergic anti-inflammatory pathway and its mechanisms in non-alcoholic steatohepatitis (NASH) model mice.

METHODS

6-week-old male C57BL/6J (B6) mice were randomly divided into four groups: the first group was normal mice, injected with saline; the second group was normal mice, injected with nicotine; the third group was NASH model mice, injected with saline; the fourth group was NASH model mice, injected with nicotine. The experimental mice were fed with either standard chow (SC) or high-fat and high-fructose (HFHF) for 17 weeks to generate an NASH model mice. The mice received injection once daily for 3 weeks [nicotine dose, 400 μg/kg]. Then, their pathological characteristics and function of the liver were assessed. The expressions of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in serum were analyzed by enzyme linked immunosorbent assay (ELISA). The expressions of alpha 7 nicotinic acetylcholine receptors (α7nAChR), Toll-like receptors-4 (TLR-4) and nuclear factor κB of phosphory-lation (p-NF-κB) in Kupffer cells were determined by Western blot and immunofluorescence assays.

RESULTS

We successfully generated NASH model mice by imitating the high-fat and high-fructose dietary style of NASH patients. The results of our investigation demonstrated that nicotine could reduce significantly the levels of IL-6, and TNF-α in serum (P<0.05). The expression of p-NF-κB protein in the group which was NASH model mice injected with nicotine declined significantly as compared with the group which was NASH model mice injected with saline (P<0.05). And the expression of α7nAChR protein elevated significantly conversely (P<0.05).

CONCLUSION

Activation of the cholinergic anti-inflammatory pathway could inhibit the release of inflammatory factors as TNF-α and IL-6 in NASH model mice, and the mechanism for the inhibition of inflammatory was mediated by NF-κB pathway.

Methylation of serum SST gene is an independent prognostic marker in colorectal cancer

There is an increasing demand for accurate prognostication for colorectal cancer (CRC). This study sought to assess prognostic potentials of methylation targets in the serum of CRC patients. A total of 165 CRC patients were enrolled in this prospective study. Promoter methylation levels of seven genes in pre-operative sera and matched tumor tissues were evaluated by quantitative methylation-specific PCR. Kaplan-Meier test, and univariate and multivariate Cox proportional hazards regression models were used for survival analyses. After a median follow-up of 56 months, 43 patients (28.7%) experienced tumor recurrence. In univariate survival analyses, serum methylation levels of SST and MAL were significantly predictive of cancer-specific death (P<0.005 for both). The former was also a significant predictor for tumor recurrence (P=0.007). Independent prognostic effects of serum methylation levels of SST were revealed by multivariate Cox regression model (P=0.031 and P=0.003 for cancer death and recurrence, respectively). When focusing on stage II and III patients, prognostication with serum methylated SST remained significant. Methylated SST detected in all serum samples can be traced back to the matched primary tumor tissues. We believe that methylated SST detected in the pre-operative sera of CRC patients appear to be a novel promising prognostic marker and probably can be auxiliary to tumor staging system and serum carcinoembryonic antigen towards better risk stratification.

Abstract 2559: Genome-wide haplotype association tests identified three candidate loci associated with sporadic colorectal cancer risk in Singapore Chinese

Colorectal cancer (CRC) is one of the most frequent cancers and leading cause of cancer mortality in the developed world. Twin study has attributed about 35% of the etiology of sporadic CRC to genes. Hitherto, more than 20 single nucleotide polymorphism (SNP) loci from genome-wide association studies (GWAS) were associated with CRC risk. Most of these index SNPs however have small effect sizes and often located in gene deserts. Thus they are unlikely to be causal. Haplotype-based methods may offer a more powerful approach to disease gene mapping. We previously performed a GWAS on 2,000 ethnicity-, age-, and gender-matched Singapore Chinese CRC patients and healthy controls using the Affymetrix SNP 6 platform. Sporadic patients were defined as aged 50 or more at the time of surgery and with no dominant family history of CRC. Haplotype block detection was performed in Golden Helix SVS after this SNP6 dataset was filtered for genotype call rate (&gt;95%), Hardy-Weinberg equilibrium in the controls and principal component analysis. Block detection was performed requiring strong linkage disequilibrium between block pairs, minor allelic frequencies (MAF) of SNPs more than 0.01, the maximum number of markers and length of the block at 30 and 160kb respectively. Genome-wide, 73,333 blocks were computed using 336, 466 markers on 22 autosomes. Haplotype frequencies were estimated using the EM algorithm. Chi-Squared and logistic regression with odds ratio tests of haplotype association were performed using these pre-computed blocks on a per-haplotype basis. Three candidate loci at chromosomes 3, 15 and 20, each with 6 to 9 SNPs and sizes ranging from 4 to 15 kb achieved genome-wide significance and encompass potential novel disease genes. These loci are currently being validated in an independent replication panel using the Fluidgm SNPtype assays and pooled analyses will be performed.

Citation Format: Peh Yean Cheah, Lai Fun Thean, Yik Ying Teo, Woon-Puay Koh, Jian-Min Yuan, Min Hoe Chew, Choong Leong Tang. Genome-wide haplotype association tests identified three candidate loci associated with sporadic colorectal cancer risk in Singapore Chinese. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2559.

Critical appraisal of laparoscopic vs open rectal cancer surgery

AIM: To evaluate the long-term clinical and oncological outcomes of laparoscopic rectal resection (LRR) and the impact of conversion in patients with rectal cancer.

METHODS: An analysis was performed on a prospective database of 633 consecutive patients with rectal cancer who underwent surgical resection. Patients were compared in three groups: Open surgery (OP), laparoscopic surgery, and converted laparoscopic surgery. Short-term outcomes, long-term outcomes, and survival analysis were compared.

RESULTS: Among 633 patients studied, 200 patients had successful laparoscopic resections with a conversion rate of 11.1% (25 out of 225). Factors predictive of survival on univariate analysis include the laparoscopic approach (P = 0.016), together with factors such as age, ASA status, stage of disease, tumor grade, presence of perineural invasion and vascular emboli, circumferential resection margin < 2 mm, and postoperative adjuvant chemotherapy. The survival benefit of laparoscopic surgery was no longer significant on multivariate analysis (P = 0.148). Neither 5-year overall survival (70.5% vs 61.8%, P = 0.217) nor 5-year cancer free survival (64.3% vs 66.6%, P = 0.854) were significantly different between the laparoscopic group and the converted group.

CONCLUSION: LRR has equivalent long-term oncologic outcomes when compared to OP. Laparoscopic conversion does not confer a worse prognosis.

Palliative surgical intervention in metastatic colorectal carcinoma: a prospective analysis of quality of life

AIM

Quality of life (QOL) was assessed after palliative surgery for incurable metastatic colorectal cancer (CRC).

METHOD

Newly diagnosed patients with incurable metastatic CRC who were offered elective palliative surgical intervention were included. The European Organization for Research and Treatment of Cancer QLQ-C30 and QLQ-CR29 questionnaire was used for the assessment of QOL at baseline and at 3 and 6 months after surgery. Generalized estimating equations were used to estimate the mean change in the QOL score from baseline.

RESULTS

Twenty-four patients formed the study group. Sixteen underwent resection of the primary tumour and eight had a proximal diversion or bypass. The Global Health (GH) score and Social Functioning (SF) score improved at 3 and 6 months after intervention respectively (GH +11, P = 0.021; SF +15, P = 0.005). Mean anxiety scores were markedly improved from the baseline of 51 to 71 (P = 0.004, 3 months) and 76 (P = 0.002, 6 months). Weight concerns also improved significantly when compared with baseline (3 months, +20, P < 0.001; 6 months, +14, P = 0.012). Symptoms of diarrhoea (3 months, --17, P = 0.007; 6 months,--16, P = 0.008) and nausea (--8, P = 0.032) improved.

CONCLUSION

In patients with incurable metastatic CRC, surgery improved QOL.

A scoring model for predicting survival following primary tumour resection in stage IV colorectal cancer patients with unresectable metastasis

BACKGROUND

Stage IV colorectal cancer patients with unresectable metastasis who undergo elective primary tumour resection experience heterogeneous post-operative survival. We aimed to develop a scoring model for predicting post-operative survival using pre-operative variables to identify patients who are least likely to experience extended survival following the procedure.

METHODS

Survival data were collected from stage IV colorectal cancer patients who had undergone elective primary tumour resection between January 1999 and December 2007. Coefficients of significant covariates from the multivariate Cox regression model were used to compute individual survival scores to classify patients into three prognostic groups. A survival function was derived for each group via Kaplan-Meier estimation. Internal validation was performed.

RESULTS

Advanced age (hazard ratio, HR 1.43 (1.16-1.78)); poorly differentiated tumour (HR 2.72 (1.49-5.04)); metastasis to liver (HR 1.76 (1.33-2.33)), lung (HR 1.37 (1.10-1.71)) and bone (HR 2.08 ((1.16-3.71)); carcinomatosis (HR 1.68 (1.30-2.16)); hypoalbuminaemia (HR 1.30 (1.04-1.61) and elevated carcinoembryonic antigen levels (HR 1.89 (1.49-2.39)) significantly shorten post-operative survival. The scoring model separated patients into three prognostic groups with distinct median survival lengths of 4.8, 12.4 and 18.6 months (p < 0.0001). Internal validation revealed a concordance probability estimate of 0.65 and a time-dependent area under receiver operating curve of 0.75 at 6 months. Temporal split-sample validation implied good local generalizability to future patient populations (p < 0.0001).

CONCLUSION

Predicting survival following elective primary tumour resection using pre-operative variables has been demonstrated with the scoring model developed. Model-based survival prognostication can support clinical decisions on elective primary tumour resection eligibility.

Analysis of colorectal cancer glyco-secretome identifies laminin β-1 (LAMB1) as a potential serological biomarker for colorectal cancer

The high mortality rate in colorectal cancer is mostly ascribed to metastasis, but the only clinical biomarker available for disease monitoring and prognosis is the carcinoembryonic antigen (CEA). However, the prognostic utility of CEA remains controversial. In an effort to identify novel biomarkers that could be potentially translated for clinical use, we collected the secretomes from the colon adenocarcinoma cell line HCT-116 and its metastatic derivative, E1, using the hollow fiber culture system, and utilized the multilectin affinity chromatography approach to enrich for the secreted glycoproteins (glyco-secretome). The HCT-116 and E1 glyco-secretomes were compared using the label-free quantitative SWATH-MS technology, and a total of 149 glycoproteins were differentially secreted in E1 cells. Among these glycoproteins, laminin β-1 (LAMB1), a glycoprotein not previously known to be secreted in colorectal cancer cells, was observed to be oversecreted in E1 cells. In addition, we showed that LAMB1 levels were significantly higher in colorectal cancer patient serum samples as compared to healthy controls when measured using ELISA. ROC analyses indicated that LAMB1 performed better than CEA at discriminating between colorectal cancer patients from controls. Moreover, the diagnostic performance was further improved when LAMB1 was used in combination with CEA.

Abstract 4587: Genome-wide copy number analysis identified a copy number polymorphism at chromosome 8p11 associated with sporadic colorectal cancer risk in Singapore Chinese

Colorectal cancer (CRC) is one of the most frequent cancers and leading cause of cancer mortality in the developed world. Twin study has attributed about 35% of the etiology of sporadic CRC to genes. Hitherto, more than 20 single nucleotide polymorphism (SNP) loci have been associated with CRC risk. The role of structural variant in CRC, however, remains unclear. We performed genome-wide association study (GWAS) on 2,000 ethnicity-, age-, and gender-matched Singapore Chinese CRC patients (aged 50 or more and with no dominant family history of CRC) and healthy controls. Genome-wide genotyping was performed using Affymetrix SNP 6 platform. Copy number polymorphism (CNP) was interrogated in 1830 samples that passed quality assurance tests using a multivariate segmentation algorithm. A 150 kb region at chromosome 8p11 was identified to be significantly associated (-log10 p-value = 29) with sporadic CRC risk. This CNP was preferentially amplified in the cases compared to the controls. The amplification was not gender-specific suggesting that it is not involved in gender-limiting pathway. It is now being replicated in an independent panel using digital polymerase chain reaction (dPCR) and multiplex endogenous reference technique. In silico analysis of a 1.5 Mb region encompassing the CNP reveals a candidate gene 300kb 5′ of the CNP previously implicated in cancer progression. The expression of this gene in cases with copy number and metastasis status is being interrogated.

Citation Format: Peh Yean Cheah, Lai Fun Thean, Yik Ying Teo, Woon-Puay Koh, Jian-Min Yuan, Min Hoe Chew, Choong Leong Tang. Genome-wide copy number analysis identified a copy number polymorphism at chromosome 8p11 associated with sporadic colorectal cancer risk in Singapore Chinese. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4587. doi:10.1158/1538-7445.AM2015-4587

Genomics of Hereditary Colorectal Cancer: Lessons Learnt from 25 Years of the Singapore Polyposis Registry

INTRODUCTION

The Singapore Polyposis Registry (SPR) was established in 1989 in Singapore General Hospital (SGH). The aims were to provide a central registry service to facilitate identification, surveillance and management of families and individuals at high risk of colorectal cancer.

MATERIALS AND METHODS

This is a review of published literature in the department.

RESULTS

The registry currently has 253 families with several genetic conditions-93 familial adenomatous polyposis (FAP) families, 138 Amsterdam-criteria positive presumed Lynch syndrome (LS) families, 12 families with Peutz Jeghers syndrome, 2 families with Cowden's syndrome, and 8 families with hereditary mixed polyposis syndrome (HMPS). There are also 169 families with a strong family history of colorectal cancer but no abnormal genes yet identified. In FAP, a diagnostic tool developed has allowed a 94% local APC germline detection rate in FAP families. Knowledge obtained studying the phenotype of FAP patients has allowed better choice of surgery between ileal pouch anal anastomosis (IPAA) against an ileal-rectal anastomosis (IRA). In LS, our review has noted a highly heterogenous mutational spectrum and novel variants made up 46.7% (28/60) of all variants identified in this cohort. This may suggest that our Southeast Asian ethnic groups have distinct mutational variants from Western populations. Pathogenic mutations were only confined to MLH1 and MSH2, and identified in 28.8% of families.

CONCLUSION

The impact of predictive gene testing for hereditary cancer risk in clinical practice has allowed evolution of care. Risk-reducing surgery and aggressive surveillance allows reduction in morbidity and mortality of patients. The SPR will continue to grow and improve outcomes in hereditary colorectal cancer patients and families.

Post-operative aspirin use and colorectal cancer-specific survival in patients with stage I-III colorectal cancer

BACKGROUND

Recent observational studies suggest that postoperative aspirin use may improve Colorectal cancer (CRC)-specific survival and overall survival (OS). In this study, we aimed to assess the effects of aspirin use on outcomes in a predominantly Asian cohort of patients with CRC.

PATIENTS AND METHODS

Case records of patients undergoing curative resection for stage I-III CRC were retrieved for clinical data and patterns of aspirin use and vital data were determined from hospital electronic prescription records, hospital pharmacy dispensing records, national clinical and prescription databases. CRC-specific and recurrence-free survival (RFS) amongst aspirin users and non-users were analyzed and compared using the Cox proportional hazards model.

RESULTS

Out of 726 patients with CRC, 103 were regular aspirin users and 623 were non-users. The median age of the cohort was 65 years (range=22-94 years) and the majority of patients were Chinese (90%). Nineteen percent, 31% and 47% had stage I, II and III CRC respectively; tumor staging was unknown for 3%. After adjusting for prognostic factors (age, stage, lymph node stage, grade, lesion site, perineural invasion, lymphvascular invasion), the risk of CRC relapse or death from CRC was approximately 60% lower compared to patients who were not postoperative aspirin users (Hazard Ratio=0.38, 95% Confidence Interval=0.17-0.84, p=0.017). No benefit was observed for preoperative use of aspirin.

CONCLUSION

In this single-Institution study, with long-term follow-up of patients with stage I-III-resected CRC, postoperative aspirin use was associated with reduced risk of relapse of and death from CRC.

Jejunojejunal intussusception secondary to submucosal lipoma resulting in a 5-year history of intermittent abdominal pain

Jejunal lipomata are an unusual cause of adult intussusception. We report a case of a 44-year-old Chinese woman who presented with a 3-day history of abdominal pain and nausea; she had a 5-year history of similar episodic symptoms after meals. Contrast-enhanced CT revealed a fat-density lead point in the jejunum resulting in intussusception. Single port laparoscopic surgery was performed with reduction of the intussusception, bowel resection and primary anastamosis. Histology confirmed a benign submucosal lipoma. We discuss the recent published literature on this rare entity and show CT images and intraoperative pictures.

Abstract 2189: A rare copy number variant at chromosome 14q11 was associated with sporadic colorectal cancer risk in Singapore Chinese

Colorectal cancer (CRC) is one of the most frequent cancers and leading cause of cancer mortality in the developed world. Twin study has attributed about 35% of the etiology of sporadic CRC to genes. Structural variations in the human genome have recently been associated with complex neurological diseases. Their role in CRC, however, is unclear. We performed genome-wide association study (GWAS) on 2,000 ethnicity-, age-, and gender-matched Singapore Chinese CRC patients (aged 50 or more and with no dominant family history of CRC) and healthy controls. Genome-wide genotyping was performed using Affymetrix SNP 6 platform, and rare copy number variants (CNV) were interrogated in 1830 samples that passed the quality assurance tests. A 400 kb region at chromosome 14q11 was identified to be significantly associated (-log10 p-value = 11) with sporadic CRC risk. A chromatin modifier implicated in the β-catenin/Wnt signalling pathway is one of the candidate genes found in the region. Primers unique for this gene applied to an optimal real-time copy number assay verified the CNV region in an independent replication panel comprising another 1,000 sporadic CRC cases. About 6% of the cases exhibit copy number alterations at this region compared to 1% in the healthy controls. A second gene, a small guanosine triphosphatase (GTPase) involved in protein trafficking and preferentially up-regulated in colonic tumors , was shown by long-range polymerase chain reaction to have more structural variations in the cases compared to the controls. Furthermore, expression of the H1 binding domain of the chromatin modifier was positively correlated to the expressions of Cyclin D1 and C-myc. The data suggest that the rare CNV in 14q11 was dynamically associated with the activation of genes implicated in sporadic CRC in the Singapore Chinese.

Citation Format: Peh Yean Cheah, Lai Fun Thean, Yik-Ying Teo, Woon-Puay Koh, Jian-Min Yuan, Poh Koon Koh, Min Hoe Chew, Choong Leong Tang. A rare copy number variant at chromosome 14q11 was associated with sporadic colorectal cancer risk in Singapore Chinese. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2189. doi:10.1158/1538-7445.AM2014-2189

Tracheotomy: an alternative for tracheobronchial foreign body removal

A 6 years old girl accidentally aspirated a plastic whistle while playing. Computed Tomography of thorax showed foreign body at carina level. Rigid bronchoscope under general anesthesia was attempted but unable to extract the whistle through vocal cord. Tracheostomy was later performed and foreign body was removed.

Evolution of laparoscopy in colorectal surgery: An evidence-based review

Open surgery for colorectal disease has progressed significantly over the past century from humble beginnings to form the mainstay of treatment for colorectal cancer and a number of benign conditions. Following the introduction of laparoscopic abdominal surgery, the next stage in the evolution of the specialty began in the 1990s with the first laparoscopic colonic resection. Following some early concerns regarding its safety and oncological efficacy during the latter part of that decade, laparoscopic colorectal surgery rapidly came into mainstream use in the early part of the current century with evidence supporting its use being made available from large scale randomised controlled trials. This article provides an evidence-based summary of this evolutionary process as it relates to both benign and malignant colorectal disease, as well as discussion of the next phase of new technologies such as robotic surgery.

Systematic study on genetic and epimutational profile of a cohort of Amsterdam criteria-defined Lynch Syndrome in Singapore

Background

Germline defects of mismatch repair (MMR) genes underlie Lynch Syndrome (LS). We aimed to gain comprehensive genetic and epigenetic profiles of LS families in Singapore, which will facilitate efficient molecular diagnosis of LS in Singapore and the region.

Methods

Fifty nine unrelated families were studied. Mutations in exons, splice-site junctions and promoters of five MMR genes were scanned by high resolution melting assay followed by DNA sequencing, large fragment deletions/duplications and promoter methylation in MLH1, MSH2, MSH6 and PMS2 were evaluated by multiplex ligation-dependent probe amplification. Tumor microsatellite instability (MSI) was assessed with five mononucleotide markers and immunohistochemical staining (IHC) was also performed.

Results

Pathogenic defects, all confined to MLH1 and MSH2, were identified in 17 out of 59 (28.8%) families. The mutational spectrum was highly heterogeneous and 28 novel variants were identified. One recurrent mutation in MLH1 (c.793C>T) was also observed. 92.9% sensitivity for indication of germline mutations conferred by IHC surpassed 64.3% sensitivity by MSI. Furthermore, 15.6% patients with MSS tumors harbored pathogenic mutations.

Conclusions

Among major ethnic groups in Singapore, all pathogenic germline defects were confined to MLH1 and MSH2. Caution should be applied when the Amsterdam criteria and consensus microsatellite marker panel recommended in the revised Bethesda guidelines are applied to the local context. We recommend a screening strategy for the local LS by starting with tumor IHC and the hotspot mutation testing at MLH1 c.793C>T followed by comprehensive mutation scanning in MLH1 and MSH2 prior to proceeding to other MMR genes.

Serum methylation levels of TAC1. SEPT9 and EYA4 as diagnostic markers for early colorectal cancers: a pilot study

OBJECTIVE

To identify methylated genes in serum with diagnostic potentials for early colorectal cancer (CRC).

METHODS

Serum methylation levels of up to 12 genes were measured in two sets of serum samples with the second set from 26 stage I CRC patients and 26 age/gender-matched controls.

RESULTS

Serum methylation levels of TAC1, SEPT9, and EYA4 were significant discriminants between stage I CRC and healthy controls. Combination of TAC1 and SEPT9 rendered 73.1% sensitivity with 92.3% specificity.

CONCLUSION

Serum methylation levels of TAC1. SEPT9 and EYA4 may be useful biomarkers for early detection of CRC though a validation study is necessary.

Opportunistic screening for colorectal neoplasia in Singapore using faecal immunochemical occult blood test

INTRODUCTION

The use of faecal immunochemical occult blood test (FIT) has been reported to decrease mortality from colorectal cancer. The Singapore Cancer Society (SCS) gives out FIT kits to encourage opportunistic screening of colorectal cancer. Any Singapore citizen or permanent resident aged ≥ 50 years is eligible to receive two FIT kits. Participants with at least one positive FIT are referred for further evaluation. We aimed to analyse the results of SCS data from the year 2008.

METHODS

The factors evaluated included compliance, positive test rate (PR) and positive predictive value (PPV) of FIT.

RESULTS

20,989 participants received 41,978 kits in 2008. Compliance was 38.9%, with 8,156 participants returning at least one kit. 8% of participants tested positive, and 75% of these test-positive participants agreed to undergo further investigations. 33 participants had colorectal cancers, 45 had advanced polyps (≥ 1 cm) and 90 had polyps < 1 cm. Histologically, 114 polyps were adenomatous, 20 were hyperplastic and 1 was serrated. PPV of colorectal neoplasia for those who underwent further colonoscopy was 34%. Over half of the participants who had only one positive test had colorectal neoplasia.

CONCLUSION

PR and PPV of FIT in our study were comparable to that in the literature. However, compliance was low and a quarter of all participants who tested positive refused further investigations. Extensive population education programmes are required to improve compliance and tackle inhibitions among the masses. It is also important to take steps to enhance the cost effectiveness of future screening programmes.