Recurrent Laryngeal Nerve Invasion by Thyroid Cancer: Laryngeal Function and Survival Outcomes

Recovery of Recurrent Laryngeal Nerve Function With Neoadjuvant Treatment: Neural Characterization

OBJECTIVES

Neoadjuvant targeted therapy has emerged as a promising treatment strategy for locally aggressive thyroid cancer. Its impact on tumor and adjacent tissues remains a nascent area of study. Here we report on a series of six subjects with locally advanced thyroid cancer and recurrent laryngeal nerve (RLN) paralysis who experienced recovery of RLN function with neoadjuvant treatment and describe the morphologic and electrophysiologic characteristics of these recovered nerves.

METHODS

This is a multicenter retrospective review. Descriptive analysis was conducted to examine the following parameters for recovered nerves: (1) nerve morphology, characterized as Type A (involving epineurium only) versus Type B (extending beyond epineurium); (2) proximal stimulability (normal vs. abnormal vs. absent); and (3) surgical management (resection vs. preservation).

RESULTS

Six subjects with unilateral VFP were identified. Median time to return of VF mobility was 3 months (range 2-13.5). All nerves (100%) were noted to have Type A morphology at surgery. Proximal stimulability was normal in four subjects (66.7%), abnormal in one (16.7%), and absent in one (16.7%). Nerves that had improvement of function through neoadjuvant therapy were able to be surgically preserved in five subjects (83.3%).

CONCLUSIONS

This represents the first characterization of RLNs that have recovered function with neoadjuvant treatment of locally advanced thyroid cancer. Although much remains unknown, our findings indicate carcinomatous neural invasion is a reversible process and recovered nerves may demonstrate normal morphology and electrophysiologic activity.

LEVEL OF EVIDENCE

4 Laryngoscope, 134:3415-3419, 2024.

The Effect of Hemithyroidectomy in Papillary Thyroid Carcinoma with an Exclusive Involvement of the Recurrent Laryngeal Nerve: A Retrospective Study with a Propensity Score-Matched Analysis

BACKGROUND

Involvement of the recurrent laryngeal nerve (RLN) in papillary thyroid carcinoma (PTC) is an important prognostic factor and is associated with a higher risk of recurrence. This study aimed to retrospectively analyze the outcomes of patients treated with hemithyroidectomy (HT) in PTC patients with an exclusive RLN invasion who could not tolerate staged surgery, did not wish to undergo another operation, or had other reasons.

METHODS

A retrospective review was conducted on 163 patients with PTC and exclusive RLN involvement at our institution between 2013 and 2019. Patients were divided into a total thyroidectomy (TT) group and HT group. The clinicopathologic factors and prognostic outcomes were compared between the two groups. A propensity score-matched analysis was carried out to reduce selection bias, with the following covariates: gender, age, tumor size, multifocality, central lymph node metastasis (CLNM), and RLN resection. The Kaplan-Meier method was used for a comparison of recurrence outcomes.

RESULTS

In the baseline data of the 163 PTC patients, tumor size (p < 0.001), multifocality (p = 0.011), CLNM (p < 0.001), and RLN resection (p < 0.008) in the TT and HT groups differed significantly, whereas age and gender did not differ between the two groups. The TT group reported significantly higher temporary and permanent hypoparathyroidism than the HT group (p < 0.001 and p = 0.042, respectively). With 72-month median follow-up, 11 (6.7%) patients developed recurrence. After propensity score matching, 24 patients with HT and 43 patients with TT were included. Recurrence-free survival (RFS) in the matched samples showed no difference between the TT and HT groups (p = 0.092).

CONCLUSION

Our results indicate that HT may be a feasible treatment for PTC patients with exclusive RLN involvement in specific circumstances without significantly increasing the risk of recurrence. Performing a thorough preoperative examination is crucial to exclude multifocal tumors and lymph node metastasis before undergoing HT.

Impact of thyroid carcinoma invasion of recurrent laryngeal nerve on cervical lymph node metastasis

PURPOSE

Papillary thyroid carcinoma (PTC) has a favorable prognosis. However, involvement of the recurrent laryngeal nerve (RLN) significantly increases the risk of recurrence. RLN invasion was an important factor in determining the extent of thyroid surgery. The purpose of this study was to compare clinicopathologic features and characterize risk factors of central and lateral lymph node metastasis (LLNM) of RLN invasion in patients with PTC.

METHODS

A retrospective review was conducted of 130 patients with PTCs who had exclusive tumor involvement of the RLN at our institution between January 2014 and February 2019. All patients underwent total thyroidectomy and high-dose radioactive iodine (RAI) therapy. The clinicopathologic factors and prognostic outcomes of the patients with solitary and multiple RLN involvements were compared. Kaplan-Meier method was performed to compare the outcomes of tumor recurrence. Univariate and multivariate logistic regression analyses were used to identify risk factors associated with LLNM.

RESULTS

The invasion of the RLN was similar on both sides, with 58.5% on the right, 40.0% on the left, and 1.5% on both sides. Significant differences were observed in tumor size (p < 0.001), lymph node metastasis classification (p = 0.002), RLN resection (p < 0.001), and thyroglobulin (p = 0.010) in the solitary and multiple groups. During the median follow-up of 67 months, 9 (6.9%) patients developed recurrence. There were no statistical differences in recurrence for age, tumor size, gender, multifocality, lymph node metastasis (LNM), and RLN resection. According to receiver operating characteristic (ROC) curve analyses, a cut-off of tumor size > 1.7 cm was identified as the most sensitive and specific predictor of RLN with multiple involvements or LNM invasion. Univariate and multivariate analyses revealed that central lymph node metastasis (CLNM) and RLN invasion by LNM can serve as independent risk factors for LLNM (p = 0.006 and p < 0.001, respectively).

CONCLUSION

Our results indicate that recurrence was comparable in patients with solitary and multiple RLN involvements. Multiple RLN involvement was associated with pathological features such as larger tumors, RLN resection, and LLNM. The presence of LNM invading RLN and multiple nerve involvement increases the risk of intraoperative RLN resection. A higher risk of multiple invasion or LNM invasion should be considered when tumor size > 1.7 cm. The presence of CLNM and RLN invaded by LNM were independent predictors for LLNM, which could aid surgeons in deciding on lateral lymph node dissection.

New strategy for intraoperative phonosurgical management of recurrent laryngeal nerve infiltrated by thyroid carcinoma

PURPOSE

Treating an infiltration of the recurrent laryngeal nerve (RLN) by thyroid carcinoma remains a subject of ongoing debate. Therefore, this study aims to provide a novel strategy for intraoperative phenosurgical management of RLN infiltrated by thyroid carcinoma.

METHODS

Forty-two patients with thyroid carcinoma infiltrating the RLN were recruited for this study and divided into three groups. Group A comprised six individuals with medullary thyroid cancer who underwent RLN resection and arytenoid adduction. Group B consisted of 29 differentiated thyroid cancer (DTC)patients who underwent RLN resection and ansa cervicalis (ACN)-to-RLN anastomosis. Group C included seven patients whose RLN was preserved.

RESULTS

The videostroboscopic analysis and voice assessment collectively indicated substantial improvements in voice quality for patients in Groups A and B one year post-surgery. Additionally, the shaving technique maintained a normal or near-normal voice in Group C one year post-surgery.

CONCLUSION

The new intraoperative phonosurgical strategy is as follows: Resection of the affected RLN and arytenoid adduction is required in cases of medullary or anaplastic carcinoma, regardless of preoperative RLN function. Suppose RLN is found infiltrated by well-differentiated thyroid cancer (WDTC) during surgery, and the RLN is preoperatively paralyzed, we recommend performing resection the involved RLN and ACN-to-RLN anastomosis immediately during surgery. If vocal folds exhibit normal mobility preoperatively, the MACIS scoring system is used to assess patient risk stratification. When the MACIS score > 6.99, resection of the involved RLN and immediate ACN-to-RLN anastomosis were performed. RLN preservation was limited to patients with MACIS scores ≤ 6.99.

Shaving Papillary Thyroid Carcinoma Involving Functioning Recurrent Laryngeal Nerve: Safety of Incomplete Tumor Resection and Nerve Sparing

BACKGROUND

Whether to sacrifice or spare the recurrent laryngeal nerve (RLN) when papillary thyroid carcinoma (PTC) involves a functioning RLN remains controversial. Oncological outcomes after shaving PTC with gross remnant on the RLN have been rarely reported. The objective of this study was to evaluate the oncological outcomes of patients who underwent shaving of a PTC from the RLN, leaving a gross residual tumor with the intent of vocal function preservation.

METHODS

A retrospective, cohort study was conducted in 47 patients who were determined to have PTC invasion of the RLN via intraoperative inspection and underwent tumor shaving with macroscopic remnant (R2 resection) less than 1 cm in length and 4 mm in thickness. Median follow-up period was 93 (range, 60-215) months. The primary endpoint was the recurrence-free survival and the progression-free survival. Secondary endpoints were biochemical outcomes (serum thyroglobulin) and vocal cord function.

RESULTS

Of the 47 patients, five (10.6%) patients showed recurrence (central neck, 3; lateral neck, 2) without death or distant metastasis. The RLN was resected along with the tumor in one (2.1%) patient who presented with progression of the residual tumor. Postoperative temporary vocal cord paralysis occurred in six (12.8%) patients without permanent cases. The final nonstimulated serum thyroglobulin was 0.7 ± 1.8 ng/ml.

CONCLUSIONS

Shaving a tumor from a RLN with gross residual disease may be considered an alternative strategy to preserve vocal function when complete tumor resection with nerve preservation is impossible in patients with PTC invading a functioning RLN.

Surgical and Biochemical Outcomes in Nerve Monitored Reoperation Surgery for Recurrent Papillary Thyroid Carcinoma

OBJECTIVE

To study the surgical and biochemical outcomes in nerve-monitored reoperation or revision surgery for recurrent thyroid cancers.

STUDY DESIGN

A single-center retrospective study.

SETTING

Tertiary center.

METHODS

We identified patients with recurrent papillary thyroid carcinoma (PTC) who underwent reoperation/revision surgery. Study outcomes were surgical complications frequency, recurrence, distant metastasis, and biological complete response (BCR) by comparing preoperative and postoperative thyroglobulin (Tg) levels.

RESULTS

Out of 227 patients, 33.9% presented for ≥2 reoperation surgeries. Nineteen (8.4%) had permanent preoperative hypoparathyroidism while 22 patients (9.7%) had preoperative vocal cord paralysis (VCP). Following reoperation surgery, there were 12 cases (5.3%) of permanent hypocalcemia and no cases of unexpected postoperative VCP. BCR was achieved in 31 patients (35.2%) with complete Tg data. Mean preoperative Tg was 47.7 ng/mL and was 19.7 ng/mL postoperatively (p = .003). The cervical nodal recurrence rate after final surgery was 7.0% (n = 16).

CONCLUSION

Reoperation surgery for recurrent PTC may help achieve biochemical remission regardless of age or the number of prior surgeries.

Aspirin-Loaded Cross-Linked Lipoic Acid Nanodrug Prevents Postoperative Tumor Recurrence by Residual Cancer Cell Killing and Inflammatory Microenvironment Improvement

In addition to residual cancer cells, the surgery resection-induced hyperinflammatory microenvironment is a key factor that leads to postsurgical cancer recurrence. Herein, we developed a dual-functional nanodrug Asp@cLANVs for postsurgical recurrence inhibition by loading the classical anti-inflammatory drug aspirin (Asp) into cross-linked lipoic acid nanovesicles (cLANVs). The Asp@cLANVs can not only kill residual cancer cells at the doses comparable to common cytotoxic drugs by synergistic interaction between Asp and cLANVs, but also improve the postsurgical inflammatory microenvironment by their strongly synergistic anti-inflammation activity between Asp and cLANVs. Using mice bearing partially removed NCI-H460 tumors, we found that Asp@cLANVs gave a much lower recurrence rate (33.3%) compared with the first-line cytotoxic drug cisplatin (100%), and no mice died for at least 60 days after Asp@cLANV treatment while no mouse survived beyond day 43 in the cisplatin group. This dual-functional nanodrug constructs the first example that combines residual cancer cell killing and postoperative inflammation microenvironment improvement to suppress postsurgical cancer recurrence.

Management of Recurrent Well-Differentiated Thyroid Carcinoma in the Neck: A Comprehensive Review

Surgery has been historically the preferred primary treatment for patients with well-differentiated thyroid carcinoma and for selected locoregional recurrences. Adjuvant therapy with radioactive iodine is typically recommended for patients with an intermediate to high risk of recurrence. Despite these treatments, locally advanced disease and locoregional relapses are not infrequent. These patients have a prolonged overall survival that may result in long periods of active disease and the possibility of requiring subsequent treatments. Recently, many new options have emerged as salvage therapies. This review offers a comprehensive discussion and considerations regarding surgery, active surveillance, radioactive iodine therapy, ultrasonography-guided percutaneous ablation, external beam radiotherapy, and systemic therapy for well-differentiated thyroid cancer based on relevant publications and current reference guidelines. We feel that the surgical member of the thyroid cancer management team is empowered by being aware and facile with all management options.

Preoperative voice analysis and survival outcomes in papillary thyroid cancer with recurrent laryngeal nerve invasion

OBJECTIVE

To investigate the clinicopathological characteristics of papillary thyroid cancer (PTC) and identify risk factors for postoperative recurrence of PTC with recurrent laryngeal nerve (RLN) involvement.

METHODS

In total, 171 patients (112 women and 59 men, age: 18-80 years, and 65 patients aged ≥ 55) with T4a PTC with RLN involvement, treated at Beijing Tongren Hospital, Capital Medical University, from January 2006 to December 2020, were retrospectively examined. Clinicopathological characteristics, including voice analysis results, and survival outcomes were assessed. The Mann-Whitney U and Kruskal-Wallis H tests were used to analyze differences in acoustic parameters. The Kaplan-Meier method was used to calculate the overall survival (OS) and recurrence-free (RFS) rates. Univariate and multivariate Cox regression analyses were performed of the clinical data.

RESULTS

The postoperative follow-up period ranged from 12 to 196 months (mean: 66.18 months). Of the 171 patients, 16 had recurrence and 8 died of thyroid-related diseases. The 5-year OS rate was 95.22%. The 5-year RFS rate was 89.38%. Jitter and shimmer were higher and maximum phonation time was shorter in patients with preoperative vocal cord paralysis (VCP) than in those without RLN involvement, and in those with RLN involvement but without preoperative VCP. Acoustic parameters were similar in patients with no preoperative VCP and those without RLN involvement. Voice analysis results did not differ between cases with RLN adhesion and RLN invasion. Univariate analysis showed that age at onset ≥ 55 years, preoperative RLN palsy, and esophageal invasion were risk factors for postoperative recurrence of PTC with RLN involvement. Multivariate analysis showed that onset age ≥ 55 years (OR 4.52, 95% confidence interval: 1.44-14.19, P = 0.010) was an independent risk factor for recurrence.

CONCLUSIONS

PTC patients with RLN invasion can achieve good outcomes. Preoperative voice analysis may offer insights into RLN function. Age of onset ≥ 55 years is an independent risk factor for postoperative recurrence in T4a PTC patients.