A cut-off value of basal serum calcitonin for detecting macroscopic medullary thyroid carcinoma

Cytology versus calcitonin assay in fine-needle aspiration biopsy wash-out fluid (FNAB-CT) in diagnosis of medullary thyroid microcarcinoma

PURPOSE

Widespread use of sensitive ultrasound examination led to an increasing detection of medullary thyroid microcarcinoma (micro-MTC). This prospective study evaluated the diagnostic accuracy of Fine-needle Aspiration Biopsy Cytology (FNAB-C) and calcitonin assay in Fine-needle Aspiration Biopsy wash-out fluid (FNAB-CT) in thyroid nodules less than 1 cm with elevated serum calcitonin(sCT).

METHODS

87 thyroid nodules from 60 patients with elevated sCT (>10 pg/ml) were included and 51 were thyroid nodules less than 1cm. FNAB-CT and FNAB-C were performed to distinguish medullary thyroid carcinoma (MTC) lesions before surgery, histopathologic diagnoses served as main reference standards.

RESULTS

FNAB-CT had a greater performance over FNAB-C for preoperative diagnosis of MTC (diagnostic accuracy: 98.85 vs 61.90%, sensitivity: 98.55 vs 55.07%, specificity: 100 vs 97.44%), especially for micro-MTC: FNAB-C established a sensitivity and diagnostic accuracy of 48.78 and 58% respectively, while FNAB-CT reached 97.56% sensitivity and 98.04% diagnostic accuracy.

CONCLUSIONS

FNAB-CT demonstrated high diagnostic accuracy in diagnosing micro-MTC. Patients with microscopic thyroid nodules and elevated sCT level should perform FNAB-CT to exclude the diagnosis of MTC lesions.

Gender-Dependent Reference Range of Serum Calcitonin Levels in Healthy Korean Adults

BACKGROUND

Serum calcitonin measurement contains various clinical and methodological aspects. Its reference level is wide and unclear despite sensitive calcitonin kits are available. This study aimed to identify the specific reference range in the healthy Korean adults.

METHODS

Subjects were ≥20 years with available calcitonin (measured by a two-site immunoradiometric assay) data by a routine health checkup. Three groups were defined as all eligible subjects (group 1, n=10,566); subjects without self or family history of thyroid disease (group 2, n=5,152); and subjects without chronic kidney disease, autoimmune thyroid disease, medication of proton pump inhibitor/H2 blocker/steroid, or other malignancies (group 3, n=4,638).

RESULTS

This study included 6,341 male and 4,225 female subjects. Males had higher mean calcitonin than females (2.3 pg/mL vs. 1.9 pg/mL, P<0.001) in group 1. This gender difference remained similar in groups 2 and 3. Calcitonin according to age or body mass index was not significant in both genders. Higher calcitonin in smoking than nonsmoking men was observed but not in women. Sixty-nine subjects had calcitonin higher than the upper reference limit (10 pg/mL) and 64 of them had factors associated with hypercalcitoninemia besides medullary thyroid cancer. Our study suggests the reference intervals for men who were non, ex-, current smokers, and women (irrespective of smoking status) as <5.7, <7.1, <7.9, and <3.6 pg/mL, respectively.

CONCLUSION

Specific calcitonin reference range should be provided considering for sex and smoking status. Taking account for several factors known to induce hypercalcitoninemia can help interpret the gray zone of moderately elevated calcitonin.

Cytologic diagnosis of medullary thyroid carcinoma in the Asia-Pacific region

BACKGROUND

The accurate preoperative identification of medullary thyroid carcinoma (MTC) is challenging due to the rarity of tumor and variable cytologic appearance. The Asian experience with diagnosing MTC by fine-needle aspiration (FNA) was scarcely reported.

METHODS

Cases of MTC with available FNA slides were enrolled from 13 hospitals representing 8 Asia-Pacific countries. Clinicopathological information, including sample preparation technique, staining method, original cytologic diagnosis and review diagnosis were collected.

RESULTS

Of a total of 145 MTC cases retrospectively recruited, 99 (68.3%) were initially interpreted as MTC/suspicious for MTC (S-MTC). The distribution of original FNA diagnostic categories was not associated with the staining method or sample preparation technique. The staining methods used were Papanicolaou, hematoxylin-eosin and Romanowsky stains. Liquid-based cytology (LBC) was used only in three countries. After reviewing all cases, the diagnostic rate of MTC/S-MTC increased to 91.7% (133/145). Cases with initially unrecognized MTC had either marked pleomorphism or cytology mimicking papillary carcinoma or follicular neoplasm. Although LBC provided certain benefits, there was no significant difference in diagnostic accuracy between conventional smear and LBC. Immunocytochemistry was available in 38 cases (26.2%), all of which were correctly recognized as MTC.

CONCLUSION

Our report summarizes how MTC is handled in contemporary Asian thyroid FNA practice. Although the detection rate of MTC by cytology alone is less satisfactory, integration with ancillary tests could achieve an excellent performance. The recognition of constitutive cytomorphologic features is needed for each cytopreparatory method, which may result in a lower threshold to initiate further workup for MTC.

Medullary Thyroid Carcinoma: Why Is Specialization Mandatory?

Medullary thyroid carcinoma (MTC) represents a distinct form of thyroid cancer with a potentially aggressive behavior, early lymph node metastases, and sporadic as well as hereditary forms. Only surgery with total thyroidectomy and lymph node dissection is able to achieve biochemical cure. Due to the uncommon nature of MTC, a specialization in endocrine surgery for diagnosis as well as therapy of MTC seem to be mandatory for a successful treatment. Knowledge of genotype-phenotype correlations for hereditary forms or routine calcitonin screening for sporadic forms is important to analyze preoperative findings and plan surgical procedures. Postoperative follow-up depends on biochemical cure or monitoring for patients with elevated calcitonin levels.

Preoperative Clinical and Sonographic Predictors for Lateral Cervical Lymph Node Metastases in Sporadic Medullary Thyroid Carcinoma

BACKGROUND

Total thyroidectomy and cervical lymph node (LN) dissection is generally recommended in patients with medullary thyroid carcinoma (MTC). However, there is no clear evidence for whom to perform prophylactic lateral neck dissection in MTC patients without evident lateral cervical lymph node (LCLN) metastasis in preoperative images. This study evaluated the preoperative features for predicting the LCLN metastasis of MTC.

METHODS

The study included 26 MTC patients with LCLN metastasis at initial surgery (N1b group) and 47 MTC patients without any LN metastasis or recurrence of disease (N0-NED group). The association between LCLN metastasis and preoperative clinical and sonographic characteristics (size, location, solid component, shape, margin, echogenicity, calcification, and subcapsular location of the tumor) were evaluated.

RESULTS

There were no significant differences in age and sex between the N1b and N0-NED groups. Preoperative serum levels of calcitonin >65 pg/mL were associated with LCLN metastasis (p < 0.001). In preoperative neck ultrasonography (US), patients in the N1b group were more commonly found with a larger tumor (>1.5 cm) of irregular shape with a spiculated margin and a subcapsular location than those in the N0-NED group (p = 0.029, p < 0.001, p < 0.001, and p < 0.001, respectively). Increases in the number of these LCLN metastasis-related features were significantly associated with higher risk for LCLN metastasis (p < 0.001). The presence of two or more predictors was an appropriate cutoff point for predicting LCLN metastasis of MTC with 73.1% sensitivity and 91.5% specificity.

CONCLUSIONS

MTC tumors with high preoperative calcitonin levels (>65 pg/mL), larger size (>1.5 cm), irregular shape, spiculated margins, and subcapsular locations in the neck US are at higher risk for LCLN metastasis. MTC patents with fewer than two predictors might be suitable for treatment without prophylactic LCLN dissection.

Detection of Biosynthetic Precursors, Discovery of Glycosylated Forms, and Homeostasis of Calcitonin in Human Cancer Cells

The peptide hormone calcitonin is intimately connected with human cancer development and proliferation. Its biosynthesis is reasoned to proceed via glycine-, α-hydroxyglycine-, glycyllysine-, and glycyllysyllysine-extended precursors; however, as a result of the limitations of current analytical methods, until now, there has been no procedure capable of detecting these individual species in cell or tissue samples. Therefore, their presence and dynamics in cancer had not been established. Here, we report the first methodology for the separation, detection, and quantification of calcitonin and each of its precursors in human cancer cells. We also report the discovery and characterization of O-glycosylated calcitonin and its analogous biosynthetic precursors. Through direct and simultaneous analysis of the glycosylated and nonglycosylated species, we interrogate the hormone biosynthesis. This shows that the cellular calcitonin level is maintained to mitigate effects of biosynthetic enzyme inhibitors that substantially change the proportions of calcitonin-related species released into the culture medium.

Ultrasonography features of medullary thyroid cancer as predictors of its biological behavior

Background Although there are many well-known prognostic predictors of medullary thyroid carcinoma (MTC), the ultrasonography (US) findings of MTC have not been sufficiently validated in this regard. Purpose To investigate the US findings of MTC and their relationship with the biological behavior of MTC. Material and Methods The US findings and clinical and pathology records of 123 MTC nodules from 108 patients were retrospectively analyzed at two tertiary referral hospitals. MTCs were classified according to US findings, i.e. MTC with benign (B-MTC) and malignant US findings (M-MTC). We then compared the clinical and pathology findings between the two groups. Results Eighty-two M-MTCs (66.7%) and 41 B-MTCs (33.3%) were identified. M-MTCs showed a significantly higher prevalence of lateral lymph node metastases as well as extrathyroidal and extranodal extension (all P < 0.05). M-MTCs larger than 1 cm showed a significantly higher prevalence of multifocality, recurrence, extrathyroidal and extranodal extension than B-MTCs larger than 1 cm in the largest dimension (all P < 0.05). Tumors > 1 cm were more likely to be B-MTC and one-third of all MTCs had benign US features. The common findings of B-MTC included a solid, ovoid to round shape, with a smooth margin, hypoechogenicity, and without calcification. Conclusion The biological behavior of M-MTCs results in poorer outcomes than that of B-MTCs.

Routine calcitonin measurement in nodular thyroid disease management: is it worthwhile?

PURPOSE

To evaluate the diagnostic accuracy of routine calcitonin measurement in patients with nodular thyroid disease.

METHODS

Consecutive patients with nodular thyroid disease (n = 640) were studied. Serum calcitonin levels were measured under basal conditions, and when basal values were between 10-100 pg/mL, testing was repeated after pentagastrin (PG) stimulation. Patients with previously diagnosed or familial medullary thyroid cancer (MTC) were excluded. Patients were operated on when basal or stimulated calcitonin >100 pg/mL or when other surgical indications were present.

RESULTS

Four cases of MTC were identified. MTC was diagnosed in 75% of patients with basal calcitonin >100 pg/mL. One out of 11 patients with basal calcitonin between 10-100 pg/mL was diagnosed with MTC. PG stimulation resulted in elevation in 4 cases, where 1 case was diagnosed with MTC. Positive predictive value for basal calcitonin levels in the preoperative diagnosis of MTC was 5% for values between 10-100 pg/mL and 100% for values >100 pg/mL. Possible reasons for false positivity were papillary thyroid cancer in 17%, renal insufficiency in 8.3%, Hashimoto thyroiditis in 17% and β-blocker use in 33%. Positive predictive value for the PG test (>100 pg/mL) was 25% in the entire series. The cost of adding calcitonin measurement (±PG stimulation) to the preoperative work-up, resulted in €912.68 per MTC patient to detect the disease.

CONCLUSION

Basal calcitonin measurement together with PG stimulation in cases of basal calcitonin >10 pg/mL detects MTC in 0.62% of patients with nodular thyroid disease.

Molecular Diagnosis Using Residual Liquid-Based Cytology Materials for Patients with Nondiagnostic or Indeterminate Thyroid Nodules

BACKGROUND

Molecular analysis for common somatic mutations in thyroid cancer can improve diagnostic accuracy of fine-needle aspiration cytology (FNAC) in the nondiagnostic or indeterminate category of thyroid nodules. In this study, we evaluated the feasibility of molecular diagnosis from residual liquid-based cytology (LBC) material after cytological diagnosis.

METHODS

This prospective study enrolled 53 patients with thyroid nodules diagnosed as nondiagnostic, atypia of undetermined significance (AUS), or follicular lesion of undetermined significance (FLUS) after FNAC. DNAs and RNAs were isolated from residual LBC materials. BRAF(V600E) and RAS point mutations, PAX8/peroxisome proliferator-activated receptor γ (PPARγ), RET/PTC1, and RET/PTC3 rearrangements were evaluated by real-time polymerase chain reaction and pyrosequencing.

RESULTS

All DNAs from 53 residual LBC samples could be analysed and point mutations were detected in 10 samples (19%). In 17 AUS nodules, seven samples (41%) had point mutations including BRAF (n=4), NRAS (n=2), and KRAS (n=1). In 20 FLUS nodules, three samples (15%) had NRAS point mutations. RNA from only one FLUS nodule could be analysed for rearrangements and there was no abnormality.

CONCLUSION

Molecular analysis for BRAF and RAS mutations was feasible in residual LBC materials and might be useful for diagnosis of indeterminate thyroid nodules.

Dynamic risk stratification for medullary thyroid cancer according to the response to initial therapy

Detecting persistent/recurrent disease of medullary thyroid carcinoma (MTC) is important. The tumor-node-metastasis (TNM) staging system is useful for predicting disease-specific mortality, but is a static system and does not include postoperative serum calcitonin levels. We have focused on the clinical usefulness of dynamic risk stratification (DRS) using the best response to the initial therapy in MTC patients. A total of 120 MTC patients were classified into three DRS groups based on their responses to initial therapy. Clinical outcomes were assessed according to TNM staging and DRS. In the DRS, 70, 23 and 7 % of the MTC patients were classified into excellent, biochemical incomplete, or structural incomplete response groups, respectively. On TNM staging, 37, 16, 13 and 35 % of patients were stages I-IV, respectively. There were significant differences in survivals according to TNM staging (p = 0.03) and DRS (p = 0.005). During the median follow-up of 6.2 years, 75 patients (63 %) demonstrated no evidence of disease (NED). About 60 and 17 % of patients in stages III and IV were NED, respectively. DRS predicted NED better than TNM staging according to the proportion of variance explained (PVE) (49.1 vs. 28.7 %, respectively). At the final follow-up, 88, 4 and 0 % of patients in excellent, biochemical incomplete, and structural incomplete response groups attained NED, respectively. DRS based on the best response to the initial therapy can provide useful prognostic information in addition to initial TNM staging for predicting of mortality, as well as the likelihood of NED in MTC patients.

Changing trends in the clinicopathological features and clinical outcomes of medullary thyroid carcinoma

BACKGROUND

The early detection of papillary thyroid cancer has contributed to the increase in the incidence and improved clinical outcomes. However, recent changes of medullary thyroid carcinoma (MTC) over time remain unclear. We evaluated changes of the clinicopathological characteristics and clinical outcomes in patients with MTC in recent years.

METHODS

A total of 109 MTC patients were classified based on the year of initial surgery: 1996-2000 (n = 14), 2001-2006 (n = 39), and 2007-2011 (n = 56).

RESULTS

The primary tumor size significantly decreased and the proportion of microMTCs (size ≤1 cm) increased over time (P = 0.002 and P < 0.001, respectively). The proportion of patients with cervical lymph node (LN) metastasis significantly decreased (P = 0.037), and the ratio of metastatic LNs significantly decreased (P = 0.011). Disease-free survival (DFS) rate of patients was significantly improved over time (P = 0.007). There was no significant difference in DFS between microMTC and macroMTC patients. However, more advanced LN stage patients demonstrated more recurrences (P < 0.001). Especially, there were significantly more recurrences in patients with N1b diseases in comparison with patients without cervical LN metastases (P < 0.001).

CONCLUSIONS

The prognosis of MTC patients has significantly improved in recent years. These changes could be associated with the early diagnosis before development of lateral and extensive cervical LN metastases. J. Surg. Oncol. 2016;113:152-158. © 2015 Wiley Periodicals, Inc.

Translational progress on tumor biomarkers

There is an urgent need to apply basic research achievements to the clinic. In particular, mechanistic studies should be developed by bench researchers, depending upon clinical demands, in order to improve the survival and quality of life of cancer patients. To date, translational medicine has been addressed in cancer biology, particularly in the identification and characterization of novel tumor biomarkers. This review focuses on the recent achievements and clinical application prospects in tumor biomarkers based on translational medicine.