Trends in the Surgical Management of Known or Suspected Differentiated Thyroid Cancer at a Single Institution, 2010-2018

The Role of Molecular Markers in Thyroid Cancer Diagnostics and Treatment

Molecular testing for cytologically indeterminate thyroid nodules has demonstrated benefit by reducing the need for diagnostic thyroidectomies and reducing costs. Its use is currently recommended in practice guidelines from the American Thyroid Association and the American Association of Endocrine Surgeons when clinically appropriate. Moreover, there is growing evidence that molecular testing may provide prognostic information and can detect targetable genetic alterations which may expand treatment options for refractory advanced thyroid cancers.

[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.

Diagnosis and Treatment of Acute Pleural Effusion following Radioiodine Remnant Ablation Post Lobectomy for Thyroid Cancer

Radioiodine remnant ablation (RRA) was previously demonstrated to be a safe and effective alternative to completion thyroidectomy for patients with differentiated thyroid cancer (DTC). However, its side effects have not been fully investigated, particularly in patients with lobectomy. We reported a young euthyroidal female who underwent RRA post lobectomy and lymph node dissection for papillary thyroid cancer, whose post-ablation ¹³¹I-whole-body scan accidentally showed diffuse radioiodine distribution on chest-mimicking pulmonary metastases. Immediately-added single-photon emission computed tomography/computed tomography (SPECT/CT), nevertheless, revealed a ¹³¹I-accumulating swollen left thyroid lobe and emerging pleural effusion, which relieved after short-term treatment with prednisone. In summary, acute pleural effusion ascribed to RRA-induced thoracic duct compression was reported for the first time. ¹³¹I-lobectomy-induced pleural effusion could be precisely diagnosed by SPECT/CT and efficiently manipulated via treating radiation thyroiditis with the short-term administration of corticosteroid.

DIAGNOSIS OF ENDOCRINE DISEASE: Usefulness of genetic testing of fine-needle aspirations for diagnosis of thyroid cancer

OBJECTIVE

Genetic testing is increasingly used to diagnose or rule out thyroid cancer in indeterminate fine-needle aspirations. This review evaluates the usefulness of these methods with considerations of advantages and limitations.

DESIGN

Given the diagnostic problem associated with the increasing incidental detection of indeterminate thyroid nodules in the context of thyroid cancer overtreatment, we consider the conditions and respective necessary settings for the role of genetic testing to improve presurgical malignancy risk stratification.

METHODS

We review diagnostic pathway requirements and commercially available molecular tests with their respective advantages and disadvantages and discuss the prerequisites required for local application and implementation including quality assurance for local ultrasound and cytopathology practices.

RESULTS

Recent improvements in available molecular diagnostic tests have brought high sensitivity and specificity in initial validation studies, but whether these promising results translate to other clinical settings depends on the quality of the local thyroid nodule diagnostic pathway.

CONCLUSIONS

Genetic testing can meaningfully improve presurgical malignancy risk assessment, but more work is needed to implement and use genetic testing effectively in local settings.

Microwave ablation vs. surgery for papillary thyroid carcinoma with minimal sonographic extrathyroid extension: a multicentre prospective study

OBJECTIVES

Minimal extrathyroid extension (mETE) was removed from the TNM staging system. This study was designed prospectively to compare the safety and efficacy of microwave ablation (MWA) versus surgery for treating T1N0M0 papillary thyroid carcinomas (PTC) with sonographically detected mETE.

METHODS

From December 2019 to April 2021, 198 patients with T1N0M0 mETE-PTCs evaluated by preoperative ultrasound from 10 hospitals were included. Ninety-two patients elected MWA, and 106 patients elected surgery for treatment. MWA was performed using extensive ablation with hydrodissection. Surgery consisted of lobectomy with ipsilateral central lymph node dissection (CLD), lobe and isthmus excision with ipsilateral CLD and total thyroidectomy with ipsilateral CLD. The rates of technical success, cost, oncologic outcomes, complications and quality of life of the two groups were assessed.

RESULTS

The follow-up times for the MWA and surgery groups were 12.7 ± 4.1 and 12.6 ± 5.0 months, respectively. The technical success rate was 100% for both groups. Oncological outcomes of the two groups were similar during the follow-up (all p > 0.05). The MWA group had a shorter operation time, less blood loss and lower costs (all p < 0.001). Three complications (3.3%) were reported in the MWA group and 4 (3.8%) in the surgery group (p = 0.846). The surgery group had higher scores for scar problems and anxiety (p < 0.001 and p = 0.003, respectively).

CONCLUSIONS

Microwave ablation was comparable in the short term to surgery in terms of treatment safety and efficacy in selected patients with T1N0M0 mETE-PTC detected by ultrasound.

KEY POINTS

• Microwave ablation is comparable to surgery in the safety and short-term efficacy for PTCs with sonographically detected mETE. • Thermal ablation is technically feasible for mETE-PTC treatment. • Patients with mETE-PTC have similar quality of life in the two groups, except for worse scar problems and anxiety in the surgery group.

Perception of risk and treatment decisions in the management of differentiated thyroid cancer

BACKGROUND AND OBJECTIVES

The recent de-escalation of care for differentiated thyroid cancer (DTC) has broadened the range of initial treatment options. We examined the association between physicians' perception of risk and their management of DTC.

METHODS

Thyroid specialists were surveyed with four clinical vignettes: (1) indeterminate nodule (2) tall cell variant papillary thyroid cancer (PTC), (3) papillary thyroid microcarcinoma (mPTC), and (4) classic PTC. Participants judged the operative risks and likelihood of structural cancer recurrence associated with more versus less aggressive treatments. A logistic mixed effect model was used to predict treatment choice.

RESULTS

Among 183 respondents (13.4% response rate), 44% were surgical and 56% medical thyroid specialists. Risk estimates and treatment recommendation varied markedly in each case. Respondents' estimated risk of 10-year cancer recurrence after lobectomy for a 2.0-cm PTC ranged from 1% to 53% (interquartile range [IQR]: 3%-12%), with 66% recommending lobectomy and 34% total thyroidectomy. Respondents' estimated 5-year risk of metastastic disease during active surveillance of an 0.8-cm mPTC ranged from 0% to 95% (IQR: 4%-15%), with 36% choosing active surveillance. Overall, differences in perceived risk reduction explained 10.3% of the observed variance in decision-making.

CONCLUSIONS

Most of the variation in thyroid cancer treatment aggressiveness is unrelated to perceived risk of cancer recurrence.

Intraoperative frozen section performance for thyroid cancer diagnosis

Objective

A primary medical relevance of thyroid nodules consists of excluding thyroid cancer, present in approximately 5% of all thyroid nodules. Fine-needle aspiration biopsy (FNAB) has a paramount role in distinguishing benign from malignant thyroid nodules due to its availability and diagnostic performance. Nevertheless, intraoperative frozen section (iFS) is still advocated as a valuable tool for surgery planning, especially for indeterminate nodules.

Methods

To compare the FNAB and iFS performances in thyroid cancer diagnosis among nodules in Bethesda Categories (BC) I to VI. The performance of FNAB and iFS tests were calculated using final histopathology results as the gold standard.

Results

In total, 316 patients were included in the analysis. Both FNAB and iFS data were available for 272 patients (86.1%). The overall malignancy rate was 30.4%% (n = 96). The FNAB sensitivity, specificity, and accuracy for benign (BC II) and malignant (BC V and VI) were 89.5%, 97.1%, and 94.1%, respectively. For all nodules evaluated, the iFS sensitivity, specificity, and accuracy were 80.9%, 100%, and 94.9%, respectively. For indeterminate nodules and follicular lesions (BC III and IV), the iFS sensitivity, specificity, and accuracy were 25%, 100%, and 88.7%, respectively. For BC I nodules, iFS had 95.2% of accuracy.

Conclusion

Our results do not support routine iFS for indeterminate nodules or follicular neoplasms (BC III and IV) due to its low sensitivity. In these categories, iFS is not sufficiently accurate to guide the intraoperative management of thyroidectomies. iFS for BC I nodules could be an option and should be specifically investigated.

Predictors of Bilateral Disease in Pediatric Differentiated Thyroid Cancer

CONTEXT

Total thyroidectomy is recommended for children with papillary thyroid carcinoma, partly because of a high prevalence of bilateral disease. Identifying characteristics that predict bilateral disease might identify candidates for more limited surgery.

OBJECTIVE

Investigate associations of preoperative or histopathological characteristics with bilateral disease in children with differentiated thyroid cancer.

METHODS

Retrospective cohort study (1998-2020) at 2 academic hospitals. Patients <19 years who underwent total thyroidectomy for differentiated thyroid cancer were included. Clinical, sonographic, and histopathological characteristics were evaluated. The presence of bilateral disease on histopathology was assessed by univariable analysis and multivariable logistic regression.

RESULTS

One hundred and fifteen subjects were analyzed (90% with papillary carcinoma). Median (range) age at diagnosis was 15.0 (8.1-18.9) years. Bilateral disease was present in 47/115 subjects (41%). Bilateral disease was associated with solid parenchyma, calcifications, irregular margins, and abnormal lymph nodes detected by ultrasound, Bethesda class V/VI cytology, papillary histology, tumor multifocality in the primary lobe, extrathyroidal extension, lymphovascular invasion, and nodal metastases. In multivariable analysis, only multifocality in the primary lobe was independently associated with bilateral disease (OR 7.61, 95% CI 2.44-23.8, P < .001). Among clinically node-negative subjects with papillary carcinoma who did not have tumor multifocality in the primary lobe, bilateral disease was present in 5/32 (16%).

CONCLUSIONS

In children with differentiated thyroid cancer, tumor multifocality in the primary lobe is associated with bilateral disease and should prompt consideration of completion thyroidectomy after initial lobectomy. Clinically node-negative children with tumors that are unifocal in the primary lobe have a low likelihood of contralateral disease.

Molecular Testing for Thyroid Nodules Including Its Interpretation and Use in Clinical Practice

Despite advances in imaging and biopsy techniques, the management of thyroid nodules often remains a diagnostic and clinical challenge. In particular, patients with cytologically indeterminate nodules often undergo diagnostic thyroidectomy although only a minority of patients are found to have thyroid malignancy on final pathology. More recently, several molecular testing platforms have been developed to improve the stratification of cancer risk for patients with cytologically indeterminate thyroid nodules. Based on numerous studies demonstrating its accuracy, molecular testing has been incorporated as an important diagnostic adjunct in the management of indeterminate thyroid nodules in the National Comprehensive Cancer Network Guidelines as well as in the American Thyroid Association (ATA) and American Association of Endocrine Surgeons (AAES) guidelines. This overview describes the currently available molecular testing platforms and highlights the published data to date on the clinical validity and utility of molecular testing in the contemporary management of thyroid nodules.

Cost analysis of reflexive versus selective molecular testing for indeterminate thyroid nodules

BACKGROUND

Molecular testing is now commonly used to refine the diagnosis of indeterminate thyroid nodules. The purpose of this study is to compare the costs of a reflexive molecular testing strategy to a selective testing strategy for indeterminate thyroid nodules.

METHODS

A Markov model was constructed to estimate the annual cost of diagnosis and treatment of a real-world cohort of patients with cytologically indeterminate thyroid nodules, comparing a reflexive testing strategy to a selective testing strategy. Model variables were abstracted from institutional clinical trial data, literature review, and the Medicare physician fee schedule.

RESULTS

The average cost per patient in the reflexive testing strategy was $8,045, compared with $6,090 in the selective testing strategy. In 10,000 Monte Carlo simulations, diagnostic thyroid lobectomy for benign nodules was performed in 2,440 patients in the reflexive testing arm, compared with 3,389 patients in the selective testing arm, and unintentional observation for malignant nodules occurred in 479 patients in the reflexive testing arm, compared with 772 patients in the selective testing arm. The cost of molecular testing had the greatest impact on overall costs, with $1,050 representing the cost below which the reflexive testing strategy was cost saving compared with the selective testing strategy.

CONCLUSION

In this cost-modeling study, reflexive molecular testing for indeterminate thyroid nodules enabled patients to avoid unnecessary thyroid lobectomy at an estimated cost of $20,600 per surgery avoided.

Outcomes of Indeterminate Thyroid Nodules Managed Nonoperatively after Molecular Testing

CONTEXT

Molecular testing to refine the diagnosis of cytologically indeterminate thyroid nodules has become increasingly popular, but data on long-term durability of test results and the rate of delayed operation are limited.

OBJECTIVE

Determine the delayed rate of surgical resection in indeterminate nodules with benign/negative molecular testing and the risk of false-negative molecular test results.

DESIGN

Prospective follow-up of the Gene Expression Classifier vs Targeted Next-Generation Sequencing in the Management of Indeterminate Thyroid Nodules randomized controlled trial comparing the diagnostic test performance of Afirma Gene Expression Classifier and ThyroSeq v2.

SETTING

University of California, Los Angeles.

PARTICIPANTS

Patients who underwent thyroid biopsy with indeterminate (Bethesda III/IV) cytology (April 2016 to July 2017).

INTERVENTION

Ultrasound surveillance.

MAIN OUTCOME MEASURE

False-negative rate of molecular testing.

RESULTS

Of 95 indeterminate nodules with negative/benign molecular test results, 12 nodules underwent immediate resection (11 benign nodules, 1 noninvasive follicular thyroid neoplasm nodule with papillary-like nuclear features). Nonoperative management was pursued for 83 (87.4%) nodules. The median surveillance was 26.7 months. Ten nodules were resected during surveillance and malignancy was identified in 4 nodules (overall false-negative rate of 5.8%). In the 4 malignant nodules that underwent delayed operation, surgery was prompted by sonographic changes during surveillance.

CONCLUSIONS

The majority of indeterminate nodules with negative molecular testing have a stable clinical course over 3 years of follow-up, but our finding of a 6% false-negative rate highlights the importance of continuing sonographic surveillance. Long-term studies are needed to determine the optimal length of follow-up.

Frequency of Thyroid Hormone Replacement After Lobectomy for Differentiated Thyroid Cancer

OBJECTIVE

To determine the frequency of levothyroxine (LT4) supplementation after therapeutic lobectomy for low-risk differentiated thyroid cancer (DTC).

METHODS

This retrospective cohort study enrolled adult patients with low-risk DTC confirmed using surgical pathology who underwent therapeutic lobectomy at a single institution from January 2016 through May 2020. The outcome measures were postoperative serum thyroid-stimulating hormone (TSH) levels and the initiation of LT4. The predictors of a postoperative TSH level of >2 mU/L and initiation of LT4 were evaluated using Cox proportional hazards models.

RESULTS

Postoperative TSH levels were available for 115 patients (91%), of whom 97 (84%) had TSH levels >2 mU/L after thyroid lobectomy. Over a median follow-up of 2.6 years, a postoperative TSH level of >2 mU/L was associated with older age (median 52 vs 37 years; P = .01), higher preoperative TSH level (1.7 vs 0.85 mU/L; P < .001), and primary tumor size of <1 cm (38% vs 11%, P = .03). Multivariate analysis revealed that only preoperative TSH level was an independent predictor of a postoperative TSH level of >2 mU/L (hazard ratio [HR] 1.53, P = .003). Among patients with a postoperative TSH level of >2 mU/L, 66 (68%) were started on LT4 at a median of 74 days (interquartile range 41-126) after lobectomy, with 51 (77%) undergoing at least 1 subsequent dose adjustment to maintain compliance with current guidelines.

CONCLUSION

More than 80% of the patients who underwent therapeutic lobectomy for DTC developed TSH levels that were elevated beyond the recommended range, and most of these patients were prescribed LT4 soon after the surgery.