Sentinel lymph node mapping: current applications and future perspectives in thyroid carcinoma

Sentinel lymph node (SLN) mapping is a standard, minimally-invasive diagnostic method in the surgical treatment of many solid tumors, as for example melanoma and breast cancer, for detecting the presence of regional nodal metastases. A negative SLN accurately indicates the absence of metastases in the other regional lymph nodes (LN), thus avoiding unnecessary lymph nodal dissection. Papillary thyroid carcinoma (PTC) is the most common type of thyroid carcinoma (TC) with cervical LN metastases at diagnosis in 20-90%, and nodal involvement correlates with local persistence/recurrence. The SLN in PTC is an intraoperative method for staging preoperative N0 patients and for detecting metastatic LNs "in and outside" the cervical LN central compartment; it represents an alternative method to prophylactic central neck node dissection. In this review we summarize different methods and results of the use of SLN in TC. The SLN identification techniques currently used include the selective vital-dye (VD) method, 99mTc-nanocolloid planar lymphoscintigraphy with intraoperative use of a hand-held gamma probe (LS), the combination LS + VD, and the combination LS and preoperative SPECT-CT (LS + SPECT/CT). The application of the SLN procedure in TC has been described in many studies, however, the techniques are heterogeneous, and the role of SLN in TC, with indications, results, advantages and limits, is still debated.

Role of one-step nucleic acid amplification in colorectal cancer lymph node metastases detection

Current histopathological staging procedures in colorectal cancer (CRC) depend on midline division of the lymph nodes (LNs) with one section of hematoxylin and eosin staining. Cancer cells outside this transection line may be missed, which could lead to understaging of Union for International Cancer Control Stage II high-risk patients. The one-step nucleic acid amplification (OSNA) assay has emerged as a rapid molecular diagnostic tool for LN metastases detection. It is a molecular technique that can analyze the entire LN tissue using a reverse-transcriptase loop-mediated isothermal amplification reaction to detect tumor-specific cytokeratin 19 mRNA. Our findings suggest that the OSNA assay has a high diagnostic accuracy in detecting metastatic LNs in CRC and a high negative predictive value. OSNA is a standardized, observer-independent technique, which may lead to more accurate staging. It has been suggested that in stage II CRC, the upstaging can reach 25% and these patients can access postoperative adjuvant chemotherapy. Moreover, intraoperative OSNA sentinel node evaluation may allow early CRC to be treated with organ-preserving surgery, while in more advanced-stage disease, a tailored lymphadenectomy can be performed considering the presence of aberrant lymphatic drainage and skip metastases.

Sentinel lymph node biopsy in papillary thyroid cancer: Accuracy and application in clinical practice

INTRODUCTION

The presence of lymph nodes metastasis in papillary thyroid cancer (PTC) modifies the type of surgical resection as well as the indication of the treatment with I¹³¹ in the postoperative period. This therapeutic approach is based on the results of the diagnostic tests, like the cervical ultrasonography. Currently other methods of diagnostic are tested as selective sentinel lymph node biopsy (SLNB). It can complement to the ultrasound results. The aim was to validate the SLNB for use in the diagnosis of lymph node metastasis by papillary thyroid cancer.

METHODS

Observational prospective cohort study of 55 patients who underwent PTC without suspicion of lymph node involvement clinical or radiological, since February 2012 through February 2015, with a follow-up between 6 and 8 years. It was used ⁹⁹Tc with intratumoral nanocoloid and a portable tube of the gamma camera for the detection of the sentinel node (SN).

VARIABLES

age, gender, histological, analytical and preoperative and postoperative staging. The sensitivity, specificity and predictive values of technique was calculated. The validation was determined by calculating the detectability and the false negative results of the test.

RESULTS

53 of the 55 patients (96,36%) there was the SN detection. The FN were 4 patients (7,5%). Of the rest, after applying the SLNB, 24 (48,9%) were kept as N0, 14 (28,5%) became N1a and 11 (22,4%) were classified as N1b. The differences observed in the study were significant (P < ,05). The sensitivity was 86,21%, the specificity of 100%, the PPV was 100% and the NPV of 85.71%. The diagnostic accuracy of 92,45%.

CONCLUSION

The SLNB is a valid technique for use in patients suffering from papillary thyroid cancer with a high diagnostic accuracy.

Clinical significance of sentinel lymph node biopsy in differentiated thyroid cancer

Differentiated thyroid cancers are the most common endocrine malignancy and include three main entities: papillary thyroid carcinoma (PTC), follicular thyroid carcinoma (FTC), and Hürthle cell carcinoma (HCC). Papillary thyroid cancer (PTC) is the most common histologic subtype. Was to review different sentinel lymph node biopsy (SLNB) techniques in patients with differentiated thyroid cancer. We also will compare the detection rates and sensitivity of the different detection methods in these patients and assessment of feasibility and side effects of the different techniques. This study was a cross sectional study, Surgical Oncology Department of National Cancer Institute, Cairo University and Damietta Cancer Center, Ministry of Health and Population. Radionuclide technique (lymphoscintigraphy and gamma probe scanning) was successful in 94.6 % (35/37) of the patients as shown in table 4 and relation between SLN and identification by gamma probe. In the 37 patients, the intraoperative frozen biopsy indicated that 22 patients were experiencing SLN metastases, while post-operative routine pathological examination was able to diagnose three additional patients with lymph node metastases. 

Sentinel lymph node biopsy in papillary thyroid cancer: Accuracy and application in clinical practice

INTRODUCTION

The presence of lymph nodes metastasis in papillary thyroid cancer modifies the type of surgical resection as well as the indication of the treatment with 131I in the postoperative period. This therapeutic approach is based on the results of the diagnostic tests, like the cervical ultrasonography. Currently other methods of diagnostic are tested as selective sentinel lymph node biopsy (SLNB). It can complement to the ultrasound results. The aim was to validate the SLNB for use in the diagnosis of lymph node metastasis by papillary thyroid cancer.

METHODS

Observational prospective cohort study of 55 patients who underwent papillary thyroid cancer without suspicion of lymph node involvement clinical or radiological, since February 2012 through February 2015, with a follow-up between 6 and 8 years. It was used 99Tc with intratumoral nanocoloid and a portable tube of the gamma camera for the detection of the sentinel node.

VARIABLES

age, gender, histological, analytical and preoperative and postoperative staging. The sensitivity, specificity and predictive values of technique was calculated. The validation was determined by calculating the detectability and the false negative results of the test.

RESULTS

In 53 of the 55 patients (96.36%) there was the sentinel node detection. The false negative were 4 patients (7.5%). Of the rest, after applying the SLNB, 24 (48.9%) were kept as N0, 14 (28.5%) became N1a and 11 (22.4%) were classified as N1b. The differences observed in the study were significant (P<.05). The sensitivity was 86.21%, the specificity of 100%, the PPV was 100% and the NPV of 85.71%. The diagnostic accuracy was 92.45%.

CONCLUSIONS

The SLNB is a valid technique for use in patients suffering from papillary thyroid cancer with a high diagnostic accuracy.

Lymphatic Drainage Mapping with Indirect Lymphography for Canine Mammary Tumors

Simple Summary

Mammary gland tumours are the most common canine neoplasms. They account for 25–50% of all tumors diagnosed in bitches. Metastases and recurrences develop in about 35–70% of bitches following excision. The presence of regional lymph node metastases is a relevant factor affecting prognosis and treatment in cases of mammary gland tumors. The sentinel lymph node (SLN) is the first lymph node (or nodes) in the regional lymphatic basin that receives lymphatic flow from the primary neoplasm. As mammary gland tumors mainly spread by lymphatic vessels invasion, conceptually, distant metastasis should not be present if the SLN does not have evidence of a tumor burden. In the present study, an indirect lymphography was used for sentinel lymph node mapping in a cohort of 14 adult female dogs with 24 mammary tumors involving the third to the fifth mammary gland. Contrast was injected around the mammary tumor, and lymph nodes that picked up the contrast were visible after 24 h. The results of this study indicate that the lymph drainage pattern of the neoplastic mammary gland may be different for each tumor. The knowledge of the SLN of the neoplastic mammary glands should be of high importance for the surgeon not only for performing the most adequate surgical excision but also for determining an accurate post-surgical prognosis.

Abstract

Mammary gland tumors are the most common canine neoplasms. They account for 25–50% of all tumors diagnosed in bitches. Metastases and recurrences develop in about 35–70% of bitches following excision. The presence of regional lymph node metastases is a relevant factor affecting prognosis and treatment in cases of mammary gland tumors. The sentinel lymph node (SLN) is the first lymph node (or nodes) in the regional lymphatic basin that receives lymphatic flow from the primary neoplasm. The aim of this study is to investigate the SLN with indirect lymphography for a mammary tumor in dogs. The knowledge of the precise drainage pattern and SLN of the neoplastic mammary glands would provide clinically relevant information to the surgeon and to the oncologist, and it would be of high importance for the surgeon not only for performing the most adequate surgical excision but also for determining an accurate post-surgical prognosis.

The evolving role of one-step nucleic acid amplification (OSNA) for the intra-operative detection of lymph node metastases: A diagnostic accuracy meta-analysis

BACKGROUND

One Step Nucleic Acid Amplification (OSNA) assay has recently emerged as a rapid molecular diagnostic tool for the detection of lymph node (LN) metastases. It is a molecular technique that analyses the entire LN tissue using a reverse-transcriptase loop-mediated isothermal amplification reaction to detect tumour specific cytoceratin 19 mRNA.

AIM

To ascertain the diagnostic accuracy of OSNA assay in detecting LN metastases amongst different types of malignancy.

DESIGN

We systematically searched MEDLINE, SCOPUS, ClinicalTrials.gov, and Cochrane Database, from inception up to August 2020. Quality assessment was performed using the Modified Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2). We calculated pooled diagnostic indices using the random-effects model. Meta-regression and sub-group analyses were performed to address heterogeneity.

RESULTS

31 studies were included in this meta-analysis, including four different types of cancer. The risk of bias and the overall quality of included studies was moderate to high. There was no evidence of publication bias. The pooled diagnostic odds ratio (DOR) for detecting LN metastases in gynaecological, head & neck/thyroid, gastrointestinal and lung cancer were 100.38, 76.17, 275.14, and 305.84, respectively.

CONCLUSIONS

Our findings suggest that OSNA assay had a high diagnostic accuracy in detecting metastatic LNs in different types of malignancy. This evidence is constrained by the limited studies available for few tumour types and the rather high heterogeneity for few outcomes.

Management of the Neck in Well-Differentiated Thyroid Cancer

PURPOSE OF REVIEW

In this narrative review, we discuss the indications for elective and therapeutic neck dissections and the postoperative surveillance and treatment options for recurrent nodal disease in patients with well-differentiated thyroid cancer.

RECENT FINDINGS

Increased availability of advanced imaging modalities has led to an increased detection rate of previously occult nodal disease in thyroid cancer. Nodal metastases are more common in young patients, large primary tumors, specific genotypes, and certain histological types. While clinically evident nodal disease in the lateral neck compartments has a significant oncological impact, particularly in the older age group, microscopic metastases to the central or the lateral neck in well-differentiated thyroid cancer do not significantly affect outcome. As patients with clinically evident nodal disease are associated with worse outcomes, they should be treated surgically in order to reduce rates of regional recurrence and improve survival. The benefit of elective neck dissection remains unverified as the impact of microscopic disease on outcomes is not significant.

Prophylactic central node dissection in differentiated thyroid cancer: A prospective tertiary care center experience

BACKGROUND

With increasing incidence of thyroid carcinoma, the optimal management of central lymph nodes remains an unanswered question although central neck nodes represent the most common site of recurrence. The aim of this study was to determine the morbidity of prophylactic central neck dissection in differentiated thyroid cancer and to evaluate histopathological correlation between nodal metastases and histological features.

METHOD

This was a prospective, observational study of 2 years duration (May 2017 to May 2019) involving 30 patients with proven differentiated thyroid cancers and clinicoradiologically negative lymph node with no history of neck surgeries. They all underwent total thyroidectomy with bilateral central neck dissection. Surgical outcomes in the form of transient or permanent hypoparathyroidism, transient and permanent recurrent nerve palsy were assessed along with histopathological correlation of primary tumor with central node positivity.

DISCUSSION

Classical histology (p = 0.05), >4 cm tumor size (p = 0.04), lymphovascular invasion (p = 0.04) and multifocality (p = 0.04) were all significantly associated with increased risk of central lymph nodal metastasis. The incidence of transient and permanent hypoparathyroidism was 36.3% and 10% respectively. Metastatic lymph node ratio of >60% is significantly associated with increased preablative serum thyroglobulin levels. Around 35% of the pT1 or T2 lesions were upstaged for postoperative radioiodine ablation CONCLUSION: An important role of prophylactic central neck dissection may lie in male patients, age > 45years, tumor size >4 cm, extrathyroidal extension, lymphovascular invasion and multifocality in accurate staging and can be performed with minimal morbidity at a high volume center.

Prophylactic lymph node dissection in clinically N0 differentiated thyroid carcinoma: example of personalized treatment

Considering the 'differentiated thyroid carcinoma (DTC) epidemic', the indolent nature of DTC imposes a treatment paradigm shift toward elimination of recurrence. Lymph node metastases in cervical compartments, encountered in 20-90% of DTC, are the main culprit of recurrent disease, affecting 5-30% of patients. Personalized risk-stratified cervical prophylactic lymph node dissection (PLND) at initial thyroidectomy in DTC with no clinical, sonographic or intraoperative evidence of lymph node metastases (clinically N0) has been advocated, though not unanimously. The present review dissects the controversy over PLND. Weighing the benefit yielded from PLND up against the PLND-related morbidity is so far hampered by the inconsistent profit yielded by PLND and the challenging patient selection. Advances in tailoring PLND are anticipated to empower optimal patient care.

The American Association of Endocrine Surgeons Guidelines for the Definitive Surgical Management of Thyroid Disease in Adults

OBJECTIVE

To develop evidence-based recommendations for safe, effective, and appropriate thyroidectomy.

BACKGROUND

Surgical management of thyroid disease has evolved considerably over several decades leading to variability in rendered care. Over 100,000 thyroid operations are performed annually in the US.

METHODS

The medical literature from 1/1/1985 to 11/9/2018 was reviewed by a panel of 19 experts in thyroid disorders representing multiple disciplines. The authors used the best available evidence to construct surgical management recommendations. Levels of evidence were determined using the American College of Physicians grading system, and management recommendations were discussed to consensus. Members of the American Association of Endocrine Surgeons reviewed and commented on preliminary drafts of the content.

RESULTS

These clinical guidelines analyze the indications for thyroidectomy as well as its definitions, technique, morbidity, and outcomes. Specific topics include Pathogenesis and Epidemiology, Initial Evaluation, Imaging, Fine Needle Aspiration Biopsy Diagnosis, Molecular Testing, Indications, Extent and Outcomes of Surgery, Preoperative Care, Initial Thyroidectomy, Perioperative Tissue Diagnosis, Nodal Dissection, Concurrent Parathyroidectomy, Hyperthyroid Conditions, Goiter, Adjuncts and Approaches to Thyroidectomy, Laryngology, Familial Thyroid Cancer, Postoperative Care and Complications, Cancer Management, and Reoperation.

CONCLUSIONS

Evidence-based guidelines were created to assist clinicians in the optimal surgical management of thyroid disease.

Sentinel lymph node biopsy in medullary thyroid microcarcinomas

The aim of this prospective study was to analyze accuracy of sentinel lymph node biopsy with methylene blue dye for intraoperative detection of lateral metastases in clinically N0M0 medullary microcarcinomas with calcitonin <1,000 pg/mL and selection of true-positive patients for one-time therapeutic lateral dissection. In addition to total thyroidectomy and central neck dissection, all patients had bilateral sentinel biopsy of jugulo-carotid regions after methylene blue injection to decide upon necessity for lateral dissection. If sentinels were benign on frozen section, additional non-sentinels were extirpated, with no further lateral dissection. If sentinels were malignant, one-time lateral dissection was performed. 20 patients were included in this study. Hereditary disease form was observed in 3/20 (15%) of patients with RET proto-oncogene mutation C634F; remaining 17/20 (85%) were negative for germline mutations. There were no allergic reactions to methylene blue and identification rate of sentinels was 100%. In total, 2/20 (10%) cN0 patients had lymphonodal metastases, thus were reclassified as pN1b. Remaining 18/20 (90%) were classified pN0 based on standard pathohistology. Frozen section findings on sentinels were 100% match with standard pathohistology, and there were no skip metastases in lateral compartments. Sensitivity, specificity and accuracy of sentinel biopsy method with methylene dye and frozen section were 100%. Dzodic's sentinel lymph node biopsy method can be used for intraoperative assessment of lateral compartments and optimization of initial surgery of medullary microcarcinomas with calcitonin <1,000 pg/mL. This way, cN0 patients with sentinel metastases can receive one-time lateral dissection, and those without benefit from less extensive surgery.

The sentinel lymph node biopsy technique in papillary thyroid carcinoma: The issue of false-negative findings

BACKGROUND

The management of papillary thyroid carcinoma (PTC) is changed after introduction of sentinel lymph node biopsy (SNB) technique for nodal staging. Some debate still surrounds the accuracy of this procedure in terms of wide heterogeneity of sentinel lymph node detection and false-negative findings.

AIM

to identify the key issues which make it difficult the usefulness of SNB in PTC.

METHODS

A comprehensive computer literature search of meta-analyses published in PubMed/MEDLINE and Cochrane library database until June 30, 2019 was conducted. We used a search algorithm based on this combination of terms: (i) "thyroid neoplasm" or "thyroid cancer" or "thyroid carcinoma" or "thyroid malignancy" or "meta-analysis" or "systematic review") AND (ii) "sentinel lymph node biopsy".

RESULTS

Comparing 4 written meta-analyses published in the literature, the diagnostic performance of SNB technique in PTC has been summarized. Relatively high false-negative rates (FNR) were reported for each SNB methods: vital-dye (VD: 12.7%; 7%; 0-38%), 99mTc-nanocolloid planar lymphoscintigraphy with the use of intraoperative hand-held gamma probes (LS: 11.3%; 16%; 0-40%), combined LS with VD (LS+VD: 0%; 0-17%), LS with the additional contribution of preoperative SPECT/CT (7-8%).

CONCLUSION

Evidence-based data about the diagnostic performance of SNB in PTC are increasing. The nuclear medicine community should reach a consensus on the operational definition of the SLN to better guide the surgeon in identifying the lymph nodes most likely contain metastatic cells. Standardization of SLN identification, removal and analysis are required.

Clinical feasibility of imaging with indocyanine green combined with carbon nanoparticles for sentinel lymph node identification in papillary thyroid microcarcinoma

BACKGROUND

Although several previous studies demonstrated the feasibility and efficacy of indocyanine green (ICG) for thyroid cancer surgery, ICG was administered through venous injection and focused on parathyroid gland protection. We thus aimed to study the feasibility of imaging using ICG combined with carbon nanoparticles (CNs) in the identification of sentinel lymph nodes (SLNs) in patients diagnosed with papillary thyroid microcarcinoma (PTMC).

METHODS

Two approaches were applied to detect lymph nodes in PTMC surgery. Patients were randomized into 2 groups. ICG and CNs were injected into the thyroid in Group A. In Group B, only CNs was injected. Black-stained or fluorescent nodes observed using near-infrared fluorescence imaging systems were defined as SLNs. SLN and central lymph node (CLN) dissection was completed in both groups. The pathological and postoperative outcomes were compared between 2 groups.

RESULTS

There were 40 patients in Group A and 60 in Group B. A total of 138 SLNs were identified; 72 and 66 SLNs were detected and dissected in Groups A and B, respectively. The number of SLNs identified (per patient) in Group A was higher than that in Group B (P = .027). The number of harvested CLNs was 161 and 192 in Groups A and B, respectively, out of which 45 and 48 lymph nodes with metastasis were confirmed by permanent pathology. The CLN metastatic rate in Group A was higher than that in Group B (P = .048).

CONCLUSION

Imaging using ICG combined CNs is feasible and safe for SLN identification in PTMC patients. Compared with using only CNs, more SLNs can be removed and more metastatic lymph nodes can be confirmed when using the combined method. Although the combined method appears to accurately stage tumors, further research is needed.

Nonselective Lymph Node Dissection and Sentinel Lymph Node Mapping and Biopsy

Clinical staging is important for determining the extent of disease in animals with malignant cancers. The status of the lymph node will help determine whether adjuvant treatment is indicated. Historically, the regional anatomic lymph node has been sampled to determine the presence or absence of metastatic disease, but there is increasing evidence that the regional anatomic lymph node is often different to the sentinel lymph node. As a result, several sentinel lymph node mapping techniques have been described for more accurate clinical staging of oncologic patients.

Sentinel Lymph Node Biopsy in Small Papillary Thyroid Cancer: A Meta-analysis

PURPOSE

The aim of this study was to compare reported results on available techniques for sentinel lymph node detection rate (SDR) in papillary thyroid cancer (PTC).

METHODS

The MEDLINE database was searched via a PubMed interface to identify original articles regarding sentinel lymph node biopsy (SNB) in thyroid cancer. Studies were stratified according to the sentinel lymph node (SLN) detection technique: vital-dye (VD), Tc-nanocolloid planar lymphoscintigraphy with the use of intraoperative hand-held gamma probes (LS), both Tc-nanocolloid planar lymphoscintigraphy with intraoperative use of hand-held gamma probe and VD (LS + VD), Tc-nanocolloid planar lymphoscintigraphy with the additional contribution of preoperative SPECT/CT, and intraoperative use of hand-held gamma probe (LS-SPECT/CT). Pooled SDR values were presented with a 95% confidence interval (CI) for each SLN detection techniques. A Z-test was used to compare pooled SDR estimates. False-negative rates were summarized for each method.

RESULTS

Forty-five studies were included. Overall SDRs for the VD, LS, LS + VD, and LS-SPECT/CT techniques were 83% (95% CI, 77%-88%; I = 78%), 96% (95% CI, 90%-98%; I = 68%), 87% (95% CI, 65%-96%; I = 75%), and 93% (95% CI, 86%-97%; I = 0%), respectively. False-negative rates were 0% to 38%, 0% to 40%, 0% to 17%, and 7% to 8%, respectively.

CONCLUSIONS

In patients with PTC, Tc-nanocolloids offer a higher SDR than that of the VD technique. The addition of SPECT/CT improved identification of metastatic SLNs outside the central neck compartment.

Sentinel lymph node biopsy in small papillary thyroid cancer. A review on novel surgical techniques

PURPOSE

Sentinel lymph node biopsy (SNB) in patients with papillary thyroid carcinoma (PTC) and negative for clinically neck lymph node metastatic involvement (N0) has emerged as a promising minimally invasive procedure to detect metastatic nodes.

METHODS

The MEDLINE database was searched via the PubMed interface on 10 January 2018 for the MeSH headings "sentinel lymph node biopsy" and "thyroid carcinoma".

RESULTS

Vital blue dye, radioisotope, and the combination of both techniques are used in PTC patients. These methods and the emerging role of SPECT/CT are discussed in this review. The sentinel lymph node (SLN) identification rates ranged from 0 to 100% for blue dye, 83 to 100% for radioisotopes, and 66 to 100% for the combination of both techniques, respectively.

CONCLUSIONS

SNB based on radioisotope technique with the use of intraoperative gamma-probe is an accurate and safe method that allows the highest SLN detection rate. There is sufficient evidence to propagate the increasing use of SNB procedure that has the potential to avoid prophylactic lymph node surgery in patients clinically N0.

Applicability of sentinel lymph node biopsy in papillary thyroid cancer

BACKGROUND

The optimal surgical management of papillary thyroid cancer (PTC) for T1-T2 tumors without pre or intrasurgical evidence of lymph node metastasis (cN0) remains controversial, since approximately 40% of patients have lymph node involvement (pN1) which becomes evident when a prophylactic lymphadenectomy (PL) is performed. The aim of this study was to investigate the feasibility of sentinel lymph node (SLN) identification with SPECT/CT lymphoscintigraphy imaging along with intraoperatory image techniques in early stages of PTC undergoing PL of central neck compartment (CNC).

METHODS

A single-center, prospective consecutive study was designed for SLN mapping in patients with high suspicion of PTC (Bethesda V or VI) in early stage (cT1-2, cN0). Twenty-four patients underwent SLN identification with preoperative SPECT/CT and planar images (^99mTc-nanocolloid albumin intratumoral injection). During surgery, SLN located in CNC was found by means of a gamma probe and portable gamma camera, and excised. Afterwards, CNC lymphadenectomy was performed in all cases without modifying the established protocol.

RESULTS

SLNs were identified and accurately located in 23 (95.8%) patients. Nodal metastases (pN1) were confirmed in 9 (37.5%) patients, with one false negative case. The sensitivity was 88.9% and negative predictive value (NPV) was 93.3%, would have allowed to avoid PL in more than half of cases, a higher proportion than those found in other similar studies. No complications associated with the procedure were observed.

CONCLUSIONS

Our results support that SLN biopsy by SPECT/CT along with intraoperatory image techniques is applicable in early stages of PTC (cT1-2, cN0), allowing to avoid unnecessary PL.

Accuracy of sentinel lymph node mapping in detecting occult neck metastasis in papillary thyroid carcinoma

OBJECTIVES

The objectives of this study were to evaluate the following: 1) the accuracy of sentinel lymph node mapping (SLNM) in detecting metastasis in papillary thyroid carcinoma (PTC), and 2) if SLNM could modify the American Joint Committee on Cancer (AJCC) staging of previous cN0 PTC patients.

SUBJECTS AND METHODS

Forty SLNM were performed prospectively in 38 consecutive cN0 PTC patients, with total thyroidectomy and elective compartment neck dissection (CND). The results of SLNM were compared with CND pathological findings to verify the accuracy of sentinel SLNM.

RESULTS

The mean patients' follow-up was 36 months. A total of 133 SLN were found at levels VI, II, III and IV. The SLN was identified in 95% of the patients with one false negative, 95% sensitivity, a 94% negative predictive value and 97% accuracy. The SLNM upstaging from cN0 to pN+ was 49%, and to stages III and IVa, it was 21%.

CONCLUSIONS

For this series of cN0 PTC patients: 1) SLNM accuracy was 97%, and 2) SLNM upstaging from cN0 to pN+ was 49%, whereas to stages III and IVa, it was 21%.

Feasibility of sentinel lymph node dissection using Tc-99m phytate in papillary thyroid carcinoma

Purpose

Various methods of sentinel lymph node (SLN) biopsy in thyroid cancer have been introduced. Tc-99m phytate as a radiotracer has been successfully utilized for SLN biopsy in breast, cervix, and endometrial cancer. We assessed the feasibility of SLN dissection using Tc-99m phytate in papillary thyroid carcinoma (PTC).

Methods

Seventeen patients with PTC were prospectively enrolled. Ultrasound-guided peritumoral injection of 55.5 MBq Tc-99m phytate in 0.25-mL normal saline was performed. Preoperative single-photon emission-computed tomography (SPECT) and intraoperative gamma-probe were used for SLN detection during operation.

Results

Identification rate of SLNs was 70.6% (12 of 17) with SPECT, and 88.2% (15 of 17) with gamma-probe. Combined SPECT and gamma-probe had identification rates of 88.2% (15 of 17). Identification rates of SLNs in central LN compartments were 82.4% (14 of 17) and 41.2% (7 of 17) in lateral LN compartments. Overall sensitivity, specificity, positive predictive value, and negative predictive value of the results of SLN biopsy were 91.6%, 100%, 88.4%, and 100%, respectively. Eight patients (47.1%) had metastasis in SLNs; all patients had SLN metastasis in the central compartment and 2 patients had SLN metastasis in both the central and lateral compartments.

Conclusion

Combined SPECT and gamma-probe could detect SLNs with an 88.2% identification rate in PTC. SLN biopsy using Tc-99m phytate is technically feasible. Further investigation is warranted for clinical application of Tc-99m phytate in PTC.

Selective sentinel lymph node biopsy in papillary thyroid carcinoma in patients with no preoperative evidence of lymph node metastasis

INTRODUCTION

Lymphadenectomy is recommended during surgery for papillary thyroid carcinoma when there is evidence of cervical lymph node metastasis (therapeutic) or in high-risk patients (prophylactic) such as those with T3 and T4 tumors of the TNM classification. Selective sentinel lymph node biopsy may improve preoperative diagnosis of nodal metastases.

OBJECTIVE

To analyze the results of selective sentinel lymph node biopsy in a group of patients with papillary thyroid carcinoma and no evidence of nodal involvement before surgery.

PATIENTS AND METHOD

A retrospective, single-center study in patients with papillary thyroid carcinoma and no clinical evidence of lymph node involvement who underwent surgery between 2011 and 2013. The sentinel node was identified by scintigraphy. When the sentinel node was positive, the affected compartment was removed, and when sentinel node was negative, central lymph node dissection was performed.

RESULTS

Forty-three patients, 34 females, with a mean age of 52.3 (±17) years, were enrolled. Forty-six (27%) of the 170 SNs resected from 24 (55.8%) patients were positive for metastasis. In addition, 94 (15.6%) out of the 612 lymph nodes removed in the lymphadenectomies were positive for metastases. Twelve of the 30 (40%) low risk patients (cT1N0 and cT2N0) changed their stage to pN1, whereas 12 of 13 (92%) high risk patients (cT3N0 and cT4N0) changed to pN1 stage.

CONCLUSIONS

Selective sentinel lymph node biopsy changes the stage of more than 50% of patients from cN0 to pN1. This confirms the need for lymph node resection in T3 and T4 tumors, but reveals the presence of lymph node metastases in 40% of T1-T2 tumors.

Indications and extent of central neck dissection for papillary thyroid cancer: An American Head and Neck Society Consensus Statement

BACKGROUND

The primary purposes of this interdisciplinary consensus statement were to review the relevant indications for central neck dissection (CND) in patients with papillary thyroid cancer (PTC) and to outline the appropriate extent and relevant techniques required to accomplish a safe and effective CND.

METHODS

A writing group convened by the American Head and Neck Society (AHNS) Endocrine Committee was tasked with identifying the important clinical elements to consider when managing the central neck compartment in patients with PTC based on available evidence in the literature, and the group's collective experience. The position statement paper was then submitted to the full Endocrine Committee, Education Committee, and AHNS Council.

RESULTS

This consensus statement was developed to inform the clinical decision-making process when managing the central neck compartment in patients with PTC from the AHNS. This document is intended to provide clarity through definitions as well as a basic guideline from which to manage the central neck. It is our hope that this improves the quality and reduces variation in management of the central neck, facilitates communication, and furthers research for patients with thyroid cancer.

CONCLUSION

This represents, in our opinion, contemporary optimal surgical care for this patient population and is endorsed by the American Head and Neck Society. © 2017 Wiley Periodicals, Inc. Head Neck 39: 1269-1279, 2017.

Radioguided sentinel lymph node biopsy in patients with papillary thyroid carcinoma

BACKGROUND

The ATA guidelines do not recommend prophylactic central compartment neck dissection in patients with T1-T2 papillary thyroid carcinoma (PTC) with no clinical evidence of lymph node metastasis, however patients' staging is recommended. Lymph node metastasis may be present also in small PTC, but preoperative ultrasound identifies suspicious cervical lymphadenopathy in 20-30% of patients. The role of sentinel lymph node biopsy (SLNB) remain open to debate. It has been shown that the identification rate of SLN in PTC patients is improved using a radiotracer compared to a dye technique. The aim of this systematic review was to evaluate the role of radioguided SLNB (rSLNB) in the treatment of PTC patients.

METHODS

A systematic search was performed in the PubMed and Embase database to identify all original articles regarding the application of rSLNB in PTC patients. The primary outcome was false negative rate (FNR) of the rSLNB; the secondary outcomes were SLN intraoperative identification rate (IIR), site of lymph node metastasis, and persistent disease during follow up.

RESULTS

Twelve studies were included. Most of PTC patients were T1-T2. The overall SLN IIR, SLN metastatic rate, and FNR were 92.1%, 33.6%, and 25.4%, respectively. Overall, lymph node metastasis were found in the central compartment (23.0%) and in the lateral compartments (10.6%). The persistent disease in patients who underwent SLNB associated to lymph node dissection (LND) in the same compartment of the SLN regardless of the SLN status was 0.6%.

CONCLUSIONS

In all PTC patients, also in T1-T2 stage, due to the high FNR the SLNB performed alone should be abandoned and converted into a technique to guide the lymphadenectomy in a specific neck compartment (i.e., central or lateral) based on the radioactivity, regardless of the SLN status, for better lymph node staging and selection of patients for postoperative radioiodine ablation.

Predictive factors and pattern of central lymph node metastasis in unilateral papillary thyroid carcinoma

OBJECTIVE

Prophylactic central neck dissection (CND) for papillary thyroid carcinoma (PTC) remains controversial. The aim of this study was to evaluate the patterns and predictive factors of central lymph node metastasis in cases of PTC that were clinically determined to be node negative.

METHODS

We studied 485 patients who have unilateral PTC without clinical lymph node metastasis and underwent total thyroidectomy and prophylactic bilateral CND from 2003 to 2012, retrospectively. The frequency, subsite and predictive factors of central lymph node metastasis were analyzed.

RESULTS

In total, 166 (32.4%) patients had occult central lymph node metastases. The most common subsite of central node metastases was the ipsilateral paratracheal lymph node (26.0%), followed by pretracheal (12.5%), prelaryngeal (5.0%), and contralateral paratracheal (3.9%) lymph nodes. The tumor size larger than 0.5cm (p=0.003), age under 45 (p<0.001) and extrathyroidal extension (p=0.028) were associated with ipsilateral central compartment metastasis in multivariate analysis. Contralateral central node metastasis was associated with tumor size >3cm, age under 45, and multifocality and ipsilateral central node metastasis in univariate analysis, but it was associated with only ipsilateral central node metastasis in multivariate analysis (p=0.001).

CONCLUSION

Prophylactic CND might be considered for PTC patients with large tumor size or extrathyroidal extension based on rates of lymph node metastasis. Unilateral CND might be appropriate as prophylactic CND due to the low metastatic rate to the contralateral paratracheal node.

Utility of sentinel lymph node biopsy for thyroid cancer: a comprehensive review

Sentinel lymph node biopsy (SLNB) is a minimally invasive lymphatic mapping technique, used to identify lymph node micrometastases and stage multiple cancer types. Despite the performance of SLNB for thyroid cancer having been under study since 1998, its role has remained controversial. The objective of this review is to summarize current research reporting on SLNB for thyroid cancer, focusing on recent studies of its application to differentiated thyroid cancer. The technique and potential benefits of SLNB are reviewed with regards to its ability to identify lymph node metastases, aid in cancer prognostication, and direct surgical and medical treatment.

Carbon nanoparticle-guided central lymph node dissection in clinically node-negative patients with papillary thyroid carcinoma

BACKGROUND

Distinguishing the involved lymph nodes from other tissues during surgery is critical for lymph node dissection. The purpose of this study was to assess the feasibility by using carbon nanoparticles as guidance for lymph node dissection in patients with papillary thyroid carcinoma (PTC).

METHODS

Eighty-one patients were injected with carbon nanoparticles (carbon nanoparticle group), whereas the other 81 patients were not (control group). Routine pathological examination was performed.

RESULTS

The lymph node dissection and metastatic lymph node dissection rates of the carbon nanoparticle group were significantly higher than that of the control group. In the carbon nanoparticle group, the number of mistakenly dissected parathyroid gland, the case number of postoperative hypocalcemia, the case number of postoperative hypoparathyroidism, and the recovery time from hypocalcemia were 4, 6, 8, and 2.33 ± 0.58 weeks, respectively, significantly less than 14, 17, 20, 3, and 3.8 ± 0.92 weeks in the control group (p < .05).

CONCLUSION

Carbon nanoparticles can be applied to more accurately guide the dissection of lymph nodes during thyroidectomy in patients with PTC. © 2015 Wiley Periodicals, Inc. Head Neck 38: 840-845, 2016.

The Utility of Sentinel Lymph Node Biopsy in Papillary Thyroid Carcinoma with Occult Lymph Nodes

Background

The sentinel lymph node (SLN) is defined as the first draining node from the primary lesion, and it has proven to be a good indicator of the metastatic status of regional lymph nodes in solid tumors. The aim of this study was to evaluate the clinical application of SLN biopsy (SLNB) in papillary thyroid carcinoma (PTC) with occult lymph nodes.

Methods

From April 2006 to October 2012, 212 consecutive PTC patients were treated with SLNB using carbon nanoparticle suspension (CNS). Then, the stained nodes defined as SLN were collected, and prophylactic central compartment neck dissection (CCND) followed by total thyroidectomy or subtotal thyroidectomy were performed. All the samples were sent for pathological examination.

Results

There were 78 (36.8%) SLN metastasis (SLNM)-positive cases and 134 (63.2%) SLNM-negative cases. The sensitivity, specificity, positive and negative predictive values, and false-positive and false-negative rates of SLNB were 78.8%, 100%, 100%, 84.3%, 0%, and 21.2%, respectively. The PTC patients with SLNM were more likely to be male (48.2% vs. 32.7%, p = 0.039) and exhibited multifocality (52.6% vs. 33.3%, p = 0.025) and extrathyroidal extension (56.7% vs. 33.5%, p = 0.015). A greater incidence of non-SLN metastases in the central compartment was found in patients with SLNM (41/78, 52.6%) than in those without SLNM (21/134, 15.7%; p < 0.05). However, the SLNM-negative PTC patients with non-SLN metastases were more likely to be male (37.9% vs. 9.5%, p < 0.05).

Conclusions

The application of SLNB using CNS is technically feasible, safe, and useful, especially for male patients with co-existing multifocality and extrathyroidal extension. However, the sensitivity of SLNB must be improved and its false-negative rate reduced before it can be a routine procedure and replace prophylactic CCND. More attention should be paid to PTC patients (especially males) without SLNM for signs of non-SLN metastases.

One-step nucleic acid amplification testing in medullary thyroid cancer lymph nodes: a case series

INTRODUCTION

Locoregional relapse in medullary thyroid cancer (MTC) may be caused by nodal micrometastases. Medullary thyroid cancer lymph nodes have not yet been evaluated by one-step nucleic acid amplification (OSNA). Therefore, the aim of this study was to detect MTC cells by OSNA in cervical lymph nodes and compare the obtained outcomes with conventional histopathology.

MATERIAL AND METHODS

Twenty-one randomized, unenlarged lymph nodes from 5 patients with MTC were examined by histopathology and OSNA. Lymph nodes were divided into four representative blocks by a sterile, single use, special cutting device in the same way as in the clinical protocol study performed by Tsujimoto et al. Two blocks were used for histopathology and immunohistochemistry, 2 for OSNA.

RESULTS

Positive results of histopathology and OSNA were revealed in 4 patients. The outcomes of OSNA and histopathology were corresponding in 3 patients. Positive histopathology results of 2 lymph nodes from 2 patients were confirmed by OSNA. In 1 patient there were only negative results of both examinations. One-step nucleic acid amplification failed to detect metastasis in 1 lymph node in 2 patients although it did not change the TNM status in these patients. There were no false positive results in the OSNA test.

CONCLUSIONS

One-step nucleic acid amplification may be an alternative method to histopathology in detecting nodal involvement in MTC. Further studies should evaluate the sensitivity and specificity of OSNA and the impact on staging in MTC.

Lymphatic drainage patterns in oral squamous cell carcinoma: findings of the ACOSOG Z0360 (Alliance) study

OBJECTIVE

The purpose of our study was to correlate sentinel lymph nodes (SLN) found on planar lymphoscintigraphy (LS) to SLN found with gamma probe-directed sentinel lymph node biopsy (SLNB) for T1/T2 N0 oral cavity cancer.

STUDY DESIGN

Prospective cooperative group trial.

SETTING

Academic medical centers.

SUBJECTS AND METHODS

One hundred forty adults with untreated T1/T2 N0 squamous cell carcinoma (SCC) of the oral cavity underwent planar LS, resection, SLNB, and neck dissection. Location of SLN by planar LS and SLNB and of metastases were compared to each other and historical data of regional metastases.

RESULTS

SLNs located by planar LS and SLNB were predominantly in levels I through IV. There was heterogeneity in the number of SLNs found at planar LS and at SLNB, which was significantly different in levels II and III (P < .0001). In 14 of 33 cases with bilateral drainage on planar LS, SLNB detected only unilateral SLN. Sensitivity of planar LS in predicting the level of SLN was 41% to 63%, and specificity was 68% to 95%. Comparison of locations of the metastases to historical data showed fewer metastases to level I in our study (P = .03). Metastases occurred predominantly in levels I through III. In 1 case of a lateral tongue cancer, a contralateral SLN was the only positive node.

CONCLUSION

Lymphatic drainage patterns and metastases involved predominantly levels I through III. Planar LS is not sensitive for predicting the levels of SLN, and in levels II and III, the rate of detection of SLN between the 2 modalities is significantly different.

Prophylactic level II neck dissection guided by frozen section for clinically node-negative papillary thyroid carcinoma: is it useful?

BACKGROUND

Prophylactic lateral neck dissection (PLND) is generally not performed for papillary thyroid carcinoma(PTC). When performed, occult metastases are found in upto 50 % of patients, although the incidence of occult level II nodes seems low. Our aim was to evaluate frozen section analysis-oriented elective level II PLND in patients with clinically node-negative (cN0) PTC.

METHODS

This retrospective study included patients with cN0 PTC treated with total thyroidectomy and prophylactic bilateral central and lateral neck dissection of ipsilateral levels III and IV. Frozen section analysis of PLND III and IV was performed. If positive, the PLND was extended to level II. We measured the accuracy of frozen section analysis, the incidence of occult level II metastasis, and oncologic outcomes.

RESULTS

A total of 295 patients were included. For frozen section analysis, the sensitivity was 71.0 %, specificity 99.6 %, positive predictive value 97.8 %, negative predictive value 92.4 %, overall accuracy 93.2 %. Definitive analysis found lateral node metastases in 63 of the 295(21 %) patients. Extension to level II was performed in 27 of 46 cases (59 %). Level II contained metastatic nodes in 12 of 27 (44 %) patients. There was no difference in total doses of 131I administered to patients with or without level II disease. Even when extension of PLND to level II was not performed, no cases of recurrent or persistent disease in level II occurred.

CONCLUSIONS

Frozen section analysis was highly accurate.The rate of occult metastases in level II was low. Detection of additional metastases in level II did not modify subsequent treatment or the rate of recurrence and is not useful for routine application.

Radio-guided selective compartment neck dissection improves staging in papillary thyroid carcinoma: a prospective study on 345 patients with a 3-year follow-up

BACKGROUND

Prospective uncontrolled study to investigate in papillary thyroid carcinoma (PTC) patients: (1) Distribution of lymph node metastases within the neck compartments, (2) factors predicting lymph nodes metastases, and (3) disease recurrence after thyroidectomy associated with radio-guided selective compartment neck dissection (RSCND).

METHODS

We studied 345 consecutive PTC patients operated on between February 2004 and October 2011 at the S. Anna University Hospital, Ferrara (Italy). Patients with cervical lymph node metastases on preoperative ultrasonography and fine needle aspiration cytology were excluded. All patients underwent total thyroidectomy associated with SLN identification followed by RSCND in the SLN compartment, without SLN frozen section.

RESULTS

In patients with lymph node metastases, metastatic nodes were not in the central neck compartment in 22.6% of the cases. The presence of infiltrating or multifocal PTC was a predicting factor for lymph nodes metastases. The median follow-up was 35.5 months. RSCND was associated with a false-negative rate of 1.1%, a persistent disease rate of 0.6%, and a recurrent disease rate of 0.9%. The permanent dysphonia rate was 1.3%.

CONCLUSION

RSCND associated with total thyroidectomy may improve: (1) the locoregional lymph node staging, and (2) the identification of the site of lymphatic drainage within the neck compartments. Thus, considering the high false-negative rate of sentinel lymph node biopsy (SLNB), a radio-guided technique in PTC patients may guide the lymphadenectomy (ie, RSCND) to increase the metastatic yield and improve staging of the disease rather than avoid prophylactic lymphadenectomy (ie, SLNB).

Impact of prophylactic central neck dissection on oncologic outcomes of papillary thyroid carcinoma: a review

Prophylactic neck dissection (PND) for papillary thyroid carcinoma (PTC) is controversial. Our aim was to assess current levels of evidence (LE) according to the Oxford Centre for Evidence-based Medicine ( http://www.cebm.net/?O=1025 ) regarding the oncologic benefits of PND. Data were analyzed via MEDLINE keywords: PTC, differentiated thyroid carcinoma, PND, central lymph node metastases, central compartment, recurrence-free survival. There was conflicting evidence regarding the rate of reoperation for recurrence, with some studies showing a lower rate after PND with increased recurrence-free survival and a higher rate of undetectable pre- and post-ablation thyroglobulin levels (LE 4), whereas other studies did not show a difference (LE 4). Only one study (LE 4) showed improved disease-specific survival with PND. PND may improve recurrence-free survival, although this is supported by only a low LE. Current recommendations can only be based on low-level evidence.

Simultaneous mapping of pan and sentinel lymph nodes for real-time image-guided surgery

The resection of regional lymph nodes in the basin of a primary tumor is of paramount importance in surgical oncology. Although sentinel lymph node mapping is now the standard of care in breast cancer and melanoma, over 20% of patients require a completion lymphadenectomy. Yet, there is currently no technology available that can image all lymph nodes in the body in real time, or assess both the sentinel node and all nodes simultaneously. In this study, we report an optical fluorescence technology that is capable of simultaneous mapping of pan lymph nodes (PLNs) and sentinel lymph nodes (SLNs) in the same subject. We developed near-infrared fluorophores, which have fluorescence emission maxima either at 700 nm or at 800 nm. One was injected intravenously for identification of all regional lymph nodes in a basin, and the other was injected locally for identification of the SLN. Using the dual-channel FLARE intraoperative imaging system, we could identify and resect all PLNs and SLNs simultaneously. The technology we describe enables simultaneous, real-time visualization of both PLNs and SLNs in the same subject.

Tumor classification in well-differentiated thyroid carcinoma and sentinel lymph node biopsy outcomes: a direct correlation

BACKGROUND

Predicting locoregional metastasis in well-differentiated thyroid carcinoma (WDTC) is a challenge for thyroid cancer surgeons. Sentinel lymph node biopsy (SLNB) has been shown to be an effective predictive tool. To our knowledge, primary tumor (T) classification has yet to be studied with regard to SLNB. We hypothesized that larger primary tumors would correlate with the rate of malignancy in SLNBs.

METHODS

A retrospective chart review was conducted on patients operated for WDTC at the McGill Thyroid Cancer Center over a 36-month period. Patients who underwent a total thyroidectomy and SLNB for WDTC were included in this study.

RESULTS

A total of 311 patients were included and separated into two groups (236 negative and 75 positive SLNBs). Among patients with negative SLNBs, 65% had T1 primary tumors, 17% T2, 16% T3, and 2% T4, whereas 18% of patients with positive SLNBs had T1 primary tumors, 5% T2, 45% T3, and 32% T4 (p<0.001). Patients under the age of 45 years had a higher rate of positive SLNs (36% in those <45 years vs. 17% in those ≥ 45 years; p<0.001).

CONCLUSIONS

Age (<45 years) and higher T category were found to be associated with a higher rate of positive SLNBs.

Sentinel node biopsy in papillary thyroid cancer--what is the potential?

PURPOSE

Sentinel node biopsy (SNB) may identify lymph node metastases in patients with papillary thyroid cancer (PTC), enabling selective application of central node dissection (CND). The aim of this study was to assess the feasibility of implementing SNB in patients undergoing thyroidectomy for a cytologically indeterminate/suspicious/malignant thyroid nodule and to determine the potential improvement in clinical outcomes and the costs associated with the SNB technique.

METHODS

The treatment strategies and clinical and pathological outcomes of two retrospective cohorts of patients who underwent preoperative thyroid FNA over a 5-year period in two different centres were studied. The potential for implementing the SNB technique and the benefits and costs associated with implementation were estimated.

RESULTS

In centre 1, in 819 adult patients who had thyroid fine-needle aspiration cytology, the final cytology was indeterminate, suspicious and diagnostic of malignancy in 113, 29 and 28 patients, respectively. One hundred eight patients were 'suitable' for SNB. Twenty-three of these patients had PTC, six of whom underwent CND. Of these six patients, node metastasis was absent in five--the cohort in whom prophylactic CND may have been avoided consequent to a negative 'sentinel node' biopsy. Morbidity attributable to CND may have been avoided in up to four patients over a 5-year period. Costs associated with implementation of SNB outweighed any potential savings. Analysis of 491 patients in centre 2 confirmed that the benefit of SNB in PTC was similarly limited; morbidity attributable to CND may have been avoided in up to seven patients over a 5-year period.

CONCLUSIONS

Even under ideal conditions (assuming 100 % node identification rate and 0 % false negative rate), the potential short- to medium-term benefit of sentinel node biopsy in patients with thyroid cancer in centres implementing a policy of selective or routine prophylactic CND is low.

Accuracy of intraoperative determination of central node metastasis by the surgeon in papillary thyroid carcinoma

OBJECTIVE

Prophylactic central neck dissection (CND) in papillary thyroid carcinoma (PTC) remains controversial. If the presence of central lymph node metastasis could be assessed preoperatively or intraoperatively, unnecessary CND could be avoided. The aim of this study was to evaluate the accuracy of intraoperative determination of central lymph node metastasis by the surgeon using palpation and inspection in clinically node-negative PTC.

STUDY DESIGN

Prospective study.

SETTING

University tertiary care facility.

SUBJECTS AND METHODS

A total of 122 consecutive patients with clinically node-negative PTC were enrolled. Any suspicious lymph nodes on intraoperative palpation or inspection were sent for frozen biopsy, and then bilateral CND with total thyroidectomy was carried out in all patients. The criteria for a suspicious lymph node included palpable hardness, dark discoloration, or size exceeding 5 mm in diameter. We compared the surgeon's judgments with the final pathologic results.

RESULTS

Suspicious lymph nodes were found in 37 (30.3%) patients, and 15 of them had metastasis on permanent biopsy. Of 85 patients with no suspicious lymph nodes, 27 (31.8%) had metastasis on permanent biopsy. The sensitivity and specificity as well as positive and negative predictive values of intraoperative determination of central lymph node metastasis were 35.7%, 72.5%, 40.5%, and 68.2%, respectively. The positive predictive values of enlarged lymph nodes, dark discoloration, and hardness were 30.4%, 50.0%, and 78.6%, respectively.

CONCLUSION

Intraoperative determination of central lymph node metastasis by the surgeon is a limited guide for CND in clinically node-negative PTC because of its low sensitivity and specificity.

Sentinel Lymph Node Biopsy Status Correlates with Postoperative Stimulated Thyroglobulin Levels in Low-risk Papillary Thyroid Cancer Patients

OBJECTIVE

Radioactive iodine (RAI) remnant ablation in low-risk papillary thyroid cancer (PTC) is controversial. Current patient selection guidelines recommend the use of postoperative stimulated thyroglobulin (stim-Tg), neck dissections, and sonography but fail to include sentinel lymph node biopsy (SLNB). The objective of this study was to evaluate the correlation between SLNB status and postoperative stimulated thyroglobulin as a surrogate marker of clinical outcome.

METHODS

Retrospective chart review of low-risk PTC patients who underwent a total thyroidectomy with SLNB at the McGill Thyroid Cancer Center. SLNBs were obtained using methylene blue dye. Biochemical measurements were acquired between 4 and 12 weeks postoperatively. Statistical analyses were performed using logistic regression models and receiver operating characterisitc (ROC) curves. A P-value <.05 was considered significant.

RESULTS

Ninety-six patients were included in this study. The positive SLNB rate was 14.6%. The mean postoperative Tg level was 1.41 μg/L. There were no significant correlations between the SLNB and the covariates analyzed (age, gender, histology, tumor size, and thyrotropin levels). Patients with negative SLNB were significantly more likely to have a lower stim-Tg (P<.0001). When postoperative Tg was analyzed as a categorical variable, a threshold of <1 μg/L was significantly associated with a negative SLNB, with a sensitivity and specificity (determined by ROC curves) of 0.86 and 0.88, respectively.

CONCLUSION

There exists a correlation between SLNB and postoperative Tg. This creates the possibility of a new approach to RAI administration among low-risk PTC patients incorporating SLNB to the current guidelines.

Frozen section analysis and sentinel lymph node biopsy in well differentiated thyroid cancer

Background

The aim of this study is to prospectively review the role of sentinel lymph node (SLN) biopsy in the management of well differentiated thyroid carcinoma (WDTC), and to determine the efficacy of intraoperative frozen section analysis at detecting SLN metastasis and central compartment involvement.

Methods

The SLN biopsy protocol using 1% methylene blue was performed in 300 patients undergoing thyroidectomy for WDTC. A limited pretracheal central compartment neck dissection (CCND) was performed on all patients. Lymph nodes staining blue were considered as SLN’s. Both frozen and permanent section analyses were performed.

Results

SLN’s with metastasis were found in 14.3% (43/300) of cases. Of this, 11% (33/300) were positive on intraoperative frozen section analysis. Frozen section results failed in predicting central compartment involvement in 15 cases (5%) whereas central neck compartment involvement was missed in 5 cases (1.7%) when based on permanent section results. On frozen section analysis, the sensitivity, specificity, positive predictive value and negative predictive value (95% CI) of our SLN biopsy technique aiming to remove all disease from the central compartment was 68.8% (53.6-80.9), 100% (98.1-100), 100% (87.0-100) and 94.4% (90.7-96.7) respectively with P < 0.0001. On permanent section analysis, the values were 89.6% (76.6-96.1), 100% (98.1-100), 100% (89.8-100), and 98.1% (95.3-99.3) with P < 0.0001.

Conclusion

This data series demonstrates that patients with WDTC have positive SLN’s in 14.3% of cases. Moreover, when the SLN’s are negative for metastasis on frozen section, the central compartment was disease-free in 94.4% of cases. Finally, this study shows that 23.3% of positive SLN’s were false negatives on intraoperative frozen section. According to this data, SLN involvement is an accurate predictor of central compartment metastasis, however surgeons should use caution when relying on intraoperative frozen section to determine whether to perform a CCND.

SPECT/CT sentinel lymph node identification in papillary thyroid cancer: lymphatic staging and surgical management improvement

PURPOSE

Lymphadenectomy in papillary thyroid carcinoma (PTC) continues to be controversial. A better staging method is needed to provide adequate individual surgical treatment. SPECT/CT lymphoscintigraphy and sentinel lymph node (SLN) biopsy may improve lymphatic staging and surgical treatment. Our main objectives were to describe the lymphatic drainage of PTC using lymphoscintigraphy, to evaluate the lymphatic spread (comparing SLN and lymphadenectomy results) and to analyse the impact of SLN identification in surgery.

METHODS

We prospectively studied 24 consecutive patients with PTC (19 women; mean age 52.7 years, range 22-81 years). The day before surgery, lymphoscintigraphy with ultrasound-guided intratumoral injection ((99m)Tc-nanocolloid, 148 MBq) was performed, obtaining planar and SPECT/CT images. All patients underwent total thyroidectomy, SLN biopsy (hand-held gamma probe) with perioperative analysis, central compartment node dissection, or laterocervical lymphadenectomy if perioperative stage N1b or positive SLNs in this lymphatic basin.

RESULTS

Lymphoscintigraphy revealed at least one SLN in 19 of 24 patients (79 %) on planar and SPECT/CT images, and in 23 of 24 patients (96 %) during surgery using a hand-held gamma probe. Lymph node metastases were detected with classical perioperative techniques (ultrasound guidance and surgical inspection) in 3 of 24 patients, by perioperative SLN analysis in 10 of 23, and by definitive histology in 13 of 24. The false-negative (FN) ratio for SLN was 7.7 % (one patient with bulky lymph nodes). The FN ratio for perioperative frozen sections was 15.4 % (two patients, one with micrometastases, the other with bilateral SLN). Lymphatic drainage was only to the central compartment in 6 of 24 patients (3 of the 6 with positive SLNs for metastases), only to the laterocervical basin in 5 of 24 patients (all unilateral, 2 of 5 positive SLNs) and to the central and laterocervical compartments in 12 of 24 patients (6 of 12 and 3 of 12 positive SLNs, respectively).

CONCLUSION

Lymphoscintigraphy reveals the lymph node drainage in a high proportion of patients. It detects laterocervical drainage in a significant percentage of patients, allowing the detection of occult lymph node metastases and improving the surgical management in PTC.

Detection and management of cervical lymph nodes in papillary thyroid cancer

Lymph node metastases in papillary thyroid cancer are a common occurrence; however, the management of clinically negative cervical lymph nodes remains controversial. Preoperative neck ultrasound mapping is crucial, and complete dissection of a nodal compartment is recommended for any metastatic lymph nodes. The role of prophylactic central neck dissection remains controversial. The BRAF V600E mutation is a common mutation in papillary thyroid cancer, and has been associated with more aggressive tumor behavior. Evaluating the BRAF status of tumors may have implications for treatment and surveillance. New areas of research continue to focus on risk stratification and identifying which patients benefit from a more aggressive treatment, such as prophylactic central lymphadenectomy and radioiodine ablation and more intense surveillance strategies.