Management of brain metastases from thyroid carcinoma: a study of 16 pathologically confirmed cases over 25 years

BACKGROUND

Brain metastasis is an uncommon, morbid complication of metastatic thyroid carcinoma. Because of its rarity, management often is problematic. To help contribute to the management of this disease entity, the authors present herein what to their knowledge is the largest series reported to date in which all patients had biopsy proven confirmation of their brain metastases.

METHODS

The authors report a series of 16 patients with metastatic thyroid carcinoma to the brain who were treated between 1976-2000. The Mayo Clinic database was used to locate and review charts and radiology and pathology reports, and all biopsy specimens were reviewed by one pathologist. The histologic types of carcinoma included 10 papillary carcinomas, 2 follicular carcinomas, 1 Hürthle cell carcinoma, 1 medullary carcinoma, 1 insular carcinoma, and 1 anaplastic carcinoma. Given the small sample size, statistical analyses were not performed.

RESULTS

Surgical resection of brain metastases was associated with a trend toward longer survival (20.8 months vs. 2.7 months for no surgical intervention in selected patients) Whole brain external beam radiation therapy produced disease regression in three of the four evaluable patients. Gamma knife radiosurgery and radioactive iodine therapy appear to play limited, but beneficial, therapeutic roles. Overall, survival after the diagnosis of brain metastasis is reported to be longer than that noted with other solid tumors (17.4 months), and the majority of patients die of their extracranial disease (85% in the current series).

CONCLUSIONS

The results of the current study indicate that local therapies appear to control brain metastases in the large majority of thyroid carcinoma patients with metastases to the brain.

High resolution loss of heterozygosity mapping of 17p13 in thyroid cancer: Hurthle cell carcinomas exhibit a small 411-kilobase common region of allelic imbalance, probably containing a novel tumor suppressor gene

There is strong evidence in many tumor types, including thyroid cancer, for a novel tumor suppressor gene (TSG) at 17p13. To identify the putative thyroid 17p13 TSG we mapped thyroid tumor loss of heterozygosity (LOH) at high resolution within this region. We examined 20 typical follicular thyroid carcinomas (FTC), 19 Hurthle cell carcinomas (HCC), 15 papillary thyroid carcinomas (PTC), and 7 follicular adenomas (FA) for LOH at 17p13 using 18 probes. Complete clinical follow-up data were available for all patients. We confirmed a high 17p13 LOH rate in FTC (18 of 20) and HCC (13 of 19) and showed an association between 17p13 LOH and advanced tumor grade. Only 4 of 15 PTC and 1 of 7 FA displayed 17p13 LOH. In the HCC we identified a narrow minimal common deleted region between D17S1308 (285 kb from the p-telomer) and D17S695 (696 kb from the p-telomer). This region was flanked centromerically by a breakpoint cluster, further suggesting nonrandom deletion. All but 1 of the PTC and FA with 17p LOH and 50% of the affected FTC also showed LOH in this region. These data suggest that a TSG, involved in HCC pathogenesis, is contained within the D17S1308-D17S695 interval. There are several potential candidate TSGs in this region that are worthy of further study.

Papillary thyroid carcinoma managed at the Mayo Clinic during six decades (1940-1999): temporal trends in initial therapy and long-term outcome in 2444 consecutively treated patients

It is uncertain whether more extensive primary surgery and increasing use of radioiodine remnant ablation (RRA) for papillary thyroid carcinoma (PTC) have resulted in improved rates of cause-specific mortality (CSM) and tumor recurrence (TR). Details of the initial presentation, therapy, and outcome of 2444 PTC patients consecutively treated during 1940-1999 were recorded in a computerized database. Patients were followed for more than 43,000 patient-years. The 25-year rates for CSM and TR were 5% and 14%, respectively. Temporal trends were analyzed for six decades. During the six decades, the proportion with initial MACIS (distant Metastasis, patient Age, Completeness of resection, local Invasion, and tumor Size) scores <6 were 77%, 82%, 84%, 86%, 85%, and 82%, respectively (p = 0.06). Lobectomy accounted for 70% of initial procedures during 1940-1949 and 22% during 1950-1959; during 1960-1999 bilateral lobar resection (BLR) accounted for 91% of surgeries (p <0.001). RRA after BLR was performed during 1950-1969 in 3% but increased to 18%, 57%, and 46% in successive decades (p <0.001). The 40-year rates for CSM and TR during 1940-1949 were significantly higher (p = 0.002) than during 1950-1999. During the last 50 years the 10-year CSM and TR rates for the 2286 cases did not significantly change with successive decades. Moreover, the 10-year rates for CSM and TR were not significantly improved during the last five decades of the study, either for the 1917 MACIS <6 patients or the 369 MACIS < 6 patients. Increasing use of RRA has not apparently improved the already excellent outcome, achieved before 1970, in low risk (MACIS <6) PTC patients managed by near-total thyroidectomy and conservative nodal excision.

Loss of heterozygosity studies revisited: prior quantification of the amplifiable DNA content of archival samples improves efficiency and reliability

Polymerase chain reaction (PCR)-based loss of heterozygosity (LOH) studies of archival formalin-fixed, paraffin-embedded (FFPE) tumor tissues have become an important tool in the search for tumor suppressor genes and oncogenes and are also used increasingly in clinical practice. However, FFPE tissue samples may contain little amplifiable DNA, resulting in frequent reaction failures and unreliable LOH data. Using pairs of serial dilutions of reference DNA, we determined the minimum amplifiable DNA concentration necessary for reliable microsatellite-PCR LOH analysis. We then measured the amplifiable DNA content of a selection of frozen and FFPE-derived tumor specimens by real-time quantitative PCR. A minimum input of 600 pg of 100% amplifiable DNA per PCR was required for reliable LOH analysis. While the total DNA concentrations of all samples exceeded this figure, most FFPE-sample-derived DNA was non-amplifiable, with ratios of actually amplifiable DNA to total DNA as low as 1 to 3625. Many FFPE samples therefore contained substantially less than 600 pg/microl of actually amplifiable DNA, making them potentially unsuitable for LOH studies. Real-time quantitative PCR before LOH studies of FFPE tissues allows: identification of samples, which will fail microsatellite-PCR; exclusion of samples, which will yield unreliable results; and optimal adjustment of template input for the remainder. Amplification reactions undertaken without this precaution can result in unreliable LOH data.

Lack of impact of radioiodine therapy in tg-positive, diagnostic whole-body scan-negative patients with follicular cell-derived thyroid cancer

Several reports have suggested a benefit from radioactive iodine (RAI) therapy in Tg-positive, whole-body scan-negative patients with follicular cell-derived thyroid cancer, who were said to have high rates of visualization of uptake in metastases after therapeutic doses of RAI. We sought to evaluate the rate of visualization of RAI uptake in these patients and determine the effect of such therapy on tumor progression and Tg levels. We studied 24 consecutive patients who had been treated with high-dose RAI, four of whom had no evidence of metastasis or persistent cancer. Our results showed that four patients had some uptake in posttherapy scans: in the neck, lung, and mediastinal metastases in one patient, in the thyroid remnant in two, and in a possible neck microrecurrence in one. In 13 patients with macrometastases-tumors 1 cm or greater-tumors progressed and serum Tg increased; five have died of thyroid cancer. The disease remained stable in the seven patients with micrometastases. We concluded that in high-risk patients with follicular cell-derived thyroid cancer with high Tg levels and negative diagnostic whole-body scans, only a small number showed meaningful uptake after high doses of RAI. Therefore, widespread use of empiric RAI therapy for such patients who have a large tumor burden should not be encouraged.

Percutaneous ethanol injection for treatment of cervical lymph node metastases in patients with papillary thyroid carcinoma

OBJECTIVE

The objective of this study was to evaluate the technique, efficacy, and side effects of percutaneous ethanol injection in patients with limited cervical nodal metastases from papillary thyroid carcinoma.

SUBJECTS AND METHODS

Fourteen patients who had undergone thyroidectomy for papillary thyroid carcinoma presented with limited nodal metastases (one to five involved nodes) in the neck between May 1993 and April 2000. All patients had received previous iodine-131 ablative therapy with a mean total dose per patient of 7,548 MBq. Ten of the patients either were considered poor surgical candidates or preferred not to have surgery, and all were unresponsive to iodine-131 therapy. Each metastatic lymph node was treated with percutaneous ethanol injection, and patients received both clinical and sonographic follow-up.

RESULTS

Twenty-nine metastatic lymph nodes in our 14 patients were injected. Mean sonographic follow-up was 18 months (range, from 2 months to 6 years 5 months). All treated lymph nodes decreased in volume from a mean of 492 mm(3) before percutaneous ethanol injection to a mean volume of 76 mm(3) at 1 year and 20 mm(3) at 2 years after treatment. Six nodes were re-treated 2-12 months after initial percutaneous ethanol injection because of persistent flow on color Doppler sonography (n = 4), stable size (n = 1), or increased size (n = 1). Two patients developed four new metastatic nodes during the follow-up period that were amenable to percutaneous ethanol injection. Two patients developed innumerable metastatic nodes that precluded retreatment with percutaneous ethanol injection. No major complications occurred. All patients experienced long-term local control of metastatic lymph nodes treated by percutaneous ethanol injection. In 12 of 14 patients, percutaneous ethanol injection was successful in controlling all known metastatic adenopathy.

CONCLUSION

Sonographically guided percutaneous ethanol injection is a valuable treatment option for patients with limited cervical nodal metastases from papillary thyroid cancer who are not amenable to further surgical or radioiodine therapy.

Managing patients with papillary thyroid carcinoma: insights gained from the Mayo Clinic's experience of treating 2,512 consecutive patients during 1940 through 2000

2,512 consecutive patients with papillary thyroid carcinoma (PTC) were managed during 1940 through 2000 at the Mayo Clinic. During that period, there were two significant therapeutic trends. The first was a change in surgical practice during 1940-69 from an initial unilateral lobectomy (UL) to a bilateral lobar resection (BLR). The second was the increasing use since 1970 of I-131 for radioactive-iodine remnant ablation (RRA). The advent of BLR resulted in significantly improved tumor recurrence (TR) rates in both low-risk (MACIS scores < 6) and high-risk (MACIS scores 6+) patients, and also reduced cause-specific mortality (CSM) in high-risk patients. By contrast, RRA did not significantly improve the outcome (either CSM or TR) in low-risk (MACIS < 6) patients previously treated with initial near-total or total thyroidectomy. These data encourage a more selective use of I-131 in PTC management and do not lend support to the current widespread use of RRA in low-risk PTC.

Anaplastic thyroid carcinoma: a 50-year experience at a single institution

BACKGROUND

Anaplastic thyroid carcinoma (ATC) is among the most aggressive of human malignancies. However, there have been few large studies of histologically well-defined ATC. We report the results of a 50-year experience of this lethal malignancy.

METHODS

We reviewed all cases of ATC managed in this institution between 1949 and 1999. One pathologist (J.R.G.) reviewed all pathologic material. Clinical details were obtained from medical records, and current status of all patients was determined.

RESULTS

There were 134 cases, with a female-to-male ratio of 1.5:1 and a mean age of 67 years. Benign thyroid disease was present in 27 cases (20%) and well-differentiated thyroid carcinoma in 31 (23%). Sixty-two patients (46%) had distant metastases at diagnosis, and 98% of the tumors were locally invasive. Primary treatment was surgical for 96 patients (72%). Complete resection was achieved in 29 cases (30%), with "minimal residual disease" in 25. Neither extent of operation nor completeness of resection affected survival (P > .4). Postoperative radiotherapy gave slightly longer median survival (5 vs 3 months), which was not significant (P < .08). Multimodal therapy, including operation, chemotherapy, and radiotherapy, did not improve survival.

CONCLUSIONS

The outlook for patients with ATC remains grim. Novel treatments for ATC are desperately needed.

Immunohistochemical analysis of sodium iodide symporter expression in metastatic differentiated thyroid cancer: correlation with radioiodine uptake

The ability of thyroid cancers to concentrate radioiodine (RAI) is dependent, in part, upon the expression and functional integrity of the sodium iodide symporter (NIS). However, some differentiated thyroid carcinomas (DTCs) and most undifferentiated thyroid carcinomas lack the ability to concentrate iodide and are thereby insensitive to 131I therapy. Variation of NIS protein expression may be an important factor in this behavior. We wished to determine whether NIS protein expression in primary DTC tumors correlated with the subsequent RAI uptake by metastatic lesions in the same patients. We obtained paraffin-embedded tissue specimens from 60 patients with metastatic thyroid cancer who had undergone total or near-total thyroidectomy at the Mayo Clinic for DTC and had known presence or absence of RAI uptake in their tumor deposits determined by total body scanning after thyroid hormone withdrawal. Tissue sections from the primary intrathyroidal tumors were subjected to immunostaining (IS) using a monoclonal antibody against human NIS. Slides were subsequently examined for specific IS by two independent reviewers. For each patient, whole body scan (WBS) uptake was recorded, and correlation between results of IS and WBS was analyzed. Of 43 patients with a positive WBS, 37 also had positive IS of their tumors. In six patients with negative IS, a positive WBS was documented, and in three of these cases TSH at the time of surgery was less than 0.3 mIU/liter. Of the 17 patients with negative WBS, 10 were also negative on IS. Positive IS accurately predicted a positive scan in our study in 84% of cases; the ability of the IS to detect all cases with a positive scan was 86%, and it increased to 90% when patients who were receiving thyroid hormone therapy at the time of surgery were excluded from the analysis. Overall, the results of our retrospective study suggest that NIS IS of the thyroidal primary tumor in patients with papillary and follicular thyroid cancers has substantial ability to predict the behavior of subsequent deposits of metastatic and recurrent cancer with respect to iodine trapping and concentration. Our findings require confirmation in prospective studies to more accurately determine the predictive ability of the test and its role in the postoperative management of patients with DTC. If confirmed, NIS IS of DTC primary lesions may prove useful in the management of patients with known or suspected metastatic thyroid cancer.

Papillary thyroid cancer with pulmonary metastases in children: long-term prognosis

BACKGROUND

Papillary thyroid cancer (PTC) in young patients may rarely be encountered with pulmonary metastases. Previous studies have suggested that, in the pediatric population, this may not portend a lethal outcome. Our present study, children with pulmonary metastases, was designed to clarify this issue.

METHODS

Fourteen children and young adolescents (mean age, 13.5 years; range, 9.8-17 years) with PTC and pulmonary metastases were treated at our institution between 1937 and 1998. Surgical treatment consisted of total thyroidectomy (n = 10 patients), subtotal thyroidectomy (n = 3 patients), and a biopsy only procedure (n = 1 patient). All patients who underwent thyroidectomy also underwent a variety of cervical lymph node dissections, and all patients proved to have regional nodal disease. After the operation, 12 patients were treated with ablative doses of (131)I, 1 patient was treated with external beam irradiation, and all patients were placed on suppressive thyroid hormone therapy. The mean length of follow-up was 19.3 years (range, 1-45 years).

RESULTS

Regional recurrent disease developed in 2 patients (15%). No patient experienced the development of worsening pulmonary disease or extra-pulmonary metastases. All patients with recurrent disease underwent selective nodal resections. No patient died of metastatic PTC. Seven patients (50%) remain completely free of disease and are probably cured; 7 patients (50%) are asymptomatic with residual pulmonary disease.

CONCLUSIONS

A stepwise treatment approach allows long-term survival and frequent cure for young patients with PTC and concomitant pulmonary metastases.

A multidisciplinary study of the 'yips' phenomenon in golf: An exploratory analysis

BACKGROUND

The 'yips' is a psychoneuromuscular impediment affecting execution of the putting stroke in golf. Yips symptoms of jerks, tremors and freezing often occur during tournament golf and may cause performance problems. Yips-affected golfers add approximately 4.7 strokes to their scores for 18 holes of golf, and have more forearm electromyogram activity and higher competitive anxiety than nonaffected golfers in both high and low anxiety putting conditions. The aetiology of the yips is not clear.

OBJECTIVE

To determine whether the yips is a neurological problem exacerbated by anxiety, or whether the behaviour is initiated by anxiety and results in a permanent neuromuscular impediment.

METHODS

In phase I, golf professionals assisted investigators in developing a yips questionnaire that was sent to tournament players (<12 handicap) to establish the prevalence and characteristics of the yips. Phase II measured putting behaviour in scenarios that contribute to the yips response. Four self-reported yips and 3 nonaffected golfers putted 3 scenarios using an uncorrected grip and a standard length putter. Heart rate was superimposed on the videotape and the putter grip was instrumented with strain gauges to measure grip force. Electromyograms and relative putting performance were also measured.

RESULTS

The questionnaire was sent to 2,630 tournament players, of whom 1,031 (39%) responded (986 men and 45 women). Of these, 541 (52%) perceived they experienced the yips compared with 490 (48%) who did not. Yips-affected golfers reported that the most troublesome putts were 3, 4 and 2 feet (0.9, 1.2 and 0.6 metres) from the hole. Fast, downhill, left-to-right breaking putts and tournament play also elicited the yips response. Golfers affected by the yips had a faster mean heart rate, increased electromyogram activity patterns and exerted more grip force than nonrffected golfers and had a poorer putting performance.

CONCLUSIONS

For <10 handicap male golfers and <12 handicap female golfers, the prevalence of the yips is between 32.5% and 47.7%, a high proportion of serious golfers. This high prevalence suggests that medical practitioners need to understand the aetiology of the yips phenomenon so that interventions can be identified and tested for effectiveness in alleviating symptoms. Although previous investigators concluded that the yips is a neuromuscular impediment aggravated but not caused by anxiety, we believe the yips represents a continuum on which 'choking' (anxiety-related) and dystonia symptoms anchor the extremes. The aetiology may well be an interaction of psychoneuromuscular influences. Future research to test the effect of medications such as beta-blockers should assist in better identifying the contributions these factors make to the yips phenomenon.

Familial splenomegaly: macrophage hypercatabolism of lipoproteins associated with apolipoprotein E mutation [apolipoprotein E (delta149 Leu)]

Splenomegaly with sea-blue histiocytes is not associated with dyslipidemia, except in severe cases of hypertriglyceridemia, Tangier disease, or lecithin cholesterol acyltransferase deficiency. We describe two kindreds in which the sea-blue histiocyte syndrome was associated with an apoE variant in the absence of severe dyslipidemia. Both patients presented with mild hypertriglyceridemia and splenomegaly. After splenectomy both patients developed severe hypertriglyceridemia. Pathological evaluation of the spleen revealed the presence of sea-blue histiocytes. A mutation of apoE was demonstrated, with a 3-bp deletion resulting in the loss of a leucine at position 149 in the receptor-binding region of the apoE molecule [apoE (delta149 Leu)]. Although both probands were unrelated, they were of French Canadian ancestry, suggesting the possibility of a founder effect. In summary, we describe two unrelated probands with primary sea-blue histiocytosis who had normal or mildly elevated serum triglyceride concentrations that markedly increased after splenectomy. In addition, we provide evidence linking the syndrome to an inherited dominant mutation in the apoE gene, a 3-bp deletion on the background of an apoE 3 allele that causes a derangement in lipid metabolism and leads to splenomegaly in the absence of severe hypertriglyceridemia.

Are posttherapy radioiodine scans informative and do they influence subsequent therapy of patients with differentiated thyroid cancer?

Posttherapy scans (PTS) with a gamma camera are typically used after therapeutic doses of 131I to visualize metastases that may not be seen with lower dose diagnostic scans. During a 16-month period, we studied 81 patients (64 with papillary thyroid cancer and 17 with follicular thyroid cancer), who had both a diagnostic whole-body scan (131I dose 3 mCi) and a PTS. A total of 117 PTS were evaluated. At the time of PTS, clinical or radiologic evidence of metastatic or residual disease was present in 68 patients (84%). The anatomic sites of known disease included, neck (63), mediastinum (23), lung (35), bone (14), trachea (16), esophagus (5), and brain (2). PTS showed focal areas of abnormal uptake not seen in diagnostic scans in 15 scans (13%). Areas with abnormal new uptake included: neck (5), lung (5), mediastinum (4), bone (2), and adrenal (1). In 7 patients (9%) the PTS results impacted future decisions regarding plans for subsequent diagnostic scanning and 131I therapy or changed the patient's risk group category.

IN CONCLUSION

(1) 13% of 117 PTS demonstrated abnormal foci of 131I uptake not seen on pretherapy scans and (2) PTS changed management strategy in 9% of the studied patients.

FHIT and TSG101 in thyroid tumours: aberrant transcripts reflect rare abnormal RNA processing events of uncertain pathogenetic or clinical significance

OBJECTIVE

The chromosomal regions containing the two putative tumour suppressors, fragile histidine triad gene (FHIT) and tumour suppressor gene 101 (TSG101), are deleted frequently in thyroid tumours. We therefore analysed FHIT and TSG101 transcripts in a group of advanced thyroid tumours to establish their role in thyroid tumorigenesis.

DESIGN

Retrospective analysis of FHIT and TSG101 mRNA transcripts and genomic DNA from cryo-preserved thyroid tumours. TP53, previously shown at the genomic level not to be mutated in this cohort of tumours, served as a control.

PATIENTS

We analysed nine follicular thyroid carcinomas (FTC), six papillary thyroid carcinomas and six follicular adenomas (FA) and histologically normal thyroid tissue from four of the FA patients.

MEASUREMENTS

Single stage and nested reverse transcription polymerase chain reaction (RT-PCR) products of FHIT, TSG101, and TP53 were analysed by agarose or polyacrylamide gel electrophoresis and sequenced. Genomic DNA was also analysed by polymerase chain reaction and sequencing (FHIT) or by Southern blotting (TSG101). Clinical data were correlated with the results of the mutation analysis.

RESULTS

Truncated FHIT transcripts were observed frequently alongside full length transcripts with nested RT-PCR, most often in FTC, while single stage RT-PCR revealed only normal length transcripts in all tumours. Similar results were obtained for TP53, while abnormal TSG101 transcripts were detectable by single stage RT-PCR. Sequence analysis of the truncated FHIT and TSG101 transcripts revealed mainly exon skipping and alternate RNA processing events. Only a single point mutation (of TSG101) was found. Southern blotting for the TSG101 gene, and PCR amplification and sequencing of the FHIT gene showed no evidence of genomic abnormalities in either case, and there was no evidence of splice site mutations in the FHIT gene, suggesting that the truncated transcripts result from altered RNA processing. There was no relationship between tumour stage, grade or survival and the presence of FHIT or TSG101 abnormalities.

CONCLUSIONS

Truncated FHIT and TSG101 transcripts in thyroid tumours reflect alternate mRNA splicing events, rather than genomic deletions. Such abnormal RNA processing seems to be common and widespread in thyroid neoplasms, as similar results were obtained by analysis of transcripts of TP53, which we had previously shown not to be mutated in these specimens. Although a pathogenetic role for these aberrant transcripts remains possible, no correlation was found with stage, histological grade or outcome in this small group of advanced thyroid malignancies. Relaxation of mRNA splice control appears to be a feature of follicular cell-derived thyroid neoplasms.

FHIT and TSG101 in thyroid tumours: aberrant transcripts reflect rare abnormal RNA processing events of uncertain pathogenetic or clinical significance

OBJECTIVE

The chromosomal regions containing the two putative tumour suppressors, fragile histidine triad gene (FHIT) and tumour suppressor gene 101 (TSG101), are deleted frequently in thyroid tumours. We therefore analysed FHIT and TSG101 transcripts in a group of advanced thyroid tumours to establish their role in thyroid tumorigenesis.

DESIGN

Retrospective analysis of FHIT and TSG101 mRNA transcripts and genomic DNA from cryo-preserved thyroid tumours. TP53, previously shown at the genomic level not to be mutated in this cohort of tumours, served as a control.

PATIENTS

We analysed nine follicular thyroid carcinomas (FTC), six papillary thyroid carcinomas and six follicular adenomas (FA) and histologically normal thyroid tissue from four of the FA patients.

MEASUREMENTS

Single stage and nested reverse transcription polymerase chain reaction (RT-PCR) products of FHIT, TSG101, and TP53 were analysed by agarose or polyacrylamide gel electrophoresis and sequenced. Genomic DNA was also analysed by polymerase chain reaction and sequencing (FHIT) or by Southern blotting (TSG101). Clinical data were correlated with the results of the mutation analysis.

RESULTS

Truncated FHIT transcripts were observed frequently alongside full length transcripts with nested RT-PCR, most often in FTC, while single stage RT-PCR revealed only normal length transcripts in all tumours. Similar results were obtained for TP53, while abnormal TSG101 transcripts were detectable by single stage RT-PCR. Sequence analysis of the truncated FHIT and TSG101 transcripts revealed mainly exon skipping and alternate RNA processing events. Only a single point mutation (of TSG101) was found. Southern blotting for the TSG101 gene, and PCR amplification and sequencing of the FHIT gene showed no evidence of genomic abnormalities in either case, and there was no evidence of splice site mutations in the FHIT gene, suggesting that the truncated transcripts result from altered RNA processing. There was no relationship between tumour stage, grade or survival and the presence of FHIT or TSG101 abnormalities.

CONCLUSIONS

Truncated FHIT and TSG101 transcripts in thyroid tumours reflect alternate mRNA splicing events, rather than genomic deletions. Such abnormal RNA processing seems to be common and widespread in thyroid neoplasms, as similar results were obtained by analysis of transcripts of TP53, which we had previously shown not to be mutated in these specimens. Although a pathogenetic role for these aberrant transcripts remains possible, no correlation was found with stage, histological grade or outcome in this small group of advanced thyroid malignancies. Relaxation of mRNA splice control appears to be a feature of follicular cell-derived thyroid neoplasms.

Prognostic indicators in differentiated thyroid carcinoma

BACKGROUND

Thyroid cancer ranges from well-differentiated lesions with an excellent prognosis to anaplastic carcinoma, which is almost uniformly fatal. Thus, methods to assess the behavior of thyroid malignancies are necessary to arrive at appropriate treatment decisions.

METHODS

We discuss the factors that affect the prognosis of patients with well-differentiated thyroid malignancies, including papillary, follicular, Hürthle cell, and medullary thyroid carcinomas. We also review the presentation, therapy, and outcome of patients seen at our center over a span of 50 years. These data have identified those prognostic factors that are predictive of survival and recurrence in differentiated thyroid cancer.

RESULTS

Several classifications with different variables have been developed to define risk-group categories. Three widely used systems, in addition to the TNM staging system, include AGES, AMES, and MACIS.

CONCLUSIONS

A better understanding of independently important prognostic variables will result in improved patient care and treatment.

Treating the patient with differentiated thyroid cancer with thyroglobulin-positive iodine-131 diagnostic scan-negative metastases: including comments on the role of serum thyroglobulin monitoring in tumor surveillance

Differentiated thyroid cancer (DTC) patients, especially the 10% to 15% at high risk of cancer-related death, should have long-term monitoring for detection of recurrence or metastasis. Conventional radiologic and ultrasonographic imaging is useful for localization of recurrent or persistent disease. For patients who have had ablation of residual thyroid tissue, measurement of serum thyroglobulin (Tg) levels and radioactive iodine (RAI) imaging provide highly sensitive tools for early detection. Serum Tg is reliable only in the absence of Tg autoantibodies. Sensitivity increases with TSH stimulation, either by withdrawal of thyroxine (T4) therapy, or administration of recombinant TSH (rTSH). In some patients, serum Tg levels are positive but the RAI whole body scan (WBS) is negative. In these patients, either the recurrent tumor is too small and below the sensitivity of the diagnostic scan, or there is a dissociation between Tg synthesis and the iodine-trapping mechanism. Recent literature suggests that empiric high-dose RAI therapy of Tg-positive diagnostic scan-negative patients may result in a high rate of visualization of uptake in posttherapy scans (PTS). Evidence for subsequent improvement of parameters of disease activity has also been presented. Almost all such reported cases had micrometastases that were not visualized by conventional imaging. In our experience, aggressive macrometastases with negative diagnostic WBS do not show significant uptake after therapeutic doses of RAI. The small size of micrometastases in the first group of patients and a possible defect of the iodine-trapping mechanism in the second group may explain this apparent discrepancy. Based on presently available information, a generalized recommendation for RAI therapy of Tg-positive, diagnostic scan-negative patients should await further studies. Meanwhile, in some high-risk patients, in the absence of alternative therapies, empiric RAI therapy is justified.

Impact of primary surgery on outcome in 300 patients with pathologic tumor-node-metastasis stage III papillary thyroid carcinoma treated at one institution from 1940 through 1989

BACKGROUND

The pathologic tumor-node-metastasis (pTNM) system is universally used to define the extent of disease in human malignancies. This study evaluated the impact of initial therapy on cause-specific mortality (CSM) rates and recurrence rates in pTNM stage III papillary thyroid carcinoma.

METHODS

Three hundred patients (median age, 58 years) were followed on average for 14 postoperative years. Of these, 246 patients (82%) had complete primary tumor resection; 208 patients (69%) had nodal metastases; 161 (54%) had locally invasive primary tumors; 45 patients (15%) underwent initial unilateral lobectomy (UL). Bilateral lobar resection (BLR) accounted for 242 patients (near-total, 54%; total thyroidectomy, 23%).

RESULTS

The 30-year rates for CSM, distant metastases, nodal metastases, and local recurrence (LR) were 29%, 22%, 19%, and 16%, respectively. The 20-year rates for CSM were significantly higher (50% vs 14%) when primary tumor was incompletely resected (P = .0001). After complete resection, 20-year rates for CSM and LR after BLR were 12% and 10%, respectively, which were significantly lower (P < .05) than the 23% and 26% rates seen after UL. There were no significant differences in nodal metastases or distant metastases rates between UL and BLR (P > .4). The 20-year LR rate after total thyroidectomy (13%) was not different (P = .5) from the 11% seen after near-total thyroidectomy.

CONCLUSIONS

In this nonrandomized evaluation of patients with pTNM stage III papillary thyroid carcinoma, the extent of primary thyroid resection appeared to significantly impact CSM and LR but did not apparently influence regional or distant metastasis.

Unilateral total lobectomy: is it sufficient surgical treatment for patients with AMES low-risk papillary thyroid carcinoma?

BACKGROUND

Controversy continues regarding the optimal extent of primary thyroid resection in most patients with papillary thyroid carcinoma (PTC), who are at minimal risk of cause-specific mortality (CSM). This study was designed to compare CSM and recurrence rates after either unilateral lobectomy (UL) or bilateral lobar resection (BLR) in patients with PTC considered low risk by AMES criteria.

METHODS

Outcome was studied in 1685 patients initially treated during 1940 through 1991 and followed for up to 54 postoperative years (mean, 18 years). One thousand six hundred fifty-six patients (98%) had complete primary tumor resection; 634 (38%) had involvement of regional nodes. One hundred ninety-five patients (12%) had UL; BLR accounted for 1468 (near-total 60%; total thyroidectomy 18%).

RESULTS

Thirty-year rates for CSM and distant metastasis were 2% and 3%, respectively. Twenty-year rates for local recurrence and nodal metastasis were 4% and 8%, respectively. There were no significant differences in CSM or distant metastasis rates between UL and BLR (P > .2). After UL, 20-year rates for local recurrence and nodal metastasis were 14% and 19%, significantly higher (P = .0001) than the 2% and 6% rates seen after BLR.

CONCLUSIONS

UL was not associated with higher CSM rates, but it was associated with a significantly higher risk of locoregional recurrence. Thus BLR probably represents a preferable initial surgical approach to patients with low-risk PTC.

Indications, technique, and efficacy of alcohol injection of enlarged parathyroid glands in patients with primary hyperparathyroidism

BACKGROUND

Percutaneous alcohol ablation of the parathyroid gland (PAAP) has been proposed as an alternative treatment for primary hyperparathyroidism in patients unsuitable for surgery. The current study aimed to determine the (1) selection criteria, (2) associated morbidity, and (3) efficacy of PAAP.

METHODS

From 1987 to 1998, 36 patients with primary hyperparathyroidism (mean age 65 years) underwent PAAP. The indications for PAAP were (1) medical comorbidity, (2) technically unsafe reoperative surgery, (3) partial ablation of a single remaining gland, and (4) patient choice.

RESULTS

There were no long-term complications. Two patients had temporary recurrent laryngeal nerve injury and 4 had temporary hypocalcemia. Over a median follow-up of 16 months, 12 (33%) of the patients remained eucalcemic. For analysis purposes patients were separated into 2 separate groups: 29 with attempted complete ablation and 7 with partial ablation of a single remaining gland only. Ten of the complete ablation group (34%) remained eucalcemic. In the partial ablation group only 2 remained eucalcemic, but all had adequately controlled serum calcium levels.

CONCLUSION

PAAP should be considered for hyperparathyroid patients with excessive reoperative morbidity or prohibitive medical comorbidity or those in whom the intent is to partially ablate a single remaining enlarged gland. In these patients close follow-up of serum calcium is required, and repeat treatments may be necessary because recurrence of hypercalcemia is likely.

Differential loss of heterozygosity at 7q31.2 in follicular and papillary thyroid tumors

We analysed 42 differentiated thyroid tumors including 15 follicular adenomas (FA), 13 papillary thyroid cancers (PTC) and 14 follicular thyroid carcinomas (FTC) with 13 microsatellite markers specific for the long arm of human chromosome 7 within 7q31; this region is deleted frequently in several other tumor types. Overall, 20 of the 42 samples analysed (48%) displayed LOH with one or more of the markers tested. LOH was detected most frequently (78%) in FTC, the most malignant of the thyroid tumors. A smallest common deleted region (SCDR) was defined in this tumor type flanked by markers D7S480 and D7S490. This SCDR is distinct from D7S522, the most commonly deleted locus in many other tumors, which was deleted in only one FTC. D7S522 did show LOH in two of six informative PTCs. None of the PTC and only two of the FAs showed LOH in the FTC SCDR. Since FA is considered a premalignant stage of FTC, our results suggest that inactivation of a putative tumor suppressor at 7q31.2 may be acquired during adenoma to carcinoma progression. The absence of LOH at this locus amongst PTC suggests that inactivation of this tumor suppressor is specific for FTC. In conclusion, LOH at 7q31 is a frequent event in differentiated thyroid cancer, and we have defined a 2 cM SCDR specific for FTC.

Biochemical testing of thyroid function

Various published guidelines recommending serum thyrotropin (TSH)-first thyroid testing are outlined. The entities called "subclinical hypothyroidism" and "subclinical hyperthyroidism" are defined on the basis of abnormal TSH concentrations and normal values of other biochemical thyroid tests. The controversies about follow-up and treatment of these disorders are discussed. The laboratory experience of Mayo Clinic Rochester in using TSH-first thyroid testing and the subsequent implementation of a thyroid test ordering cascade are presented. Finally, recommendations are given for further optimizing laboratory testing for thyroid disorders.