Practice patterns in the management of patients with differentiated thyroid cancer in Ontario Canada 2000-2008

The overtreatment of papillary thyroid microcarcinoma in the community

INTRODUCTION

Total thyroidectomy is the traditional primary approach for papillary thyroid cancer. However, recent evidence supports conservative management for low-risk tumors like papillary thyroid microcarcinomas (PTMCs). This study explores the adoption of these practices in our community, using a cancer database to analyze treatment strategies.

METHODS

A retrospective review of a 1433-patient institutional database identified 258 ​PTMC cases. Outcomes, including 30-day mortality, reoperation rate, postoperative hypocalcemia, and recurrent laryngeal nerve (RLN) injury, were assessed.

RESULTS

Of PTMC patients, 63.4% underwent total thyroidectomy, with higher rates of RLN injury (8.8% vs. 2.3%) and hypocalcemia (12.4% vs. 0.0%) compared to lobectomy. Non-endocrine surgeons had higher postoperative radioactive iodine administration rates (28.6% vs. 6.1%). Subgroup analysis revealed a shift in total thyroidectomy rates based on tumor size and surgery period.

CONCLUSION

Our community favors total thyroidectomy for PTMC, despite associated complications. Enhanced awareness and adherence to PTMC best practice guidelines are warranted.

Too Deep: The Rate of Inappropriate Deep Resections while Practicing a Single Stage Laser Cordectomy

OBJECTIVE

Whenever a cortectomy is indicated, obviating preoperative biopsy and practicing a single-stage-laser-cordectomy (SSLC) may expedite treatment and preserve surgical planes. This may result in more superficial resections and improved vocal function. Yet, SSLC holds a risk for over-treating nonmalignant lesions. Our study aims to evaluate this risk.

METHODS

A retrospective cohort of patients who underwent SSLC. Cordectomy types were compared with final pathology. Type-1 cordectomy was subcategorized into superficial-type-1 (superficial-lamina-propria preserved) and deep-type-1 (ligament exposed). Superficial-type-1 cordectomy was considered adequate for epithelial lesions not invading the basement membrane: nonmalignant, dysplasia, and carcinoma-in-situ (CIS). Deeper resections for these pathologies were considered inappropriately deep. All resections were considered appropriate for squamous cell carcinoma (SCC).

RESULTS

Ninety-seven patients who underwent 139 SSLC were included. SCC was found in 30% (N = 42), CIS/severe-dysplasia in 15% (N = 21), mild/moderate-dysplasia in 23% (N = 32), nondysplastic lesions in 31% (N = 43), and lymphoma in 0.5% (N = 1). Superficial-type-1 cordectomy was performed in 64% (N = 89). Altogether, 15 lesions (11%) underwent inappropriately deep resections. Smoking history, current smoking status, prior glottic surgery, radiation or fungal infection, did not increase the rate of inappropriate deep resection. While the general rate of inappropriately deep resection is 11%, for deep-type-1 cordectomy or deeper the rate was 29.4%. The highest rate was associated with deep-type-1 cordectomy, reaching 52.9%.

CONCLUSION

The general rate of inappropriately deep resection during a SSLC is low. However, when the depth of resection involves exposure of the vocal ligament or deeper, the rate increases. Hence, to avoid unnecessary morbidity, whenever a deep resection is considered, the authors recommend preceding a deeper resection with frozen section sampling.

Interactions of Equine Viruses with the Host Kinase Machinery and Implications for One Health and Human Disease

Zoonotic pathogens that are vector-transmitted have and continue to contribute to several emerging infections globally. In recent years, spillover events of such zoonotic pathogens have increased in frequency as a result of direct contact with livestock, wildlife, and urbanization, forcing animals from their natural habitats. Equines serve as reservoir hosts for vector-transmitted zoonotic viruses that are also capable of infecting humans and causing disease. From a One Health perspective, equine viruses, therefore, pose major concerns for periodic outbreaks globally. Several equine viruses have spread out of their indigenous regions, such as West Nile virus (WNV) and equine encephalitis viruses (EEVs), making them of paramount concern to public health. Viruses have evolved many mechanisms to support the establishment of productive infection and to avoid host defense mechanisms, including promoting or decreasing inflammatory responses and regulating host machinery for protein synthesis. Viral interactions with the host enzymatic machinery, specifically kinases, can support the viral infectious process and downplay innate immune mechanisms, cumulatively leading to a more severe course of the disease. In this review, we will focus on how select equine viruses interact with host kinases to support viral multiplication.

Microscopic positive surgical margins in thyroid carcinoma: a proposal for thyroid oncology teams

PURPOSE

In the case of well-differentiated thyroid cancer, the importance of microscopic margin status remains controversial. We discuss the relevance of the effect of microscopic positive surgical margins in the early stages of differentiated thyroid cancer.

METHODS

A comprehensive literature search and review of available evidence in English literature was undertaken.

RESULTS

A previous meta-analysis did not find an association between microscopic positive surgical margins and local recurrence. Heterogeneity of definitions and differences between microscopic surgical margins and extrathyroid extension are discussed. Impact on clinical decision-making is explored.

CONCLUSION

The finding of microscopic positive surgical margins in a patient with a thyroid tumor without intraoperative evidence of macroscopic invasion to adjacent structures, with complete resection made by the surgeon and without pathological report of extrathyroid extension, does not have a worse prognostic effect. We present a classification of surgical margins that may help thyroid oncology teams to tailor further management in patients with thyroid cancer.

Use and overuse of diagnostic neck ultrasound in Ontario: Retrospective population-based cohort study

OBJECTIVE

To provide an overview of the use and possible overuse of diagnostic neck ultrasound (DNUS) by describing and comparing both the ordering rates and the downstream results of DNUS by regions across Ontario.

DESIGN

Retrospective population-based cohort study based on electronic health care data.

SETTING

Ontario.

PARTICIPANTS

Ontario residents (adults aged > 18 years) who had a diagnosis of thyroid cancer between October 1, 1999, and June 30, 2014, and residents who had a DNUS in 2012.

MAIN OUTCOME MEASURES

Proportion of Ontario residents in each sub-Local Health Integration Network (LHIN) group who had their first DNUS in 2012 and went on to other relevant tests, diagnoses, and surgery. The sub-LHIN groups were based on increasing age- and sex-adjusted rates of first DNUS.

RESULTS

There were 77 238 DNUS tests in 2012 and there was a 7.4-fold variation in the rate of test ordering across the sub-LHIN populations leading to variable rates of actual disease, suggesting screening or uncertain indications for tests.

CONCLUSION

Across Ontario, the indications for ordering DNUS are variable, and screening or testing without indication might be a common practice. Establishing effective guidelines for the ordering of DNUS would potentially reduce costs and ultimately reduce the rates of thyroid cancer.

Explaining the Variation in Surgical Practice for Differentiated Thyroid Cancer in Ontario, Canada

IMPORTANCE

In the management of differentiated thyroid cancer (DTC), the extent of surgical treatment required for most patients remains controversial and varies widely. This variation may be associated with the Enthusiasm Hypothesis, the notion that geographic differences in use of health care services are driven by the prevalence of physicians with a preference for particular services.

OBJECTIVE

To evaluate the Enthusiasm Hypothesis and its applicability to the variation in the surgical treatment of thyroid cancer in Ontario, Canada.

DESIGN, SETTING, AND PARTICIPANTS

This population-based study obtained electronic data on all health care-associated events for the complete population of insured residents of Ontario, Canada. Patients (n = 28 754) who were 18 years of age or older and underwent an initial therapeutic thyroid surgical procedure for a papillary or follicular carcinoma diagnosis between January 1, 2000, and December 31, 2015, were included. The final data analysis was performed January 31, 2019.

EXPOSURES

Therapeutic thyroid cancer surgical procedure.

MAIN OUTCOMES AND MEASURES

Numbers of surgeons, extent of surgical treatment, and case volumes in 14 geographic regions in Ontario.

RESULTS

In total, 28 754 patients with DTC were included, of whom 22 600 (78.6%) were female, with a mean (SD) age of 49 (14) years. The use of total thyroidectomy for DTC varied widely across geographic regions of Ontario, from 45.8% to 77.1% of all cancer cases. More than 90% of the overall variation in practice (total thyroidectomy vs less-than-total thyroidectomy) could be explained by the practices of the high-volume surgeons (enthusiasts) in regions with the highest rates of thyroid cancer diagnosis.

CONCLUSIONS AND RELEVANCE

The Enthusiasm Hypothesis appears to be consistent with the findings of this study. The practices of the high-volume surgeons who were enthusiastic for total thyroidectomy in the geographic regions with the highest rates of thyroid cancer diagnosis may account for the variation in practice across Ontario between 2000 and 2015.

Microscopically positive surgical margins and local recurrence in thyroid cancer. A meta-analysis

BACKGROUND

Microscopically positive surgical margins are a prognostic factor of recurrence in advanced thyroid carcinoma. However, information on early and completely resected thyroid tumors is scarce. Some studies do not identify any association between positive margin and local recurrence. The objective of this study was to perform a meta-analysis to measure the association of microscopically positive surgical margins and local recurrence in patients who underwent total thyroidectomy.

METHODS

Clinical trials assessing the association between microscopically positive surgical margin and local recurrence in patients with early-stage, well-differentiated thyroid carcinoma who underwent total thyroidectomy were evaluated. The outcome measured was local recurrence in the thyroid bed. A systematic review and meta-analysis was done using a random-effects model.

RESULTS

Six studies with 7696 patients were identified. Methodological quality was good, and we did not identify statistical heterogeneity or publication bias. The risk difference for microscopically positive surgical margin and local recurrence was 0% (95% CI 0 to 1).

CONCLUSION

Meta-analysis did not find a statistically significant association between microscopically positive surgical margin and local recurrence in this population. A finding of microscopically positive surgical margin in the absence of other adverse factors is not an indication for adjuvant treatment.

Development of a binational thyroid cancer clinical quality registry: a protocol paper

INTRODUCTION

The occurrence of thyroid cancer is increasing throughout the developed world and since the 1990s has become the fastest increasing malignancy. In 2014, a total of 2693 Australians and 302 New Zealanders were diagnosed with thyroid cancer, with this number projected to rise to 3650 in 2018. The purpose of this protocol is to establish a binational population-based clinical quality registry with the aim of monitoring and improving the quality of care provided to patients diagnosed with thyroid cancer in Australia and New Zealand.

METHODS AND ANALYSIS

The Australian and New Zealand Thyroid Cancer Registry (ANZTCR) aims to capture clinical data for all patients over the age of 16 years with thyroid cancer, confirmed by histopathology report, who have been diagnosed, assessed or treated at a contributing hospital. A multidisciplinary steering committee was formed which, with operational support from Monash University, established the ANZTCR in early 2017. The pilot phase of the registry is currently operating in Victoria, New South Wales, Queensland, Western Australia and South Australia, with over 20 sites expected to come on board across Australia in 2018. A modified Delphi process was undertaken to determine the clinical quality indicators to be reported by the registry, and a minimum data set was developed comprising information regarding thyroid cancer diagnosis, pathology, surgery and 90-day follow-up.

FUTURE PLANS

The establishment of the ANZTCR provides the opportunity for Australia and New Zealand to further understand current practice in the treatment of thyroid cancer and identify variation in outcomes. The engagement of endocrine surgeons in supporting this initiative is crucial. While the pilot registry has a focus on early clinical outcomes, it is anticipated that future collection of longer term outcome data particularly for patients with poor prognostic disease will add significant further value to the registry.