Chung-Yau Lo

Early versus delayed-interval laparoscopic cholecystectomy for acute cholecystitis : A metaanalysis

BackgroundEarly laparoscopic cholecystectomy has been advocated for the management of acute cholecystitis, but little evidence exists to support the superiority of this approach over delayed-interval operation. The current systematic review was undertaken to compare the outcomes and efficacy between early and delayed-interval laparoscopic cholecystectomy for acute cholecystitis in an evidence-based approach using metaanalytical techniques.MethodsA search of electronic databases, including MEDLINE and EMBASE, was conducted to identify relevant articles published between January 1988 and June 2004. Only randomized or quasi-randomized prospective clinical trials in the English language comparing the outcomes of early and delayed-interval laparoscopic cholecystectomy for acute cholecystitis were recruited. Both qualitative and quantitative statistical analyses were performed. The effect size of outcome parameters was estimated by odds ratio or weighted mean difference where feasible and appropriate.ResultsA total of four clinical trials comprising 504 patients met the inclusion criteria. Failure of conservative treatment requiring emergency cholecystectomy occurred for 43 patients (23%) in the delayed group. Metaanalyses demonstrated a significantly shortened total length of hospital stay in the early group (weighted mean difference, −1.12; 95% confidence interval [CI], −1.42 to −0.99; p < 0.001). Pooled estimates did not show any significant differences between the two approaches in terms of operation time, conversion rate, overall complication rate, incidence of bile leakage, and intraabdominal collection.ConclusionsThe safety and efficacy of early and delayed-interval laparoscopic cholecystectomy for acute cholecystitis were comparable. Because evidence suggested that early laparoscopic cholecystectomy reduced the total length of hospital stay and the risk of readmissions attributable to recurrent acute cholecystitis, it is therefore a more cost-effective approach for the management of acute cholecystitis.

Staging Systems for Papillary Thyroid Carcinoma : a review and comparison

Objective:To find out the most predictive staging system for papillary thyroid carcinoma (PTC) currently available in the literature. Background:Various staging systems or risk group stratifications have been used extensively in the clinical management of patients with PTC, but the most predictive system for cancer-specific survival (CSS) based on distinct histologic types remains unclear. Methods:Through a comprehensive MEDLINE search from 1965 to 2005, a total of 17 staging systems were found in the literature and 14 systems were applied to the 589 PTC patients managed at our institution from 1961 to 2001. CSS were calculated by Kaplan-Meier method and were compared by log-rank test. Using Cox proportional hazards analysis, the relative importance of each staging system in determining CSS was calculated by the proportion of variation (PVE). Results:All 14 staging systems significantly predicted CSS (P < 0.001). The 3 highest ranked staging systems by PVE were the Metastases, Age, Completeness of Resection, Invasion, Size (MACIS) (18.7) followed by the new AJCC/UICC 6th edition tumor, node, metastases (TNM) (17.9), and the European Organization for Research and Treatment of Cancer (EORTC) (16.6). Conclusions:All of the currently available staging systems predicted CSS well in patients with PTC regardless of which histologic type from which they were derived. When predictability was measured by PVE, the MACIS system was the most predictive staging system and so should be the staging system of choice for PTC in the future.

Follicular Thyroid Carcinoma: The Role of Histology and Staging Systems in Predicting Survival

Objective:To evaluate the risk factors including tumor histomorphology for survival specific to follicular thyroid carcinoma (FTC) and to apply commonly employed staging systems in predicting survival for patients with FTC. Summary Background Data:FTC is usually analyzed collectively with papillary thyroid carcinoma (PTC) in risk group analysis. Risk factors and risk group analysis are important in the management of patients with FTC, although current published therapeutic guidelines call for total thyroidectomy followed by radioactive iodine (I131) ablation for all FTC patients. Methods:Over a 40-year period, 156 patients surgically treated for FTC with an average follow-up of 14.4 years were retrospectively studied after histologic reclassification according to the type and degree of invasiveness of the tumor. Potential risk factors for survival were calculated using multivariate analysis, and the prognostic accuracy of AMES risk group stratification, UICC/AJCC pTNM staging, Degroot classification, and MACIS scoring schemes in predicting survival was compared. Results:Seventeen (11%) patients had distant metastases at presentation, and bilateral thyroid resection was performed for 131 (84%) patients. Seventeen (11%) patients died of recurrent or metastatic disease. The overall and cancer-specific survival (CSS) rates at 10 years were 79% and 88%, respectively. None of the patients with minimally invasive (n = 49) or angioinvasive (n = 23) carcinomas died compared with 17 of 84 patients with widely invasive carcinomas (P = 0.0007). Using the Cox proportional hazards model, old age, the presence of distant metastases, and incomplete tumor excision were independent prognostic factors for survival. For patients who underwent curative treatment, old age and widely invasive carcinoma were risk factors for poor survival. All staging systems studied accurately predicted CSS, and the pTNM UICC/AJCC staging system yielded the best prognostic information. Conclusions:Commonly adopted staging systems can be applied specifically to patients with FTC. The distinction of FTC in minimally invasive and widely invasive carcinoma based on the extent of invasiveness rather than vascular invasion is important in identifying low-risk FTC patients for a more conservative management.

Insular and Anaplastic Carcinoma of the Thyroid: A 45-year Comparative Study at a Single Institution and a Review of the Significance of p53 and p21

OBJECTIVE To analyze the clinicopathologic features of a large cohort of patients with insular or anaplastic carcinomas treated at a single institution. SUMMARY BACKGROUND DATA Insular and anaplastic carcinomas of the thyroid, although uncommon, have more aggressive clinical behavior than well-differentiated carcinomas of the thyroid. In the literature, the incidence and features of these carcinomas have not been fully characterized. METHODS The authors reclassified 740 primary thyroid carcinomas diagnosed and treated between January 1, 1954, and December 30, 1998, to select those with features that met the histologic criteria of insular or anaplastic carcinoma. The clinicopathologic features of these carcinomas were studied and compared. The expression of p53 and p21 in these tumors was analyzed by immunohistochemistry. RESULTS Twenty-two patients (5 men, 17 women) with insular carcinoma and 38 patients (7 men, 31 women) with anaplastic carcinoma were found. Patients with insular carcinomas were younger (mean age 45 vs. 70 years) and had smaller tumors than those with anaplastic carcinomas (mean diameter 5 vs. 8 cm). Insular carcinomas were commonly mislabeled as other histologic subtypes, whereas anaplastic carcinomas might be overdiagnosed on pathologic examination. A history of longstanding goiter (>10 years) was noted in 27% of patients with insular carcinoma and 24% of patients with anaplastic carcinomas. Concomitant well-differentiated carcinomas of the thyroid were noted in 59% of patients with insular carcinoma and 39% of patients with anaplastic carcinoma. In anaplastic carcinomas, 13% of patients had concomitant insular carcinoma. Calcification or bone was noted in the stroma of 23% of patients with insular carcinomas and 47% of those with anaplastic carcinomas. The 10-year survival rates for patients with insular carcinoma and anaplastic carcinoma were 42% and 3%, respectively. Distant metastases were seen in 32% of patients with insular carcinoma and in 47% of patients with anaplastic carcinomas. In both types of carcinomas, metastatic tumors were often seen in bone and lung. Distant metastases were noted in a variety of organs in anaplastic carcinomas. In insular carcinoma, neither p53 nor p21 expression was present. In anaplastic carcinoma, p53 and p21 expression was identified in 69% and 3%, respectively. Concomitant expression of p53 and p21 was noted in one tumor. CONCLUSIONS Insular carcinoma and anaplastic carcinoma had distinctive clinicopathologic features, and recognition of these histologic variants is important for better management of these tumors in the future. p53 overexpression might have a role in dedifferentiation from insular carcinoma to anaplastic carcinoma.

Pitfalls of Intraoperative Neuromonitoring for Predicting Postoperative Recurrent Laryngeal Nerve Function during Thyroidectomy

Intraoperative neuromonitoring has been widely adopted to facilitate the identification and preservation of recurrent laryngeal nerve (RLN) function during thyroid surgery. The present prospective study validated the ability of this technique to predict postoperative RLN outcomes in a single endocrine surgical unit. Neuromonitoring was performed using Neurosign 100 with laryngeal surface electrodes in 171 patients with 271 nerves at risk during thyroidectomy. Vocal cord function was routinely documented perioperatively. Patients were also stratified to low risk (primary surgery for benign disease) and high risk (malignancy and recurrent disease) for subgroup analysis. Unilateral vocal cord palsy occurred in 15 patients (5.5%) postoperatively. The incidence of postoperative nerve palsy in the low risk and high risk groups was 4.4% and 7.8%, respectively. All but two patients had recovery of function within a median period of 4 months after the operation. The rates of transient and permanent RLN palsy based on nerves at risk were 4.8% (n = 13) and 0.7% (n = 2), respectively. There were 241 true-negative (positive signal and no cord palsy), 15 false-positive (negative signal but no cord palsy), 8 true-positive (negative signal and cord palsy), and 7 false-negative (positive signal but cord palsy) results, as correlated with the postoperative assessment. The sensitivity, specificity, and positive and negative predictive values were 53%, 94%, 35%, and 97%, respectively. For the high risk group, the sensitivity and positive predictive value increased to 86% and 60%, respectively. There are pitfalls associated with the use of intraoperative neuromonitoring during thyroid surgery. Routine application is not recommended except for selected high risk patients.

Prognostic Factors in Papillary and Follicular Thyroid Carcinoma: Their Implications for Cancer Staging

Papillary thyroid carcinoma (PTC) and follicular thyroid carcinoma (FTC) are two distinct histological types of thyroid carcinoma but have often been studied and staged as a collective group, known as differentiated thyroid carcinoma (DTC). However, this may not be an optimal approach to cancer staging. A total of 760 patients with DTC, comprising 589 (77.5%) with PTC and 171 with (22.5%) FTC, being managed at our institution from 1961 to 2001 were retrospectively reviewed. Their clinicopathological features, treatment modalities received, and postoperative outcome were analyzed. Both univariate and multivariate analyses were performed to identify prognostic factors related to cancer-specific survival (CSS) for PTC and FTC. There were statistically significant differences between PTC and FTC in terms of age ≥50 years at diagnosis (P = .040), tumor size (P < .001), lymph node metastases (P < .001), distant metastases (P < .001), extrathyroidal extension (P < .001), multifocality (P = .002), capsular invasion (P < .001), extent of thyroid resection (P < .001), radioiodine ablation (P < .001), and external-beam irradiation (P = .003). Although PTC and FTC had similar 10-year and 15-year CSS (P = .846), each possessed its own set of independent prognostic factors for CSS. Age at diagnosis and completeness of resection were independent prognostic factors in both PTC and FTC. There were marked differences in clinicopathologic features, treatment, and prognostic factors between the two histologic types of DTC. Different staging systems should be evaluated and validated for PTC and FTC individually in the future.

Classical and follicular variant of papillary thyroid carcinoma: a comparative study on clinicopathologic features and long-term outcome.

IntroductionThe follicular variant of papillary thyroid carcinoma (FVPTC) is the most common histologic subtype of papillary thyroid carcinoma (PTC). However, it is still controversial whether FVPTC should behave differently from classical PTC (CPTC). The present study aimed at evaluating any potential difference in clinicopathologic features and long-term outcome of FVPTC as compared with CPTC.Patients and MethodsOf 568 patients with PTC managed from 1973 to 2004, 308 were shown to have CPTC (54.2%) and 67 (11.8%) FVPTC after histologic review. The mean (± SD) follow-up period was 11.3 (± 8.9) years. The two groups were compared in terms of clinicopathological features, treatment received, and outcome regarding recurrence and disease-specific survival.ResultsThere was no difference in age and gender ratio between the CPTC and FVPTC patients. Both groups had similar tumor characteristics in terms of tumor size, presence of multifocality, capsular invasion, lymphovascular permeation, and perineural infiltration. However, FVPTC patients had significantly fewer histologically confirmed cervical lymph node metastases (P = 0.027) and extrathyroidal involvement (P = 0.005). The proportion of bilateral resection, adjuvant radioactive iodine, and lymph node dissection did not differ significantly between the two groups. The FVPTC patients had a more favorable tumor risk by DeGroot classification (P = 0.003) and MACIS (Metastasis, Age, Completeness of excision, Invasiveness, and Size) score (P = 0.026). The 10- and 15-year actuarial disease-specific survivals did not differ significantly between FVPTC and CPTC patients (96.2% versus 90.7% and 96.2% versus 89.1%, respectively).ConclusionsAlthough patients with FVPTC had more favorable clinicopathologic features and a better tumor risk group profile, their long-term outcome was similar to that of CPTC patients.

Parathyroid autotransplantation during thyroidectomy

Permanent hypoparathyroidism is a debilitating morbidity following thyroidectomy, with a reported incidence of up to 43%. Apart from meticulous dissection to preserve parathyroid glands and their blood supply, parathyroid autotransplantation (PA) has been increasingly employed to preserve parathyroid function. The adoption of PA during thyroidectomy has been reported to be associated with a low incidence of permanent hypoparathyroidism. Biochemical function of parathyroid autografts can be demonstrated objectively by forearm reimplantation or during long‐term follow up. The clearest indication for PA is for inadvertently removed or devascularized parathyroid glands during thyroid surgery. Other strategies, including routine autotransplantation of at least one parathyroid gland, can be considered, but is associated with a high incidence of transient hypocalcaemia. Apart from refinement in technique to facilitate graft success, a reliable way to assess overall parathyroid function or viability of individual parathyroid gland may assist in monitoring parathyroid function and selecting patients requiring this procedure to prevent permanent hypoparathyroidism.

Obturator hernia presenting as small bowel obstruction

Obturator hernia is a rare but important cause of small bowel obstruction that is associated with difficult diagnosis and high mortality. In the past 7 years, 16 patients with small bowel obstruction due to obturator hernia diagnosed at operation were seen at the Department of Surgery, the University of Hong Kong, Queen Mary Hospital. They represented 1% (16 of 1,554) of all hernia repair performed and 1.6% (16 of 1,000) of mechanical intestinal obstruction encountered during the same period. Elderly emaciated women with chronic disease were commonly affected. All patients presented with partial or complete mechanical small bowel obstruction. Right-sided obturator hernia outnumbered left-sided hernia, and bilateral hernia was found in only one patient. The majority of patients required resection of their strangulated small bowel. Most of the hernial orifices were closed with interrupted nonabsorbable sutures. Morbidity and mortality rates were significantly high for this group of debilitated patients with chronic disease who underwent late operation for this elusive diagnosis.

Primary aldosteronism. Results of surgical treatment.

SUMMARY BACKGROUND DATA Management of primary hyperaldosteronism has undergone dramatic changes in the past 40 years. This retrospective study was carried out to review our recent surgical experience and to identify potential factors associated with postoperative persistent hypertension. METHODS Forty-six patients who had adrenal surgery for primary hyperaldosteronism from 1983 to 1994 were included in the study. RESULTS Periodic paralysis occurred in 12 (26%) patients. Hypertension and hypokalemia (mean serum potassium, 2.2 + 0.5 [+ standard deviation (SD) mmol/L) were present in all patients. Postural study was diagnostic in 85% (23 of 27). Computed tomography scan correctly localized the tumor in all except 1 patient, and venous sampling was performed in 11 patients. There was no operative mortality, and complications developed in six patients (13%), including one patient requiring re-exploration for hemostasis. All patients had a histologically documented adenoma. During a mean follow-up of 51 months, 34 (77%) of the 44 patients required no further antihypertensive treatment. Two patients were lost to follow-up. Age, response to spironolactone treatment, and blood pressure on discharge were risk factors identified for persistent hypertension. CONCLUSION Primary hyperaldosteronism due to aldosterone-producing adenoma can be diagnosed and localized expeditiously, whereas surgical treatment can be performed safely. Hypokalemia may be cured by surgical treatment, although persistent hypertension, usually of a mild degree, still occurs in selected patients.