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Biomedical subjects

K C Soo

Publications and source records attributed to K C Soo.

At least 19 recordsLinked to original sources

Lessons learned from initial experience with peritonectomy and intra-peritoneal chemotherapy infusion.

INTRODUCTION: Patients diagnosed with peritoneal carcinomatous usually survive for less than 6 months. Cytoreductive surgery allows relief of the obstruction and improvement in functional status, while intraperitoneal chemotherapy infusion provides high local concentrations of chemotherapeutic agents. Our institutional experience is reviewed to assess the selection criteria, peri-operative complications, and outcomes. MATERIALS AND METHODS: We carried out a retrospective review of nine patients who had undergone aggressive cytoreductive surgery and hyperthermic intra- and early post-operative chemotherapy by a single surgeon between April 2000 and October 2004. The inclusion criteria were: (1) a demonstrated absence of extra-peritoneal and hepatic spread, (2) fitness of the patient and ability to tolerate cytoreductive surgery and intra-operative chemotherapy, and (3) the presence of a primary tumor originating form the gastro-intestinal tract (colonic, appendiceal, and gastric primaries). RESULTS: Seven women and two men, with a median age of 55 years, were treated. The median duration of the operation was 12 hours and 55 minutes. Seven of the nine patients required the insertion of at least one chest tube. All patients were monitored in the surgical intensive care unit (SICU) for a median of 1 day, started on feeds after a median of 6 days, and were hospitalized for a median of 16 days (range:11-18 days). There was no peri-operative mortality and only one major peri-operative complication (11.1%). At the time of analysis, the median follow-up was 16 months (range: 2-40 months), and the median disease-free survival was 8 months, with four of the nine patients showing no evidence of recurrence. To date, all of the patients are still alive. A 1-year survival rate of 100% is also documented. CONCLUSIONS: This article describes our initial experience with peritonectomy and intra-operative, intra-peritoneal chemotherapy infusion. Our initial problems included difficulty with leakage of the chemotherapeutic agents into the thoracic cavity that had to be overcome by the early insertion of chest-tubes. With appropriate patient selection, cytoreductive surgery with the infusion of intra-operative chemotherapy can be considered to be a therapeutic option for some patients with diffuse peritoneal metastases, and good disease-free and overall survival can be achieved with minimal morbidity.

Adult↗

Singapore's proposed graduate medical school--an expensive medical tutorial college or an opportunity for transforming Singapore medicine?

The proposed Graduate Medical School at the Outram Campus will open in 2007. The main value of this medical school is the transformation of the medical institutions in the campus and SingHealth into Academic Medical Centres. Such centres will train and host quality physicians and physician-scientists. It will help push the development of translational research, complementing the country's investment in Biopolis. It will also underpin Singapore's push into regional medical tourism and its development as an educational hub in the biomedical sciences.

Academic Medical Centers↗

Concurrent chemoradiotherapy followed by surgery in locally advanced squamous cell carcinoma of the oesophagus: a single centre experience.

INTRODUCTION: Data on combined modality treatment for locally advanced squamous cell carcinoma of the oesophagus involving Asian patients are limited. MATERIALS AND METHODS: A retrospective study of 56 consecutive patients with this condition treated with concurrent chemoradiotherapy followed by surgery in a single tertiary institution in Singapore was performed. RESULTS: The median overall survival of the entire cohort was 14.1 months [95% confidence interval (CI); range, 8.6 to 19.6 months]. In patients who underwent successful oesophagectomy after chemoradiotherapy (n = 17), the median survival was 27.8 months compared to 9.8 months for those who did not have surgery (n = 39) (P = 0.046, log-rank test). The median time to first relapse for the entire cohort was 16.1 months (95% CI, 7.7 to 24.5 months). The time to first relapse was 23.9 months in the subgroup of patients with successful surgery and 12.1 months in the group which did not (P = 0.147, log-rank test). The high proportion of patients who were medically unfit for surgery or declined surgery may have conferred a selection bias. CONCLUSION: Concurrent chemoradiotherapy followed by surgery is feasible in selected patients. The benefit of adding of surgery to chemoradiotherapy is still controversial and we await the results of randomised controlled trials comparing chemoradiotherapy with surgery versus chemoradiotherapy alone.

Carcinoma, Squamous Cell↗

Extracellular signal-regulated kinase induces cyclin D1 and Cdk-2 expression and phosphorylation of retinoblastoma in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is one of the most common malignancies in Southeast Asia. Hyperphosphorylation of retinoblastoma (pRB) by cyclin/CDKs in G1/S transition is required for its inactivation and cell cycle progression. In the present study, we report that phosphorylation of pRB at Ser780 and Ser795 was detected in 71% (33 of 46) and 63% (29 of 46) of HCCs examined respectively. pRB protein was undetectable in 13% (6 of 46) of HCCs examined. Phosphorylated pRB was localized in the nuclei of hepatocarcinoma cells. Benign hepatocytes exhibited very weakly or no nuclear staining for phosphorylated pRB. Over-expression of E2F-1, cyclin D1, Cdk-2, Cdk-4 and cyclin A was found in 64% (30 of 46), 43% (26 of 46), 28% (11 of 46), 71% (33 of 46) and 63% (29 of 46) of HCCs examined respectively and this was correlated with elevation of ERK. Treatment of HepG2 cells with MEK1/2 inhibitor U0126 resulted in cell cycle arrest, downregulation of cyclin D1 and Cdk-2 expression and inhibition of pRB phosphorylation at Ser780 and Ser795. Ectopic expression of activated MEK1 in HepG2 cells increased cyclin D1 and Cdk-2 expression, phosphorylation of pRB at Ser780 and Ser795, and percentage of cells in S phase. Our data indicate that activated ERK plays an important role in cyclin D1 and Cdk-2 expression and phosphorylation of pRB at Ser780 and Ser795 in liver cancer cells.

CDC2-CDC28 Kinases↗

Single institution's initial experience with sentinel lymph node biopsy in breast cancer patients.

BACKGROUND: The sentinel lymph node is the first draining node from a cancer-bearing area and is therefore the first to manifest metastasis. In breast cancer it has been shown to predict the axillary status. Axillary dissection provides information determining prognosis and need for adjuvant therapy but carries a certain morbidity. Our aim was to determine the feasibility of detecting the sentinel node in a teaching hospital and whether the sentinel node accurately predicts the axillary status. METHODS: All patients with stage I and II breast cancer and non-palpable axillary nodes were eligible, including those with previous excision biopsy. We excluded pregnant women, those with previous axillary surgery and women with advanced breast cancer with enlarged axillary nodes. The sentinel node was detected with technetium-99m-labelled tin colloid and vital blue dye and removed, and axillary clearance was performed. RESULTS: A total of 312 patients were examined from August 1996 to December 1998. The mean age was 53 years (range 28-83) and mean tumour size 2.6 cm (range 0.2-9.0). The detection rate of the sentinel node was 86%. The sentinel lymph node predicted the axillary status with a sensitivity of 83% and specificity of 100%. The false-negative rate was 16.7%. CONCLUSIONS: Detection of the sentinel lymph node is feasible and it can accurately predict the nodal status of the axilla. However, the high false-negative rate precludes as yet the use of sentinel lymph node biopsy in replacing axillary clearance as the standard of care for breast cancer.

Adult↗

Does laparoscopic fenestration provide long-term alleviation for symptomatic cystic disease of the liver?

BACKGROUND: The use of laparoscopic technique for management of symptomatic liver cysts is documented to be a feasible and safe procedure with good short-term symptomatic relief. However, it cannot be recommended as the standard of care as long-term results are scarce. The present study was initiated to review the long-term results of this approach in the management of symptomatic liver cysts. METHODS: A retrospective review of all patients with symptomatic liver cysts that were treated by laparoscopic fenestration in our department over an 8-year period from 1993 to 2001. The clinical and radiographical data were analysed at follow-up to assess the -outcome. RESULTS: Eleven patients were treated using a laparoscopic approach; 10 patients with solitary cysts and one with adult polycystic liver disease. All patients achieved short-term alleviation of symptoms and an uneventful postoperative course. The mean hospital stay was 3 days. Long-term follow up was available for 9 patients with a mean of 44 months. Histologically, one of the patients was diagnosed with a biliary cystadenoma and she had a symptomatic recurrence and a liver resection at 20 months. In the other seven patients, there was no clinical recurrence but a radiographical recurrence of 28.5%. The patient with adult polycystic liver disease had two symptomatic recurrences: at 26 months where he underwent a repeat laparoscopic fenestration and at 43 months where he underwent an open fenestration. CONCLUSION: The present study confirms that with adequate patients election, long-term alleviation of symptoms can be achieved with the laparoscopic approach for solitary simple liver cysts but not for polycystic liver disease or cystic tumours of the liver.

Adult↗

Surgical management and outcome of carotid body tumours.

INTRODUCTION: Carotid body tumours are rare but are interesting in their manner of presentation and challenging with respect to surgical extirpation. They may present as a neck mass from which a bloody aspirate is obtained on fine needle aspiration. They are occasionally diagnosed only at the time of surgery, when one encounters the vascular tumour mass. METHODS: We reviewed the results of 8 cases operated in our department over a 10-year period from 1989 to 1999. We evaluated in-hospital mortality and morbidity, as well as the long-term outcome especially with regards to functional disability. RESULTS: Preoperative evaluation included angiography, computed tomography (CT) or magnetic resonance angiography. Operative technique involves good exposure, vascular control, identification and preservation of neurovascular structures and subadventitial tumour dissection. In all cases the vagus nerve was preserved, except in 1 case who had a malignant tumour and resection of the vagus nerve together with the accessory nerve and sympathetic chain. Two patients had unexpected hoarseness of voice postoperatively, 1 was due to permanent vagus nerve palsy and the other to transient vagus nerve palsy. One of them needed vocal cord medialisation and long-term tube feeding. One patient had bilateral tumours and developed a stroke after an operation on the second tumour. No patients exhibited local or metastatic disease during follow-up. There was no mortality in all cases. CONCLUSION: Although resection of the carotid body tumour is safe in experienced hands, long-term morbidity is still a significant problem and can be debilitating to the patient.

Adult↗

Well-differentiated thyroid carcinoma: factors predicting recurrence and survival.

AIMS: 1) Determine the patient and tumour characteristics for well-differentiated thyroid carcinoma--towards developing a unique risk classification for our largely Chinese population. 2) Assess extent of thyroid surgery required. 3) Document prognostic value of UICC and AMES classification. METHODS: Retrospective review of 175 patients treated for primary thyroid epithelial malignancy by the Department of General Surgery at the Singapore General Hospital. RESULTS: There were 78% papillary carcinomas (PC) and 19% follicular carcinomas (FC). Female: male ratio was 3:1. Patient distribution in the UICC stages I, II, III, IV is respectively 56, 11, 31 and 2%. Twenty-six percent had hemithyroidectomy, and 74% total thyroidectomy. Neck dissections were required in 6% of FC compared to 34% of PC. Mean follow-up was 40 months. Extent of surgery did not affect PC/FC survival nor recurrence rates (p=0.53 and 0.06 respectively). Recurrences occurred in 15% FC and 9% PC. Death occurred in one FC and two PC. Survival correlated with UICC stage I/II and stage III/IV groups (p=0.04), and recurrence correlated with AMES High and Low Risk groups (p=0.004). No statistically significant difference was shown for survival between PC and FC or AMES groups and recurrence between PC and FC or UICC groups. CONCLUSIONS: Extent of thyroid surgery does not significantly affect local recurrences of PC/FC. The characterisation of thyroid carcinoma here is an important step towards developing a risk classification unique to our largely Chinese population.

Adenocarcinoma, Follicular↗

Resurfacing of the nasopharynx after nasopharyngectomy using a free radial forearm flap.

BACKGROUND: Nasopharyngectomy is emerging as an important treatment option for salvaging locally recurrent nasopharyngeal carcinoma (NPC). After nasopharyngectomy, resurfacing the nasopharynx and covering the internal carotid artery is important to minimize the risk of infection, osteoradionecrosis, and carotid rupture. Previous authors have advocated the use of free grafts of skin and mucosa for this purpose but have also described significant rates of partial and total graft failure. METHODS: We believe that the best and most reliable way to resurface the nasopharynx is with vascularized tissue, and our preference is for the use of a free radial forearm flap. To illustrate our approach, we present two patients who underwent nasopharyngectomy by means of a maxillary swing approach and who had resurfacing of the surgical defect with a free radial forearm flap. RESULTS: Both patients had complete en bloc resection of tumor followed by the insetting of a free radial forearm flap to reline the surgical defect. Both flaps remained completely viable, and both patients achieved successful resurfacing of the entire nasopharynx. The morbidity of surgery was minimal, and there were no perioperative complications. On assessment 1 year later, the free radial forearm flap continues to reline the entire neonasopharynx, and the long-term functional recovery after surgery is excellent. CONCLUSION: Resurfacing the nasopharynx after nasopharyngectomy with a free radial forearm flap aids healing and minimizes the risk of complications. The morbidity of surgery is minimal and the functional recovery is excellent.

Humans↗

Pattern of cervical lymph node metastases from papillary carcinoma of the thyroid.

INTRODUCTION: The management of cervical metastases from papillary thyroid carcinoma ranges from selective removal (berry picking) to a formal comprehensive neck dissection. Without a clear understanding of the distribution of nodes at risk, the formulation of strategies on how best to manage the clinically positive neck is difficult. This study reports on observations made in patients who underwent a therapeutic comprehensive neck dissection for metastatic papillary thyroid carcinoma by defining lymph node involvement with respect to neck level. METHODS: The clinical records and pathological reports of 75 consecutive patients who underwent a neck dissection for cervical metastases from papillary thyroid carcinoma over a 10-year period were reviewed. All dissections were therapeutic in nature, being performed in patients with clinically positive neck nodes. Eighty neck dissection specimens were obtained and analyses were divided into three groups by virtue of the type of dissection performed: a bilateral comprehensive neck dissection, unilateral radical neck dissection and unilateral comprehensive neck dissection. The relative involvement of cervical nodes was analysed with reference to node levels I-V. RESULTS: Patients in the anterolateral group (levels II, III and IV) were at greatest risk of metastatic disease, with level III nodes consistently the most frequently involved, across all treatment groups. Only three patients exhibited level I involvement, all of whom had extensive neck disease involving all or almost all neck levels. CONCLUSION: The majority of patients present with multiple level node disease, with the anterolateral group at greatest risk. A comprehensive neck dissection is recommended for all patients with palpable cervical lymphadenopathy.

Adult↗

Prevalence of Helicobacter pylori in gastric cancer in a South-East Asian population by 14C-urea breath test.

BACKGROUND: Helicobacter pylori is believed to play an important role in the aetiology of gastric cancer. There is a great variability in seropositivity and histological frequency of H. pylori in gastric cancer. The present prospective study investigates the prevalence of H. pylori infection in gastric cancer patients using 14C-urea breath testing. METHODS: Patients with endoscopic biopsy-proven gastric cancer were fasted for 6 h prior to ingesting 18.5 x 104 Bq of 14C-urea cocktail orally. Breath samples were collected after 20 min by asking them to blow into a hyamine solution and measurements were read in a scintillation counter. RESULTS: Fifty out of 51 patients (98%) with gastric cancer were positive on the 14C-urea breath test compared to 29 patients (61%) who were positive on histology. There was no association between sex, age or tumour site, stage, differentiation, Lauren type and H. pylori status. The test was negative in one patient with cardial tumour in which histology of the resected specimen was also negative for the bacteria. CONCLUSIONS: Active H. pylori infection is highly prevalent in gastric cancer in a South-East Asian population. The 14C-urea breath test is a highly sensitive method for detecting the presence of H. pylori even in gastric adenocarcinoma irrespective of the stage.

Adenocarcinoma↗

Adjuvant postoperative 5-fluorouracil chemotherapy combined with pelvic radiation for rectal cancer: results from an Asian population.

Prospective randomized clinical trials have shown the effectiveness of combined adjuvant 5-fluorouracil-based chemotherapy and radiotherapy after surgical resection of rectal cancer. To assess toxicity of this therapy, prospective data were collected from 236 Asian rectal cancer patients treated with combined 5-fluorouracil-based chemotherapy and radiotherapy after surgery. Almost 82% of patients completed planned therapy. Grade 3 and 4 diarrhea, stomatitis, and granulocytopenia occurred in approximately 18-21% of patients. There were two treatment-related deaths from granulocytopenia and sepsis. With median follow-up of 3.5 years, median disease-free and overall survival was 75 and 88 months, respectively. In conclusion, combined adjuvant 5-fluorouracil-based chemotherapy and radiotherapy after surgical resection of rectal cancer is tolerable in Asian patients with moderate toxicity.

Adenocarcinoma↗

Novel germline BRCA1 mutations detected in women in singapore who developed breast carcinoma before the age of 36 years.

BACKGROUND: In recent years, although BRCA1 has been extensively investigated, the contribution of inherited BRCA1 mutations to breast carcinoma in Asian populations is largely unknown. The authors undertook this study to determine the prevalence and spectrum of germline BRCA1 mutations among women in Singapore with early onset breast carcinoma. METHODS: Forty-three of 72 eligible patients whose breast carcinoma was diagnosed before the age of 36 years were studied, independent of family history. DNA samples from 50 unrelated individuals randomly selected from the National Thalassemia Registry served as controls. Mutational screening was performed by single-strand conformation polymorphism analysis and protein truncation test, and alterations were confirmed by sequencing. First-degree relatives of patients with definite BRCA1 mutations were offered screening. RESULTS: A total of 6 novel alterations in BRCA1 were identified, including 2 frameshift mutations in exon 11 (2846insA and 2885delA), 3 rare sequence variants, and 1 polymorphism. Three women (7%) carried deleterious mutations, and the mutation was present in at least 1 unaffected first-degree relative of the proband. The same mutation (2846insA) was identified in 2 of the 7 unrelated subjects of Malay ethnicity. One mutation and three rare variants were identified in four women with no family history of breast or ovarian carcinoma whereas all women with affected first-degree relatives did not harbor BRCA1 mutations. No mutation was identified in the controls. CONCLUSIONS: The spectrum of germline BRCA1 mutations among the patients in this study was distinct from that in Caucasian populations although a similar prevalence was observed. Larger studies are necessary to clarify the significance of the mutation 2846insA in the Malay community and the penetrance of specific mutations in the Singapore population.

Adult↗

Influence of respiration and portal pressure on transabdominal duplex Doppler ultrasound measurement of portal blood flow: a porcine model for experimental studies.

Transabdominal duplex Doppler ultrasonography (TDDU) is commonly used for measuring hepatic blood flow (HBF) in clinical practice. Flow velocity and the cross-sectional area (CSA) of vessels are obtained separately and used to compute blood flow. Respiration and changes in portal pressure are known to cause variations in the CSA of the portal vein, but the impact of these parameters on TDDU measurement of portal blood flow is unclear. Eight Yorkshire pigs (20.7-25.1 kg) were used for the study. TDDU determination of portal blood flow was carried out using CSA of the portal vein obtained at inspiration (maximal) and at expiration (minimal) for computation, and the differences obtained were compared. Determination of HBF was carried out simultaneously on the same animals using diisopropyliminodiacetic acid (DISIDA) clearance. A physiological increase in portal pressure was then created by 50% hepatectomy and TDDU measurement similarly carried out on the second postoperative day. Computing portal blood flow in the intact liver using maximal and minimal CSA gave rise to a mean difference of 7.0 ml kg(-1) min(-1) (P < 0.001). A significant correlation was obtained between HBF and portal flow computed from maximal CSA (Pearson's correlation = 0.85, P < 0.033). The respiratory index of the portal vein (maximal CSA/minimal CSA) decreased from 1.5 to 1.2 after hepatectomy, which also caused a 90% increase in portal pressure. Respiration and portal pressure thus significantly impact on TDDU determination of HBF, and in this porcine model, computation using maximal CS more accurately reflects HBF.

Animals↗

Diagnostic failures in endoscopy for acute upper gastrointestinal haemorrhage.

BACKGROUND: Oesophagogastroduodenoscopy (OGD) is the diagnostic tool of choice in acute upper gastrointestinal haemorrhage. However, the factors causing diagnostic failure are not well documented or discussed. METHODS: OGDs performed by a single surgeon for acute upper gastrointestinal haemorrhage were reviewed retrospectively for 'missed' diagnosis. RESULTS: There were nine cases (1.4 per cent) of 'missed' diagnosis in 638 OGDs performed over a 3-year period. Incomplete examination caused by a fundal pool precluded three examinations in which two Dieulafoy's lesions and one chronic gastric ulcer were later found. Other difficult examination sites were the cardia/high lesser curve (three cases), the stomal line of a gastrojejunostomy anastomosis (two) and at the junction of the first and second part of the duodenum (one). Four of the overlooked diagnoses were Dieulafoy's lesions. CONCLUSION: OGD was able to diagnose the cause of bleeding in 98.6 per cent of patients with acute upper gastrointestinal haemorrhage. The factors that caused diagnostic failure were a difficult examination site and failure to recognize lesions (Dieulafoy's).

Diagnostic Errors↗

Pancreaticoduodenectomy with pancreaticogastrostomy: assessment of patients' nutritional status, quality of life and pancreatic exocrine function.

BACKGROUND: The changes in digestive function of patients with pancreaticoduodenectomy (PD) and pancreaticogastrostomy reconstruction have not been well-documented. The present study sought to assess the nutritional status, quality of life and pancreatic exocrine function in this group of patients. METHODS: The study group consisted of 11 PD with pancreaticogastrostomy patients. The control group consisted of 11 consecutive patients who had subtotal gastrectomy (SG) for distal stomach tumours. RESULTS: The median ages for the PD and SG groups were 57 and 59 years, respectively. The median intervals between surgery to assessment were 68 and 60 weeks, respectively. The PD group attained a mean of 92.7% of their pre-surgery weight compared to 91.3% in the SG group. Both groups had a comparable gastrointestinal quality of life index and Visick scale scores. Exocrine insufficiency using the faecal chymotrypsin test was present in 36% of patients with PD. None of the patients in the SG group had exocrine insufficiency. CONCLUSION: Pancreaticoduodenectomy patients had a significant occurrence of pancreatic exocrine insufficiency compared to the SG group. But patients with PD and pancreaticogastrostomy reconstruction maintained a nutritional status and quality of life similar to those with curative SG for stomach malignancy. Apart from exocrine insufficiency, the concomitant gastrectomy in the PD group is an important factor responsible for their inability to gain weight.

Aged↗