Role of RAI in the management of incidental N1a disease in papillary thyroid cancer

Feasibility of Lobectomy in Selected Patients with Unilateral N1b Papillary Thyroid Cancer

BACKGROUND

Total thyroidectomy (TT) is usually recommended for unilateral papillary thyroid cancer (PTC) with lateral lymph node metastasis (LLNM), but no significant improvement in recurrence-free survival (RFS) is seen upon treatment. As an initial surgery, lobectomy may have advantages in appropriately selected unilateral PTC with ipsilateral LLNM.

OBJECTIVE

This study aimed to explore the feasibility of lobectomy for selected unilateral PTC with ipsilateral LLNM.

METHODS

From January 2014 to December 2021, we retrospectively reviewed patients with PTC and LLNM who were treated at our center. Patients preoperatively diagnosed with unilateral PTC and ipsilateral LLNM were recruited. Overall, 102 patients who chose lobectomy as their initial surgery were included in the lobectomy group and 96 patients who chose TT were included in the control group, defined as the TT group.

RESULTS

The mean follow-up time of the lobectomy group was 47.5 ± 22.2 months. Patients in the lobectomy group had a significantly lower rate of hypoparathyroidism than those in the TT group (0% vs. 11.5%; p < 0.001). RFS after lobectomy was comparable with that after TT according to Kaplan-Meier curve analysis (log-rank p = 0.80). Lobectomy achieved a significantly lower incidence of unsatisfactory TSH control than TT (5.9% vs. 20.8%; p = 0.006).

CONCLUSIONS

Lobectomy may be an appropriate initial therapy for selected unilateral PTC with ipsilateral LLNM. A randomized prospective study with long-term follow-up is warranted.

Radioactive iodine therapy dose impact on recurrence and survival in N1 papillary thyroid cancer

OBJECTIVE

The objective of this study is to investigate radioactive iodine therapy (RAIT) dose impact on survival and recurrence in patients with papillary thyroid cancer (PTC) with regional lymph node metastasis (N1).

METHODS

A retrospective study of PTC patients with N1 disease from 2007 to 2011 at a tertiary academic hospital collected demographics, tumor characteristics, and RAIT treatment dose. RAIT dose was stratified by total dosage less than or greater than 150 mCi. Outcomes included recurrence, immediate RAIT side-effects, and mortality.

RESULTS

A total of 60 N1a and 21 N1b patients were studied with a median follow-up of about 9 years. No statistically significant differences were found between N1a PTC patients who received high-dose vs low-dose RAIT in recurrence rate (6.9% vs 6.7%, P  > 0.999) or immediate RAIT side effects (6.9% vs 16.1%, P  = 0.426). There were no mortalities in the N1a group. For patients with N1b PTC, there were no differences between high-dose and low-dose RAIT in recurrence rate (41.7% vs 44.4%, P  > 0.999), mortality (0% vs 16.7%, P  = 0.375), or immediate RAIT side effects (8.3% vs 11.1%, P  > 0.999).

CONCLUSION

Dosages of RAIT ≥ 150 mCi do not appear to provide additional benefit in reducing recurrence compared to doses <150 mCi for N1a or N1b PTC patients. No differences in mortality or immediate RAIT side effects were observed between the two dosing regimens; however, interpretation is limited by low event rates. Large randomized trials are needed for further individualized recommendations regarding optimal RAIT dosage in N1 PTC.

Current practice in intermediate risk differentiated thyroid cancer - a review

Although the overall prognosis for differentiated thyroid cancer (DTC) is excellent, a subset of patients will experience disease recurrence or may not respond to standard treatments. In recent years, DTC management has become more personalized in order to enhance treatment efficacy and avoid unnecessary interventions.In this context, major guidelines recommend post-surgery staging to assess the risk of disease persistence, recurrence, and mortality. Consequently, risk stratification becomes pivotal in determining the necessity of postoperative adjuvant therapy, which may include radioiodine therapy (RIT), the degree of TSH suppression, additional imaging studies, and the frequency of follow-up.However, the intermediate risk of recurrence is a highly heterogeneous category that encompasses various risk criteria, often combined, resulting in varying degrees of aggressiveness and a recurrence risk ranging from 5 to 20%. Furthermore, there is not enough long-term prognosis data for these patients. Unlike low- and high-risk DTC, the available literature is contradictory, and there is no consensus regarding adjuvant therapy.We aim to provide an overview of intermediate-risk differentiated thyroid cancer, focusing on criteria to consider when deciding on adjuvant therapy in the current context of personalized approach, including molecular analysis to enhance the accuracy of patient management.

Incidental Node Metastasis as an Independent Factor of Worse Disease-Free Survival in Patients with Papillary Thyroid Carcinoma

INTRODUCTION

Papillary thyroid carcinoma (PTC) have high node metastasis rates. Occasionally after thyroidectomy, the pathological report reveals node metastasis unintentionally resected. The present study aimed to evaluate the prognosis of these patients.

METHODS

A retrospective cohort of patients submitted to thyroidectomy with or without central compartment neck dissection (CCND) due to PTC with a minimum follow-up of five years.

RESULTS

A total of 698 patients were included: 320 Nx, 264 pN0-incidental, 37 pN1a-incidental, 32 pN0-CCND and 45 pN1a-CCND. Patients with node metastasis were younger, had larger tumors, higher rates of microscopic extra-thyroidal extension, and angiolymphatic invasion and most received radioiodine therapy. Treatment failure was higher in patients pN1a-incidental and pN1a-CCND (32% and 16%, respectively; p < 0.001-Chi-square test). Disease-free survival (DFS) was lower in patients pN1a-incidental compared to patients Nx and pN0-incidental (p < 0.001 vs. Nx and pN0-incidental and p = 0.005 vs. pN0-CCND) but similar when compared to patients pN1a-CCND (p = 0.091)-Log-Rank test. Multivariate analysis demonstrated as independent risk factors: pT4a (HR = 5.524; 95%CI: 1.380-22.113; p = 0.016), pN1a-incidental (HR = 3.691; 95%CI: 1.556-8.755; p = 0.003), microscopic extra-thyroidal extension (HR = 2.560; 95%CI: 1.303-5.030; p = 0.006) and angiolymphatic invasion (HR = 2.240; 95%CI: 1.077-4.510; p = 0.030).

CONCLUSION

Patients that were pN1a-incidental were independently associated with lower DFS.

Radioactive iodine in low- to intermediate-risk papillary thyroid cancer

It remains controversial whether papillary thyroid cancer (PTC) patients with low- to intermediate-risk disease should receive radioactive iodine (RAI) after total thyroidectomy (TT). We aim to identify those who might benefit from RAI treatment in PTC patients with cervical nodal metastasis after TT. Patients were divided into TT and TT+RAI groups from the Surveillance, Epidemiology, and End Results (SEER) database (2004-2018). Overall survival (OS) and cancer-specific survival (CSS) were compared, and propensity score matching (PSM) was performed between groups. A total of 15,179 patients were enrolled, including 3,387 (22.3%) who underwent TT and 11,792 (77.7%) who received TT+RAI. The following characteristics were more likely to present in the TT+RAI group: multifocality, capsular extension, T3, N1b, and more metastatic cervical lymph nodes. RAI was associated with better OS in low- to intermediate-risk PTC patients in the multivariate Cox regression model. The subgroup analysis showed that RAI predicted better OS in patients ≥55 years, American Joint Committee on Cancer (AJCC) stage II, and capsular extension with a hazard ratio (HR) (95% CI) of 0.57 (0.45-0.72), 0.57 (0.45-0.72), and 0.68 (0.51-0.91), respectively. However, RAI failed to improve the prognoses of patients with age <55 years, AJCC stage I, PTC ≤1 cm, and capsular invasion. In the PSM cohort with 3,385 paired patients, TT+RAI treatment predicted better OS compared with TT alone. In addition, TT+RAI predicted better OS in patients with metastatic cervical lymph nodes ≥2, multifocality, extracapsular extension, and American Thyroid Association (ATA) intermediate risk. In conclusion, RAI was associated with better OS in low- to intermediate-risk PTC patients with age ≥55 years, multifocality, extrathyroidal extension, and ATA intermediate risk. However, the survival benefit from RAI may be limited in patients with AJCC stage I, PTC ≤1 cm, unifocality, capsular invasion, and ATA low-risk diseases; these patients even showed pathological cervical lymph node metastasis.

Is Postoperative Adjuvant Radioactive Iodine Ablation Therapy Always Necessary for Intermediate-Risk Papillary Thyroid Cancer Patients With Central Neck Metastasis?

BACKGROUND

Papillary thyroid cancer (PTC) is commonly associated with neck lymph node metastasis (LNM), and recurrence does occur after radioactive iodine (RAI) ablation therapy. This study aimed to analyze the effectiveness of RAI ablation with regard to disease recurrence in intermediate-risk PTC patients with neck LNM. In addition, the study identified possible predisposing risk factors that might benefit from RAI ablation and analyzed common RAI therapy complications among these patients.

METHODS

A retrospective analysis of 349 intermediate-risk PTC patients with neck LNM who underwent thyroidectomy with neck dissection was performed. The oncologic results and clinicopathologic characteristics of these patients together with the incidence of postoperative RAI therapy complications were evaluated.

RESULTS

Of the 349 patients, disease recurrence after treatment occurred for 27 patients (8%) during a mean follow-up period of 58.7 months (range 7-133 months). The recurrence-free survival curve of the patients who received postoperative RAI therapy (n = 208) did not differ significantly from that of the patients who did not receive it (n = 141) (P = 0.567). Nine patients without adjuvant RAI therapy (6%, 9/141) had recurrence. The recurrence rate for the central LNM patients without RAI therapy was only 2% (2/106). Both of these patients with recurrence had pathologic extranodal spread (ENS) and a high number (> 5) of metastatic central LNs. Postoperative RAI-related complications were observed in 24 patients (12%).

CONCLUSIONS

Postoperative RAI is not necessary for intermediate-risk papillary thyroid cancer patients with central LNM, especially for patients with negative ENS and low number (< 5) of metastatic lymph nodes.

A Diagnostic Dilemma: Skip Metastasis in Papillary Thyroid Cancer

The frequency, pattern, and predictive factors for skip LN metastasis in patients with papillary thyroid carcinoma (PTC) remain controversial. In this study, we evaluated predictive factors of skip LN metastasis in these patients. We reviewed the medical records of 68 PTC patients who underwent total thyroidectomy, central neck dissection, and lateral neck dissection at the initial operation. The relationships between skip LN metastasis and clinicopathologic factors were analyzed. After careful examination of electronic medical records of patients, 19 patients were excluded from the study. Of the remaining 49 patients, 9 (18.4%) had skip LN metastasis. Multivariate analysis showed that tumor size <1 cm was an independent risk factor for the presence of skip metastasis ( P = 0.035, odds ratio: 3.78, 95% confidence interval: 1.09–13.15). The rate of positive LN was relatively higher in micro-PTC patients than PTC patients. This finding is clinically significant and should be considered in routine clinical practice.

Nodal metastases in thyroid cancer: prognostic implications and management

The significance of cervical lymph node metastases in differentiated thyroid cancer has been controversial and continues to evolve. Current staging systems consider nodal metastases to confer a poorer prognosis, particularly in older patients. Increasingly, the literature suggests that characteristics of the metastatic lymph nodes such as size and number are also prognostic. There is a growing trend toward less aggressive treatment of low-volume nodal disease. The aim of this review is to summarize the current literature and discuss prognostic and management implications of lymph node metastases in differentiated thyroid cancer.

Radioactive Iodine Administration Is Associated with Persistent Related Symptoms in Patients with Differentiated Thyroid Cancer

Context. Radioiodine (RAI) administration has adverse effects in patients treated for thyroid cancer (DTC), but there is scarce information regarding their intensity and duration. Objective. To evaluate frequency and intensity of early and late RAI-related symptoms in patients with DTC. Design. Observational prospective study. Patients. DTC patients who underwent thyroidectomy, with or without RAI. Measurements. Patients answered 2 surveys: (1) from 0 to 6 months and (2) between 6 and 18 months after initial treatment. Results. 110 patients answered the first survey and 61 both. Nearly 80 percent received RAI. Among early symptoms, periorbital edema, excessive tearing, salivary gland disturbances, dry mouth, taste disorders, and nausea were more frequent and intense among RAI patients. Regarding late symptoms, periorbital edema, salivary gland pain and swelling, and dry mouth were more frequent and intense in RAI patients. Frequency and intensity of adverse effects were not different between low and high RAI doses (50 versus ≥100 mCi). Conclusion. RAI-related symptoms are frequent and usually persist after 6 months of administration, even when low doses are given. This finding must be considered when deciding RAI administration, especially in low risk patients, among whom RAI benefit is controversial.