Risk stratification of 282 differentiated thyroid cancers found incidentally in 1369 total thyroidectomies according to the 2015 ATA guidelines; implications for management and treatment

Incidental thyroid carcinoma: Correlation between FNAB cytology and pathological examination in 1093 cases

OBJECTIVE

To investigate Incidental Thyroid Carcinoma (ITC) by comparing the results of Fine Needle Aspiration Biopsy (FNAB) cytology and the postoperative pathological findings.

METHODS

Data of 1479 patients who underwent total thyroidectomy were retrieved. Three hundred eighty-six patients were excluded due to insufficient data. Each surgical specimen studied received two histopathological diagnoses: the local diagnosis ‒ for the same area in which the FNAB was performed; and the final diagnosis, which includes a study of the entire surgical specimen.

RESULTS

A thousand and ninety-three patients were investigated. FNAB result was malignant in 187 patients, benign in 204, suspicious or indeterminate in 668 cases, and inconclusive in 34 cases. The prevalence of ITC was 15.1%. Most of the ITC in this series was less than 0.5 cm. The incidence of ITC was higher in Bethesda III (17.5% ITC) and IV (19% ITC) than in Bethesda II cases (1.5% false negatives and 9% ITC).

CONCLUSION

Although the incidence of false-negative results in Bethesda II nodules is only 1.5%, 9% of these patients had ITC in the thyroid parenchyma outside the nodule that underwent preoperative FNAB. The incidence of ITC in the same scenario was even higher in Bethesda III (17.5%) and Bethesda IV cases (19%). Ultrasonography-guided FNAB is an excellent method for the assessment of thyroid nodules. However, biopsy sites should be carefully selected. Despite the high incidence of incidentalomas, total thyroidectomy should not always be the treatment of choice due to its rare but potentially serious complications. The findings of the present study can assist future clinical decisions towards active surveillance strategies for the management of papillary thyroid carcinoma.

Clinical Management of End-Stage Renal Disease Patients on Dialysis Receiving Radioactive Iodine Treatment

PURPOSE

Radioactive iodine (RAI) is used to treat thyroid cancer patients with a clear paradigm for most patients. End-stage renal disease (ESRD) patients pose several challenges when undergoing RAI treatment, primarily due to the lack of renal clearance. We retrospectively report our experience with RAI treatment in a cohort of patients with ESRD and provide a set of recommendations on aspects such as the need for adjusted dose activity, balancing scheduling between RAI therapy and dialysis, and radiation safety precautions.

PATIENTS AND METHODS

In this study, we report on 5 patients (6 cases), with ESRD on dialysis, treated with RAI for thyroid cancer. Retention measurements to determine individual biological clearance of RAI from the patient's body before and after dialysis sessions were assessed using external exposure dose rates measured at 1 m.

RESULTS

Delayed biological clearance of RAI, after the first hemodialysis session, resulted in a longer RAI effective half-life as a consequence of longer retention periods, consistent with observations reported in scientific literature. To achieve a much closer radiation exposure compared with a nondialysis patient, one would recommend administering ~20%-30% of the dose activity normally administered to a thyroid cancer patient based on their medical history, histopathology, and uptake with the appropriate dialysis schedule.

CONCLUSIONS

Special precautions should be taken with the administration of RAI in ESRD patients by adjusting the prescribed dose activity, dialysis sessions, and paying special attention to wastes. Pooling data from multiple centers may be useful to build a consensus and substantiated recommendations.

Current surgical treatment of intermediate risk differentiated thyroid cancer: a systematic review

Introduction: Surgical treatment of thyroid cancer has become less aggressive but for many patients, the threshold for performing total thyroidectomy (TT), as opposed to thyroid lobectomy (TL), has remained unclear. Current American Thyroid Association (ATA) guidelines encourage more individualization of treatment options, which necessitates explicit review of the pros and cons of the different options with patients.Areas covered: This review focuses on the extent of surgery for treatment of intermediate-risk differentiated thyroid cancer, restricted to relevant literature available after publication of the 2015 ATA guidelines.Expert opinion: Dynamic risk-stratification facilitates a tailored approach when deciding on the extent of surgery for thyroid cancer. Treatment with TT allows for a lower recurrence risk, a simpler follow-up regimen, and treatment with adjuvant post-operative radioactive iodine. Treatment with TL has a lower associated risk of complications and avoidance of lifelong thyroid hormone replacement but has a significant risk of requiring a completion thyroid lobectomy (CT). Overall, treatment with TL and TT have comparable survival outcomes, but TL is the more cost-effective option. Larger cancer size is correlated with worse clinical outcomes, and numerous subgroup analyses have shown poorer outcomes for cancers with a diameter that is 2-4 cm compared to 1-2 cm.