Surgical strategy for the treatment of medullary thyroid carcinoma

OBJECTIVE: To evaluate surgical complications, patterns of lymph node metastases, and calcitonin response to compartment-oriented lymphadenectomy in patients with primary or recurrent medullary thyroid carcinoma (MTC). SUMMARY BACKGROUND DATA: The majority of patients with invasive MTC have metastasis to regional lymph nodes at the time of diagnosis, as evidenced by the frequent finding of persistently elevated calcitonin levels after thyroidectomy and the high rates of recurrence in the cervical lymph nodes reported in retrospective studies. These data have provided the rationale for surgeons to perform a more extensive lymphadenectomy at the time of initial thyroidectomy and to consider reoperative cervical lymphadenectomy in patients with persistently elevated calcitonin levels after thyroidectomy. METHODS: Forty patients underwent surgery for MTC from 1991 to 1997 (23 sporadic cases, 17 familial cases). Patients were divided into three groups based on whether they had undergone previous thyroidectomy and on the results of standardized staging studies performed after referral to the authors' institution. Group 1 (11 patients) had received no previous surgery; group 2 (13) underwent thyroidectomy before referral and had an elevated calcitonin level without radiologic evidence of local regional or distant metastases; and group 3 (16) underwent thyroidectomy before referral and had an elevated calcitonin level with radiologic evidence of local-regional recurrence. The central neck compartment was dissected in all patients; preoperative staging and the extent of previous surgery dictated the need for lateral (modified radical) neck dissection. After primary or reoperative surgery, calcitonin levels were assessed. RESULTS: All patients had major reductions in postoperative calcitonin levels. Seven (29%) of 24 patients in groups 1 and 2 achieved normal calcitonin values compared with only 1 (6%) of 16 in group 3. Postoperative complications included seven cases (17%) of permanent hypoparathyroidism; five (71%) of these occurred in group 3. There were no iatrogenic recurrent laryngeal nerve injuries; one patient required recurrent nerve resection to achieve complete tumor extirpation. At a median follow up of 35 months, local recurrence was documented in 5 (13%) of 40 patients. CONCLUSIONS: Compartment-oriented lymphadenectomy performed early in the course of MTC is safe and may return calcitonin levels to normal in up to 25% of carefully selected patients. However, reoperation for bulky cervical disease (group 3) rarely results in normal calcitonin levels and is associated with a high incidence of permanent hypoparathyroidism.     

Long-term Outcome of Reoperations for Medullary Thyroid Carcinoma

Background Most patients with medullary thyroid carcinoma (MTC) have persistent disease after primary surgery, as evidenced by calcitonin elevation. Previous reports showed that reoperation on selected patients yields immediate calcitonin normalization in one-third of patients. Long-term follow-up data are needed to assess the outcome in such patients. This report aims to provide 8– to 10–year follow-up on reoperations for persistent or recurrent MTC. Methods An Internal Review Board (IRB) approved database on patients treated for MTC has been prospectively maintained. This database was reviewed to report follow-up data on calcitonin levels and survival. Results Between 1992 and 2006, 148 patients underwent reoperations for recurrent or persistent MTC (55 patients had 59 reoperations for palliation, and 93 patients had 105 reoperations for cure). Of the 93 patients operated on for cure (44 with hereditary MTC, 49 with the sporadic form), 8–10-year follow-up data were available on 56. Four patients died of disease (4.3% of 93). Two died of unrelated causes, and were excluded from calcitonin outcome analysis. Fourteen patients of 54 (26.0%) have unstimulated calcitonin levels of < 10 pg/ml at 8–10 years. Eleven additional patients (20.4%) have levels < 100 pg/ml. None of these 25 patients (46.4%) have radiologic recurrence. Conclusions Previous reports demonstrated the low morbidity of reoperation for MTC in experienced hands, and success was determined by lowering of calcitonin levels. Follow-up data demonstrate that at least one third of such patients have long-term eradication of their disease following reoperation, as evidenced by biochemical and imaging studies.     

Long-term results of reoperation and localizing studies in patients with persistent or recurrent medullary thyroid cancer

HYPOTHESIS: Reoperation benefits patients with locoregional, persistent, or recurrent medullary thyroid cancer (MTC). Currently available localizing studies have limited utility for detecting all foci of residual MTC. DESIGN: A retrospective study with a mean follow-up time of 7.5 years (median, 13 years; range, 2.2-29 years). SETTING: A tertiary referral medical center. PATIENTS: Thirty-three patients who underwent 46 reoperations for locoregional residual MTC. RESULTS: Sixty-four percent of residual MTC was located in the lateral cervical nodes, 22% in the central cervical nodes or thyroid bed, and 14% in the anterior mediastinum (197 of 1128 nodes resected were positive for MTC). After reoperation, basal calcitonin levels were undetectable in 2 patients, reduced by greater than 50% in 10 patients, and either increased or were not reduced by greater than 50% in the remaining patients. On reoperation, one patient had a thoracic duct injury that required reexploration and ligation. Patients who had a greater than 50% decrease in calcitonin levels after reoperation were less likely to develop distant metastases compared with patients who did not have a greater than 50% decrease (P<.05). The sensitivities of magnetic resonance imaging (n = 31), computed tomographic scan (n = 16), ultrasound (n = 9), and dimercaptosuccinic acid scan (n = 3) were 91%, 86%, 88%, and 100%, respectively. CONCLUSIONS: Although reoperation in patients with residual MTC rarely results in biochemical cure, cervical reexploration is safe and in selected patients may limit MTC progression. Lateral cervical node dissection could be beneficial at the time of initial surgical treatment because of the high frequency of residual MTC in the lateral cervical nodes. Noninvasive imaging studies were helpful but far from perfect for guiding the reexploration for locoregional residual MTC.     

Prophylactic thyroidectomy in MEN 2A syndrome: experience in a single center

BACKGROUND: Genetic study of the RET proto-oncogene has modified the management, treatment, and prognosis of medullary thyroid carcinoma (MTC), multiple endocrine neoplasia 2A (MEN 2A), for patients with less advanced tumor stages. Classically, the diagnosis was based on an increase in basal and poststimulus peak calcitonin (bCT and pCT). Prophylactic thyroidectomy, based on results of genetic testing, may reduce recurrences in MTC. STUDY DESIGN: Of 82 MTC (MEN 2A) patients genetically diagnosed and surgically treated at our center, 22 received a prophylactic thyroidectomy (RET +, bCT and pCT with normal values and asymptomatic). We analyzed age, gender, phenotype, RET mutation, cervical ultrasound, laboratory tests (bCT, pCT, and CEA), surgery, histologic data, TNM, and followup. RESULTS: The 22 patients belonged to 8 families with MTC (MEN 2A). Mean age was 15.2 years (range 5 to 36 years). The RET mutation in 21 patients was Cys-->Tyr and in the remaining patient both in codon 634 in exon 11. The median values of bCT and pCT were 38 pg/mL (range < 15 to 75 pg/mL) and 148.5 pg/mL (range < 15 to 250 pg/mL), respectively. Total thyroidectomy was performed in 8 patients (age < or = 10 years) and associated central neck dissection in 14 patients (age> 10 years). Histologic study showed 7 C-cell hyperplasias and 15 MTCs (8 bilateral); the median size was 0.2 cm (range < 0.1 to 0.7cm); 1 patient had metastatic adenopathies. According to TNM, 7 were stage 0, 14 were stage I, and 1 was stage III. Postsurgery bCT and pCT values were normal in all patients, with a curative rate of 100%. MTC patients compared with C-cell hyperplasia patients were older on average, had higher mean bCT, mean pCT, and mean CEA. CONCLUSIONS: Prophylactic thyroidectomy based on genetic testing allows identification and treatment of patients at an early stage of the disease and decreases recurrence rates. pCT values above the upper limit of normal may be markers for the presence of MTC and should be considered in selecting operative procedures for these patients.     

甲状腺结节患者常规行血清降钙素检查对早期发现甲状腺髓样癌的临床价值

目的:探讨甲状腺结节患者血清降钙素(Ct)检测对甲状腺髓样癌(MTC)的诊断价值。方法:回顾性分析2016年10月—2017年8月1922例因甲状腺结节就诊于郑州大学第一附属医院甲状腺外科并行手术治疗的患者资料。所有患者术前均常规行血清Ct检测,术后均有明确的常规病理结果。分析Ct水平与MTC的关系、用受试者工作特征曲线分析Ct对MTC的诊断效能。结果:在1922例甲状腺结节患者中,新发现的MTC患者有12例(0.62%)。在术前血清Ct值为10~100pg/mL的155例、100~500pg/mL的12例和500pg/mL的10例中,术后确诊为MTC的分别为1例(0.65%)、1例(8.33%)和9例(90.00%)。在血清Ct500pg/mL的9例MTC患者中,有8例(88.89%)出现了不同程度的颈部淋巴结转移。血清Ct诊断MTC的截断值为258.5pg/mL,敏感性为90.91%,特异性为96.99%。结论:术前常规检测血清Ct有助于MTC的早期诊断,对患者接受彻底的手术治疗,避免二次手术有十分重要的意义。     

Presurgical assessment of the tumor burden of familial medullary thyroid carcinoma by calcitonin testing

BACKGROUND: Early diagnosis of familial medullary thyroid carcinoma (MTC) is currently done by genetic analysis. These techniques have replaced calcitonin stimulation testing, which was previously used for this purpose. Some studies suggest a relationship between MTC spread and calcitonin levels. The aim of this study was to assess whether the tumor burden of MTC associated with multiple endocrine neoplasia type 2A (MEN 2A) syndrome can be estimated from the plasma calcitonin values before surgery. STUDY DESIGN: We retrospectively studied the relationship of basal and peak calcitonin values before thyroidectomy with histopathologic findings in 53 patients with MEN 2A syndrome from 14 families. The MTC was classified according to TNM staging. Analysis of variance was used for statistical analysis complemented with equality contrasts for pairs of means by the least significant difference method with a Student's t-test and with the Bonferroni's adjustment. RESULTS: A positive association was found between tumor stage and basal and peak calcitonin levels. There were significant differences between the following: mean basal concentrations of patients with C cell hyperplasia (CCH) (34.3 pg/mL) and TNM stage II (1,097.4 pg/mL), p < 0.01; CCH and TNM stage III (2,940.8 pg/mL), p < 0.001; TNM stage I (165.3 pg/mL) and stage II (1,097.4 pg/mL), p < 0.01, and between TNM stages I and III, p < 0.001. Poststimulation mean concentrations were different between CCH (48.7 pg/mL) and TNM I (514.2 pg/mL), p < 0.001. CONCLUSIONS: Preoperative calcitonin testing may be useful for assessing tumor spread and should be considered when deciding the extent of surgery for MEN 2A MTC.     

Lymph node involvement in macroscopic medullary thyroid carcinoma

BACKGROUND: Medullary thyroid carcinoma (MTC) is a rare disease, with variable tendency to lymphatic spread. The aim of this retrospective study was to identify distinctive features of large MTC with and without nodal metastases. METHODS: Between 1993 and 2003, 28 consecutive patients underwent total thyroidectomy and neck node dissection for sporadic MTC larger than 10 mm in diameter. RESULTS: All tumours were confirmed to be malignant with a locally invasive pattern of growth. Lymph node metastases were present in 16 patients (N1) and absent in 12 (N0). There were no statistically significant differences between patients with N0 and N1 tumours concerning age (mean 52.1 versus 53.4 years), male:female ratio (0.7 versus 1.0), basal preoperative calcitonin concentration (mean 3238 versus 3076 pg/ml) and tumour size (23.3 versus 23.9 mm). There were differences in the incidence of tumour invasion (P < 0.001), vascular embolism (P = 0.011) and peritumoral thyroiditis (P = 0.039). Measurement of basal and stimulated calcitonin levels after surgery confirmed biochemical cure in all patients with N0 tumours and half of those with N1 disease (P = 0.006). CONCLUSION: There were no preoperative factors that predicted node status for MTC larger than 1 cm in this series. Total thyroidectomy and nodal dissection remains the optimal treatment.     

Effective long-term palliation of symptomatic, incurable metastatic medullary thyroid cancer by operative resection.

OBJECTIVE: To evaluate the short- and long-term consequences of palliative reresection of specific symptomatic lesions in patients with widely disseminated (incurable) medullary thyroid cancer (MTC). SUMMARY BACKGROUND DATA: Although reoperative neck microdissections can normalize calcitonin levels in patients with metastatic MTC confined to regional lymph nodes, there is no curative therapy for widely metastatic disease. However, these patients frequently have prolonged survival, but often with debilitating symptoms. METHODS: Between October 1981 and January 1997, 16 patients (mean age, 46 +/- 3 years; 10/16 female) underwent 21 palliative reoperations for unresectable MTC at the Johns Hopkins Hospital. All patients had significant symptom(s) or impending compromise of vital structures by a discrete lesion and had unequivocal preoperative evidence of a total disease burden that was unresectable. RESULTS: The mean interval from initial thyroidectomy to palliative surgery was 5.8 +/- 1.5 years. All patients had significant tumor burdens as evidenced by preoperative calcitonin values ranging from 900 to 222,500 pg/mL (nL < or = 17 pg/mL). The palliative operations consisted of reoperative neck dissection/mass excision (11), mediastinal mass resection (4), esophagectomy (1), liver trisegmentectomy (1), sigmoidectomy (1), bilateral simple mastectomies (1), pituitary resection (1), and subcutaneous mass excisions (1). All but two of the operative specimens contained MTC. There was no perioperative mortality. The long-term morbidity rate was limited to one recurrent laryngeal nerve injury. All patients had initial relief of the index symptom(s) after the palliative surgery, followed by a median actuarial symptom-free survival rate of 8.2 years. CONCLUSIONS: Patients with widely metastatic MTC often live for years, but many develop symptoms secondary to tumor persistence or progression. Judicious palliative, reoperative resection of discrete, symptomatic lesions can provide significant long-term relief of symptoms with minimal operative mortality and morbidity. In selected patients with metastatic MTC lesions causing significant symptoms or physical compromise, palliative reoperative resection should be considered despite the presence of widespread incurable metastatic disease.     

Ergebnisse des seletiven venösen Etagenkatheters (SVK) beim okkulten C-Zell-Karzinom der Schilddrüse

Background: Medullary thyroid carcinoma (MTC) can — even in recurrent cases — only be treated surgically. Therefore, preoperative localization of the tumor is essential.Methods: From April 1986 through April 1997, 137 patients with MTC were operated on at our clinic. In 22 patients with recurrent tumor which had not been radiologically localized, 28 selective venous catheterizations (SVC) with determination of calcitonin levels were carried out.Results: In 23 examinations a suspected tumor could be identified (nine cervical unilateral, seven mediastinal, four cervical unilateral and mediastinal, one cervical bilateral and mediastinal, one liver, one cervical unilateral and liver). In 18 cases surgery was performed for recurrence (nine cervical revisions, one mediastinal dissection, six cervicomediastinal dissections, two laparotomies). In 15 of 18 cases, tumor tissue was found in the previously suspected area. In ten cases serum calcitonin levels dropped postoperatively by 6%–75%. A normalization of the hormone level was achieved only once by yet another operation. During further follow-up, five of the reoperated patients died from their disease. The other 17 patients are being followed up, whereby calcitonin levels are elevated but there is no clinical or radiological evidence of tumor.Conclusions: Although in the patient cohort presented a normalization of serum calcitonin could be achieved only once, the authors consider SVC useful because it is the only means of localization of tumor tissue in cases of negative radiologic studies and therefore allows a planned approach to the operation procedure in these cases.     

Impact of modified radical neck dissection on biochemical cure in medullary thyroid carcinomas.

BACKGROUND: This study evaluated the outcome of total thyroidectomy and modified radical neck dissection in primary treatment of patients with medullary thyroid carcinoma (MTC). METHODS: Thirty-six patients with sporadic (n = 16) and hereditary (n = 20) MTC underwent thyroidectomy and systematic central and lateral lymph node dissection (unilateral, 23; bilateral, 13) between 1994 and 2000. Postoperative serum calcitonin levels were correlated with immediate or delayed surgery, tumor categories, and lymph node metastases. RESULTS: Sixteen of 36 (44%) patients with clinically evident MTC treated with central and lateral neck dissection exhibited normal basal and stimulated calcitonin levels at a median follow-up of 3.7 years. Lymph node involvement was detected in 75% of these patients and correlated with the TNM stages. Biochemical cure was achieved according to the T categories in 83% of the patients in stage T1, 42% in stage T2, and none of the patients in stage T4 (P = .011). Basal and stimulated calcitonin levels were found to be normal in 89% of the patients without lymph node involvement and in 30% of the patients with lymph node metastases (P = .005). CONCLUSIONS: Screening for MTC and primary treatment with total thyroidectomy and modified radical neck dissection are essential for biochemical cure of MTC.     

Evaluation of children with multiple endocrine neoplasia type IIb following thyroidectomy

Medullary thyroid carcinoma (MTC) develops in all patients with multiple endocrine neoplasia type IIb (MEN IIb), a rare syndrome that either occurs sporadically or is inherited in an autosomal dominant pattern. The MTC in patients with MEN IIb has been reported to be biologically aggressive with onset at a young age and rapid progression as evidenced by widespread metastases and death, frequently in the teenage years. Seven children, aged 2 to 11 years (mean, 7 years), from three kindreds with MEN IIb were evaluated for evidence of tumor recurrence 3 to 10 years following thyroidectomy. In one child, age 11, a thyroid mass was palpable preoperatively. However, in the remaining six children (aged 2 to 10 years), the diagnosis of MTC was established by an increased concentration of plasma calcitonin (CT), either basally or following pentagastrin (Pg) stimulation. All patients underwent total thyroidectomy with removal of central lymph nodes from the neck. At the time of surgery, six children were found to have bilateral macroscopic MTC, five without and one with cervical metastases. One child (age 2 years) had C-cell hyperplasia, a premalignant precursor of MTC. Currently, five of the seven children are without evidence of recurrent disease clinically and have normal plasma CT levels (less than 0.3 ng/mL) following calcium (Ca) and Pg stimulation 3, 3, 10, 10, and 10 years after thyroidectomy. Two of the seven children have biochemical evidence of residual MTC.(ABSTRACT TRUNCATED AT 250 WORDS)     

Hypercalcitoninemia in thyroid conditions other than medullary thyroid carcinoma: a comparative analysis of calcium and pentagastrin stimulation of serum calcitonin

Purpose

Calcitonin screening aims at uncovering occult medullary thyroid cancer (MTC) in patients with nodular thyroid disease. Elevated basal calcitonin serum levels call for calcitonin stimulation, the level of which may direct the extent of surgery. Because pentagastrin has become restricted, calcium has increasingly been used instead for stimulation. This study identified a new spectrum of patients demonstrating a false-positive hypercalcitoninemia in the absence of C-cell disease, carrying multinodular goiter (MNG), thyroiditis, and non-MTC thyroid malignancy, and endeavored to explore the feasibility of extrapolating pentagastrin-stimulated to calcium-stimulated calcitonin thresholds.

Methods

Altogether, 43 (9.5 %) of 455 patients with nodular thyroid disease revealed increased basal calcitonin serum levels between 2005 and 2012, for which they underwent intravenous stimulation with pentagastrin (31 patients) or calcium gluconate (12 patients) before and after primary thyroidectomy.

Results

Stimulation with calcium gluconate resulted in significantly higher and more variable preoperative calcitonin serum levels after 2 (241.2 vs. 104.9 pg/mL; P?=?0.018) and 5 min (240.6 vs. 87.4 pg/mL; P?=?0.007) than stimulation with pentagastrin. Stimulation with calcium gluconate produced 10-fold (nodular goiter), 15-fold (thyroiditis), and 21-fold (thyroid neoplasia other than MTC) calcitonin increases over baseline, as opposed to 5-fold, 10-fold, and 8-fold increases after stimulation with pentagastrin. None of the 43 patients, all of whom reverted to undetectable calcitonin serum levels after thyroidectomy, had immunohistochemical evidence of C-cell disease. Subgroup analyses according to gender and thyroid disease, being limited by the low number of patients in each subgroup, did not yield significant differences.

Conclusions

Calcium stimulation yields significantly greater calcitonin levels than pentagastrin stimulation, precluding generalization of pentagastrin-stimulated to calcium-stimulated calcitonin thresholds. After calcium stimulation, false-positive findings appear to be more common in patients of female gender and patients with thyroiditis and thyroid neoplasia other than MTC, potentially effecting surgical overtreatment.     

Long-term course of patients with persistent hypercalcitoninemia after apparent curative primary surgery for medullary thyroid carcinoma.

Thirty-one patients with persistent hypercalcitoninemia after seemingly adequate primary operation for medullary thyroid carcinoma (MTC) were followed for a mean period of 11.9 years after operation. Ten patients had sporadic MTC and the remaining patients were members of families with multiple endocrine neoplasia (MEN)--either MEN 2A (15 patients) or MEN 2B (six patients). Overall 5- and 10-year survival rates were 90% and 86%, respectively. Only four patients died at the completion of the study: two of MTC and two of unrelated causes. Eleven patients (35.5%) underwent surgical re-exploration after demonstration of recurrent disease clinically or radiologically. In no patient did the calcitonin level return to normal after re-exploration. The presence of more than three metastatic nodes at the time of initial operation was a statistically significant (p = 0.003) predictor for disease recurrence. Factors approaching statistical significance were patients younger than age 35 (p = 0.06) and the percentage of cells in the S phase of cell division (0.07). This data supports a conservative surgical philosophy in the management of the patient with persistent hypercalcitoninemia after resection of MTC.     

Familial nonmultiple endocrine neoplasia medullary thyroid carcinoma: an evolving clinical entity.

BACKGROUND. A rare kindred of familial nonmultiple endocrine neoplasia medullary thyroid carcinoma arising from a 73-year-old proband case is reported to further define this distinct entity. METHODS. Twenty-four family members across four generations, four with medullary thyroid carcinoma (MTC) and two with C-cell hyperplasia (CCH), were studied. RESULTS. Basal calcitonin levels were elevated in three patients with MTC and were normal in one patient with microscopic MTC and two patients with CCH who had persistent subtle elevation in calcium and/or pentagastrin-stimulated calcitonin levels. One patient had unilateral MTC without CCH. Associated abnormalities included papillary carcinoma (2), thyroiditis (4), adenoma (2), and colloid nodule (1). Minimum treatment was total thyroidectomy. Two patients with MTC and marked hypercalcitonemia have recurrent disease at 2.5-year and 11-year follow-up. Two patients with MTC and normal or minor elevations in basal calcitonin and two with CCH had normal provocative calcitonin testing at 6 to 18 months follow-up. CONCLUSIONS. Unilateral MTC without CCH and MTC in the elderly do not preclude a familial cause. Microscopic MTC or CCH may be seen with subtle elevations in stimulated calcitonin levels, and recognition allows for curative thyroidectomy. Other apparent dominant thyroid pathologic conditions may occur concomitantly with familial medullary thyroid carcinoma and thus routine calcitonin, and immunohistochemical testing should be performed in patients with an appropriate family history.     

Importance of Early Screening and Prophylactic Thyroidectomy in Asymptomatic Nonindex RET Germline Carriers

Genetic testing for RET germline mutations affords rapid identification of germline carriers, offering the prospect of cure before C-cell hyperplasia (CCH) has progressed to medullary thyroid carcinoma (MTC). Although nonindex RET mutation carriers have a better prognosis than do the index patients, it remains to be ascertained whether age represents a risk factor for MTC when screening patients. The current institutional study (October 1994 through June 1999) was set up to compare asymptomatic nonindex patients who were grouped by age: < 20 years and ≥ 20 years. Inclusion criteria were confirmed RET mutations in the germline, with no MTC being more advanced than pT1pN1M0. Adult patients (≥ 20 years) had MTC significantly more often (84% vs. 43%), significantly larger tumors (5 mm vs. 3 mm), and significantly higher basal calcitonin levels preoperatively (78.0 vs. 9.7 pg/ml) than their pediatric/adolescent counterparts (< 20 years). There was a close correlation between pT1 MTC and an elevated basal serum calcitonin level (r= 0.67; Spearman's rho). All three patients with lymph node metastases from MTC had elevated basal calcitonin levels. The two groups did not differ in terms of multifocality of MTC (pT1b), lymph node involvement (pN1) or bilateral lymph node metastasis (pN1b), or preoperative stimulated and postoperative basal and stimulated serum calcitonin. Prophylactic thyroidectomy should not be postponed beyond the age of 20, and it should be performed before basal serum calcitonin has turned positive. Pathologic conversion of stimulated serum calcitonin obviously marks the time in carriers of RET germline mutations when surgery should be scheduled at the latest to be prophylactic.     

Improved results of cervical reoperation for medullary thyroid carcinoma.

OBJECTIVE: The purpose of the study is to determine whether reoperation for medullary thyroid carcinoma (MTC), performed with low morbidity in carefully selected patients, consistently results in improvement as determined by lowering of stimulated calcitonin levels. BACKGROUND: Persistent or recurrent elevation of stimulated plasma calcitonin levels occurs in > 50% of patients after primary operation for MTC. Success of reoperation with clearance of metastatic cervical nodal disease has been hampered by failure to identify patients with distant metastases and by inadequate removal of involved nodal groups. METHODS: Since 1992, the authors have evaluated 115 patients with recurrent or residual MTC. Fifty-three patients have not undergone operation because of extent of disease, previous extensive treatment, medical condition, or patient choice. Sixty-two patients underwent surgery. Ten patients had laparoscopic or open examination of the liver, the results of which showed liver metastases. Seven patients had palliative debulking of cervical tumor. In 45 patients without evidence of distant metastases, cervical operation was carried out with curative intent. Removal of central, upper mediastinal, and lateral nodes (levels II, III, IV, VI, and VII) was done. RESULTS: Seven of eight patients who had palliative resections are alive without symptoms. In patients who underwent curative resections, postoperative stimulated calcitonin levels were in the normal range in 17 patients (38%) and were not significantly lowered in 6 patients (13%). There were no deaths, and no transfusions were used. CONCLUSIONS: These results are a significant improvement over the authors' previous series and reflect better preoperative identification of patients with disease confined to the neck and improved operative strategy based on knowledge of the pattern of nodal spread of MTC.     

Measurement of plasma calcitonin gene-related peptide (CGRP) level in patients with thyroid disease

To elucidate the pathophysiology of CGRP in patients with medullary thyroid carcinoma (MTC), we measured the plasma CGRP level in patients with thyroid disease employing RIA. The plasma CGRP level (normal level 12.7 pg/ml) was elevated in all five preoperative patients with MTC, ranging from 128 pg/ml to 2010 pg/ml, and in ten of 17 postoperative patients who indicated possible recurrence. On the other hand, CGRP levels showed low frequencies of elevation in 96 patients with other thyroid tumors (anaplastic carcinoma, malignant lymphoma, follicular adenoma and adenomatous goiter), subacute thyroiditis, chronic thyroiditis and Graves' disease. Provocation test (calcium gluconate plus pentagastrin) in 12 MTC patients showed that, although the CGRP level fluctuated in parallel with the calcitonin level, the elevation rate (maximum level after administration/basal level) of CGRP was lower than that of calcitonin. Particularly, the rate of elevation of CGRP in three virulent and advanced patients with poorly differentiated MTC was below 2.0, while that in nine patients with well-differentiated MTC ranged from 2.8 to 23.3. These results suggest that CGRP may be a humoral marker of MTC and is possibly related to the degree of malignancy.     

Kalzitoninbestimmung zur Frühdiagnose des medullären Schilddrüsenkarzinoms

Calcitonin is considered to be a sensitive marker for medullary thyroid cancer (MTC) therefore early detection and surgical treatment may help to improve the clinical prognosis of MTC. Routine calcitonin measurement has therefore been recommended in the diagnostic evaluation of patients with nodular thyroid disease. In the case of elevated serum calcitonin (>20 pg/ml) stimulation testing is recommended to improve the predictive power for MTC particularly in patients with small nodules. Serum calcitonin measurement cannot reliably discriminate between micro-MTC (<10 mm) and C cell hyperplasia. In patients with stimulated calcitonin levels exceeding 100 pg/ml thyroidectomy is recommended because of a high inherent risk of MTC. Highly elevated basal and stimulated serum calcitonin levels are strongly suggestive of MTC with practical implications for surgical management.     

Prognostic Significance of Disseminated Tumor Cells in the Connective Tissue of Patients with Medullary Thyroid Carcinoma

Introduction Disseminated tumor cells in the connective tissue (CT-DTCs) do not have any connection to a primary tumor or the lymph nodes. They are identified quite often in patients with medullary thyroid carcinoma (MTC), but nothing is known regarding their prognostic significance. Methods Among 450 patients with MTC, 69 (15%) were identified as having CT-DTCs. A case-control group of patients without CT-DTCs was selected. The two groups were matched concerning TNM classification, age, heredity, and sex. Because many patients with CT-DTCs had extrathyroidal tumor extension (pT4 category), distant metastases (M1 category), or both, only 35 matched pairs could be identified. The TNM classification in both groups was as follows: pT1, n = 8; pT2, n = 15; pT3, n = 4; pT4, n = 8; pN0, n = 4; pN1, n = 31; M0, n = 30; M1, n = 5. The mean age was 46.8 ± 17.0 years in the CT-DTC group and 44.4 ± 15.0 years in the case-control group (NS). Results In both groups, 23 patients had sporadic MTC, and 12 patients had hereditary MTC. Neither mean basal preoperative nor postoperative calcitonin levels differed significantly between the two groups. In contrast, none of the patients with CT-DTCs was biochemically cured (normal calcitonin level after pentagastrin stimulation) compared to eight patients without CT-DTCs (P < 0.005). The two groups did not differ concerning other parameters (basal calcitonin level >3000 pg/ml, more than 10 lymph node metastases, more than two involved locoregional lymph node compartments, mediastinal lymph node metastases) that have been reported to correlate with the lack of or almost (<10%) lack of biochemical cure. Conclusions In patients with MTC, disseminated tumor cells in the connective tissue correlate with advanced tumor stages and appear to be of prognostic significance.     

Surgical Strategy in a Kindred with a Rare RET Protooncogene Mutation of Variable Penetrance with Regard to Multiple Endocrine Neoplasia

Prophylactic thyroidectomy is recommended for carriers of RET protooncogene mutations owing to their nearly complete penetrance for medullary thyroid carcinoma (MTC). However, this guideline is challenged by mutations exhibiting variable penetrance of C-cell pathology. A 38-year-old woman presented with pathologic basal and pentagastrin-stimulated calcitonin levels. Genetic analysis revealed a heterozygous RET protooncogene germline mutation in codon 791 (exon 13) (TAT(Tyr)-->TTT(Phe)), followed by thyroidectomy and systematic central lymph node dissection. Histology showed C-cell hyperplasia (CCH) only. Three additional carriers were identified among family members. The 71-year-old father refused surgery despite pathologic calcitonin levels. The index patient's 37-year-old sister had normal basal and stimulated calcitonin levels, and her 6-year-old son had a 10-fold rise of calcitonin after pentagastrin stimulation. Both patients underwent the same operation as the index patient. The sister had 25 hyperplastic C-cells, but the her son had extensive CCH without MTC. The eldest uncle of the index patient had died of metastatic MTC at the age of 52 with unknown carrier status. Despite variable penetrance, each carrier of a RET protooncogene germline mutation should undergo thyroidectomy, even if basal and stimulated calcitonin levels are normal because at present no test can exclude or predict the age of development of MTC. Moreover, pathologic calcitonin levels cannot differentiate between CCH and MTC. Central lymph node dissection is recommended, as lymph node metastases occur early, significantly worsening the prognosis.