Wai-Fan Chan

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.

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.

Papillary Microcarcinoma: Is There Any Difference between Clinically Overt and Occult Tumors?

Papillary microcarcinoma (PMC) is a subtype of papillary thyroid carcinoma (PTC) associated with excellent prognosis. However, clinical and biologic behaviors of PMC may vary considerably between tumors that are clinically overt and those that are occult. From 1964 to 2003, 185 of 628 patients with PTC were identified as having PMC, based on tumor size ≤1 cm. There were 110 overt and 75 occult PMCs detected based on clinical presentation. The clinicopathologic features, treatment, and long-term outcome of PMCs were evaluated and compared between the two groups. There were 37 men and 148 women with a median age of 45 years (range: 11–84 years). The median tumor size was 6.2 mm. Thirty-eight (21%) patients presented with cervical nodal metastases. Three (1.6%) had distant metastases and 5 (2.7%) underwent incomplete resection. Bilateral procedures were performed for 129 patients (70%) and 53 (29%) received postoperative I131treatment. During a mean follow-up of 8.2 years, 4 patients died of the disease and 13 developed recurrence. Clinically overt PMCs were significantly larger, were more likely to be multifocal, and more likely to lead to bilateral thyroidectomy. Extrathyroidal or lymphovascular invasion, nodal metastases, I131ablation, high-risk tumors, and postoperative recurrence occurred in overt PMC only. Patients with nodal metastases had a decreased survival and an increase in locoregional recurrence. Despite a relatively good prognosis in PMC, a distinction should be made between clinically overt and occult PMCs in which clinically overt PMC should be managed according to tumor risk profile and clinical presentation.

Total thyroidectomy replaces subtotal thyroidectomy as the preferred surgical treatment for Graves’ disease

Background:  Total thyroidectomy is increasingly being adopted for patients requiring surgical treatment for Graves’ disease based on a comparable surgical risk and the lack of recurrence, as well as the questionable ability of subtotal thyroidectomy to maintain euthyroidism. The purpose of the present paper was to evaluate its safety and efficiency.

Restaging of Differentiated Thyroid Carcinoma by the Sixth Edition AJCC/UICC TNM Staging System: Stage Migration and Predictability

The AJCC/UICC TNM staging system (TNM) is a widely accepted system for differentiated thyroid carcinoma (DTC). The objective of the present study was to evaluate the potential changes in cancer-specific survival (CSS) after reclassification from fifth to sixth edition TNM. A total of 760 DTC patients managed at our institution from 1961 to 2001 were retrospectively restaged from the fifth to sixth edition TNM. CSS were calculated using Kaplan–Meier method and were compared by the log-rank test. The relative ability of each edition in predicting CSS was calculated by the proportion of variance explained (PVE). Upon reclassification, the proportion of T1 and T3 tumors increased from 14.2 to 33.4% and 10.0 to 33.7%; T2 and T4 decreased from 44.2 to 25.0% and 31.6 to 7.9%, respectively; N0 remained unchanged at 66.0%; N1a decreased from 25.7 to 4.7%; N1b increased from 8.4 to 29.3%; stages I and IV tumors increased from 55.7 to 60.3% and 3.4 to 17.6%, respectively; stages II and III tumors decreased from 20.5 to 13.9% and 20.4 to 8.2%, respectively. The sixth edition had a higher PVE value than the fifth edition. Significant differences in CSS were observed between stage III (fifth edition) and stage III (sixth edition) and between stage IV (fifth edition) and stage IVA (sixth edition). The sixth edition TNM caused marked changes in the pT, pN and allocation of patients into different tumor stages. It appeared to have superior predictability over the fifth edition.

Recurrent Laryngeal Nerve Palsy in Well-differentiated Thyroid Carcinoma: Clinicopathologic Features and Outcome Study

Involvement of the recurrent laryngeal nerve (RLN) by well-differentiated thyroid carcinoma may not invariably lead to unilateral cord palsy, although the presence of RLN palsy is associated with locally advanced disease. The present study evaluates the clinicopathologic features and outcomes of patients surgically treated for well-differentiated thyroid carcinoma with documented nonfunctioning RLN at presentation. From 1970 to 2002, 20 of 709 patients undergoing surgical treatment for well-differentiated thyroid carcinoma were found to have ipsilateral unilateral cord palsy by routine preoperative laryngoscopy. There were 5 men and 15 women with a median age of 70 years. Nine patients (45%) did not have a clinically palpable thyroid mass, and hoarseness was the primary presenting symptom. All patients had histologically confirmed pT4 papillary thyroid carcinoma with a median size of 4 cm. Cervical nodal and pulmonary metastases were detected in 14 (70%) and 2 (10%) patients, respectively. The ipsilateral recurrent nerve was transected in all patients because of gross tumor involvement, and 19 patients underwent total or completion total thyroidectomy. Resection was incomplete in 15 patients, including 2 who underwent a debulking procedure and required reoperation for local control. Postoperative radioactive iodine ablation and external-beam irradiation were administered to 18 and 13 patients, respectively. Over a median follow-up of 4.5 years, 10 patients survived without evidence of recurrence, 5 died of disease recurrence, and 5 died of unrelated causes. The 5-year and 10-year cause-specific mortality was 17% and 42%, respectively. Patients developing distant metastasis at presentation or during follow-up had a significantly increased cause-specific mortality (p = 0.002). Preoperative RLN palsy can be the first symptom in patients with locally advanced papillary thyroid carcinoma. Despite the adoption of a relatively conservative surgical treatment, long-term survival can be achieved in selected patients.

Laparoscopic resection of a pancreatic polypeptidoma with a solitary liver metastasis

Pancreatic neuroendocrine tumor is an uncommon disease, and surgery is the only potentially curative treatment even when there is hepatic metastasis. A patient undergoing concomitant laparoscopic distal pancreatectomy and hepatectomy for pancreatic polypeptidoma with a solitary liver metastasis is reported.