Ministry of health clinical practice guidelines: cancer screening

The Ministry of Health publishes national clinical practice guidelines to provide doctors and patients in Singapore with evidence-based guidance on managing important medical conditions. This article reproduces the introduction and executive summary (with key recommendations from the guidelines) from the Ministry of Health clinical practice guidelines on cancer screening, for the information of readers of the Singapore Medical Journal. Chapters and page numbers mentioned in the reproduced extract refer to the full text of the guidelines, which are available from the Ministry of Health website (http://www.moh.gov. sg/mohcorp/publications.aspx?id=24018). The recommendations should be used with reference to the full text of the guidelines. Following this article are multiple choice questions based on the full text of the guidelines.

Spleen-preserving distal pancreatectomy

INTRODUCTION

Splenectomy is routinely performed in conventional distal pancreatectomies. Spleen removal with its possible sequelae of infections and haematological complications has prompted the development of spleen-preserving techniques. This study aimed to evaluate the safety and clinical outcomes of distal pancreatectomy with preservation of the spleen.

METHODS

A retrospective review of 24 consecutive patients who underwent spleen-preserving distal pancreatectomy in a tertiary care hospital was conducted.

RESULTS

There were 17 female and seven male patients, and the mean age was 47 (range 14-77) years. Median American Society of Anesthesiologists score was II (range I-III) . The indications were as follows : mucinous cystadenoma (n = 7), serous cystadenoma (n = 6), insulinoma (n = 3), intraductal papillary mucinous tumour (n = 2), pseudocyst (n = 3), papillary cystic adenoma (n = 1), neuroendocrine neoplasm (n = 1), and metastatic carcinoma of the thyroid (n = 1). Two patients developed postoperative pancreatic fistula and another two patients developed postoperative ileus with spontaneous resolution. Mean operative time was 172 (range 105-250) minutes. Mean length of postoperative hospital stay was 6.7 (range 5-11) days. There was no perioperative mortality in this series.

CONCLUSION

Spleen-preserving distal pancreatectomy can be safely performed with low morbidity, and should be considered in the surgical management of distal pancreatic disease.

Systemic administration of naked DNA with targeting specificity to mammalian kidneys

A major challenge for gene therapy is to be able to deliver efficiently the gene of interest to specific cell types. Here we describe a safe and simple effective naked DNA gene delivery method, via inferior vena cava (IVC) injection, to the recipient's kidneys. It was further demonstrated that gene expression was concentrated in the proximal tubular epithelial cells of the cortico-medullary region of the kidney. Confocal microscopy analyses demonstrated the presence of the exogenous DNA in the renal cell membrane 10 min postgene delivery. However, it was only by 30 min that the presence of the exogenous DNA could be detected in the cell cytoplasm and in the nuclei of the renal cells. Stable expression of the beta-galactosidase gene could be detected for up to 35 days and no toxicity or any adverse pathological effect associated with the delivery method could be observed. Importantly, this IVC gene delivery method could promote the targeting of genes to carcinoma established in the kidney of SCID mice. These results provide the first evidence to support that stable gene expression could be achieved in the renal cells of kidney and the established carcinoma in the kidneys following in vivo gene delivery with naked DNA and could therefore provide the potential to design protocols for the gene therapy of the kidney diseases.

Founder mutation in the BRCA1 gene in Malay breast cancer patients from Singapore

The mutation spectrum of the BRCA1 gene among ethnic groups from Asia has not been well studied. We investigated the frequency of mutations in the BRCA1 gene among Malay breast cancer patients from Singapore, independent of family history. By using the protein truncation test (PTT) and direct sequencing, BRCA1 mutations were detected in 6 of 49 (12.2%) unrelated patients. Four novel missense mutations in exon 11, T557A (1788A>G), T582A (1863A>G), N656S (2086A>G) and P684S (2169C>T) were identified in one patient. Two patients had missense mutations in exon 23, V1809A (5545T>C), which has been previously detected in individuals from Central and Eastern Europe. Three unrelated patients had the deleterious 2846insA frameshift mutation in exon 11. Methylation specific PCR (MSP) of the promoter region of the BRCA1 gene detected hypermethylation of tumor DNA in an additional 2 patients. Haplotype analysis using the microsatellite markers D17S855, D17S1323 and D17S1325 revealed a common haplotype for the three unrelated patients and their three relatives with the 2846insA mutation. These findings strongly suggest that the 2846insA mutation, the most common deleterious mutation in this study, may possibly be a founder mutation in breast cancer patients of Malay ethnic background.

Clinical applications of MR cholangiopancreatography

INTRODUCTION

We review the clinical applications of magnetic resonance cholangiopancreatography (MRCP) and illustrate them with clinical examples.

METHODS

A literature search was performed in MedLine using the keywords "MR cholangiopancreatography" and "MRCP". The relevant articles were reviewed. The radiology information system was searched for MRCP examinations performed from July 1999 to December 2002. A surgical database of resected cases was also referenced. Illustrative cases were chosen in consultation with surgical authors to show the clinical applications of MRCP.

RESULTS

MRCP is useful for assessment of choledocholithiasis, choledochal cysts, pancreas divisum, primary sclerosing cholangitis, pancreatitis and anatomical variation of the biliary ducts. When complemented with dynamic gadolinium-enhanced studies, MRCP is useful for assessment of ductal cholangiocarcinoma, pancreatic and gall bladder neoplasms. Illustrative cases are provided.

CONCLUSION

MRCP is an important modality for the clinical assessment of biliary and pancreatic disorders.

Breath-hold fast recovery fast spin echo versus conventional non-breath-hold fast spin echo T2-weighted MR imaging of focal liver lesions

INTRODUCTION

We compare the breath-hold fast recovery fast spin echo (BHFRFSE) T2-weighted and non-breath-hold fast spin echo (NBHFSE) T2-weighted sequences in image quality and lesion characterisation of focal liver lesions.

MATERIALS AND METHODS

Fat-suppressed T2-weighted magnetic resonance (MR) images obtained with the 2 sequences (BHFRFSE and NBHFSE) in 79 patients with 113 liver lesions were analysed retrospectively. The image quality and nature of the lesions were evaluated by 2 experienced radiologists.

RESULTS

Based on receiver operating characteristic curve analysis, lesion characterisation was comparable for both sequences. The image quality of BHFRFSE was significantly better than that of NBHFSE. The NBHFSE missed 4 malignant lesions while BHFRFSE missed 2 malignant lesions.

CONCLUSION

BHFRFSE performs similarly to NBHFSE in image quality and liver lesion characterisation.

Bile duct injuries during laparoscopic cholecystectomy: a collective experience of four teaching hospitals and results of repair

BACKGROUND

Laparoscopic cholecystectomy has been performed in Singapore since 1990 and, up until the end of 1997, a total of 4445 procedures had been performed in the four major teaching hospitals. Although bile duct injuries were thought to have increased following the introduction of laparoscopic cholecystectomy, there have been no reviews done on the incidence of these injuries in the Singapore context.

METHODS

The present retrospective review aimed to audit the rate of bile duct injuries in the four major teaching hospitals in Singapore and to document the results of management of these injuries.

RESULTS

Of the 4445 procedures performed, there were 19 (0.43%) cases of bile duct injuries. These involved the common hepatic duct (n = 8), common bile duct (n = 10), and the right hepatic duct (n = 1). The underlying gall bladder pathology included non-inflamed gall bladders (n = 10), acute cholecystitis (n = 4), Mirrizzi's syndrome (n = 3) and mucocele of the gall bladder (n = 2). Transection of the duct accounted for the majority of the injuries. Eleven bile duct injuries were identified at the time of operation. These were primarily repaired over a T tube (n = 4) or by a bilio-enteric bypass (n = 7). The remainder were diagnosed at a median of 7 days (range: 1-556 days) after surgery with a presentation of jaundice or pain. These were repaired by bilio-enteric anastomosis (n = 7) and closure over a T tube (n = 1). Three patients developed strictures subsequently, two following bilio-enteric repair after delayed diagnosis and one following immediate primary repair over a T tube. One patient developed intrahepatic stones and required a left lateral segmentectomy.

CONCLUSIONS

The experience of a 0.43% bile duct injury rate is comparable to the best results from most large series in the West. Inflammation at Calot's triangle is an important associated factor for injury. Early recognition and prompt repair affords good results, and hepaticojejunostomy is recommended as the repair of choice.

3rd Yahya Cohen Lecture: the role of the myofibroblast-like cell in hepatocellular carcinoma--host defence?

Hepatocellular carcinoma is a common cancer in Asia with a poor prognosis. Tumour encapsulation has been shown to be a good, independent prognostic factor. The main cell in the liver responsible for extracellular matrix formation is the hepatic stellate cell, and this was investigated as the cell type responsible for encapsulation. This lecture discusses the role of hepatic stellate cells in hepatocellular carcinoma, in particular with tumour encapsulation as a host defence mechanism. The study involved four phases: (1) comparing encapsulated tumours with non-encapsulated tumours, (2) comparing with metastatic tumours to the liver, (3) creation of an animal model, and (4) investigating known cytokines with hepatic stellate cell stimulating activity. The results showed that the hepatic stellate cells were responsible for tumour encapsulation and that this was impaired in non-encapsulated tumours and in metastatic tumours. A successful animal model was created which allowed further work. However, the known cytokines that normally stimulate hepatic stellate cells were not shown to be involved in tumour encapsulation, suggesting that an unknown factor may be involved.

An animal model for the study of hepatic stellate cell and hepatocellular carcinoma interaction

The recognition of hepatic stellate cells (HSC) around and within hepatocellular carcinoma (HCC) in human livers has generated interest in the interactions between HSC and HCC. We explored the possibility of creating an animal model to allow in vivo investigations of this interaction. Eighteen adult Buffalo rats were inoculated with 1 x 10(6) cells obtained from cultures of Morris 7777 hepatoma cell line (ATCC). The rats were sacrificed at 2-, 3-, and 4-week intervals. Identification of activated HSC was with immunohistochemistry for alpha-smooth muscle actin (alpha-SMA). There was 100% survival of all animals until sacrifice. Tumour formation occurred in 94.4% of rats, and was of a good size by two weeks. Expression of alpha-SMA was observed around and within all HCC, but absent from normal tissue, and this showed colocalisation with collagen deposition. These findings are consistent with those previously reported in resected HCC in humans. The high survival, good tumour yield, consistent generation of activated HSC around the tumours, and similarities in histological appearance to the human HSC-HCC distribution pattern, make this a reliable animal model for in vivo studies on HSC-HCC interaction.

Cystic tumours of the pancreas: a diagnostic dilemma

BACKGROUND

Cystic neoplasm of the pancreas is an uncommon entity that encompasses a range of tumours with varying potential for malignancy. These tumours are frequently misdiagnosed as pseudocysts and are inappropriately managed.

METHODS

A retrospective review was undertaken of 18 cases of cystic tumours of the pancreas over an 8-year period in two large hospitals in Singapore.

RESULTS

All patients were Asian, with a younger age group (mean 43.5 years) and a lesser degree of female predominance (3.5:1 ratio) compared to other series. Pain was the most common symptom. Pre-operative diagnosis using ultrasound and computed tomography was not diagnostic in half of the cases and misdiagnosed as pseudocyst in a sixth. There were five serous cystadenomas, four mucinous cystadenomas, two mucinous cystadenocarcinomas, one mucinous cystadenocarcinoma with cystic degeneration in a ductal adenocarcinoma, three Frantz tumours, one acinar cell tumour, one glucagonoma, and one benign epithelial cyst. Two-thirds of tumours were malignant or had the potential to become malignant. Resection was curative in all cases, and no recurrence was noted at a mean follow-up of 34.5 months.

CONCLUSIONS

The difficulties with pre-operative diagnosis, the high incidence of tumours with potential malignancy, and the good outcome with resection, suggest that all suspected cystic tumours of the pancreas should be resected.

Human liver transplant perfusate: an abundant source of donor liver-associated leukocytes

In vitro studies designed to examine the mechanisms of immune tolerance after liver transplantation in humans have been hampered by the difficulty in obtaining sufficient numbers of donor liver-associated leukocytes (LALs). We have investigated whether the ex vivo perfusion of donor livers releases a population of LALs that can be readily retrieved from the waste fluid. The mean number of cells recovered after Ficoll-Hypaque density-gradient separation was 2.6 +/- 0.5 x 10(8) cells, with a viability of 94% +/- 2%. The perfusate lymphocytes comprised mainly T cells (39% +/- 2%) with a very low CD4/CD8 ratio and natural killer (NK) cells (56% +/- 6%) with an increase in the proportion of the CD3-CD56+CD16- subset. The activation marker CD69 was present on the majority of the perfusate lymphocytes. These are the phenotypic characteristics that have been previously reported for lymphocytes isolated from hepatic sinusoids. In mixed lymphocyte reactions, the perfusate cells showed a marked increase in the ability to stimulate allogeneic responder cells, resulting in 353% +/- 78% (P = .003) greater incorporation of [3H]thymidine in responder cells when compared with stimulation by donor peripheral blood mononuclear cells. The results show that large numbers of viable donor lymphocytes can be readily isolated from the liver perfusate solution. These cells have the characteristics of liver-associated lymphocytes with a predominance of activated NK and CD8+ T cells. This population can now be used in in vitro assays to elucidate the influence of donor leukocytes on the development of graft acceptance.

Splenic abscesses from 1987 to 1995

BACKGROUND

Isolated splenic abscesses is an uncommon clinical entity that is being increasingly recognized as a cause of intraabdominal sepsis in a wide variety of clinical situations, and involving a wide range of organisms. The increasing incidence of immunosuppressed states in this decade due to the use of chemotherapy for oncology, immunosuppression therapy for transplantation, and acquired immune deficiency syndrome, has changed the disease pattern of splenic abscesses.

METHOD

Data from 287 cases reported in the English literature between 1987 and 1995 were collected, analyzed, and compared with two previous reviews of cases reported before 1987.

RESULTS

Staphylococcus, Salmonella, and Escherichia coli are the most common organisms cultured. Immunosuppressed states were present in 33.5% of cases, with intravenous drug abuse and acquired immune deficiency syndrome accounting for half these cases. Computerized tomography and ultrasonography are diagnostic, with a sensitivity of 92.2% and 87.2%, respectively. Nonoperative management has a success rate of less than 65%, but salvage splenectomy does not increase mortality compared with splenectomy as initial therapy.

CONCLUSIONS

Splenic abscesses are increasingly recognized with immunosuppressed states. Percutaneous radiologically guided drainage may be suitable in some cases, but splenectomy with appropriate antibiotics is the definitive treatment.

Training in laparoscopic surgery--have we got it right yet?

Training in laparoscopic surgery started with short two to three-day courses, frequently unstructured and unaccredited, in a rush to provide surgeons with supposedly adequate training in laparoscopic techniques before performing laparoscopic cholecystectomy in patients. The high incidence of complications with this situation led to guidelines on training, credentialling and auditing being drawn up by several responsible professional bodies. Almost a decade after the introduction of laparoscopic cholecystectomy, the situation with training in laparoscopic surgery is still unresolved in many countries. This article reviews the current opinion on training in laparoscopic surgery, and presents the various teaching models and techniques employed to facilitate this process. Training in laparoscopic surgery should form part of the general surgery training programme, and should involve a combination of short introductory courses with hands-on animal models, and a period of preceptorship following this.

Laparoscopic hernia repair in Singapore--views from a cross-section of surgeons

Laparoscopic cholecystectomy was introduced into Singapore in 1990, and has since replaced conventional cholecystectomy as the treatment of choice for gallstone disease in most situations. In contrast, laparoscopic hernia repair introduced two years later in the same wave of enthusiasm, was received with scepticism and much less acceptance. A survey of 27 general surgeons in three large institutions in Singapore was performed to analyse this observation. The majority of surgeons felt that laparoscopic hernia repair (i) had limited applications, mainly for bilateral and recurrent hernias, (ii) was not completely established as a technique, requiring refinement in the procedure, (iii) was costly, and (iv) did not have objective evidence of long-term benefits over conventional hernia repair.

Kimura's disease involving the median nerve: a case report

Kimura's disease is an uncommon chronic inflammatory process of obscure origin. It is more common among Orientals and affects particularly the young male. Sites of predilection include the head and neck region, primarily the subcutaneous tissue and dermis. Unusual sites of occurrence that have been reported include the kidney, the orbit, the ear and the spermatic cord. Kimura's disease involving a major nerve bundle has not been described, and we report here the findings of a case of histologically proven Kimura's disease of the median nerve occurring in a 21-year-old Chinese girl. Typical diagnostic histological features of Kimura's disease in contrast to angiolymphoid hyperplasia, and the treatment options for Kimura's disease are also described.

Color Doppler imaging for vocal cord palsy

BACKGROUND

Conventional techniques of laryngoscopy for vocal cord palsy can sometimes be difficult or impossible to perform, and B-mode real-time ultrasonography has been previously reported by the authors to be helpful in these situations. In some cases, however, B-mode ultrasonography can be inconclusive. We investigated whether color Doppler imaging can significantly improve vocal cord examination in these cases.

METHOD

Ten normal volunteers were examined using the Acuson 128XP/5 with a 7-MHz L7384 linear transducer. The thyroid cartilage was used as an acoustic window. Several distinct color flow patterns were observed with the subjects breathing quietly at rest, at the start of vocalization, and in prolonged phonation. Eight patients with hoarseness of voice were then examined by two separate observers in a double-blinded fashion. The first observer performed B-mode ultrasonography and color Doppler imaging, while the second observer performed indirect laryngoscopy and direct fiberoptic laryngoscopy.

RESULTS

Laryngoscopy was used as the standard for comparison. B-mode real-time ultrasonography correctly identified vocal cord palsy in three patients and normal vocal cords in one. The remaining four patients were reported as equivocal or normal. Color Doppler imaging correctly identified the problem in all eight patients.

CONCLUSION

Color Doppler imaging for vocal cord examination is more sensitive than B-mode real-time ultrasonography, and seems to be as accurate as laryngoscopy in determining vocal cord palsy or paresis.

Thoracoscopic vagotomy for peptic ulcer disease--report of two cases

Thoracoscopic vagotomy is a well-established technique in the management of recurrent peptic ulceration after previous abdominal vagotomy. The procedure allows an easy approach to the vagus nerves without having to dissect through dense adhesions from previous surgery. With thoracic vagotomy, the main morbidity is postoperative pain from the thoracotomy incision and rib spreading. Advances in endoscopic camera systems and instrumentation allow thoracic vagotomy to be safely and effectively accomplished by thoracoscopic surgery techniques, with reduced postoperative pain. We describe our experiences with thoracoscopic vagotomy in two cases of recurrent peptic ulceration.

Video-assisted endoscopic thoracic sympathectomy in the management of intractable palmar hyperhydrosis

Minimally invasive endoscopic surgical techniques have revolutionised patient management. We present our findings in our first 10 cases of bilateral video-assisted endoscopic thoracic sympathectomy in the management of intractable palmar hyperhydrosis including the first such procedure in Singapore. We have found the procedure to have minimal morbidity, good patient acceptance and all patients have remained with dry palms.

Laparoscopic marsupialization of liver cysts

The majority of benign, non-parasitic liver cysts are asymptomatic. Surgical treatment is reserved for symptomatic patients and frequently involves partial excision or marsupialization via a laparotomy. Surgery is occasionally offered for asymptomatic large cysts, where complications of cyst rupture, intra-cystic bleeding and infection are more common. The authors describe three cases of symptomatic liver cysts that were effectively marsupialized laparoscopically with good results.

Laparoscopic assessment and orchidectomy for the undescended testis

Cryptorchidism is the most common disorder of male sexual differentiation. Pre-operative assessment and localization of undescended testes by various investigatory modalities have been of limited clinical value. The recent use of diagnostic and therapeutic laparoscopy for undescended testis peri-operatively has been shown to be safe and informative in the planning of appropriate surgical management. The authors' initial experience with this procedure, for five patients with unilateral undescended testis, is presented.

Primary papillary carcinoma in a thyroglossal cyst--a case report

A benign thyroglossal cyst is a common clinical condition and is second only to a cervical lymph node as the most common cause of a solitary neck swelling. Primary carcinoma of a thyroglossal cyst, however, is rare and has been described in only 115 cases in the literature. The malignant cysts are clinically difficult to differentiate from benign lesions and the diagnosis often rests on histopathological examination. Before initiating treatment, primary papillary carcinoma of the thyroid gland must be excluded. The treatment options range from simple excision to a Sistrunk operation with concurrent cervical lymph node dissection. We describe here a case of papillary carcinoma of a thyroglossal cyst and review the 115 reported cases.

Laparoscopy-guided percutaneous cholecystolithotomy: an evolving technique

Gall-bladder conservation therapy has been evolving during the past decade. Popular techniques of conservative therapy are extracorporeal shock wave lithotripsy (ESWL) and medical dissolution therapy. The limitations of these procedures have prompted a search for alternative techniques, particularly in relation to percutaneous stone extraction. The cases of four patients with symptomatic gallstones who underwent percutaneous cholecystolithotomy under laparoscopic guidance are reported. The gall-bladder was punctured with a long needle and the tract dilated so that a nephroscope could be introduced. Three cases required stone fragmentation by an ultrasonic lithotripter before removal. Postoperative recovery was uneventful in all cases.

Splenic abscess

Isolated splenic abscess is an uncommon condition. Seven cases seen between 1980 and 1990 are reviewed. The clinical presentation is non-specific and diagnosis is usually delayed. Computerized tomography allowed for accurate diagnosis in all cases. Pseudomonas species as a causative organism is reported to be rare, but were present in three of the present cases. Antibiotic therapy alone is insufficient and splenectomy remains the treatment of choice.

Tracheo-oesophageal groove clearance in well differentiated thyroid carcinoma

Papillary carcinoma of the thyroid has a propensity for spread to the regional lymph nodes, in particular those along the recurrent laryngeal nerve. Twenty cases of papillary carcinoma of the thyroid had prophylactic clearance of the lymph nodes along the tracheo-oesophageal groove, and one patient had removal of recurrent disease in the groove. Eleven of the twenty patients had, in addition, some form of cervical lymph node clearance for clinically palpable ipsilateral cervical lymph nodes. Metastases to the tracheo-oesophageal groove lymph nodes was seen in seven of the twenty patients (35%). Tumour size, age, sex, race and cervical lymph node involvement did not appear to predict involvement of the tracheo-oesophageal groove lymph nodes. Clearance of the lymph nodes along the tracheo-oesophageal groove at the time of resection of primary disease is worthwhile for thyroid papillary carcinoma, because of the high incidence rate (35%) and also clearance for subsequent recurrence will be more difficult with a higher risk of damage to the recurrent laryngeal nerve and parathyroids.

Calcifying epithelioma of Malherbe--a case report of a large preauricular tumour

Calcifying epithelioma of Malherbe (pilomatrixoma) is a relatively uncommon benign skin tumour of hair follicle origin. It usually presents in the face and upper extremities of young adults as an asymptomatic subcutaneous or dermal tumour. Treatment is surgical excision. This paper presents a case of a large tumour in the preauricular region with difficulty in diagnosis preoperatively and required a superficial parotidectomy to clear the tumour from the facial nerve.

B-mode real-time ultrasound assessment of vocal cord function in recurrent laryngeal nerve palsy

B-mode real-time ultrasound was used to assess vocal cord function in six patients with recurrent laryngeal nerve palsy. The thyroid cartilage acted as an acoustic window through which the true cords appear as hypoechoic structures. Vocal cord palsy detected on ultrasound was compared with fibreoptic direct laryngoscopy and indirect laryngoscopy mirror examination. Good correlation was seen in all the cases.

Non-functioning cyst of the adrenal gland--a case report

Adrenal cysts are a rare entity. Only about 300 cases have been reported throughout the world. A case of an asymptomatic, benign, non-functioning adrenal cyst of the left adrenal gland is presented. Pre-operative diagnosis is usually by incidental imaging findings as the majority of adrenal cysts are asymptomatic. The adrenal cyst in this case was detected on an abdominal ultrasound for the investigation of jaundice, and confirmed by a CT scan examination. Selective biochemical studies are needed to assess adrenal function, and here they were normal. Simple surgical enucleation of the cyst, with preservation of remaining adrenal tissue is the treatment of choice.

Benign retroperitoneal neurilemmoma--a case report

Retroperitoneal neurilemmomas are the rarest of all retroperitoneal tumours. A rare case of a very large benign retroperitoneal neurilemmoma is presented. Pre-operative diagnosis of these tumours is difficult and the majority are asymptomatic. They are usually detected as an abdominal mass on routine examination as in this case. Despite severe displacement and distortion of the inferior vena cava in this patient, there were no clinical abnormalities detected. The predominantly cystic nature of the tumour was well demonstrated by ultrasound and CT scan examination but the true nature of the tumour could not be diagnosed. It is very rare for these tumours to be malignant and recurrence after surgical excision is rare.