Use of radioiodine after thyroid lobectomy in patients with differentiated thyroid cancer: does it change outcomes?

Contemporary trends in extent of surgery for differentiated thyroid cancer with extrathyroidal extension

OBJECTIVE

Although lobectomy is acceptable for patients with small, low-risk differentiated thyroid cancer (DTC), gross extrathyroidal extension (ETE) remains an indication for total thyroidectomy (TT). Here we investigate evolving trends in extent of surgery for ​+ ​ETE DTC.

METHODS

Patients with +ETE DTC who underwent resection from 2010 to 2020 were identified using the National Cancer Database. The primary outcome was performance of TT versus lobectomy.

RESULTS

Among 5851 patients, most were female (79.7%), white (80.0%), and had minimal ETE (91.8%). Ninety-two percent of patients received TT. Year of treatment was influential (p ​< ​0.001), with increasing lobectomy rates in later years. On multivariable analyses, a decreased likelihood of TT was seen in years 2015 through 2020.

CONCLUSIONS

Most patients with +ETE DTC underwent guideline-concordant TT, but lobectomy rates doubled over the study period. These findings may reflect increased preference for lobectomy in low-risk DTC, but could undertreat patients with high-risk features.

[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.

Impact of completion thyroidectomy on postoperative recovery in patients with differentiated thyroid cancer

While an increasing number of patients now undergo lobectomy for low-risk differentiated thyroid cancer, a subset of patients require completion thyroidectomy to facilitate radioactive iodine therapy. Completion thyroidectomy is generally as safe as the initial operation, but a previous study showed that a longer hospitalization is required for completion thyroidectomy. In this study, we reviewed 61 consecutive patients who had been treated with an initial lobectomy and subsequent completion thyroidectomy at our institution from 2012 to 2021. We detected a changepoint in 2016 for the proportion of patients who were treated with a thyroid lobectomy (Pettitt's test P = 0.049). The rate of completion thyroidectomy remained stable throughout the study period. There was no difference in operating time, intraoperative blood loss, perioperative drop in calcium levels, and postoperative hospital stay between surgeries. The patients reported higher pain scores on the day of operation (P = 0.007) and the postoperative day 1 (P = 0.022). Occult papillary microcarcinomas were identified in the contralateral thyroid lobe in 13 (21%) patients. Multifocality was the only predictor for residual malignancy in multivariate regression. In conclusion, patients with differentiated thyroid cancer experienced more pain in the immediate postoperative period following completion thyroidectomy. Hospital stays do not change with appropriate opioid-free pain control.

Internal Staging Discordance in National Cancer Databases for Non-Small-Cell Lung Cancer

BACKGROUND

The Surveillance, Epidemiology and End Results (SEER) and the National Cancer Database (NCDB) are databases for cancer analysis which may be subject to error in data reporting. We examined rates and impact of discordant data for non-small cell lung cancer.

METHODS

NCDB and SEER were queried for non-small cell lung cancer pathologic Tumor, Node, Metastasis data (NCDB) or "derived" data (SEER). Discordancy between descriptors with stage and impact of outlier data were analyzed.

RESULTS

Incomplete staging was noted in 71.5% of NCDB and 10.3% of SEER. 174,829 patients from NCDB and 117,114 from SEER were analyzed. NCDB had 97 cases with ≥20 positive lymph nodes recorded vs. 27 in SEER (p<0.001). Mean and median sampled lymph nodes were skewed with inclusion of these data-points (p<0.001). NCDB misclassified 0.99% tumors >5cm as stage I vs. 0.04% in SEER (p<0.001). NCDB mis-staged positive lymph nodes as pathologic N0 (0.59%) or Stage 0/Stage I (0.65%). NCDB misclassified pathologic N1 as < Stage II (0.91%) or N2 as < Stage III (0.36%). NCDB misclassified Stage I with documentation of pathologic N1-N3 disease (0.24%) or Stage II with evidence of N2 or N3 disease (0.50%). NCDB misclassified pathologic M1 as pathologic Stage <IV in 0.9% of cases and misclassified 19.8% of stage IV as pathologic M0. SEER collaborative staging had no discordancy (p<0.001).

CONCLUSIONS

NCDB and SEER are two powerful cancer databases. However, cumulative discordancy rate was 4.9% for NCDB and 0.008% for SEER with more mistaging and outliers in NCDB.

Controversies in Radioiodine Treatment of Low- and Intermediate-risk Thyroid Cancer

In differentiated thyroid cancer, radioiodine therapy (RIT) is usually carried out after thyroidectomy. Although the potent beneficial effects of radioiodine are undisputed in high-risk patients, much controversy remains surrounding many aspects of RIT in low- and intermediate-risk patients. Other than the indication for postoperative RIT, controversies also include, among others, the intent of RIT and the choice of activity for RIT or the mode of thyroid stimulating hormone stimulation. Furthermore, there is even controversy on the definition of what constitutes low- or intermediate-risk patients. Here the various issues will be discussed and an overview of the different points of view in a number of more prominent national and international guidelines and current literature is presented.

Radioactive Iodine Therapy in Differentiated Thyroid Cancer: 2020 Update

OBJECTIVE. The paradigm of theranostics is based on tailoring therapy for the purpose of optimizing outcomes. This principle is being applied to radioactive iodine therapy. Consequently, thyroid cancer therapy protocols are evolving. The purpose of this article is to promote a modern approach to radioiodine therapy. CONCLUSION. This article highlights guidelines and position statements, summarizes the prognostication systems of thyroid cancer, and reviews which prescribed activities of ¹³¹I.

Radioiodine Ablation of Remaining Thyroid Lobe in Patients with Differentiated Thyroid Cancer Treated by Lobectomy: A Systematic Review and Metaanalysis

We aimed to conduct a systematic review and metaanalysis of studies reporting the performance of radioactive iodine (¹³¹I) therapy in differentiated thyroid cancer (DTC) patients requiring a completion treatment after lobectomy. We also evaluated the response to ¹³¹I therapy according to 2015 American Thyroid Association guidelines and the adverse events. Methods: A specific search strategy was designed to find articles evaluating the use of ¹³¹I in patients with evidence of DTC after lobectomy. PubMed, Cochrane Central Register of Controlled Trials, Scopus, and Web of Science were searched. The search was updated until January 2020, without language restriction. Data were cross-checked and any discrepancy discussed. A proportion metaanalysis (with 95% confidence interval) was performed using the random-effects model. Metaregressions on ¹³¹I success were attempted. Results: The pooled success ablation rate was 69%, with better results in patients receiving a single administration of about 3.7 GBq; high heterogeneity was found (I² test, 85%), and publication bias was absent (Egger test, P = 0.57). Incomplete structural responses were recorded in only 14 of 695 (2%) patients enrolled in our analysis. Incomplete biochemical responses were observed in 8%-24% of patients, with higher rates (24%) in patients receiving low radioiodine activities (∼1.1 GBq) and lower rates (8%-18%) in patients receiving higher activities of radioiodine (∼3.7 GBq). Neck pain due to thyroiditis was reported in up to 18% of patients, but in most cases, symptoms resolved after oral paracetamol or a short course of prednisone. Conclusion: Lobar ablation with ¹³¹I is effective, especially when high ¹³¹I activities are used. However, the rate of incomplete biochemical response to initial treatment appears to be slightly higher than in the classic scheme of initial treatment of DTC. Radioisotopic lobectomy should be considered for patients with low- to intermediate-risk DTC requiring completion treatment after lobectomy due to specific individual risk factors or patient preferences.

The role of radioactive iodine in the management of patients with differentiated thyroid cancer - An oncologic surgical perspective

With improved understanding of the biology of differentiated thyroid carcinoma its management is evolving. The approach to surgery for the primary tumour and elective nodal surgery is moving from a "one-size-fits-all" recommendation to a more personalised approach based on risk group stratification. With this selective approach to initial surgery, the indications for adjuvant radioactive iodine (RAI) therapy are also changing. This selective approach to adjuvant therapy requires understanding by the entire treatment team of the rationale for RAI, the potential for benefit, the limitations of the evidence, and the potential for side-effects. This review considers the evidence base for the benefits of using RAI in the primary and recurrent setting as well as the side-effects and risks from RAI treatment. By considering the pros and cons of adjuvant therapy we present an oncologic surgical perspective on selection of treatment for patients, both following pre-operative diagnostic biopsy and in the setting of a post-operative diagnosis of malignancy.

Differentiated thyroid cancer patients potentially benefitting from postoperative I-131 therapy: a review of the literature of the past decade

BACKGROUND

Since the last major review of literature on the benefit of I-131 therapy, the continued debate on postoperative radioiodine treatment (RIT) in differentiated thyroid carcinoma (DTC) has led to a number of further studies being published on this topic.

AIM

The aim of the present paper is to report the results of an updated structured review of the literature pertaining to the prognostic benefits of postoperative RIT in DTC in terms of recurrence-free and disease-specific survival.

METHODS

A systematic search of the literature was performed using the Medline and Cochrane Library database. The search period started in August 2007 and ended on December 6, 2017. Search terms used included "differentiated thyroid cancer" and "radioiodine therapy" amended by specific terms for recurrence/disease-free survival or overall and/or cancer-specific survival. Included in the search were systematic reviews, randomized clinical trials, or cohort studies consisting of both patients who underwent postoperative RIT and patients treated by surgery alone.

RESULTS

Eleven retrospective cohort studies met the defined inclusion criteria and were included in the present review. Results of the studies were mixed, with some showing a benefit of RIT even in microcarcinoma whereas others showed no benefit at all.

CONCLUSION

Literature published in the last decade offers data that support adjuvant postoperative RIT in DTC patients with a tumor diameter exceeding 1 cm. Therefore, at least until randomized prospective studies prove otherwise, the prescription of adjuvant I-131 treatment to all DTC patients with a primary tumor diameter exceeding 1 cm remains a reasonable option.

Clinical significance of the BRAFV600E mutation in PTC and its effect on radioiodine therapy

The goal of this study was to explore the relationship of the BRAFV600E mutation with clinicopathologic factors and evaluate the effect of radioactive iodine (RAI) therapy in a large group of intermediate- and high-risk papillary thyroid cancer (PTC) patients with the BRAFV600E mutation and without distant metastases. We collected data for PTC patients who underwent total or near-total thyroidectomy and RAI treatment in our hospital from January 2014-December 2017. There were 1220 PTC patients who met the criteria, and the BRAFV600E mutation was observed in 979 of them (80.2%). Multivariate analysis identified that the BRAFV600E mutation remained independently associated with age at diagnosis, and bilaterality (OR = 1.023, 95% CI = 1.012-1.039, P < 0.001; OR = 1.685, 95% CI = 1.213-2.341, P = 0.002, respectively). In addition, the patients with bilateral PTCs had a higher prevalence of extrathyroid invasion, capsular invasion and fusion of metastatic lymph nodes than the unilateral PTC patients. The response to RAI therapy was evaluated in both the entire series and the patients with a high recurrence risk; no significant difference was discerned between the BRAFV600E mutation and the wild-type groups (P = 0.237 and P = 0.498, respectively). To summarize, our results confirmed that PTC patients with the BRAFV600E mutation exhibit more aggressive characteristics. In addition, the patients with bilateral PTC have a higher incidence of extrathyroid invasion. Moreover, BRAFV600E mutation PTC patients did not show a poorer clinical response after postsurgical RAI therapy, suggesting that RAI therapy may improve the general clinical outcome of these patients.

How Many Contralateral Carcinomas in Patients with Unilateral Papillary Thyroid Microcarcinoma are Preoperatively Misdiagnosed as Benign?

BACKGROUND

The decision to perform a total thyroidectomy (TT) for unilateral papillary thyroid microcarcinoma (PTMC) with nodules in the contralateral lobe remains controversial. The aim of this study was to investigate the rate of contralateral carcinomas that are preoperatively misdiagnosed as benign.

METHODS

From October 2011 to October 2015, a total of 347 patients with unilateral PTMC and contralateral benign nodules who were treated with a TT at a single institution were enrolled. All patients underwent preoperative fine needle aspiration and ultrasonography (US). Clinicopathological features such as age, sex, laterality, tumor size, central lymph node metastases, capsular invasion, TgAb and TPOAb levels, Hashimoto's thyroiditis, nodule number in both lobes according to preoperative US, and primary carcinoma number in the final postoperative pathology report were all analyzed to investigate the rate and predictive factors of contralateral carcinoma.

RESULTS

A total of 100 patients (28.9 %) were diagnosed with papillary thyroid carcinoma in the contralateral lobe. A multivariate analysis showed that tumor size, nodule number in the contralateral lobe, and multifocality of the primary tumor were all independent predictive factors of contralateral carcinoma in patients with unilateral PTMC and contralateral benign nodules.

CONCLUSIONS

According to our findings, the rate at which contralateral carcinomas are preoperatively misdiagnosed as benign is 28.9 %. A TT is essential for unilateral PTMC with a primary tumor size >5 mm, multifocal primary carcinomas or multifocal benign nodules in the contralateral lobe.

Extent of Thyroidectomy in Differentiated Thyroid Cancers-Review of Evidence

Differentiated thyroid cancers (DTC) are seen with increasing incidence in clinical practice. These tumours have good prognosis and the extent of surgery can be tailored to the size and pathological characteristics of the lesion. Historically total thyroidectomy was the recommended procedure for tumours >1 cm; however, current recommendations suggest a more conservative approach. This review focuses on the evolution of the extent of surgery in differentiated thyroid cancer.