Triggers of thyroid cancer diagnosis: a systematic review and meta-analysis

Abstract

Purpose Understanding the method of thyroid cancer detection has potential implications on interpreting incidence rates, the diagnosis and management of thyroid cancer. We conducted a systematic review of studies reporting methods of thyroid cancer detection to estimate the frequency of incidentally found cancers and classify triggers of incidental thyroid cancer diagnosis. Methods We searched multiple bibliographic databases from inception to June 2020. A pair of reviewers, working independently and in duplicate selected studies for inclusion, extracted data, and evaluated each trial's risk of bias. Studies enrolling patients older than 18 years with thyroid cancer confirmed histologically were included. Results In total, 17 cohorts and 1 cross-sectional study, conducted between 1991 and 2018, enrolling 4668 patients with thyroid cancer were included: 88% had papillary thyroid cancer and 23% had papillary thyroid microcarcinoma. The proportion of patients with non-incidental and incidental thyroid cancer was similar: 49% [95% confidence interval (CI): 40-58%]. Subgroup analysis showed that most patients with incidental thyroid cancers had tumor size <10 mm (76%; 95% CI: 56-92%), age >45 (61%; 95% CI: 56-67%), and were detected through imaging (35%; 95% CI: 26-45%), of which ultrasound was the most common modality (27%; 95% CI: 14-43%). The heterogeneity for all the effect sizes was large and significant. Conclusions About half of thyroid cancers were found incidentally through the use of imaging studies, in particular neck ultrasound. These incidentally found cancers were mostly small papillary thyroid cancer. These results highlight opportunities for interventions aimed at reducing drivers of overdiagnosis.

Cost-Effectiveness Analysis of Ultrasound Screening for Thyroid Cancer in Asymptomatic Adults

“…There were some assumptions underlying the use of these two strategies. First, considering that all Koreans underwent thyroid cancer screening in 2008, we used the Korean thyroid cancer epidemiological data for 1990 and 2010 to determine the transition probabilities for the screening group and the non-screening group, respectively, assuming that the natural incidence of thyroid cancer had remained unchanged between these years (17)(18)(19). Second, we assumed that the cost of routine Abbreviations: QALYs, quality-adjusted life years; CER, cost-effectiveness ratio; ICER, incremental cost-effectiveness ratio.…”

Inappropriate use of thyroid ultrasound: a systematic review and meta-analysis

“…We used the number of people with iUS indications and the total number of people with thyroid ultrasounds in each study to determine the mean overall proportion estimates and their 95% confidence intervals (95% CI). The mean overall proportion was estimated with generalized linear mixed models, as these models perform better with proportions close to 0 and 1 [2,16]. The confidence interval was calculated by using the exact method for binomial proportions [17].…”

“…Thyroid cancer is one of the most rapidly increasing malignancies in the United States, with an incidence that has tripled over the last three decades [1]. Approximately 50% of the increased incidence is attributable to the identification of small and asymptomatic papillary thyroid cancers (PTCs) that will not increase mortality [2]. These small PTCs have been found in 11% of thyroid glands removed for benign thyroid conditions or examined at autopsy in patients who died of unrelated causes [3].…”

“…One of the drivers of thyroid cancer overdiagnosis is the use of thyroid ultrasound [2]. Thyroid ultrasounds have the potential to reveal incidentally small thyroid cancers in asymptomatic patients [8].…”

Black thyroid: a benign finding

“…4 5 Thyroid neoplasm has been reported in 65% of patients with black thyroid; nevertheless, the high prevalence of malignancy can be explained by the fact that black thyroid is diagnosed during the thyroid malignancy diagnostic workup triggered by the overdiagnosis of thyroid cancer. 6 Neither black thyroid nor minocycline has been associated with an increased risk of malignancy or more aggressive cancer.…”