Significance of Size of Persistent/Recurrent Central Nodal Disease on Surgical Morbidity and Response to Therapy in Reoperative Neck Dissection for Papillary Thyroid Carcinoma

Comparison of unilateral versus bilateral central neck dissection for clinically invasive papillary thyroid carcinoma

BACKGROUND

The American Thyroid Association guidelines primarily recommend central neck dissection for papillary thyroid carcinoma with advanced primary tumors or clinically positive neck nodes. However, the appropriate extent of dissection remains unclear. We aimed to compare the rate of locoregional recurrence between unilateral and bilateral central neck dissection in invasive papillary thyroid carcinoma.

METHODS

Among 330 consecutive patients who underwent total thyroidectomy with central neck dissection for advanced papillary thyroid carcinoma, 212 underwent unilateral central neck dissection (UCND group) while 118 underwent bilateral central neck dissection (BCND group). We performed 1:1 propensity score matching, resulting in 99 matched pairs. Surgical outcomes and safety were compared between the two groups. Additionally, the impact of surgery on locoregional recurrence was compared using survival analysis.

RESULTS

During a follow-up of 47.8 ± 20.4 months, 29 (8.8%) patients experienced locoregional recurrence within the entire study cohort. Following propensity score matching, no significant difference in recurrence-free survival was observed between the two groups (log-rank p = 0.516). Multivariate analysis revealed that only T4 staging was an independent risk factor for locoregional recurrence (p = 0.006). The mean number of total and metastatic central lymph nodes retrieved were significantly greater in BCND group (14.1 vs. 9.3, p < 0.001 and 6.8 vs. 4.6, p = 0.005, respectively). There was no significant difference in postoperative stimulated thyroglobulin levels between the two groups (0.79 ng/mL vs. 1.44 ng/mL, p = 0.389).

CONCLUSION

The present study demonstrates no prognostic benefit in conducting bilateral central neck dissection. Unilateral central neck dissection may be the preferred choice for clinically invasive papillary thyroid carcinoma.

The TOFr of 0.75 to 0.85 is the optimal timing for IONM during thyroid surgery: a prospective observational cohort study

BACKGROUD

Recurrent laryngeal nerve (RLN) injury is one of the serious complications of thyroid tumour surgery, surgical treatment of thyroid cancer requires careful consideration of the RLN and its impact on glottis function. There has been no unified standard for precise neuromuscular block monitoring to guide the monitoring of RLN in thyroid surgery. This study aimed to investigate the correlation between Train-of-four stabilization ratio (TOFr) and neural signal values of intraoperative neurophysiological monitoring (INOM) during thyroid operation, and further to determine the optimal timing for INOM during thyroid operation.

METHODS

Patients scheduled for thyroid tumour resection with INOM and RLN monitoring from April 2018 to July 2018 in our center were recruited. Electromyography (EMG) signals and corresponding TOFr were collected. All nerve stimulation data were included in group VR. Vagus nerve stimulation data were included in Subgroup V. RLN stimulation data were included in Subgroup R. The timing of recording was as follows: Vagus nerve EMG amplitude after opening the lateral space between the thyroid and carotid sheath and before the initiation of thyroid dissection, RLN EMG amplitude at first recognition, RLN EMG amplitude after complete thyroid dissection (Repeat three times), and Vagus nerve EMG amplitude after resection of the thyroid (Repeat three times). Correlation analysis of continuous variables was described by a scatter diagram. Pearson correlation analysis or Spearman correlation analysis was used for the two groups of variables.

RESULTS

Finally, 134 vagus nerve signals and 143 RLN signals were analysed after matching with TOFr. The EMG amplitude in the VR group and subgroups after nerve stimulation was positively correlated with TOFr (p < 0.05). In the VR, V and R group, the incidence of EMG ≥ 500 µV in the 0.75 < TOFr ≤ 0.85 interval was significantly higher than the 0 < TOFr ≤ 0.75 interval (P = 0.002, P = 0.013 and P = 0.029), and has no statistical difference compared to 0.85 < TOFr ≤ 0.95 interval (P > 0.05).

CONCLUSIONS

The EMG signals of the RLN and vagus nerve stimulation during thyroid surgery were positively correlated with TOFr. TOFr > 0.75 could reflect more than 50% of the effective nerve electrophysiological signals, 0.75 < TOFr ≤ 0.85 interval was the optimal timing for IONM during thyroid surgery.

TRIAL REGISTRATION

Chinese Clinical Trial Registry (ChiCTR1800015797) Registered on 20/04/2018. https://www.chictr.org.cn .

Guideline for the Surgical Management of Locally Invasive Differentiated Thyroid Cancer From the Korean Society of Head and Neck Surgery

The aim of this study was to develop evidence-based recommendations for determining the surgical extent in patients with locally invasive differentiated thyroid cancer (DTC). Locally invasive DTC with gross extrathyroidal extension invading surrounding anatomical structures may lead to several functional deficits and poor oncological outcomes. At present, the optimal extent of surgery in locally invasive DTC remains a matter of debate, and there are no adequate guidelines. On October 8, 2021, four experts searched the PubMed, Embase, and Cochrane Library databases; the identified papers were reviewed by 39 experts in thyroid and head and neck surgery. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to assess the quality of evidence, and to develop and report recommendations. The strength of a recommendation reflects the confidence of a guideline panel that the desirable effects of an intervention outweigh any undesirable effects, across all patients for whom the recommendation is applicable. After completing the draft guidelines, Delphi questionnaires were completed by members of the Korean Society of Head and Neck Surgery. Twenty-seven evidence-based recommendations were made for several factors, including the preoperative workup; surgical extent of thyroidectomy; surgery for cancer invading the strap muscles, recurrent laryngeal nerve, laryngeal framework, trachea, or esophagus; and surgery for patients with central and lateral cervical lymph node involvement. Evidence-based guidelines were devised to help clinicians make safer and more efficient clinical decisions for the optimal surgical treatment of patients with locally invasive DTC.

The outcomes and prognostic factors of patients who underwent reoperation for persistent/recurrent papillary thyroid carcinoma

BACKGROUND

While the most suitable approach for treating persistent/recurrent papillary thyroid carcinoma (PTC) remains controversial, reoperation may be considered an effective method. The efficacy of reoperation in patients with locoregional persistent/recurrent PTC, especially those with unsatisfactory radioactive iodine (RAI) ablation results, is still uncertain. This study aimed to clarify the clinical management strategies for locoregional persistent/recurrent PTC and to explore factors that may affect long-term patient outcomes after reoperation.

METHODS

In total, 124 patients who initially underwent thyroidectomy and variable extents of RAI therapy and finally received reoperation for locoregionally persistent/recurrent PTC were included. The parameters associated with recurrence-free survival (RFS) were analysed using a Cox proportional hazards model.

RESULTS

Overall, 124 patients presented with structural disease after initial therapy and underwent secondary surgical resection, of whom 32 patients developed further structural disease during follow-up after reoperation. At the time of reoperation, metastatic lymph nodes with extranodal extension (P = 0.023) and high unstimulated thyroglobulin (unstim-Tg) levels after reoperation (post-reop) (P = 0.001) were independent prognostic factors for RFS. Neither RAI avidity nor the frequency and dose of RAI therapies before reoperation affected RFS.

CONCLUSIONS

Reoperation is an ideal clinical treatment strategy for structural locoregional persistent/recurrent PTC, and repeated empirical RAI therapies performed prior to reoperation may not contribute to the long-term outcomes of persistent/recurrent PTC patients. Metastatic lymph nodes with extranodal extension and post-reop unstim-Tg > 10.1 ng/mL may predict a poor prognosis.

Macroscopic extranodal extension is an independent predictor of lung metastasis in papillary thyroid cancer

PURPOSE

Lymph node metastasis is common in patients with papillary thyroid cancer (PTC). Some metastatic lymph nodes may present extranodal extension (ENE). The clinical role of ENE in PTC has yet to be clearly identified. We evaluated macroscopic ENE as a potential prognostic indicator of lung metastasis in PTC.

PATIENTS AND METHODS

We identified 1140 consecutive patients who had PTC initially resected at our cancer center. Clinical data and pathological results were reviewed. Univariate and multivariate logistic regression analyses were used to figure out the association between clinicopathological variables and lung metastasis.

RESULTS

In this cohort, 51.7% of PTC patients had lymph node metastasis; 10.4% had macroscopic ENE positive nodes; 2.3% had lung metastasis. In patients with lymph node metastasis, the average number of positive nodes was 5.10 ± 4.91. Multivariable analysis of clinicopathological factors revealed that extrathyroidal extension (odds ratio [OR], 3.57; 95% CI, 1.41-9.04), macroscopic ENE (OR, 7.08; 95% CI, 2.54-19.74), and number of positive nodes were significantly associated with lung metastasis. Compared with 0-3 positive nodes, 7-9 positive nodes denoted a moderate risk of lung metastasis (OR, 4.53; 95% CI, 1.03-19.85). And 10 positive nodes or more indicated a high risk of lung metastasis (OR, 9.63; 95% CI, 2.65-35.02).

CONCLUSION

Macroscopic ENE could serve as a strong independent prognostic factor of lungmetastasis in PTC. More attention should be paid to patients with ENE positive nodes duringfollow-up.

Hyperthermal liquid, spray, and smog may be potential risk factors for recurrent laryngeal nerve thermal injury during thyroid surgeries

PURPOSE

The hyperthermal liquid, spray and smog caused by energy-based surgical devices (EBDs) may be the potential risk factors for recurrent laryngeal nerve (RLN) thermal injury, but not been reported previously. We aim to demonstrated it both in thyroid surgeries and animal experiments.

METHODS

321 thyroid patients and 32 rats were divided into two groups respectively. A type of endoscopic gauze was implemented in the protected group to prevent nerve from thermal risks. Electromyography and laryngoscope were recorded to determine nerve's conductive ability. Microstructural morphological damage to nerves and muscles were evaluated by light and electron microscopy in the animal experiments.

RESULTS

After thyroid surgeries, the incidence of transient vocal cord (VC) palsy was decreased in the protected group (1.4%) compared with the conventional group (4.7%) (P = 0.037). In animal experiments, the average nerve conductive velocity was significantly decreased in the conventional group (5.8 ± 2.1 vs. 25.5 ± 4.7 m/s, P < 0.01). Typical acute morphological thermal changes of edema, coagulation and homogenization in nerve tissues were recorded by light microscopy in the conventional group. Four weeks later, the average weight of gastrocnemius muscles in the injured limb was significantly decreased (1.3 ± 0.2 vs. 2.2 ± 0.2 g, P < 0.01), while no significant difference was noted in the protected group (2.0 ± 0.3 vs. 2.3 ± 0.4 g, P = 0.61).

CONCLUSIONS

Hyperthermal liquid, spray or smog may represent risk factors contributing to RLN thermal injury caused by EBDs. Damage to the nerve's conductive ability and morphological changes in nerves and muscles likely represent typical responses to thermal injury. Implementation of endoscopic gauze may be a promising method to protect the RLN from thermal damage especially in endoscopic thyroid surgeries.

Utility of Activated Carbon Nanoparticle (CNP) During total Thyroidectomy for Clinically Nodal Positive Papillary Thyroid Carcinoma (PTC)

BACKGROUND

Activated carbon nanoparticle (CNP) is a novel tracer that may facilitate nodal dissection in clinically nodal positive (cN1) papillary thyroid carcinoma (PTC). The present study compared the nodal yield and surgical outcomes between surgery with CNP and without CNP.

METHODS

Patients who underwent total thyroidectomy with therapeutic nodal dissection for cN1 PTC were given the option of intraoperative CNP injection. Among those who received CNP, 0.2 mL CNP suspension was injected in both thyroid lobes before dissection. Study endpoints included number of total and metastatic lymph nodes, inadvertently removed parathyroid glands (PGs), postoperative parathyroid hormone, calcium, and post-6-month thyroglobulin (Tg). Biochemical complete response (BCR) was defined as Tg ≤ 1 ng/mL and/or stimulated Tg ≤ 2 ng/mL.

RESULTS

One-hundred and twenty patients (58.3%) received CNP, while 86 (41.7%) had surgery without CNP. Demographics, tumor characteristics, and operative time were comparable between the two groups. However, total mean number of normal and metastatic lymph nodes retrieved were significantly greater in CNP group (10.0 vs. 8.1, p = 0.032 and 4.5 vs. 2.7, p = 0.002, respectively). Rate of inadvertently removed PG was significantly less in CNP group (13.3% vs. 23.3%, p = 0.042). Postoperative Tg level and BCR were significantly lower in CNP group (9.9 ng/mL vs. 14.7 ng/mL, p = 0.297 and 82.4% vs. 72.9%, p = 0.002, respectively). However, large-sized ( ≥ 3 cm) PTCs had a significantly lower nodal staining rate than smaller-sized PTCs (10.3% vs. 69.4%, p < 0.001).

CONCLUSIONS

CNP injection can facilitate therapeutic central nodal dissection by increasing the nodal yield rates and reducing inadvertent PG removal. To enhance its utility, a greater volume of CNP might be necessary in larger-sized (> 3 cm) PTCs.

Expression of miRNA-146b-5p in patients with thyroid cancer in combination with Hashimoto's disease and its clinical significance

The expression level of microRNA (miRNA)-146b in patients with thyroid carcinoma (TC) in combination with Hashimoto's thyroditis (HT) was evaluated to analyze the clinical significance. Eighty-seven patients who underwent thyroid surgery in The Third Affiliated Hospital of Southern Medical University from March 2010 to February 2013 were enrolled. Of the patients, 37 were diagnosed with TC (group A), and 50 were diagnosed with TC in combination with HT (group B). Forty patients were diagnosed with HT (group C). The expression levels of miRNA-146b-5p in cancer tissue and paracancerous tissue of patients in the two groups were measured by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Correlation between the miRNA-146b-5p levels and the clinicopathological characteristics of patients with combined TC and HT were evaluated. According to the expression of miRNA-146b-5p, patients in group B were separated into the high and low expression groups to observe the five-year cancer recurrence rate. There was no significant difference in miRNA-146b-5p expression between the papillary carcinoma group, the follicular carcinoma group and the medullary carcinoma group (P>0.05). The miRNA-146b-5p expression in the lesion tissue of group B was significantly higher than that of groups A and C, while the miRNA-146b-5p expression in the lesion tissue of group A was significantly higher than that of group C (P<0.05), and the lesion tissue of the three groups was higher than that of the corresponding parastatal tissue (P<0.05). The miRNA-146b-5p expression level was associated with tumor size, lymph node metastasis and TNM stage (P<0.05), while not associated with sex, age, lesion multiplicity, smoking history, diabetes history and pathological type in group B (P>0.05). The non-recurrence rate of group B high expression subgroup was lower than that of group B low expression subgroup (P=0.045). High expression of miRNA-146b-5p was found in the cancer tissues of patients with combined TC and HT. The expression level of miRNA-146b-5p was associated with tumor size, lymph node metastasis and TNM stage. It is a potential prognostic indicator for patients with combined TC and HT.