Microscopic positive margins in papillary thyroid cancer do not impact disease recurrence

"Micro" Extrathyroidal Extension in Risk Stratification for Papillary Thyroid Carcinoma: Should It Be in the Intermediate-Risk or High-Risk Group? A Single-Center Retrospective Study

Introduction

Currently, there is no consensus on the specific effect of Extrathyroidal Extension (ETE) on prognosis. The purpose of our study was to study the relationship between different states of ETE and its disease-free survival rate and to determine the basic standard of Micro ETE (tumor extends through capsule only) in risk stratification.

Material and Methods

We conducted a retrospective and single-center study that included the clinical data of all papillary thyroid carcinoma (PTC) patients with ETE in our hospital from 2013 to 2017 and followed them up after rigorous screening. According to ETE state, it is divided into four groups: Microscopic, Micro, Minimal, Macro. Kaplan-Meier method was used to calculate disease-free survival (DFS). Log-rank test was used to compare the differences between the groups and to polt the survival curves. P<0.05 was considered statistically significant. Micro ETE was included in different risk stratification subgroups and their DFS was compared.

Results

A total of 436 patients were included: Microscopic group N=50 (11.47%), Micro group N=74 (16.97%), Minimal group N=135 (30.96%), and Macro group N=177 (40.60%). The frequency of ETE was in strap muscles N=191, trachea N=114, laryngeal recurrent nerve N=92, and capsule N=74, etc. The 5-year DFS rate in Micro group was 95.3%, higher than that in Macro group (P<0.05). The 5-year DFS rate of Micro ETE was 90.0% in the intermediate-risk group and 84.9% in the high-risk group when Micro ETE was included in different risk stratification subgroups.

Conclusion

Micro ETE deserves more attention, has a batter prognosis than Macro ETE, and may have little effect on recurrence. It seems more appropriate to treat Micro ETE as the intermediate-risk group in risk stratification.

Clinical outcomes of T4a papillary thyroid cancer with recurrent laryngeal nerve involvement: a retrospective analysis

Preoperative vocal cord palsy (VCP) may indicate locally invasive papillary thyroid cancer (PTC); using this relationship, we evaluated the clinical outcomes and risk factors for recurrence in post-thyroidectomy T4a PTC patients with recurrent laryngeal nerve (RLN) involvement. We retrospectively investigated thyroidectomy patients, recorded their clinical factors, recurrence rate, and pathological findings, and analysed the relationship between recurrence rate and clinical factors. Of 72 patients, 37 (51%) had preoperative VCP and 35 (49%) had normal preoperative vocal cord movement with confirmed intraoperative RLN invasion. Tracheal and esophageal invasion was observed in 13 (18%) and 15 (21%) patients, respectively. Thyroid cancer recurred in 18 (25%) patients over 58 months, resulting in 2 (3%) deaths. Recurrence was not associated with surgical extent, organ invasion, enlarged tumour size, or lymph node infiltration (p > 0.05). The recurrence rate was significantly higher in patients with positive resection margins (p < 0.05). T4a PTC patients with RLN involvement showed a poor prognosis. The recurrence rate was not affected by preoperative VCP, intraoperative detection of RLN invasion, nerve resection, nerve preservation by shaving, lymph node metastasis, or tracheal or esophageal invasion. The most important prognostic factor for recurrence was a positive resection margin.

Preoperative Factors Associated with Extrathyroidal Extension in Papillary Thyroid Cancer

OBJECTIVE

Extrathyroidal extension may not be accurately recognized during thyroidectomy and can increase the risk of positive margins and even recurrence. This study aimed to investigate the preoperative factors associated with extrathyroidal extension.

METHODS

We analyzed 887 patients with papillary thyroid cancer (PTC) who underwent surgery in the period of 2005-2017. Binary logistic regression analyses and generalized additive models were used to identify associations.

RESULTS

Minimal extrathyroidal extension was present in 233 (26%) patients and advanced extrathyroidal extension was found in 60 (7%) patients. Age, BMI, and tumor size were independent predictors of all or advanced extrathyroidal extension. Among the 493 patients whose BRAF mutation status was available, age (OR = 1.025), BMI (OR = 1.091), tumor size (OR = 1.544), and BRAF V600E mutation (OR = 2.311) were independently associated with extrathyroidal extension.

CONCLUSIONS

Older age, a greater BMI, a larger tumor size, and presence of the BRAF mutation were predictive of extrathyroidal extension. These factors should be taken into consideration in decision-making before surgery is performed.