Medullary thyroid carcinoma: the influence of policy changing in clinical characteristics and disease progression

Metastatic medullary thyroid carcinoma (MTC): disease course, treatment modalities and factors predisposing for drug resistance

PURPOSE

MTC has varying clinical course. In cases with metastatic disease (meta-MTC) further therapeutic modalities (locoregional and/or Tyrosine-Kinase-Inhibitors, TKIs) are needed. Clinical features, disease progression, response to therapy and possible factors predisposing to TKIs response-resistance in meta-MTCs were investigated.

METHODS

Out of 338 MTC patients 54 had meta-MTC and were followed for 0.7-46 years (median 10.5); therapeutic interventions and response to therapy were recorded retrospectively.

RESULTS

Of 54 meta-MTC patients, 34/54 were men, 44/54 sporadic (age-at-diagnosis 47 ± 17.4 years, range: 5-78). Distant metastases at diagnosis were present in 12/54 (≥2 loci in 8/12), 7/12 received TKIs; During follow-up metastases occurred in 42/54 (within 0.6-25 years from diagnosis, median 5 yrs). Locoregional therapies were administered to 44/54 (81.5%) and TKIs to 40/54 (74.1%). Vandetanib was administered in 30 patients (24 as first-line therapy). The median progression-free-survival, PFS) was 48 months (range 4-120), partial response (PR): 26.7%, stable disease (SD): 23.3%, progressive disease (PD): 50.0%, cancer-specific survival: 44.8%, (16 in ongoing-therapy). More favorable disease course was recorded in familial-MTC compared to sporadic (p = 0.02) and in those patients with serious-adverse-events (SAEs) under treatment (p = 0.027). Those with biochemical progression under vandetanib, later showed more frequently structural progression (p = 0.007). Ten patients received cabozantinib (8/10 as second-line therapy, median PFS:11 months (3-36 months), 8/10 died). Three RET-mutant patients received selpercatinib; all showed PR. Within the total follow-up period, the response to therapy was: PR: 8/54 (14.8%), SD: 15/54 (27.8%), PD: 31/54 (57.4%), cancer-specific survival 46.3%. Mortality was higher in older patients (≥60 years) compared to younger ones (<60 yrs) (83.3 vs 45.2%, p = 0.021). Outcome was better in familial-MTC vs sporadic (PR: 50 vs 6.8%, SD: 20 vs 29.5%, PD: 30 vs 59.1%, p = 0.007).

CONCLUSIONS

Meta-MTCs treatment results in disease stabilization in 42.6% during a median 10.5 year follow-up. Combination of locoregional and systemic therapies may result in more favorable PFS. Family history, younger age, SAEs may predict better response; biochemical escape under TKI needs to be followed-up closely as it may indicate disease progression.

Medullary thyroid carcinoma (MTC): unusual metastatic sites

SUMMARY

Medullary thyroid carcinoma (MTC) has a varying clinical course; distant metastases are frequently present even at diagnosis. We present two MTC cases with unusual metastatic sites. Two female patients are presented with slow progressive MTC. The first case developed distant metastases 23 years after diagnosis and underwent locoregional therapies. At the same time a breast mass developed representing MTC metastasis. Treatment with vandetanib led to long-term disease stabilization. The second patient is presented with metastases in the pancreas 13 years after diagnosis. Shortly, a painful mass developed in the mandible and metastasis of MTC was diagnosed. Disease progression was recorded 20 months after the initiation of local and systemic therapy. Such cases have only rarely been reported in the literature and highlight the need for prompt recognition of unexpected MTC metastases.

LEARNING POINTS

Unusual sites of metastasis may appear in patients with medullary thyroid carcinoma (MTC) years after the initial diagnosis. Although rare, unexpected MTC metastases highlight the need for prompt recognition and appropriate treatment. Local recurrences accompanied by inappropriately low calcitonin levels should prompt further investigation for possible distant metastatic disease. Systemic treatment with tyrosine kinase inhibitors may be effective even in patients with unusual metastases from MTC.

Calcitonin testing for detection of medullary thyroid cancer in people with thyroid nodules

BACKGROUND

Thyroid nodules are very common in general medical practice, but rarely turn out to be a medullary thyroid carcinoma (MTC). Calcitonin is a sensitive tumour marker for the detection of MTC (basal calcitonin). Sometimes a stimulation test is used to improve specificity (stimulated calcitonin). Although the European Thyroid Association's guideline advocates calcitonin determination in people with thyroid nodules, the role of routine calcitonin testing in individuals with thyroid nodules is still questionable.

OBJECTIVES

The objective of this review was to determine the diagnostic accuracy of basal and/or stimulated calcitonin as a triage or add-on test for detection of MTC in people with thyroid nodules.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase and Web of Science from inception to June 2018.

SELECTION CRITERIA

We included all retrospective and prospective cohort studies in which all participants with thyroid nodules had undergone determination of basal calcitonin levels (and stimulated calcitonin, if performed).

DATA COLLECTION AND ANALYSIS

Two review authors independently scanned all retrieved records. We extracted data using a standard data extraction form. We assessed risk of bias and applicability using the QUADAS-2 tool. Using the hierarchical summary receiver operating characteristic (HSROC) model, we estimated summary curves across different thresholds and also obtained summary estimates of sensitivity and specificity at a common threshold when possible.

MAIN RESULTS

In 16 studies, we identified 72,368 participants with nodular thyroid disease in whom routinely calcitonin testing was performed. All included studies performed the calcitonin test as a triage test. Median prevalence of MTC was 0.32%. Sensitivity in these studies ranged between 83% and 100% and specificity ranged between 94% and 100%. An important limitation in 15 of the 16 studies (94%) was the absence of adequate reference standards and follow-up in calcitonin-negative participants. This resulted in a high risk of bias with regard to flow and timing in the methodological quality assessment. At the median specificity of 96.6% from the included studies, the estimated sensitivity (95% confidence interval (CI)) from the summary curve was 99.7% ( 68.8% to 100%). For the median prevalence of MTC of 0.23%, the positive predictive value (PPV) for basal calcitonin testing at a threshold of 10 pg/mL was 7.7% (4.9% to 12.1%). Summary estimates of sensitivity and specificity for the threshold of 10 pg/mL of basal calcitonin testing was 100% (95% CI 99.7 to 100) and 97.2% (95% CI 95.9 to 98.6), respectively. For combined basal and stimulated calcitonin testing, sensitivity ranged between 82% and 100% with specificity between 99% and 100%. The median specificity was 99.8% with an estimated sensitivity of 98.8% (95% CI 65.8 to 100) .

AUTHORS' CONCLUSIONS

Both basal and combined basal and stimulated calcitonin testing have a high sensitivity and specificity. However, this may be an overestimation due to high risk of bias in the use and choice of reference standard The value of routine testing in patients with thyroid nodules remains questionable, due to the low prevalence, which results in a low PPV of basal calcitonin testing. Whether routine calcitonin testing improves prognosis in MTC patients remains unclear.

RET Proto-oncogene Gene Mutation Is Related to Cervical Lymph Node Metastasis in Medullary Thyroid Carcinoma

RET proto-oncogene (RET) mutations were proved to be related to the development of medullary thyroid carcinoma (MTC). We aimed to analyze the role of RET mutations in cervical lymph node metastasis in patients with MTC. Forty-nine patients with preoperatively diagnosed MTC by fine-needle aspiration cytology (FNAC) who underwent bilateral total thyroidectomy with cervical lymphadenectomy were included. Postoperative RET gene test and pathological analysis were performed with the surgical specimens; serum calcitonin (Ctn) and carcinoembryonic antigen (CEA) levels were tested pre- and postoperatively, to evaluate the association between RET mutations and cervical lymph node metastasis in MTC. In these 49 patients, the RET mutation rates of Exon 11, Exon 10, Exon 11&13, Exon 13, and Exon 16 were 20.4%, 4.1%, 38.8%, 22.4%, and 0%, respectively. The lymph node metastasis rates of patients with RET mutation in the central and lateral compartments were 71.4% and 64.3%, respectively, versus 28.6% and 14.3% of patients without RET mutation. The preoperative basal serum levels of Ctn (234.8 ± 188.4 vs. 44.4 ± 27.5, p < 0.01) and postoperative Ctn (49.8 ± 86.4 vs. 3.7 ± 2.2, p = 0.001) in MTC patients with RET mutations were significantly higher than those in MTC patients without RET mutation. In addition, the preoperative (50.2 ± 76.7 vs. 7.4 ± 6.8, p = 0.001) and postoperative serum levels of CEA (13.2 ± 19.5 vs. 1.3 ± 1.6, p < 0.01) in MTC patients with RET mutations were significantly higher than those in MTC patients without RET mutation (p < 0.05). RET mutation was related to cervical lymph node metastasis in patients with MTC, especially the mutation in Exon 11&13. Patients with RET mutation in Exon 11&13 might be regarded as the predictor for prophylactic ipsilateral total cervical lymphadenectomy even without clear evidence of lateral cervical lymph node metastasis.

CALCITONIN REVISITED IN 2020

Calcitonin (CT) is a polypeptidic hormone specifically secreted by the thyroid parafollicular cells (C cells) and tangentially involved in human phosphocalcic and bone metabolism. CT from other species (e.g. salmon) is more potent than human CT and has limited therapeutic applications. The neoplastic proliferation of C cells leads to medullary thyroid carcinoma (MTC) generally characterized by an increase of CT secretion. Serum CT is therefore the ideal marker for MTC and can confirm its presence at an early stage, as well as the follow up of its remission or progression/relapse/survival after surgery. There are, however, controversies such as the necessity of CT screening in patients with thyroid nodules, or particular situations causing false positive or false negative results. Our minireview also deals with an up-to-date of surgical procedures for MTC, as well as with non-surgical therapy.

Long-Term Outcomes and Aggressiveness of Hereditary Medullary Thyroid Carcinoma: 40 Years of Experience at One Center

CONTEXT

Recent data on long-term outcomes and aggressiveness of medullary thyroid carcinoma (MTC) are lacking for patients with multiple endocrine neoplasia type 2 (MEN2).

OBJECTIVES

To analyze the long-term outcomes in MEN2 and compare MTC aggressiveness in three defined RET mutation-risk categories: moderate risk (MOD), high risk (H), and highest risk (HST).

DESIGN, SETTING

Retrospective study of 263 operated patients with MEN2 from one German tertiary referral center from 1979 to 2017 comparing demographic, biochemical, genetic, and outcome parameters.

INTERVENTION

None (observational study).

MAIN OUTCOME MEASURE

Long-term survival and outcomes in three risk groups.

RESULTS

Surgery was performed at a mean age of 35.3 ± 18.8 (MOD, n = 122), 23.0 ± 15.7 years (H, n = 120), and 14.9 ± 9.3 (HST, n = 21) years (P < 0.05). The mean follow-up was 12.9 ± 9.8 years. Age and tumor stage at diagnosis differed among the three risk groups (P < 0.0001). Multivariate analysis of disease-specific survival (DSS) showed that increasing age [hazard ratio (HR), 1.06; 95% CI, 1.02 to 1.09], stage III/IV at diagnosis (HR, 7.39; 95% CI, 2.39 to 22.8), and HST group (HR, 14.4; 95% CI, 3.32 to 62.6) were significantly associated with worse DSS; the H group was not (P = 0.175). The DSS rates and outcomes were not different between the MOD and H groups (P = 0.179 and P = 0.893, respectively) but were significantly inferior in the HST group (P < 0.0008 and P < 0.0001, respectively).

CONCLUSION

MTC in patients with MEN2 showed a clearly different age of onset in the different risk groups. DSS and outcomes after MTC diagnosis were similar in the MOD and H groups, suggesting similar tumor behavior. The HST group had inferior outcomes and survival vs the MOD and or H groups.

Survival and Long-Term Biochemical Cure in Medullary Thyroid Carcinoma in Denmark 1997-2014: A Nationwide Study

BACKGROUND

Survival of medullary thyroid carcinoma (MTC) subgroups in relation to the general population is poorly described. Data on the factors predicting long-term biochemical cure in MTC patients are nonexistent at a population level. A nationwide retrospective cohort study of MTC in Denmark from 1997 to 2014 was conducted, aiming to detect subgroups with survival similar to that of the general population and to identify prognostic factors for disease-specific survival and long-term biochemical cure.

METHODS

The study included 220 patients identified from the nationwide Danish MTC cohort between 1997 and 2014. As a representative sample of the general population, a reference population matched 50:1 to the MTC cohort was used.

RESULTS

Patients diagnosed with hereditary MTC by screening (hazard ratio [HR] = 1.5 [confidence interval (CI) 0.5-4.3]), patients without regional metastases (HR = 1.4 [CI 0.9-2.3]), and patients with stage I (HR = 1.3 [CI 0.6-3.1]), stage II (HR = 1.1 [CI 0.6-2.3]), and III (HR = 1.3 [CI 0.4-4.2]) disease had an overall survival similar to the reference population. On multivariate analysis, the presence of distant metastases (HR = 12.3 [CI 6.0-25.0]) predicted worse disease-specific survival, while the absence of regional lymph node metastases (odds ratio = 40.1 [CI 12.0-133.7]) was the only independent prognostic factor for long-term biochemical cure.

CONCLUSIONS

Patients with hereditary MTC diagnosed by screening, patients without regional metastases, and patients with stages I, II, and III disease may have similar survival as the general population. The presence of distant metastases predicted worse disease-specific survival, while the absence of regional metastases predicted long-term biochemical cure.

Different outcomes in sporadic versus familial medullary thyroid cancer

BACKGROUND

Medullary thyroid carcinoma (MTC) has varying clinical course with familial cases (fMTC) diagnosed earlier than sporadic MTC (spMTC).

METHODS

A total of 273 MTCs (familial: n = 110 [40.3%], males: 38.5%) were followed for 1-35 years (median 5.0 years). Fifty one of the familial cases were operated because of positive findings at genetic screening. Disease extent at diagnosis and follow-up was recorded.

RESULTS

Mean age at diagnosis was: fMTC = 33.85 ± 16.5 years (range 4-74) and spMTC = 52.6 ± 14.0 years (range 16-81, P < .001). This difference remained when genetic screening cases were excluded. fMTCs had more frequently multifocality, smaller size, and more favorable stage at diagnosis (stages I and II: 60.9% vs 47.9%, stage III: 30.0% vs 23.9%, stage IV: 9.1% vs 28.9%, P = .01). fMTC had lower preoperative and postoperative calcitonin, more frequently remission (59.1% vs 47.2%) and less frequently progressive disease (8.2% vs 35.0%, P < .001). After excluding genetic screening cases, no difference in stage at diagnosis was observed. Outcome was more favorable in fMTC compared to sporadic (P = .002); the 10-year probability of lack of progression of disease differed significantly between fMTCs and spMTCs (86.4% vs 65.0%, P < .001).

CONCLUSION

After excluding genetic screening cases, although stage at diagnosis is similar, disease outcome remains worse in sporadic compared to fMTCs.

Metastatic lymph node ratio can further stratify risk for mortality in medullary thyroid cancer patients: A population-based analysis

Medullary thyroid cancer (MTC) has a propensity to cervical lymph node metastases (LNM). Recent studies have shown that both the number of involved lymph nodes (LNs) and the metastatic lymph node ratio (MLNR) confer prognostic information. This study was to determine the predictive value of MLNR on cancer-specific survival (CSS) in SEER (Surveillance, Epidemiology and End Results)-registered MTC patients treated with thyroidectomy and lymphadenectomy between 1991 and 2012, investigate the cutoff points for MLNR in stratifying risk of mortality and provide evidence for selection of appropriate treatment strategies. X-tile program determined 0.5 as optimal cut-off value for MLNR in terms of CSS in 890 MTC patients. According to multivariate Cox regression analysis, MLNR (0.50–1.00) is a significant independent prognostic factor for CSS (hazard ratio 2.161, 95% confidence interval 1.327–3.519, p=0.002). MLNR (0.50–1.00) has a greater prognostic impact on CSS in female, non-Hispanic white, T3/4, N1b and M1 patients. The lymph node yield (LNY) influences the effect of MLNR on CSS; LNY ≥9 results in MLNR (0.50–1.00) having a higher HR for CSS than MLNR (0.00-0.49). In conclusion, higher MLNRs predict poorer survival in MTC patients. Eradication of involved nodes ensures accurate staging and maximizes the ability of MLNR to predict prognosis.

Prognostic significance and optimal cutoff of age in medullary thyroid cancer

Age has been found to correlate with the prognosis for medullary thyroid cancer (MTC). This study was conducted to investigate whether age can predict long-term unfavorable prognosis and evaluate its predictive accuracy associated with TNM staging, using data of patients diagnosed with MTC between 2000 and 2010 from Surveillance, Epidemiology and End Results database. The relationship between the patients' age at diagnosis and cancer-specific survival (CSS) was evaluated using multivariate Cox regression analysis. Age stratifications were combined into a nomogram model to predict the CSS of MTC. The X-tile program determined 49 and 69 as optimal age cutoff values for CSS. On multivariate analysis, independent factors for survival were age (50-69 years, HR 2.853, 95% CI 1.631-4.991; ≥70 years, HR 5.804, 95% CI 2.91-11.555), race (white, HR 0.344, 95% CI 0.188-0.630), T (T3/4, HR 3.931, 95% CI 2.093-7.381), N (N1a, HR 3.269, 95% CI 1.386-7.710) and M (M1, HR 3.998, 95% CI 2.419-6.606). The C-index for CSS prediction with TNM, age (cutoff of 45)/sex/race/TNM and age (cutoff of 49 and 69)/sex/race/TNM were 0.832 (95% CI 0.763-0.901), 0.863 (95% CI 0.799-0.928), and 0.876 (95% CI 0.817-0.935), respectively. Subgroup multivariate analyses also showed that age significantly increased the risk for CSS in females, non-Hispanic white patients, and those with stage IV MTC. In conclusion, CSS was independently associated with ages between 49 and 69 years, which might be applied for risk stratification in MTC patients.

Postoperative biochemical remission of serum calcitonin is the best predictive factor for recurrence-free survival of medullary thyroid cancer: a large-scale retrospective analysis over 30 years

CONTEXT

The increase in thyroid screening in the general population may lead to earlier detection of medullary thyroid carcinoma (MTC).

OBJECTIVE

We aimed to evaluate secular trends in clinicopathological characteristics and long-term prognosis of MTC and its prognostic factors.

DESIGN

This was a retrospective analysis from 1982 to 2012.

PATIENTS

Three hundred and thirty-one patients with MTC were included and grouped based on the year of diagnosis (1982-2000, 2001-2005, 2006-2010 and 2011-2012).

MEASUREMENTS

These included recurrence and mortality as well as biochemical remission (BCR) of serum calcitonin.

RESULTS

Mean tumour size (from 2·5 cm to 1·7 cm, P < 0·001) and percentage of extrathyroidal extension (from 52·0% to 26·0%, P = 0·026) decreased. The percentage of patients achieving BCR within six postoperative months (po-BCR) increased with time (from 39·6% to 76·1%, P < 0·001). The 5-year overall recurrence rate significantly decreased in 2006-2012 compared to 1982-2005 (10% vs 18%, respectively, P = 0·031), although the 5-year survival rate did not improve (92% vs 92%, P = 0·929). Failure to achieve po-BCR was the strongest predictive factor associated with recurrence (hazard ratio [HR] = 58·04, 95% CI 7·14-472·11; P < 0·001). Male gender (HR = 3·18, 95% CI 1·18-8·56; P = 0·022), tumour size >2 cm (HR = 18·33, 95% CI 2·35-143·06; P = 0·006) and distant metastasis (HR = 4·00, 95% CI 1·31-12·21; P = 0·015) were significant prognostic factors for mortality.

CONCLUSIONS

Clinicopathological characteristics and recurrence of MTC improved with time. Po-BCR was the best predictive factor for recurrence-free survival.

Recurrent spinal metastasis of a sporadic medullary carcinoma of the thyroid after radiation therapy: a case report and review of the literature

Sporadic Medullary Carcinoma of the Thyroid is a relatively uncommon entity and at the time of diagnosis, most already present loco-regional metastasis. Therapy should be aggressive to reduce recurrence and mortality. Follow-up period should continue lifelong and should also include calcium/pentagastrin infusion test, as well as 6-month interval diagnostic imaging.

Small medullary thyroid carcinoma: post-operative calcitonin rather than tumour size predicts disease persistence and progression

OBJECTIVE

Recently, small medullary thyroid carcinomas (smallMTCs; ≤1.5 cm) are frequently diagnosed, occasionally as incidental findings in surgical specimens. Their clinical course varies. We examined tumour size as a predictor of clinical behaviour.

DESIGN

A retrospective study.

METHODS

A total of 128 smallMTC patients (35.2% males and 45% familial) were followed up for 0.9-30.9 years. According to tumour size (cm), patients were classified into four groups: group 1, 0.1-0.5 (n=33); group 2, 0.6-0.8 (n=33); group 3, 0.8-1.0 (n=29) and group 4, 1.1-1.5 (n=33).

RESULTS

Pre- and post-operative calcitonin levels were positively associated with the tumour size (P<0.001). Capsular and lymph node invasion were more frequent in groups 3 and 4 (P<0.03); the stage was more advanced and the outcome was less favourable with an increasing tumour size (P<0.001). Groups 1 and 2 patients were more frequently cured (group 1, 87.8%; group 2, 72.7%; group 3, 68.9%; and group 4, 48.5%; P=0.002). The 10-year probability of lack of disease progression according to the tumour size differed between patients with tumour sizes of 0.1-1.0 and 1.1-1.5 cm (96.6%, 81.3%, x(2)=4.03, P=0.045 for log-rank test). Post-operative calcitonin was the only predictor significantly associated with the 10-year progression of disease. Post-operative calcitonin levels ≥4.65 pg/ml predicted disease persistence (sensitivity 93.8% and specificity 90%) and ≥14.5 pg/ml predicted disease progression (sensitivity 100%, specificity 82%, receiver operating characteristic curve analysis).

CONCLUSIONS

Tumour size may be of clinical importance only in patients with MTCs >1 cm in size. Post-operative calcitonin is a more important predictor than size for disease progression.

Metachronous appearance of second malignancies in medullary thyroid carcinoma (MTC) patients: a diagnostic challenge and brief review of the literature

Medullary thyroid carcinoma (MTC) is a rare tumour which frequently occurs in the context of the multiple endocrine neoplasia syndromes, where it coexists with other usually benign tumours. The clinical picture varies and distant metastases are frequently present at diagnosis. Calcitonin levels are elevated in the presence of metastatic disease. Two MTC cases are presented, which had elevated postoperative calcitonin levels. Imaging revealed lung lesions which were originally attributed to metastatic disease from the MTC. However, at follow-up, these cases presented unusual features. The rapid increase in the lung lesions and the development of hypercalcaemia in the first patient suggested a second unrelated tumour. Biopsy of the lung lesion was compatible with lung adenocarcinoma. In the second patient, the appearance of a liver mass, although calcitonin levels remained stable, led to biopsy of the lesion: this was negative for calcitonin and compatible with metastatic lung adenocarcinoma. These MTC cases show that further malignancies may coexist with MTC and may obscure the clinical picture and influence the therapeutic decisions, especially in the case of metastatic disease. Features such as unusual imaging characteristics and the development of hypercalcemia, never encountered in MTC outside the MEN2 syndromes, as well as 'disproportionately' low calcitonin levels, incompatible with extensive metastatic disease, were the factors that led to further work-up. Both the cases subsequently proved to carry an unsuspected second malignancy. It is crucial to discriminate the metastatic lesion attributed to MTC from another coexisting primary malignancy, because different therapeutic strategies are needed for each setting.