Thyroid Cancer Overdiagnosis and Overtreatment: a cross- sectional study at a thyroid cancer referral center in Ecuador

Abstract

Background: In contrast to the rapid increase in thyroid cancer incidence, the mortality has remained low and stable over the last decades. In Ecuador, however, thyroid cancer mortality has increased. The objective of this study is to determine possible drivers of high rates of thyroid cancer mortality, through a cross-sectional analysis of all patients attending a thyroid cancer referral center in Ecuador.Methods: From June 2014 to December 2017, a cross-sectional study was conducted at the Hospital de Especialidades Eugenio Espejo, a regional reference public hospital for endocrine neoplasia in adults in Quito, Ecuador. We identified the mechanism of detection, histopathology and treatment modalities from a patient interview and review of clinical records. Results: Among 452 patients, 74.8% were young adults and 94.2% (426) were female. 13.7% had a family history of thyroid cancer, and patients’ median tumor size was 2 cm. The incidental finding was 54.2% whereas 45.8% was non-incidental. Thyroid cancer histology reported that 93.3% had papillary thyroid cancer (PTC), 2.7% follicular, 1.5% Hurtle cells, 1.6% medullary, 0.7% poor differentiated, and 0.2% anaplastic carcinoma. The mean MACIS (metastasis, age, completeness, invasion, and size) score was 4.95 (CI 4.15-5.95) with 76.2% of the thyroid cancer patients having MACIS score less than or equal to 6. The very low and low risk of recurrence was 18.1% (79) and 62% (271) respectively. An analysis of 319 patients with non-metastatic thyroid cancer showed that 10.7% (34) of patients had surgical complications. Moreover, around 62.5% (80 from 128 patients with thyroglobulin laboratory results) of TC patients had a stimulated-thyroglobulin value equal or higher than 2 ng/ml. Overall, a poor surgical outcome was present in 35.1% (112) patients. Out of 436 patients with differentiated thyroid carcinoma, 86% (375) received radioactive iodine. Conclusion: Thyroid cancer histological characteristics and method of diagnosis are like those described in other reports without any evidence of the high frequency of aggressive thyroid cancer histology. However, we observed evidence of overtreatment and poor surgical outcomes that demand additional studies to understand their association with thyroid cancer mortality in Ecuador.

Nomogram prediction for the involution of the ablation zone after radiofrequency ablation treatment in patients with low-risk papillary thyroid carcinoma

“…Thyroidectomy is recommended as the first-line treatment method for PTC [5,6]. However, for lowrisk patients (defined as having intrathyroidal PTC with no evidence of extrathyroidal extension, vascular invasion, or metastases) [3], the necessity of thyroidectomy has become a focus of controversy both in China and abroad [7,8]. Active surveillance for low-risk papillary thyroid microcarcinoma (PTMC) was mentioned in the 2015 American Thyroid Association guidelines (ATA, 2015).…”

“…However, it is still unclear which patients are suitable for long-term active surveillance and how to standardize the follow-up intervals and clinical indicators. Considering the rapidly increasing incidence of PTC in recent years worldwide [8][9][10][11] and the clinical application of new treatments for this disease, researchers have investigated long-term outcomes of thermal ablation techniques [12][13][14][15][16].…”

The influence of incidental detection of thyroid nodule on thyroid cancer risk and prognosis—A systematic review

“…Of the 14 studies included, 12 were retrospective cohort studies 19,20,22,23,27,28,31–36 and 2 37,38 were cross‐sectional studies; the study periods ranged from 1998 to 2020. The inclusion and exclusion criteria for the individual studies are described in Table S6.…”

“…The inclusion and exclusion criteria for the individual studies are described in Table S6. Eight studies were carried out in the United States and the rest were from Italy, 19 Israel, 27 Korea, 32 Canada, 33 Ecuador 37 and Australia 38 . One study 23 only included individuals under the age of 18 while the others were in the adult population.…”

“…Two studies 32,33 focussed exclusively on PTC whilst two studies 19,35 focussed on differentiated thyroid cancer (DTC) which included papillary, follicular and Hurtle cell carcinomas. The rest of the studies 22,27,28,31,34,36–38 included patients with DTC, medullary and anaplastic carcinomas. Three direct and thirteen indirect prognostic markers were discussed in respective studies (shown in Table S8).…”