The definition of lymph node micrometastases in pathologic N1a papillary thyroid carcinoma should be revised

Babu M, Vasudevan Pillai A. Prophylactic Central Compartment Dissection on the Long-Term Outcome of Advanced (N0-T3/T4) Papillary Thyroid Cancer

Aim

To see whether prophylactic central compartment dissection is recommended for advanced papillary thyroid cancer or as part of selective neck node dissection. Central compartment dissection is a technically demanding surgical procedure and carries a higher incidence of complications. The present retrospective case-control study analysed the impact of prophylactic central compartment dissection on the long-term outcome of advanced (N0-T3/T4) papillary thyroid cancer.

Materials and methods

Case records of patients operated on for papillary thyroid cancer from 2005 to 2010 were reviewed and patients with Tumour stage 3-4 and N0 nodal status were included in the study. The institutional protocol was to perform total thyroidectomy with central compartment dissection during the early phase of the study period (2005 to 2008) but this strategy was shifted to total thyroidectomy alone during the latter phase. Fifty-five patients were included in the study and 29 of the cohort had total thyroidectomy with prophylactic central compartment dissection as the primary surgery and the remaining 26 had a total thyroidectomy as the primary surgical procedure.

Result

Patients were followed up for a median duration of 115 months and found to have no significant difference in the incidences of loco-regional recurrences between the groups. (n:4 (14%) Vs n: 3 (12%) p = .463). The disease-free survival and overall survival were not significantly different in the groups. There was a trend to an increase in the incidence of permanent hypoparathyroidism in patients who had central compartment dissection.

Conclusion

Prophylactic central compartment dissection did not influence the 10-year outcome of advanced node-negative papillary thyroid cancers.

Partial Thyroidectomy With Incidental Metastatic Lymph Nodes

Importance

The need for completion thyroidectomy in patients with incidental metastatic lymph nodes after partial thyroidectomy is unclear.

Objective

To investigate the outcomes of patients with incidental metastatic lymph nodes following partial thyroidectomy.

Design, Setting, and Participants

A retrospective review of a prospectively maintained thyroid cancer database from 1985 to 2015 was carried out at a head and neck surgery practice at a tertiary referral cancer center. A total of 74 patients who underwent thyroid lobectomy or thyroid isthmusectomy between 1985 and 2015 and were found to have incidental metastatic lymph nodes on final pathologic analysis and were selected to be observed without immediate completion thyroidectomy were included. A separate group of additional 11 patients who underwent immediate completion thyroidectomy was also identified and reviewed.

Main Outcome and Measure

Analysis took place from February to May 2022. Recurrence-free survival outcomes of patients found to have incidental metastatic lymph nodes on final pathologic analysis following partial thyroidectomy with no immediate completion thyroidectomy.

Results

A total of 74 patients were observed, with a median (IQR) age of 39 (28-49) years; 44 (59%) were women. Sixty-four patients underwent thyroid lobectomy and 10 patients had isthmusectomy. Classic papillary thyroid carcinoma was the most common histologic type (34 [46%]). Vascular invasion and microscopic extrathyroidal extension were present in 11 patients (16%) and 22 patients (30%), respectively. Positive margins were identified in 5 patients (7.8%). Size of metastatic lymph nodes ranged between 0.07 cm and 1.2 cm. No extranodal extension was reported. A total of 52 patients (70%) were classified as intermediate risk for recurrence based on the American Thyroid Association risk stratification system. The median (IQR) follow up was 48.15 (15.4-86.1) months, during which only 1 patient had a regional recurrence. Another patient underwent delayed completion thyroidectomy for a contralateral lobe malignant abnormality. Recurrence-free survival, disease-specific survival, and overall survival were 97.4%, 100%, and 96.2%, respectively. A separate group of 11 patients who underwent immediate completion thyroidectomy were reviewed. These patients were more likely to have tall-cell papillary thyroid carcinoma (6 [55%] vs 13 [18%]), multifocality (9 [82%] vs 28 [41%]), microscopic extrathyroidal extension (8 [73%] vs 22 [30%]), and positive margins (3 [30%] vs 5 [7.8%]) compared with patients who were under observation only.

Conclusion and Relevance

Completion thyroidectomy may not be necessary in appropriately selected patients who are found to have incidental metastatic lymph nodes (N1a) after partial thyroidectomy for localized well-differentiated thyroid cancer.

The prognostic value of lymphatic metastatic size in head and neck squamous cell carcinoma

BACKGROUND

Lymphatic metastatic size was proved to predict prognosis in different types of carcinomas, except in head and neck squamous cell carcinoma (HNSCC) located in hypopharynx, oropharynx and supraglottic region et al. The aim of this study is to evaluate the prognostic value of lymphatic metastatic size in HNSCC, which may guide clinical decision-making in practice.

METHODS

From 2008 to 2022, 171 patients, who were diagnosed as HNSCC in our center, were included. The demographic data, clinicopathological characteristics and lymphatic metastatic size were recorded and analyzed using the Kaplan-Meier method and Cox regression analysis.

RESULTS

Among 171 patients, 107 cases were hypopharyngeal cancer, 38 cases supraglottic cancer and 26 cases oropharyngeal cancer. The median of lymphatic metastatic size was 8 mm (range 0-46). According to lymphatic metastatic size, the patients were assigned to three subgroups: Group I (0 mm), Group II ( ≤ 10 mm) and Group III (> 10 mm). Kaplan-Meier analysis with log rank test revealed that Group I and Group II had similar locoregional control rate, distant metastasis free probability, disease-free survival and overall survival (all p > 0.05), whereas Group III had significant worse prognosis. Adjusted for demographic and other clinicopathological characteristics, lymphatic metastatic size was an independent predictor of disease-free survival and overall survival in HNSCC.

CONCLUSIONS

Lymphatic metastatic size was an independently prognostic factor in HNSCC, which may assist in postoperative adjuvant treatment decisions.

Recurrence Risk Evaluation in Patients with Papillary Thyroid Carcinoma: Multicenter Machine Learning Evaluation of Lymph Node Variables

Background: Lymph node (LN)-related risk factors have been updated to predict long-term outcomes in patients with papillary thyroid carcinoma (PTC). However, those factors’ analytic appropriateness and general applicability must be validated. This study aimed to assess LN-related risk factors, and suggest new LN-related risk categories. Methods: This multicenter observational cohort study included 1232 patients with PTC with N1 disease treated with a total thyroidectomy and neck dissection followed by radioactive iodine remnant ablation. Results: The median follow-up duration was 117 months. In the follow-up period, structural recurrence occurred in 225 patients (18.3%). Among LN-related variables, the presence of extranodal extension (p < 0.001), the maximal diameter of metastatic LN foci (p = 0.029), the number of retrieved LNs (p = 0.003), the number of metastatic LNs (p = 0.003), and the metastatic LN ratio (p < 0.001) were independent risk factors for structural recurrence. Since these factors showed a nonlinear association with the hazard ratio of recurrence-free survival (RFS) rates, we calculated their optimal cutoff values using the K-means clustering algorithm, selecting 0.2 cm and 1.1 cm for the maximal diameter of metastatic LN foci, 4 and 13 for the number of metastatic LN, and 0.28 and 0.58 for the metastatic LN ratio. The RFS curves of each subgroup classified by these newly determined cutoff values showed significant differences (p < 0.001). Each LN risk group also showed significantly different RFS rates from the others (p < 0.001). Conclusions: In PTC patients with an N1 classification, our novel LN-related risk estimates may help predict long-term outcomes and design postoperative management and follow-up strategies. After further validation studies based on independent datasets, these risk categories might be considered when redefining risk stratification or staging systems.

[Hemithyroidectomy or total thyroidectomy for low-risk papillary thyroid cancer? : Surgical criteria for primary and secondary choice of treatment in an interdisciplinary treatment concept]

The increase in small intrathyroid papillary thyroid cancer (PTC) observed worldwide over the past two decades, with no increase in cancer-specific mortality, has challenged the previous concept of total thyroidectomy as a one-size-fits-all panacea. After exclusion of papillary microcarcinomas, a systematic review of 20 clinical studies published since 2002, which compared hemithyroidectomy (HT) to total thyroidectomy (TT), found comparable long-term oncological outcomes for low-risk papillary thyroid cancer (LRPTC) 1-4 cm in diameter, whereas postoperative complication rates were markedly lower for HT. To refine individual treatment plans, HT should be combined with ipsilateral central lymph node dissection and intraoperative frozen section analysis for staging. Based on recent evidence from studies and in consideration of individual risk factors, patients with LRPTC can be offered the concept of HT as an alternative to the standard TT. A prerequisite for the treatment selection and decision is a comprehensive patient clarification of the possible advantages and disadvantages of both approaches.

Incorporation size of lymph node metastasis focus and pre-ablation stimulated Tg could more effectively predict clinical outcomes in differentiated thyroid cancer patients without distant metastases

BACKGROUND

The size of lymph node metastasis (LNM) and pre-ablation stimulated Tg (ps-Tg) were key predictors of clinical prognosis in differentiated thyroid cancer (DTC) patients, however, very few studies combine the above two as predictors of clinical prognosis of DTC patients.

METHODS

Persistent/recurrent disease and clinicopathologic factors were analyzed in 543 DTC patients without distant metastases who underwent LN dissection, near-total/total thyroidectomy, and radioiodine ablation.

RESULTS

In the multivariate analysis, size of LNM, ps-Tg, and the activity of ¹³¹I significantly correlated with long-term remission. The optimal cutoff size of LNM 0.4 cm-1.4 cm (intermediate-risk patients) and >1.4cm (high-risk patients) increased the recurrence risk (hazard ratio [95% CI], 4.674 [2.881-7.583] and 13.653 [8.135-22.913], respectively). Integration of ps-Tg into the reclassification risk stratification showed that ps-Tg ≤ 10.0 ng/mL was relevant to a greatly heightened possibility of long-term remission (92.2%-95.4% in low-risk patients, 67.3%-87.0% in intermediate-risk patients, and 32.3%-57.7% in high-risk patients).

CONCLUSION

The cutoff of 0.4 cm and 1.4 cm for a definition of size of LNM in DTC patients without distant metastases can reclassify risk assessment, and incorporating ps-Tg could more effectively predict clinical outcomes and modify the postoperative management plan.

Completion thyroidectomy may not be required for papillary thyroid carcinoma with multifocality, lymphovascular invasion, extrathyroidal extension to the strap muscles, or five or more central lymph node micrometastasis

OBJECTIVE

This study aimed to determine whether completion thyroidectomy is necessary based on long-term follow-up oncological results according to various clinical and pathological characteristics of patients with papillary thyroid carcinoma (PTC) who underwent lobectomy.

MATERIALS AND METHODS

We enrolled 1815 patients with PTC who underwent thyroid lobectomy from January 2003 to December 2014. Various clinical and pathological characteristics were reviewed retrospectively, and clinicopathologic characteristics and recurrence rates were analyzed.

RESULTS

Eighty-two (4.5%) patients showed locoregional recurrence during the average 10.2-year follow-up period. There was no significant difference in tumor size, multifocality, lymphovascular invasion (LVI), microscopic or strap muscle-extrathyroidal extension, and central neck lymph node (LN) micrometastasis between the recurrence and non-recurrence groups. The gross strap muscle-extrathyroidal extension group was associated with older age (p < 0.001), larger tumor size (p < 0.001), more capsular invasion (p < 0.001), and more LVI (p < 0.001) than the negative extrathyroidal extension group; there was no significant difference in recurrence between the groups (p = 0.096). Patients with five or more central LN micrometastases were associated with younger age (p = 0.006), larger tumor size (p = 0.04), and presence of LVI (p = 0.033) than patients with less than five central LN metastases; there was no significant difference in recurrence between the groups (p = 0.867). All patients with recurrence were cured through reoperation after recurrence was confirmed.

CONCLUSION

After thyroid lobectomy, PTC patients with multifocality, LVI, extrathyroidal extension to the strap muscles, or five or more central LN micrometastases may not require immediate completion thyroidectomy.

Restratification of Patients with Intermediate-Risk Papillary Thyroid Carcinoma

BACKGROUND

Long-term management and follow-up strategies in patients with intermediate-risk papillary thyroid carcinoma (PTC) according to the American Thyroid Association (ATA) are still controversial due to the paucity of data on unique risk factors or a risk stratification system predictive of long-term outcomes.

PATIENTS AND METHODS

This study included 649 patients with PTC who underwent an initial surgical treatment. Retrospectively enrolled patients were categorized according to the ATA risk stratification system. Intermediate-risk patients were further categorized into subgroups by the number of ATA intermediate risk factors. The recurrence-free survival (RFS) rates of these subgroups were compared with those of low- and high-risk patient groups. Additionally, the patients were classified according to their response to the initial therapy using the dynamic risk stratification (DRS) system, and the percentages of patients in each category were compared among the subgroups.

RESULTS

The median follow-up period was 102 months. Structural recurrence occurred in 9.2% of all enrolled patients (60/649) and in 13.0% of intermediate-risk patients (40/308). Patients with two or more current intermediate risk factors had a poorer RFS than patients with only one risk factor (p < 0.001) and showed a comparable RFS to high-risk patients (p > 0.050). The percentages of patients with an excellent response category for DRS significantly decreased with an increase in the number of intermediate risk factors.

CONCLUSION

Subclassification according to the number of intermediate risk factors may be useful to better predict the RFS and the response to initial therapy in patients with intermediate-risk PTC.

Ultrasound-Based Radiomic Nomogram for Predicting Lateral Cervical Lymph Node Metastasis in Papillary Thyroid Carcinoma

RATIONALE AND OBJECTIVES

Accurate preoperative identification of lateral cervical lymph node metastasis (LNM) is important for decision-making and clinical management of patients with papillary thyroid carcinoma (PTC). The aim of this study was to develop an ultrasound (US)-based radiomic nomogram to preoperatively predict the lateral LNM in PTC patients.

METHODS

In this retrospective study, a total of 886 patients were enrolled and randomly divided into 2 groups. Radiomic features were extracted from the preoperative US images. A radiomic signature was constructed using the least absolute shrinkage and selection operator algorithm in the training set. Multivariate logistic regression was performed to develop the radiomic nomogram, which incorporating the radiomic signature and the selected clinical characteristics. The performance of the nomogram was assessed by its discrimination, calibration, and clinical usefulness in both the training and validation sets.

RESULTS

The radiomic signature was significantly associated with the lateral LNM in both cohorts (p< 0.001). The nomogram that consisted of radiomic signature, US-reported cervical lymph node (CLN) status, and CT-reported CLN status demonstrated good discrimination and calibration in the training and validation sets with an AUC of 0.946 and 0.914, respectively. The decision curve analysis indicated that the radiomic nomogram was worthy of clinical application.

CONCLUSION

The radiomic nomogram proposed here has good performance for noninvasively predicting the lateral LNM and might be used to facilitate clinical decision-making and potentially improve the survival outcome in selected patients.

Lobectomy in patients with differentiated thyroid cancer: indications and follow-up

The extent of thyroid surgery for patients with low- and intermediate-risk differentiated thyroid carcinoma (DTC), with a primary tumour <4 cm and no extrathyroidal extension (ETE) or lymph node (LN) metastases, has shifted in a more conservative direction. However, clinicopathological risk factors, including microscopic ETE, aggressive histology, vascular invasion in papillary thyroid carcinoma (PTC) and intermediate volume of LN metastases, can only be identified after completing thyroid lobectomy. It is controversial whether patients with these risk factors should immediately undergo complete thyroidectomy and/or radioactive iodine remnant ablation or should be monitored without further treatments. Data are conflicting about the prognostic impact of these risk factors on clinical DTC outcomes. Notably, the recurrence rate in patients who underwent thyroid lobectomy is low and the few recurrences that develop during long-term follow-up can readily be detected by neck ultrasonography and treated by salvage surgery with no impact on survival. These findings suggest that a more conservative approach may be a preferred management strategy over immediate completion surgery, despite a slightly higher risk of structural recurrence. Regarding follow-up of post-lobectomy DTC patients, it is reasonable that an initial risk stratification system based on clinicohistological findings be used to guide the short-term follow-up prior to evaluating the response to initial therapy and that the dynamic risk stratification system based on the response to initial therapy be used to guide long-term follow-up.