Influenza-associated hospitalizations, Singapore, 2004-2008 and 2010-2012

Studies of influenza-associated hospitalizations in tropical settings are lacking. To increase understanding of the effect of influenza in Singapore, we estimated the age-specific influenza-associated hospitalizations for pneumonia and influenza during 2004-2008 and 2010-2012. The rate of hospitalization was 28.3/100,000 person-years during 2004-2008 and 29.6/100,000 person-years during 2010-2012. The age-specific influenza-associated hospitalization rates followed a J-shaped pattern: rates in persons >75 years of age and in children <6 months of age were >47 times and >26 times higher, respectively, than those for persons 25-44 years of age. Across all ages during these 2 study periods, ≈12% of the hospitalizations for pneumonia and influenza were attributable to influenza. The rates and proportions of hospitalizations for influenza, particularly among the very young and the elderly, are considerable in Singapore and highlight the importance of vaccination in protecting populations at risk.

On growth measurements of abdominal aortic aneurysms using maximally inscribed spheres

The maximum diameter, total volume of the abdominal aorta, and its growth rate are usually regarded as key factors for making a decision on the therapeutic operation time for an abdominal aortic aneurysm (AAA) patient. There is, however, a debate on what is the best standard method to measure the diameter. Currently, two dominant methods for measuring the maximum diameter are used. One is measured on the planes perpendicular to the aneurism's central line (orthogonal diameter) and the other one is measured on the axial planes (axial diameter). In this paper, another method called 'inscribed-spherical diameter' is proposed to measure the diameter. The main idea is to find the diameter of the largest sphere that fits within the aorta. An algorithm is employed to establish a centerline for the AAA geometries obtained from a set of longitudinal scans obtained from South Korea. This centerline, besides being the base of the inscribed spherical method, is used for the determination of orthogonal and axial diameter. The growth rate parameters are calculated in different diameters and the total volume and the correlations between them are studied. Furthermore, an exponential growth pattern is sought for the maximum diameters over time to examine a nonlinear growth pattern of AAA expansion both globally and locally. The results present the similarities and discrepancies of these three methods. We report the shortcomings and the advantages of each method and its performance in the quantification of expansion rates. While the orthogonal diameter measurement has an ability of capturing a realistic diameter, it fluctuated. On the other hand, the inscribed sphere diameter method tends to underestimate the diameter measurement but the growth rate can be bounded in a narrow region for aiding prediction capability. Moreover, expansion rate parameters derived from this measurement exhibit good correlation with each other and with growth rate of volume. In conclusion, although the orthogonal method remains the main method of measuring the diameter of an abdominal aorta, employing the idea of maximally inscribed spheres provides both a tool for generation of the centerline, and an additional parameter for quantification of aneurysmal growth rates.

Impact of Smoking and Brain Metastasis on Outcomes of Advanced EGFR Mutation Lung Adenocarcinoma Patients Treated with First Line Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors

Objectives

This purpose of this study was to examine clinical-pathologic factors – particularly smoking and brain metastases – in EGFR mutation positive (M+) lung adenocarcinoma (ADC) to determine their impact on survival in patients treated with first line EGFR TKI.

Methods

A retrospective review of EGFR mutation reflex testing experience for all ADC diagnosed at a tertiary Asian cancer centre from January 2009 to April 2013. Amongst this cohort, patients with advanced EGFR M+ ADC treated with first line EGFR TKI were identified to determine factors that influence progression free and overall survival.

Results

444/742 (59.8%) ADC reflex tested for EGFR mutations were EGFR M+. Amongst never-smokers (n=468), EGFR M+ were found in 74.5% of females and 76.3% of males, and amongst ever smokers (n=283), in 53.3% of females and 35.6% of males. Exon 20 mutations were found more commonly amongst heavy smokers (> 50 pack years and > 20 pack years, Pearson’s chi square p=0.044, and p=0.038 respectively). 211 patients treated with palliative first line TKI had a median PFS and OS of 9.2 and 19.6 months respectively. 26% of patients had brain metastasis at diagnosis. This was significantly detrimental to overall survival (HR 1.85, CI 1.09-3.16, p=0.024) on multivariate analysis. There was no evidence that smoking status had a significant impact on survival.

Conclusions

The high prevalence of EGFR M+ in our patient population warrants reflex testing regardless of gender and smoking status. Smoking status and dosage did not impact progression free or overall survival in patients treated with first line EGFR TKI. The presence of brain metastasis at diagnosis negatively impacts overall survival.

Abstract P6-08-52: Predicting the likelihood of additional non sentinel lymph node metastasis in early breast cancer: Novel sentinel nodal station status versus Singapore General Hospital nomogram

Background: Sentinel lymph node biopsy (SLNB) has been widely used in early breast cancer patients for the detection of axillary nodal metastasis. We were the first to describe 2 novel sentinel nodal stations (SNS) in relation to the intercostobrachial nerve (ICB) and the medial pectoral neurovascular bundle (MP) at which sentinel lymph nodes (SLN) were consistently identified, even only with the use of blue dye. In a pilot study involving 176 cases, we have shown that the ICB and MP SNS represent sequential echelons of SLN draining the breast. It was observed that the status of the MP SNS can be used in predicting the likelihood of additional non sentinel lymph node metastasis in early breast cancer. Thus, we aim to compare this against the Singapore General Hospital (SGH) nomogram, the existing standard predictive model in the local population. The SGH nomogram was developed from predictors in the Memorial Sloan-Kettering Cancer Centre (MSKCC) nomogram. It uses only 3 pathological parameters: lymphovascular invasion, number of positive and negative SLN. This has been shown to be at least equal if not better than the MSKCC nomogram as a predictive model in the Singapore population.

Methods : All patients who underwent oncologic breast surgery and SLNB (using the SNS identification technique) at the Department of Surgical Oncology, National Cancer Centre Singapore from February 2012 to December 2013 inclusive were reviewed. Patients who fulfilled the following selection criteria were included in the study: [1] invasive ductal or lobular carcinoma, [2] SLN identified in both ICB and MP SNS,[3] axillary clearance done with total lymph nodes ≥ 10, based on a positive SLNB. The performance of the MP SNS status and SGH nomogram in predicting the likelihood of additional non sentinel lymph node metastasis was compared with the calculation of the area under the receiver-operating characteristic curve (AUC).

Results: A total of 49 patients were identified. Majority of the patients had early breast cancers: 94% had tumour size ≤5cm and 71% had N1 disease. The median number of total SLN, ICB and MP nodes identified were 3 (range 2-14), 2 (range 1-7) and 1 (range 1-12) respectively. The median number of positive and negative SLN were both 1 (range 1-5 and 0-9 respectively). The positive predictive value of MP SNS status for additional non sentinel lymph node metastasis was 76.5% (95% CI: 50.1-93.2). The strong association was proven by an odds ratio of 7.15 (95% CI 1.86-27.50, p-value: 0.002). The negative predictive value of MP SNS for eventual N stage was 93.8% (95% CI: 79.2-99.2). In most of the cases, the nodal stage remained at N1 in the presence of negative MP node. The model with MP SNS status yielded an AUC of 0.706 (95% CI: 0.579-0.832) which was higher than that of the SGH nomogram, 0.658 (95% CI: 0.503-0.813).

Conclusions: The novel MP SNS proved to be a single parameter which predicts the likelihood of additional non sentinel lymph nodes metastasis better than the SGH nomogram. More importantly, from the clinical point of view, the MP SNS status can be made available intra-operatively and hence guide the decision for further axillary dissection.

Citation Format: Sue Zann Lim, Puay Hoon Tan, Gay Hui Ho, Preetha Madhukumar, Yirong Sim, Shaun Shi Yan Tan, Cindy Lim, Veronique Kiak Mien Tan, Kong Wee Ong. Predicting the likelihood of additional non sentinel lymph node metastasis in early breast cancer: Novel sentinel nodal station status versus Singapore General Hospital nomogram [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P6-08-52.

Abstract P2-01-25: Not all sentinel lymph nodes are equal – A predictive model for axillary burden in early breast cancer

Introduction

The Z11 trial demonstrates that an axillary lymph node dissection (ALND) can be avoided in patients with low axillary burden who undergo breast conserving surgery (BCS), combined with whole-breast radiotherapy and systemic therapy. Our group propose a standardisation of sentinel lymph node biopsy (SLNB), incorporating 2 novel sentinel nodal stations (SNS) which represent sequential echelons of SLN draining the breast – the intercostalbrachial nerve (ICB) and the medial pectoral neurovascular bundle (MP). By increasing the specificity and positive predictive value of SLNB, we aim to identify a subgroup of patients who undergo mastectomy who can be spared from ALND and its associated complications.

Materials and Methods

313 female patients who underwent sentinel lymph node biopsy for breast cancer from 2 February 2012 to 19 December 2013 were prospectively studied. 12 patients had bilateral breast cancers, and each laterality was counted as distinct cases, giving a total of 325 cases. 7 had breast surgery performed prior to the SLNB, and the rest had their oncological surgery performed at the same setting of the SLNB. The surgeries were performed by three surgeons in the National Cancer Centre Singapore, using a specific surgical technique to identify SLN at the 2 SNS. Relevant patient demographics, status of SNS and the rates of metastatic non-sentinel lymph nodes were collected and analysed.

Results

A total of 325 SLNBs using the ICB and MP SNS were identified from 169 simple mastectomies, 35 skin sparing mastectomies, and 129 breast conserving surgeries. The median age was 56 (range 27-89). The ICB SLN and MP SLN were identified in 313 (96.3%) and 258 (79.4%) cases respectively. In 249 (76.6%) cases were both ICB and MP nodes identified, of which 55 (16.9%) had metastatic involvement of the SLN.

An axillary clearance was performed if at least one ICB or MP node was positive, and only 27 (49.1%) had further axillary involvement. More than 2 positive SLNs had 100% positive predictive value for further axillary LN metastases. There was a low sensitivity (29.6%) and high false negative rate (70.4%) for positive axillary nodes in patients with ≤2 positive SLNs.

MP nodal status, however, was 85.7% specific (p&lt;0.001) and 48.1% sensitive (p=0.649) and a positive predictive value of 76.5% for axillary nodal involvement. Logistic regression also shows that MP node status is significant for predicting axillary nodal status (OR 5.57, p=0.006).

Conclusion

Our study shows that MP node status is specific, and has a positive predictive value for further axillary LN metastases. Therefore, we propose that in all patients who undergo SLNB with their BCS or mastectomy, an axillary clearance should be performed if the MP node is positive, regardless of the number of positive SLNs.

Citation Format: Yirong Sim, Sue Zann Lim, Shaun S Tan, Alvona Z Loh, Cindy Lim, Preetha Madhukumar, Gay H Ho, Veronique KM Tan, Kong Wee Ong. Not all sentinel lymph nodes are equal – A predictive model for axillary burden in early breast cancer [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P2-01-25.

Associating liver partition and portal vein ligation for staged hepatectomy (ALPPS): impact of the inter-stages course on morbi-mortality and implications for management

BACKGROUND

Associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) was recently developed to induce rapid hypertrophy and reduce post-hepatectomy liver failure in patients with insufficient remnant liver volume (RLV). However, mortality rates >12% have been reported. This study aimed to analyze the perioperative course of ALPPS and to identify factors associated with morbi-mortality.

METHODS

Between April 2011 and September 2013, 62 patients operated in 9 Franco-Belgian hepatobiliary centres underwent ALPPS for colorectal metastases (N = 50) or primary tumors, following chemotherapy (N = 50) and/or portal vein embolization (PVE; N = 9).

RESULTS

Most patients had right (N = 31) or right extended hepatectomy (N = 25) (median RLV/body weight ratio of 0.54% [0.21-0.77%]). RLV increased by 48.6% [-15.3 to 192%] 7.8 ± 4.5 days after stage1, but the hypertrophy decelerated beyond 7 days. Stage2 was cancelled in 3 patients (4.8%) for insufficient hypertrophy, portal vein thrombosis or death and delayed to ≥9 days in 32 (54.2%). Overall, 25 patients (40.3%) had major complication(s) and 8 (12.9%) died. Fourteen patients (22.6%) had post-stage1 complication of whom 5 (35.7%) died after stage2. Factors associated with major morbi-mortality were obesity, post-stage1 biliary fistula or ascites, and infected and/or bilious peritoneal fluid at stage2. The latter was the only predictor of Clavien ≥3 by multivariate analysis (OR: 4.9; 95% CI: 1.227-19.97; p = 0.025). PVE did not impact the morbi-mortality rates but prevented major cytolysis that was associated with poor outcome.

CONCLUSIONS

The inter-stages course was crucial in determining ALPPS outcome. The factors of high morbi-mortality rates associated with ALPPS are linked to the technique complexity.

Comparison of severely ill patients with influenza A(H1N1)pdm09 infection during the pandemic and post-pandemic periods in Singapore

BACKGROUND/OBJECTIVES

Singapore is a tropical country with influenza seasons occurring bi-annually. We compared the profile of severely ill patients with laboratory confirmed influenza A(H1N1)pdm09 infection in Singapore during the pandemic and post-pandemic periods, and studied their risk factors associated with mortality.

PATIENTS/METHODS

Three periods were defined for this study; pandemic period from 18 June to 29 August 2009, early post-pandemic period from 30 August 2009 to 12 February 2010, and late post-pandemic period from 13 February to 10 August 2010.

RESULTS

A total of 172 severely ill patients were admitted to hospitals from 18 June 2009 to 10 August 2010, of whom 23.8% died. The median age in the late post-pandemic period was significantly older than that in the early post-pandemic period (52 years versus 35 years, P=0.02). The median age of patients who died was significantly older than those who survived (52 years versus 44 years, P<0.01). The median length of stay under intensive care in the late post-pandemic period was twice that in the early post-pandemic (6 days versus 3 days, P=0.045). The proportion who died in the late post-pandemic period was more than 2.5 times that in the early post-pandemic period (29.8% versus 11.1%, P=0.043).

CONCLUSIONS

Severely ill patients were of older age in the late post-pandemic period. Older age was also significantly associated with mortality. It is important to maintain heightened vigilance and continue the surveillance of severely ill patients with influenza post-pandemic, so that patients with suspected infections could be promptly identified for early diagnosis and treatment.

Accessory liver lobes: anatomical description and clinical implications

Accessory liver lobes are a rare condition and appear to be due to excessive development of the liver. The presence of an accessory hepatic lobe is often diagnosed incidentally and sometimes revealed if it develops torsion, especially in pedunculated forms. In most cases, the accessory lobe is located below the liver, i.e., infrahepatic. Riedel's lobe is the best-known example of an accessory lobe, corresponding to hypertrophy of segments V and VI. While accessories lobes can simulate tumors, there have also been reports of hepatocellular tumor(s) that developed in these accessory lobes. Based on a review of the literature, this update focuses on accessory hepatic lobes.

Transcriptional regulation during Drosophila spermatogenesis

Drosophila spermatogenesis has become a paradigmatic system for the study of mechanisms that regulate adult stem cell maintenance, proliferation and differentiation. The dramatic cellular differentiation process from germline stem cell (GSC) to mature sperm is accompanied by dynamic changes in gene expression, which are regulated at transcriptional, post-transcriptional (including translational) and post-translational levels. Post-transcriptional regulation has been proposed as a unique feature of germ cells. However, recent studies have provided new insights into transcriptional regulation during Drosophila spermatogenesis. Both signaling pathways and epigenetic mechanisms act to orchestrate the transcriptional regulation of distinct genes at different germ cell differentiation stages. Many of the regulatory pathways that control male gamete differentiation in Drosophila are conserved in mammals. Therefore, studies using Drosophila spermatogenesis will provide insight into the molecular mechanisms that regulate mammalian germ cell differentiation pathways.

Colorectal peritoneal carcinomatosis treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy: the experience of a tertiary Asian center

INTRODUCTION

Compared with intravenous chemotherapy, cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) have been shown to improve survival in patients with recurrent colorectal disease confined to the peritoneum. We report our experience with CRS and HIPEC for colorectal cancer patients with peritoneal carcinomatosis, evaluating prognostic factors for disease-free survival (DFS), overall survival (OS), and perioperative morbidity and mortality.

METHODS

All patients who underwent CRS and HIPEC were included in our study. Clinical characteristics, operative data, and 30-day morbidity and mortality were collected and evaluated.

RESULTS

Between January 2001 and December 2012, there were 35 consecutive patients who underwent CRS and HIPEC at our institution. Thirty-three patients (94%) had optimal cytoreduction. No 30-day mortality was reported, but 14 patients had postoperative complications. The median DFS was 9.4 months (95% confidence interval 5.5-18.7 months), and DFS at 1 year, 3 years, and 5 years were 43.8%, 22.3%, and 22.3%, respectively. The median OS was calculated to be 27.1 months (95% confidence interval 15.3-39.1), and the OS at 1 year, 3 years, and 5 years were 83.7%, 38.2%, and 19.1%, respectively.

CONCLUSION

CRS and HIPEC can provide survival benefit, with reasonable morbidity and mortality for Asian patients with peritoneal carcinomatosis from colorectal cancer. Patient selection and perioperative management of the patients are key to the success of the procedure.

The development and validation of the treatment of autoimmune bullous disease quality of life questionnaire, a tool to measure the quality of life impacts of treatments used in patients with autoimmune blistering disease

BACKGROUND

Treatments for autoimmune blistering diseases have significant risk of medical complications and quality of life impacts during treatment, and it is difficult to differentiate these impacts from disease burden or the effects of treatment.

OBJECTIVES

To develop a quality of life instrument specific to the effects of treatments used in patients with autoimmune bullous disease (AIBD).

METHODS

A comprehensive item generation process was used to build a 45-item pilot Autoimmune Bullous Disease Quality of Life (ABQOL) questionnaire, distributed to 70 patients with AIBD. Experts in bullous disease refined the pilot ABQOL, selecting only those questions pertaining to the treatment effects. This pilot Treatment of Autoimmune Bullous Disease Quality of Life (TABQOL) questionnaire was administered to 70 patients, before factor analysis was performed to yield the final questionnaire of 17 questions. Validity and reliability were evaluated across a range of indices.

RESULTS

Face and content validity were established through a comprehensive patient interview process, expert review and summaries of treatments used. The questionnaire was found to have appropriate correlation with the Dermatology Life Quality Index (r = 0.64) and the level of treatments used (P < 0.01), and was found to be responsive to overall variations in treatment burden. The TABQOL was also found to be a reliable instrument as evaluated by internal consistency (Cronbach α = 0.892) and test-retest reliability (r = 0.99).

CONCLUSIONS

We have shown that the TABQOL questionnaire is a valid and reliable instrument that may to be used to measure treatment burden in AIBD and serve as an end point in clinical trials.

Primary intracranial germ cell tumours: experience of a single South-East Asian institution

Primary intracranial germ cell tumours (ICGCT) are a rare group of brain tumours arising predominantly in the paediatric and pre-adult population, accounting for up to 9.5% of paediatric brain tumours in East Asia. The National Cancer Centre Singapore (NCCS) is a tertiary referral centre for patients from all over South-East Asia. Our study aims to describe the characteristics of ICGCT patients in South-East Asia. Data on all patients with ICGCT who were seen at the Therapeutic Radiology Department of NCCS from 2000 to 2013 were collected retrospectively. Patient demographics, disease characteristics and treatment outcomes were analysed. Characteristics and survival of our patients were similar to other centres. Pure germinomas demonstrated 5 year overall survival (OS) and disease-free survival (DFS) rates of 89.2% (95% confidence interval [CI] 60.2-97.5) and 85.2% (95%CI 60.8-95.0) respectively. Secreting germinomas, non-germinomatous germ cell tumours and mixed germ cell tumours were evaluated together and demonstrated 5 year OS of 70.6% (95%CI 41.0-87.3) and DFS of 61.4% (95%CI 31.9-81.3). Patients ⩽ 12 years had marginally better 5 year OS than their older counterparts (81.0% [95%CI 49.5-93.9] versus 77.9% [95%CI 47.3-92.0], respectively). Patients who underwent extended field radiotherapy had longer OS and DFS than those who received local field irradiation. Treatment outcomes of our ICGCT patients are comparable with those in other Asian and Western centres. Extended field radiotherapy is a pivotal component of ICGCT treatment. Adding chemotherapy confers no extra survival benefit in treating germinomas. Treatment of mixed germ cell tumours and non-germinomatous germ cell tumours involves a multidisciplinary approach that varies for each histological subtype.