Extent of cervical lymph node dissection: Recommendations from the Francophone Association for Endocrine Surgery, the French Society of Endocrinology and the French Society of Nuclear Medicine

When metastatic ipsilateral central lymph nodes from thyroid cancer are identified pre- or intraoperatively (cN1a), ipsilateral central lymph node dissection should be performed concomitantly with thyroidectomy. When the patient is N1a on one side, contralateral prophylactic central lymph node dissection can also be considered. Prophylactic ipsilateral lymph dissection is not recommended. Ipsilateral compartment lymph node dissection is recommended in the corresponding sector for treatment of thyroid cancer with lymph node involvement (cN1b). Lymph node dissection can be limited to sectors III and IV when one of these sectors (or both) is involved and ultrasound does not demonstrate involvement of the other lateral sectors. Associated prophylactic lymph node dissection of sectors IIA and IIB is not recommended, while lymph node dissection of sector V (and exceptionally sector I) is indicated only when metastatic lymph nodes are proven. Prophylactic lymph node dissection of sector VB can be considered when positive lymph nodes are identified in sectors II, III and IV. When isolated metastatic lateral lymph nodes are identified (cN1b), prophylactic central (sector VI) lymph node dissection is recommended on the same side as the lateral compartment in addition to ipsilateral lateral lymph node compartment dissection. The level of evidence is insufficient to recommend prophylactic lateral lymph node dissection on the contralateral side for unilateral cN1b tumors. This type of lymph node dissection can be discussed for tumors that are at high risk of recurrence, bilateral tumors, in case of ipsilateral lateral lymph nodes > 3cm or in presence of > 4 metastatic lymph nodes in the central compartment.

Recommendations of the AFCE (Association francophone de chirurgie endocrinienne) with the SFE (Société française d'endocrinologie) and the SFMN (Société française de médecine nucléaire)

Prophylactic lymph node dissection is considered only for papillary cancers. It is not indicated for vesicular cancers or oncocytic cancers, nor should it entail a secondary surgical intervention in the event of an incidental discovery of papillary cancer on a thyroidectomy specimen. Prophylactic lymph node dissection means a cervical lymph node dissection in the absence of any pre- or intraoperative evidence (biological, cytological, histological, clinical or ultrasound) of lymph node metastases. There is currently no evidence in the literature that prophylactic central dissection improves overall survival, which is similar for N0 and NX patients. Yet although prophylactic lymph node dissection is not justified by overall survival, it does seem to reduce the risk of locoregional recurrence in the case of micro-N1, and it allows occult metastases to be detected and a tumour to be reclassified. This enables patients at risk of recurrence to be more surely identified and therapeutic strategy and follow-up adapted accordingly. Prophylactic homolateral central lymph node dissection is warranted for papillary cancers with largest ultrasound diameter 4cm and above and/or with intraoperative macroscopic evidence of perithyroid tissue invasion. The benefits and risks of lymph node dissection must be assessed and discussed on a case-by-case basis. Only a central lymph node dissection homolateral to the tumour is recommended, except for bilateral or isthmic cancers, for which a prophylactic bilateral central lymph node dissection may be considered. This bilateral lymph node dissection incurs an increased risk of complications (parathyroids, recurrent laryngeal nerve). Prophylactic lateral lymph node dissection is not recommended.

Relationship between subgroups of central and lateral lymph node metastasis in clinically node-negative papillary thyroid carcinoma

BACKGROUND

Lymph node metastasis (LNM) of papillary thyroid carcinoma (PTC) has a certain regularity and occurs first to the central lymph node and then to the lateral lymph node. The pathway of PTC LNM can guide surgical prophylactic lymph node dissection (LND) for clinical surgeons.

AIM

To investigate the relationship between subgroups of central LNM and lateral LNM in unilateral clinically node-negative PTC (cN0-PTC).

METHODS

Data were collected for 1089 PTC patients who underwent surgical treatment at the Department of Endocrine and Breast Surgery of the First Hospital of Chongqing Medical University from January 2016 to December 2017. A total of 388 unilateral cN0-PTC patients met the inclusion criteria and were enrolled in this study. The clinical and pathological data for these 388 patients who underwent total thyroidectomy + central LND + lateral LND were retrospectively analyzed. The relationship between the central LNM and lateral LNM subgroups was investigated.

RESULTS

The coincidence rate of cN0-PTC was only 30.0%.Optimal scaling regression analysis showed that sex (57.1% vs 42.9%, P = 0.026), primary tumor size (68.8% vs 31.2%, P = 0.008), tumor location (59.7% vs 40.3%, P = 0.007), extrathyroid extension (ETE) (50.6% vs 49.9%, P = 0.046), and prelaryngeal LNM (57.1% vs 42.9%, P = 0.004) were significantly associated with ipsilateral level-II LNM. Their importance levels were 0.122, 0.213, 0.172, 0.110, and 0.227, respectively. Primary tumor size (74.6% vs 30.2%, P = 0.016), pretracheal LNM (67.5% vs 32.5%, P < 0.001), and paratracheal LNM (71.4% vs 28.6%, P < 0.001) were significantly associated with ipsilateral level-III LNM. Their importance levels were 0.120, 0.408, and 0.351, respectively. Primary tumor size (72.1% vs 27.9%, P = 0.003), ETE (70.4% vs 29.6%, P = 0.016), pretracheal LNM (68.3% vs 31.7%, P=0.001), and paratracheal LNM (80.8% vs 19.2%, P < 0.001) were significantly associated with ipsilateral level-IV LNM. Their importance levels were 0.164, 0.146, 0.216, and 0.472, respectively.

CONCLUSION

The LNM pathway of thyroid cancer has a certain regularity. For unilateral cN0-PTC patients with a tumor diameter > 2 cm and pretracheal or ipsilateral paratracheal LNM, LND at ipsilateral level III and level IV must be considered. When there is a tumor in the upper third of the thyroid with prelaryngeal LNM, LND at level II, level III and level IV must be considered.

The Role of Calcitonin in Predicting the Extent of Surgery in Medullary Thyroid Carcinoma: A Nationwide Population-Based Study in Norway

BACKGROUND

Preoperative predictors for the need of prophylactic lymph node dissection in the lateral neck have been studied in patients with medullary thyroid carcinoma (MTC).

OBJECTIVES

To evaluate the ability of serum calcitonin to predict the extent of surgery needed in the lateral neck.

METHODS

This retrospective population-based cohort study includes data from 94 of 139 patients with MTC surgically treated in Norway from 2003 to 2016. Patients were identified in the 4 regional centers treating MTC and by the Cancer Registry of Norway, and grouped according to calcitonin levels. In 58 patients without distant metastases or disease progression to the next tumor level (NPNL), data were compared in prognostic groups (N0-NPNL), (N1a-NPNL), and (N1b-NPNL).

RESULTS

At calcitonin levels ≤500, 501-1,000, and >1,000 pmol/L, metastatic lymph nodes in the lateral neck were found in 16, 50, and 71% of the patients, respectively. In the prognostic groups, 19% of N0-NPNL patients had calcitonin >500 pmol/L and 17% of N1b-NPNL patients had calcitonin ≤500 pmol/L. In multivariate analysis, factors predicting biochemical cure and calcitonin level ≤500 pmol/L were no metastatic lymph nodes in the lateral neck (p = 0.030) and tumor diameter ≤20 mm (p < 0.001), respectively. Factors related to metastatic lymph nodes in the lateral neck were extrathyroidal extension (p = 0.007) and no biochemical cure (p = 0.028).

CONCLUSIONS

Basal calcitonin cannot predict the need for prophylactic lateral lymph node dissection in patients with MTC. Further prospective, randomized studies are warranted.

The synergic effect of BRAFV600E mutation and multifocality on central lymph node metastasis in unilateral papillary thyroid carcinoma

The purpose of this study is to evaluate the potential synergic effect of BRAF^V600E mutation and multifocality on central lymph nodes metastasis (CLNM) in the patients with unilateral papillary thyroid carcinoma (PTC). We enrolled 413 patients with unilateral PTCs who accepted prophylactic unilateral or bilateral central lymph node dissection (LND). Univariate and multivariate analyses were made to determine the association between related factors and CLNM. Then, all patients were divided into 4 groups based on their status of BRAF^V600E mutation and multifocality. Relative excess risk of interaction (RERI), attributable proportion (AP) of interaction and synergy index (SI) were applied to evaluate the interactive effect of these two factors on CLNM. Results showed that BRAF^V600E mutation and multifocality were independent risk factors for CLNM. A further study revealed that unilateral PTCs accompanying multifocality with BRAF^V600E mutation had the highest incidence of CLNM compared with other subgroups. Besides, RERI was 4.323 (95% CI = 1.276-7.369), AP was 0.523 (95% CI = 0.364-0.682) and SI was 2.469 (95% CI = 1.607 to 3.794), indicating a significant additive interaction of BRAF^V600E mutation and multifocality on CLNM. The present study has confirmed that BRAF^V600E mutation and multifocality are risk factors for CLNM in unilateral PTC. Additionally, unilateral PTC patients accompanying multifocality with BRAF^V600E mutation may have an increased risk of CLNM in clinically negative CLNM.

Clinical significance of prophylactic central compartment neck dissection in the treatment of clinically node-negative papillary thyroid cancer patients

Background

Lymph nodal involvement is very common in differentiated thyroid cancer, and in addition, cervical lymph node micrometastases are observed in up to 80 % of papillary thyroid cancers. During the last decades, the role of routine central lymph node dissection (RCLD) in the treatment of papillary thyroid cancer (PTC) has been an object of research, and it is now still controversial. Nevertheless, many scientific societies and referral authors have definitely stated that even if in expert hands, RCLD is not associated to higher morbidity; it should be indicated only in selected cases.

Main body

In order to better analyze the current role of prophylactic neck dissection in the surgical treatment of papillary thyroid cancers, an analysis of the most recent literature data was performed. Prophylactic or therapeutic lymph node dissection, selective, lateral or central lymph node dissection, modified radical neck dissection, and papillary thyroid cancer were used by the authors as keywords performing a PubMed database research. Literature reviews, PTCs large clinical series and the most recent guidelines of different referral endocrine societies, inhering neck dissection for papillary thyroid cancers, were also specifically evaluated. A higher PTC incidence was nowadays reported in differentiated thyroid cancer (DTC) clinical series. In addition, ultrasound guided fine-needle aspiration citology allowed a more precocious diagnosis in the early phases of disease. The role of prophylactic neck dissection in papillary thyroid cancer management remains controversial especially regarding indications, approach, and surgical extension. Even if morbidity rates seem to be similar to those reported after total thyroidectomy alone, RCLD impact on local recurrence and long-term survival is still a matter of research. Nevertheless, only a selective use in high-risk cases is supported by more and more scientific data.

Conclusions

In the last years, higher papillary thyroid cancer incidence and more precocious diagnoses were worldwide reported. Among endocrine and neck surgeons, there is agreement about indications to prophylactic treatment of node-negative “high-risk” patients. A recent trend toward RCLD avoiding radioactive treatment is still debated, but nevertheless, prophylactic dissections in low-risk cases should be avoided. Prospective randomized trials are needed to evaluate the benefits of different approaches and allow to drawn definitive conclusions.

Knowledge of pathologically versus clinically negative lymph nodes is associated with reduced use of radioactive iodine post-thyroidectomy for low-risk papillary thyroid cancer

Cervical lymph node metastases are common in papillary thyroid cancer (PTC). Clinically negative lymph nodes confer uncertainty about true lymph node status, potentially prompting empiric postoperative radioactive iodine (RAI) administration even in low-risk patients. We examined the association of clinically (cN0) versus pathologically negative (pN0) lymph nodes with utilization of RAI for low-risk PTC. Using the National Cancer Database 1998-2011, adults with PTC who underwent total thyroidectomy for Stage I/II tumors 1-4 cm were evaluated for receipt of RAI based on cN0 versus pN0 status. Cut-point analysis was conducted to determine the number of pN0 nodes associated with the greatest decrease in the odds of receipt of RAI. Survival models and multivariate analyses predicting RAI use were conducted separately for all patients and patients <45 years. 64,980 patients met study criteria; 39,778 (61.2 %) were cN0 versus 25,202 (38.8 %) pN0. Patients with pN0 nodes were more likely to have negative surgical margins and multifocal disease (all p < 0.001). The mean negative nodes reported in surgical pathology specimens was 4; ≥5 pathologically negative lymph nodes provided the best cut-point associated with reduced RAI administration (OR 0.91, CI 0.85-0.97). After multivariable adjustment, pN0 patients with ≥5 nodes examined were less likely to receive RAI compared to cN0 patients across all ages (OR 0.89, p < 0.001) and for patients aged <45 years (0R 0.86, p = 0.001). Patients with <5 pN0 nodes did not differ in RAI use compared to cN0 controls. Unadjusted survival was improved for pN0 versus cN0 patients across all ages (p < 0.001), but not for patients <45 years (p = 0.11); adjusted survival for all ages did not differ (p = 0.13). Pathological confirmation of negative lymph nodes in patients with PTC appears to influence the decision to administer postoperative RAI if ≥5 negative lymph nodes are removed. It is possible that fewer excised lymph nodes may be viewed by clinicians as incidentally resected and thus may suboptimally represent the true nodal status of the central neck. Further research is warranted to determine if there is an optimal number of lymph nodes that should be resected to standardize pathological diagnosis.