Researchers recently described clinical characteristics, preoperative and postoperative laryngeal function, surgical management, survival, and recurrence in patients with medullary thyroid carcinoma (MTC) with the invasion of the recurrent laryngeal nerve (RLN) and published their findings in Laryngoscope.

Brooks and colleagues established that preoperative vocal cord paralysis (VCP) accompanies less than half of patients with RLN invasion while still conserving existent electrophysiologic stimulability.

They also identified that radioactive iodine was the only statistically significant factor linked with improvement in both 5-year recurrence-free survival (P =.006) and 5-year overall survival (P =.004), regardless of RLN resection status during surgery. This displayed similar results to prior studies of differentiated thyroid carcinomas, which showed no survival benefit difference in patients based on resection of an invaded RLN vs leaving it intact with a surrounding tumor.


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Conversely, the researchers showed no association between complete tumor resection or RLN resection with neither 5-year recurrence-free survival nor overall survival.

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“Additionally, we report that RLNs without preoperative VCP had a higher median amplitude compared with RLNs with preoperative VCP. This suggests a nerve invasion may be a gradual process and some neural function is maintained throughout long periods of the invasive process,” the authors explained.

This retrospective single-center study included patients with invaded RLNs operated between December 1995 and December 2015 while using nerve monitoring techniques. MTC was the second most common subtype (9.2%) found during this study, surpassed only by papillary thyroid carcinoma (80.0%), followed by the follicular (6.2%) and undifferentiated subtypes (3.1%).

RLN is among the usually invaded structures in the setting of invasive MTC, associated with higher potential comorbidities and higher recurrence rates than those without RLN invasion.

“Surgeons need to discuss the tumor extent and RLN resection in the preoperative planning and consenting process,” the authors said. “A multidisciplinary team can achieve optimal survival and vocal outcomes in the setting of advanced thyroid cancer.”

Reference

Brooks J, Abdelhamid Ahmed A, Al‐Qurayshi Z, et al. Recurrent laryngeal nerve invasion by thyroid cancer: laryngeal function and survival outcomes. Laryngoscope. Published online April 1, 2022. doi:10.1002/lary.30115