Differentiated thyroid carcinoma: prognostic factors

Factors influencing prognosis and long term outcome of thyroid cancer have been described by several groups. It is, however, not clear how the moderate iodine deficiency in Hungary can influence the previously described prognostic factors by other means than shifting differentiated cancer incidence toward the follicular type. Data of 423 out of 472 patients who had been operated on for papillary (372) and follicular (100) thyroid cancer between 1971 and 1997 at our institution have been analyzed retrospectively. Histological specimens were re-evaluated and, if needed, revised. Survival curves were compared using the Kaplan-Meier method. The overall 5 and 10 year survival rates were 93% and 89% for papillary, and 92% and 80% for follicular carcinoma. As an independent factor extrathyroidal invasion (papillary p = 0.000, follicular p = 0.000), lymph node involvement (papillary p = 0.000, follicular 0.011), distant metastases (papillary p = 0.000, follicular p = 0.000), and age over 40 years (papillary p = 0.000, follicular p = 0.000) had negative influence on survival. Multifocality, gender, type of surgery (total or near-total thyroidectomy vs. less than near-total thyroidectomy), and lymphocytic infiltration did not influence survival. Iodine intake did not influence survival, however, the incidence of follicular cancer was higher in iodine deficient regions. When analyzing the papillary and follicular groups separately by Cox regression, extrathyroidal invasion (p = 0.008), lymph node metastasis (p = 0.004), distant metastasis (p = 0.000), and age over 40 years (p = 0.000) were significant predictors in the papillary group, while only tumor extrathyroidal invasion (p = 0.019), and distant metastases (p = 0.000) were significant negative factors in the follicular group.     

Clinicopathologic significance of histologic vascular invasion in papillary and follicular thyroid carcinomas

BACKGROUND: The association of angioinvasion with tumor aggressiveness in follicular and papillary thyroid carcinoma remains unclear. This study addresses this problem focusing on clinicopathologic relevance of angioinvasion in the treatment of papillary thyroid carcinoma and follicular thyroid carcinoma. METHODS: From a university hospital database, 358 patients with papillary thyroid carcinoma or follicular thyroid carcinoma were randomly selected. Their charts were retrospectively analyzed and divided into papillary thyroid carcinoma and follicular thyroid carcinoma groups. Each group was subdivided into angioinvasive and nonangioinvasive tumor subgroups. All data were analyzed using Student's t-test, Mann-Whitney rank sum test, chi-square test, and Fisher's exact test. RESULTS: There were 289 women and 69 men, ages 18 to 89 years. Papillary thyroid carcinoma (86%) was more frequent than follicular thyroid carcinoma. Most patients had nonangioinvasive tumor (90.2%). After a mean followup of 43.6 months, there were no significant differences between papillary thyroid carcinoma subgroups for local recurrence (p = 0.69), persistent elevated serum thyroglobulin (p = 0.568), and distant metastasis rates (p = 0.422). No death related to the cancer was observed in both papillary thyroid carcinoma subgroups (p = 1), except for one death resulting from a concomitant nasopharyngeal cancer. The longterm prognosis was less favorable for angioinvasive papillary thyroid carcinoma based on AJCC (American Joint Committee on Cancer staging), AMES (age, distant metastasis, tumor extent, and size), and MACIS (distant metastasis, age, completeness of primary tumor resection, local invasion, and tumor size), but the angioinvasive papillary thyroid carcinoma were larger than nonangioinvasive papillary thyroid carcinomas. The short-term clinical outcomes in both follicular thyroid carcinoma, after a mean followup of 72.3 months, were comparable in terms of local recurrence (p = 0.34), persistent elevated serum thyroglobulin (p = 1), and distant metastasis (p = 0.597). There was no death related to cancer in both follicular thyroid carcinoma subgroups (p = 1). There were no significant differences between both follicular thyroid carcinoma subgroups for longterm prognosis. CONCLUSIONS: Our results indicate that angioinvasion does not adversely influence short-term outcomes or longterm prognosis in follicular thyroid carcinoma and short-term outcomes in papillary thyroid carcinoma. Angioinvasion is a postoperative pathologic finding that does not justify an ominous prognosis or drastic therapeutic measures.     

组织蛋白酶D在甲状腺乳头状腺癌中的表达及临床意义

目的:研究组织蛋白酶D在甲状腺乳头状腺癌中的表达并探讨其能否成为甲状腺乳头状腺癌独立的预后因素。方法:应用免疫组化方法,对40例甲状腺乳头状腺癌、10例甲状腺滤泡型腺瘤及10例甲状腺正常组织进行了组织蛋白酶D表达的研究,并对可能影响甲状腺癌病人预后的有关因素进行了时序检验单因素生存分析。结果:19例(47.5％)甲状腺乳头状腺癌的组织蛋白酶D表达阳性,而甲状腺滤泡型腺瘤及正常组织的表达均为阴性,差异有显著性(P<0.05)。肿瘤大于4cm及有腺外侵犯者的甲状腺癌组织蛋白酶D阳性表达率(69.23％)明显高于肿瘤小于4cm及无腺外侵犯者(37.04％)(P<0.05)。经时序检验,组织蛋白酶D与甲状腺癌病人的预后并未表现出明显的相关关系。但组织蛋白酶D表达阳性病人的术后复发率为26.3％,表达阴性者复发率为14.3％,有一定的差异。结论:组织蛋白酶D在甲状腺乳头状腺癌中有一定的阳性表达率;当肿瘤大于4cm时,发生转移和侵袭的可能性明显增加,组织蛋白酶D表达阳性者其复发率有升高趋势。     

Prognostic factors of insular versus papillary/follicular thyroid carcinoma

The study aims were to characterize patients with insular thyroid cancer and to provide data on patient outcome after surgical therapy. We compared nine patients with insular thyroid cancer at the Department of Surgical Science of "La Sapienza" University of Rome with 27 patients of similar age and tumor size who had follicular and papillary cancer, for a minimum follow-up period of 24 months (range, 24-72 months). All of the patients examined underwent total thyroidectomy. Vascular invasion was observed in 44.4 per cent of insular carcinomas (P < 0.05 vs papillary carcinomas). No significant differences were observed regarding diagnostic method, multifocality, tumor nodes metastases (TNM), or stage. The death rate of patients with insular carcinoma (33.3%) was found to be higher than that of patients with follicular carcinoma (P < 0.05) and papillary carcinoma (P < 0.01). Relapsing lymph-node pathologies were observed in 4 patients (44.4%) with insular carcinoma (P < 0.05 vs those with follicular and papillary carcinomas). Distant metastases were observed in 66.6 per cent of insular carcinomas (P < 0.005 vs follicular carcinoma and P < 0.001 vs papillary carcinoma). At the end of follow-up, 2 patients (22.2%) with insular carcinoma were disease-free (P < 0.001 vs those with follicular and papillary carcinomas). Our study demonstrates an unfavorable prognostic role of the insular phenotype of thyroid cancer, such that this tumor can be classified as an autonomous clinical and pathological entity.     

Prognostic value of MCM2 immunoreactivity in stage T1 transitional cell carcinoma of the bladder

OBJECTIVE: Due to the heterogeneous biologic behavior of stage T1 bladder carcinomas, there is a need for new markers allowing to assess the prognosis more accurately. To our knowledge, there are no reports on studies investigating minichromosome maintenance protein 2 (MCM2) expression in bladder carcinomas. Thus, we investigated the prognostic value of MCM2 immunoreactivity in stage T1 bladder tumors. METHODS: Fifty-four tumors were analyzed using Biochip microarrays. Also p53 and Ki67 antigen expression were examined. Immunohistochemical scores were compared with the clinical outcome. RESULTS: During a median follow-up of 43 months, tumor recurrence was registered in 43 and progression to stage T2 in 19 patients. Kaplan-Meier curves demonstrated that high-level MCM2 expression was significantly associated with early tumor recurrence when using a cutoff of 60% (p=0.0035 by log-rank test), and with early tumor progression when using a cutoff of 20% (p=0.0454). There was no relationship (p=0.604) between MCM2 and p53, but a tendentious relationship (p=0.082) between MCM2 and Ki67 antigen expression. MCM2 (p=0.006), Ki67 antigen (p=0.035) and p53 expression (p=0.049) as well as tumor grade (p=0.026) and age (p=0.025) were found significantly associated with recurrence-free survival by univariate Cox regression analysis, among which only Ki67 antigen expression (p=0.015) and age (p=0.019) proved to be of independent predictive value by multivariate analysis. Concerning tumor progression, MCM2 expression was identified as the only predictive parameter by log-rank test, but it was not of independent predictive value by multivariate analysis (p=0.101). CONCLUSION: Our data suggest that MCM2 expression may bear some prognostic relevance in stage T1 bladder carcinomas.     

Clinical Relevance of Vascular Endothelial Growth Factor for Thyroid Neoplasms

Angiogenesis is of vital importance during the development and progression of solid tumors. Vascular endothelial growth factor (VEGF) is a major regulator of angiogenesis and could be produced by some cancer cells. To investigate the clinical relevance of VEGF in the tumorigenesis of human thyroid, an immunohistochemical study was performed on archival materials of follicular adenomas (n= 13), Hürthle cell adenomas (n= 6), papillary carcinomas (n= 76), follicular carcinomas (n= 12), Hürthle cell carcinomas (n= 2), and anaplastic carcinomas (n= 8). Patterns of VEGF expression were analyzed in relation to histologic subtypes of thyroid tumors and were correlated to biologic indicators of papillary carcinoma. All papillary carcinomas and Hürthle cell neoplasms revealed a strong, diffuse staining reaction, whereas anaplastic carcinoma usually exhibited weak and infrequent immunoreactivity. VEGF levels were usually higher in follicular adenomas than in follicular carcinomas. With regard to prognostic value, VEGF expression did not correlate with tumor size, extent of invasion, or scores on the AGES system (i.e., patient age, tumor size, histologic grade, tumor extent, distant metastasis) or the MACIS system (i.e., metastasis, age, completeness of resection, invasion, tumor size) for papillary carcinomas (p > 0.05, respectively). The results of the current study indicate that VEGF may play a role in the development of human thyroid cancer. Determination of the angiogenic phenotype may have limited prognostic value for patients with papillary carcinoma.     

甲状腺乳头状癌中PDK1、ZEB1和Vimentin的表达及其临床意义

目的:探讨磷酸肌醇依赖性蛋白激酶1 (PDK1)、E盒结合锌指蛋白1(ZEB1)和波形蛋白(Vi-mentin)在甲状腺乳头状癌(PTC)组织中的表达情况,并探究三指标与PTC临床病理参数的相关性.方法:免疫组化EnVision法检测206例PTC及45例癌旁组织中PDK1、ZEB1和Vimentin表达,分析其与PT...     

Prospective therapy study of differentiated thyroid cancer

During a 15-year period (1973-1988) a consecutive series of papillary (n = 52) and follicular (n = 48) thyroid carcinomas was prospectively selected, on the basis of a clinico-pathologic and prognostic classification, for 1. non-total thyroidectomy, mostly hemithyroidectomy (n = 37), 2. total thyroidectomy (n = 19), or 3. total thyroidectomy and radioiodine (n = 44), together with exogenous suppressive thyroxine therapy in most patients. Patients with an occult or with an intrathyroidal, single papillary carcinoma without nodes, and microangioinvasive follicular carcinoma were often treated by non-total thyroidectomy or without radioiodine. During the follow-up period of 1-15 (7 +/- 4) years 5 recurrences (nodes n = 4, pulmonary n = 2) and 3 deaths occurred. Seven out of the 8 patients (age 58-76 years) had total thyroidectomy and radioiodine as initial treatment of an intrathyroidal papillary (n = 1), an extrathyroidal papillary (n = 3), and of an angioinvasive follicular (n = 4) carcinoma, respectively (no radioiodine in 1 patient). The study confirms that the outcome may be favourable in selected patients following hemithyroidectomy or without radioiodine treatment. Recurrences or death occurred in some biologically unfavourable tumors despite total thyroidectomy and radioiodine; the relatively frequent total thyroidectomy (73% of the patients) and radioiodine (51%) may have contributed to the disease-free course in the remaining patients.     

Insular carcinomas of the thyroid exhibit poor prognosis and long-term survival in comparison to follicular and papillary T4 carcinomas

Background Insular thyroid carcinoma was described as a tumor with aggressive behavior, and patients usually present themselves with an advanced tumor stage. Whether the insular component is an independent factor for poor prognosis remains unclear. Therefore, in the present study, we compared the survival of patients with advanced insular, follicular, and papillary thyroid cancer. Materials and methods The clinical behavior of tumors in three groups of patients with T4 thyroid carcinoma—8 patients with insular, 11 patients with follicular, and 21 patients with papillary thyroid carcinomas—was compared. Disease-free survival and disease-specific death were analyzed statistically. Cox regression analysis was used to evaluate the influence of histotype and other prognostic factors. Results At 3 years, survival was 37.5% (mean 26 months) among patients with insular thyroid carcinoma, 80% (mean 59 months) among those with follicular, and 89% (mean 126 months) among those with papillary thyroid carcinomas (p = 0.007). Disease-free survival in patients without initial distant metastasis was worst in patients with insular thyroid carcinoma (20%) compared to those with follicular (75%) and those with papillary thyroid carcinomas (71%). Conclusion Patients with advanced insular thyroid carcinoma have a poorer outcome in comparison to patients with similar advanced stage who have follicular or papillary thyroid carcinoma.     

A population-based analysis of survival factors in differentiated and medullary thyroid carcinoma.

OBJECTIVE: The study purpose was to determine survival and prognostic factors for differentiated thyroid carcinoma (DTC). METHODS: Cases of DTC were extracted from the Surveillance, Epidemiology and End Results database from 1988 through 1998. Kaplan-Meier survival analysis was conducted for papillary, follicular, and medullary histologies. Cox proportional hazard analysis was used to examine the influence of age, gender, tumor size, local extension, and cervical node involvement on overall survival. RESULTS: A total of 18,118 cases were identified, including 15,820 (87.3%) papillary carcinomas, 1799 (9.9%) follicular carcinomas, and 499 (2.8%) medullary carcinomas. Mean survival (10-year survival) was 122 (87.7%), 117 (80.2%), and 108 (73.7%) months for papillary, follicular, and medullary tumors, respectively. For each histology, increasing age, male gender, and degree of local extension substantially reduced survival. Cervical metastasis did not influence survival for papillary or follicular carcinomas but approached significance for medullary carcinoma (P = 0.065). CONCLUSIONS: Degree of local extension in thyroid carcinoma should be subclassified to more accurately determine prognosis. Treatment of the neck should be considered for medullary thyroid carcinoma.     

Prognostic factors in patients with differentiated thyroid carcinoma.

OBJECTIVE: To study the prognostic factors in patients with differentiated thyroid carcinoma. DESIGN: Retrospective analysis. SETTING: University hospital, Germany. PATIENTS: 139 consecutive patients who underwent surgery for follicular (n = 42) and papillary thyroid carcinoma (n = 97). MAIN OUTCOME MEASURES: Survival rate, type of operation (systematic lymphadenectomy or no lymphadenectomy). RESULTS: Median observation time was 72 months (range 1-203). The 5 and 10 year survival rates in patients with papillary carcinoma were 92% and 89% respectively, and in those with follicular carcinoma 88% and 80%, respectively. Prognostic factors for papillary carcinoma were distant metastases, age, and extrathyroidal growth, and for follicular carcinoma they were distant metastases, extrathyroidal extension, and multifocal growth. The Union International contre le Cancer and European Organisation for Research and Treatment of Cancer scores and the age, grade, extent and size score were all highly significant. The extent of lymphadenectomy, primary or secondary thyroidectomy, and partial or total thyroidectomy did not influence survival. CONCLUSION: Staging and score systems may be helpful in calculating prognosis in differentiated thyroid carcinoma, but the benefit of systematic lymphadenectomy remains controversial.     

Well-differentiated thyroid carcinoma in Hong Kong Chinese patients under 21 years of age: a 35-year experience

Background:

Sporadic well-differentiated thyroid cancer is an uncommon condition in children, adolescents, and young adults. It is associated with distinct clinicopathologic features and prognosis. The present study reviews our experience in management of this condition in ethnic Chinese in Hong Kong.

Study Design:

A retrospective study was performed to review the clinicopathologic features and outcomes of 34 patients less than 21 years of age with well-differentiated thyroid carcinoma over a 35-year period. Median followup was 15.2 years (range 1 to 32.5 years).

Results:

There were 27 girls and 7 boys with a median age of 19 years (range 10 to 21 years). None had previous history of irradiation. Twenty-eight patients had papillary and six had follicular carcinomas. Operative procedures included total thyroidectomy (n = 27) and unilateral lobectomy (n = 7) with concomitant neck dissection performed in nine patients. The median tumor size was 2 cm and extrathyroidal invasion was present in 19 tumors. Adjuvant radioactive iodine treatment was administered to 18 patients after total thyroidectomy. Disease progression or recurrence rate was 24% and 27% at 5 and 10 years, respectively. The presence of lymph node metastases was associated with a higher incidence of disease recurrence. One patient with advanced local disease died from tumor bed recurrence with anaplastic transformation 18 years after the initial operation.

Conclusions:

Well-differentiated thyroid carcinoma is a relatively indolent tumor associated with good prognosis in young patients. Although death from this condition is rare, recurrence is frequent and longterm followup is necessary.     

Thyroid carcinomas with distant metastases: a review of 111 cases with emphasis on the prognostic significance of an insular component

Distant metastases (DM) are rare in well-differentiated thyroid carcinomas and correlate with a poor survival. Among the histologic subtypes, insular carcinoma has an intermediate prognosis that lies between well and undifferentiated carcinomas. To assess the characteristics that could predict a worse prognosis, we reviewed the initial thyroid cancer slides from patients with DM. We achieved a comparative statistical analysis with a control group without DM. Among 1230 differentiated carcinomas treated from 1960 to 1999, 9% developed DM. In this group the mean age was 53 years, with a 73% rate of death. The histologic slides were available in 80 cases. The primary thyroid tumors were classified as papillary (51 cases), follicular (25), and pure insular carcinomas (4). Extrathyroidal extension was present in 47% of papillary carcinomas. The mean tumor size was above 5 cm for all the histologic subtypes, and at least a vascular invasion was found in 69%. Fifty-four percent of these tumors had an insular component compared with only 6.5% in the control group. The statistical analysis confirmed by univariate and multivariate logistic regression that the risk of DM was highly elevated in the presence of insular carcinoma. Our study indicates that elevated age, large tumor size, vascular invasion, and extrathyroidal extension are important prognostic factors in well-differentiated carcinomas. We also demonstrate that the presence of an insular component in an otherwise differentiated carcinoma is a strong independent poor prognostic factor.     

Correlation between genetic alterations and microscopic features, clinical manifestations, and prognostic characteristics of thyroid papillary carcinomas

Papillary carcinoma is the most common type of thyroid malignancy. It has been recently shown that these tumors commonly have one of three genetic alterations: BRAF point mutations, RET/PTC rearrangements, or RAS point mutations. In this study, we analyze the relationship between these alterations and the microscopic features of papillary carcinomas, their clinical features, and prognostic characteristics. Ninety-seven papillary carcinomas were studied; in all cases, frozen tissue was available for nucleic acid extraction. Of 96 unselected cases, 42% were positive for BRAF, 18% for RET/PTC, and 15% for RAS mutations. Morphologic features were evaluated in detail in 61 cases and 6 characteristic nuclear features and 3 additional microscopic features were assessed quantitatively. At least 4 nuclear features were found in each tumor, with nuclear pseudoinclusions being the least frequent finding in all mutation groups. BRAF mutations were associated with older patient age, typical papillary appearance or the tall cell variant, a higher rate of extrathyroidal extension, and more advanced tumor stage at presentation. RET/PTC rearrangements presented at younger age and had predominantly typical papillary histology, frequent psammoma bodies, and a high rate of lymph node metastases. Tumors with RAS mutations were exclusively the follicular variant of papillary carcinoma and correlated with significantly less prominent nuclear features and low rate of lymph node metastases. These findings demonstrate that BRAF, RET/PTC, and RAS mutations are associated with distinct microscopic, clinical, and biologic features of thyroid papillary carcinomas.     

Flow cytometric DNA analysis of thyroid carcinoma

Abnormal DNA content has been considered as an additional criterion for determining the biological behavior of a tumor. Flowcytometric DNA analysis was done on 121 patients with thyroid carcinoma encountered during the period between 1975 and 1987. Tumor tissues were sampled from paraffin-embedded blocks and the histology of thyroid carcinoma found to consist of 91 papillary, 23 follicular, 2 medullary, 1 squamous cell and 4 anaplastic carcinomas. The incidence of aneuploidy in thyroid carcinoma was 7.4 per cent (9 patients) while that of diploidy was 92.6 per cent (112 patients). The aneuploid specimens consisted of 6 papillary, 1 follicular, 1 medullary and 1 anaplastic carcinomas and, of 4 anaplastic carcinoma patients with subsequent death within 6 months, only 1 was aneuploid. As an indicator of proliferative potential, S-phase fraction (SPF) was also determined by flow cytometry, but this could not be used as an independent prognostic factor. The aneuploid patients showed a significantly decreased survival rate (p less than 0.01). Thus, although DNA measurement proved useful for predicting the survival of aneuploid patients, there is some discrepancy between DNA content and the biological behavior of the tumor.     

Characteristics of well-differentiated thyroid cancer associated with multinodular goiter

BACKGROUND: The likelihood of thyroid cancer is similar in patients with one or more nodules, but tumor characteristics of thyroid cancer in glands with multinodular goiter are unclear. MATERIALS AND METHODS: This study consisted of 100 consecutive patients (ages 15-81 years; 84 women), who underwent thyroidectomy for papillary or follicular thyroid carcinoma between 2005 and 2006. Patient demographics, diagnostic tests, operations, and pathological findings were reviewed. RESULTS: In a univariate analysis, cancer diagnosed within multinodular goiter was different from solitary cancer nodule in age of diagnosis (48 vs 40 years, p = 0.002), tumor size (1.42 vs 2.20 cm, p = 0.024), and the presence of cervical lymph node metastases (p = 0.035). There was no difference in gender, extrathyroidal invasion, multifocality, and types of operation. Only age (odds ratio, 1.056) and tumor size (odds ratio, 0.730) revealed independent correlation in multivariate analysis. CONCLUSION: Thyroid cancer in glands with multiple nodules is associated with older age at diagnosis and smaller tumor size.     

Application of prognostic scoring systems in differentiated thyroid carcinoma.

BACKGROUND: Total thyroidectomy is widely practised in Australasia for papillary and follicular thyroid carcinoma. Data from large overseas series have demonstrated that patients with these cancers may be separated into risk groups based on clinicopathological prognostic factors. Furthermore, evidence suggests that low-risk patients may be safely treated with less than total thyroidectomy. The aim of the present paper was to determine what proportion of our patients with papillary and follicular thyroid cancer were in the low-risk group in order to select candidates for less aggressive treatment. METHODS: A prospectively documented series of 175 previously untreated patients with papillary and follicular thyroid carcinoma, treated principally by total thyroidectomy over a 10-year period, was divided into risk groups using the Mayo Clinic, Lahey Clinic and Memorial Hospital prognostic scoring systems. Complication rates for 103 patients treated by total thyroidectomy were also studied and reported. RESULTS: Women outnumbered men by 2.3:1. There were 128 papillary carcinomas (73%) and 47 follicular cancers (27%). These tumours were < 4 cm in diameter in 81% of patients, and 41% of patients were 40 years of age or younger. Low-risk patients accounted for 75, 81 and 45% of the study group, respectively, when the three prognostic scoring systems were applied to our patient population. The rates for recurrent laryngeal nerve palsy and permanent hypoparathyroidism for patients having total thyroidectomy were 1 and 1.9%, respectively. In the low-risk group there were no permanent complications. CONCLUSION: Most patients treated at Royal Prince Alfred Hospital during the past 10 years were low-risk patients who may have been eligible for less aggressive surgical treatment.     

Multivariate analysis of clinicopathologic parameters for the insular subtype of differentiated thyroid carcinoma

HYPOTHESIS: Insular carcinoma represents a more aggressive subtype of differentiated thyroid cancer on multivariate analysis after controlling for various clinicopathologic parameters. DESIGN: Retrospective analysis. SETTING: Tertiary referral center at a university hospital. PATIENTS: One hundred twenty-seven consecutive patients having a histological diagnosis of the follicular variant of papillary thyroid carcinoma or follicular thyroid carcinoma. MAIN OUTCOME MEASURE: A logistic regression model was used to examine the relationship between various clinicopathologic parameters and the insular subtype. RESULTS: The insular subtype involved 14 of 127 tumors. Unlike extrathyroidal extension and nodal metastasis, primary tumor diameter (> 40 mm vs < or = 40 mm; P = .008) and distant metastasis (P = .003) correlated with the insular subtype. Both parameters were interrelated since tumors greater than 40 mm displayed distant metastasis more often (30% vs 8%; P = .008) than tumors measuring 40 mm or less. CONCLUSIONS: These findings suggest that an unidentified somatic event may induce an accelerated proliferation of the transformed thyrocytes, which may ultimately result in enhanced rates of distant metastasis with increasing tumor volume.     

APPLICATION OF PROGNOSTIC SCORING SYSTEMS IN DIFFERENTIATED THYROID CARCINOMA

Background : Total thyroidectomy is widely practised in Australasia for papillary and follicular thyroid carcinoma. Data from large overseas series have demonstrated that patients with these cancers may be separated into risk groups based on clinicopathological prognostic factors. Furthermore, evidence suggests that low-risk patients may be safely treated with less than total thyroidectomy. The aim of the present paper was to determine what proportion of our patients with papillary and follicular thyroid cancer were in the low-risk group in order to select candidates for less aggressive treatment. Methods : A prospectively documented series of 175 previously untreated patients with papillary and follicular thyroid carcinoma, treated principally by total thyroidectomy over a 10-year period, was divided into risk groups using the Mayo Clinic, Lahey Clinic and Memorial Hospital prognostic scoring systems. Complication rates for 103 patients treated by total thyroidectomy were also studied and reported. Results : Women outnumbered men by 2.3:1. There were 128 papillary carcinomas (73%) and 47 follicular cancers (27%). These tumours were < 4 cm in diameter in 81% of patients, and 41% of patients were 40 years of age or younger. Low-risk patients accounted for 75, 81 and 45% of the study group, respectively, when the three prognostic scoring systems were applied to our patient population. The rates for recurrent laryngeal nerve palsy and permanent hypoparathyroidism for patients having total thyroidectomy were 1 and 1.9%, respectively. In the low-risk group there were no permanent complications. Conclusion : Most patients treated at Royal Prince Alfred Hospital during the past 10 years were low-risk patients who may have been eligible for less aggressive surgical treatment.     

Analysis of ultrasound B-mode histogram in thyroid tumors

B-mode histograms of preoperative ultrasound texture were correlated to final pathological diagnoses and findings in 50 thyroid tumors (18 follicular adenomas, 6 follicular carcinomas and 26 papillary carcinomas) and 10 cases without any thyroid disease. Histograms were taken in the region of interest (ROI) and in the control area of the normal thyroid tissue. The following parameters, after subtracting the statistics of the control region from that of ROI, were evaluated; the difference of mean (D1), of standard deviation (D2), of skewness (D3), and of krutosis (D4). Likewise, Maharanobis distance (MD) was also studied. D1 was lower in papillary carcinomas than in follicular adenomas, and diminished by the relative proportion of some pathological findings, D2 and D3 of papillary carcinomas was higher than those of follicular adenomas. MD, having a significant correlation to D1 (r = -.8), revealed similar relationship with pathology as that of D1. No significant difference was observed between normal thyroid tissue and follicular adenoma, nor between follicular adenoma and follicular carcinoma in any parameter. MD showed the best correlation to malignancy. The criterion which judges the the tumor with D1 less than -2.5, or D2 more than 1 to be malignant, was expected to have sensitivity of 83% and specificity of 88%.