Dataset Information

Overdiagnosis and overtreatment of thyroid cancer: A population-based temporal trend study.

ABSTRACT:

Background

The increase in incidence of thyroid cancer during the last decades without concomitant rise in mortality may reflect the growing detection of indolent forms of thyroid cancer, and may have fueled unnecessary thyroidectomies. Our aim was therefore, to compare recent secular trends in surgical intervention rate for thyroid cancer with the incidence and mortality of thyroid cancer to assess overdiagnosis and resulting overtreatment.

Methods

We conducted a population-based temporal trend study in Switzerland from 1998 to 2012. All cases of invasive thyroid cancer, deaths from thyroid cancer, and cancer-related thyroidectomies were analyzed. We calculated changes in age-standardized thyroid cancer incidence rates, stratified by histologic subtype and tumor stage, thyroid cancer-specific mortality, and thyroidectomy rates.

Results

Between 1998 and 2012, the age-standardized annual incidence of thyroid cancer increased from 5.9 to 11.7 cases/100,000 among women (annual mean absolute increase: +0.43/100,000/year) and from 2.7 to 3.9 cases/100,000 among men (+0.11/100,000/year). The increase was limited to the papillary subtype, the most indolent form of thyroid cancer. The incidence of early stages increased sharply, the incidence of advanced stages increased marginally, and the mortality from thyroid cancer decreased slightly. There was a three- to four-fold increase in the age-standardized annual thyroidectomy rate in both sexes.

Conclusions

We observed a large increase in the incidence of thyroid cancer, limited to papillary and early stage tumors, with a three- to four-fold parallel increase in thyroidectomy. The mortality slightly decreased. These findings suggest that a substantial and growing part of the detected thyroid cancers are overdiagnosed and overtreated.

Impact

Targeted screening and diagnostic strategies are warranted to avoid overdetection and unnecessary treatment of thyroid cancers.

SUBMITTER: Jegerlehner S

PROVIDER: S-EPMC5470703 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Overdiagnosis and overtreatment of thyroid cancer: A population-based temporal trend study.

Jegerlehner Sabrina S Bulliard Jean-Luc JL Aujesky Drahomir D Rodondi Nicolas N Germann Simon S Konzelmann Isabelle I Chiolero Arnaud A

PloS one 20170614 6

<h4>Background</h4>The increase in incidence of thyroid cancer during the last decades without concomitant rise in mortality may reflect the growing detection of indolent forms of thyroid cancer, and may have fueled unnecessary thyroidectomies. Our aim was therefore, to compare recent secular trends in surgical intervention rate for thyroid cancer with the incidence and mortality of thyroid cancer to assess overdiagnosis and resulting overtreatment.<h4>Methods</h4>We conducted a population-based ...[more]

PMID: 28614405

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Project description:BackgroundIt is estimated that one of the potential cause of the increasing prevalence of thyroid cancer (TC) is the easier and widespread access to diagnostic tools. If an individual evaluates the thyroid gland due to a mentioned mechanism without considering TC risk factors or symptoms, we can describe this phenomenon as cancer screening activity (CSA).Aim of the studyWe 1) estimated what types of TC were diagnosed due to CSA, 2) analyzed what clinicopathological features were characteristic of TCs diagnosed by CSA, 3) determined if these features were characteristic of indolent cases, and finally we 4) assessed whether CSA could have resulted in the increasing incidence of potentially indolent papillary thyroid cancer (PTC).Materials and methodsA retrospective review of 4,701 medical records of patients admitted and surgically treated at one surgical center between 2008 and 2017 was performed. Among the enrolled patients, 569 (12.1%) had thyroid malignancy, and 514 (10.9%) were diagnosed with PTC. We divided these patients into two groups: 1) patients in whom TC diagnostics were performed without considering any TC risk factors or symptoms (CSA-yes) and 2) those in whom TC was diagnosed due to TC risk factors or symptoms (CSA-no). We then compared the clinicopathological features of these two groups.ResultsThe most common type of TC diagnosed in the CSA-group was PTC (p = 0.024). CSA-yes patients showed a significantly lower degree of Tumor-Node-Metastasis (TNM) staging and demonstrated a significantly lower rate of multifocality, but not of bilaterality (p<0.0001 and p = 0.198, respectively). In the CSA-yes group, the number of TC foci was significantly lower than that in the CSA-no group (p<0.0001). All clinicopathological features characteristic of aggressive cases of TC were absent in CSA-yes patients (p<0.0001), while all features observed in CSA-yes patients were characteristic of indolent cases (p<0.0001).ConclusionsThe use of CSA results in the diagnosis of indolent cases of PTC and may be one of the potential causes of overdiagnosis and overtreatment of this malignancy.

Project description:BACKGROUND:Screening for prostate cancer is frequent in high-income countries, including Switzerland. Notably due to overdiagnosis and overtreatment, various organisations have recently recommended against routine screening, potentially having an impact on incidence, mortality, and surgery rates. Our aim was therefore to examine whether secular trends in the incidence and mortality of prostate cancer, and in prostatectomy rates, have recently changed in Switzerland. METHODS:We conducted a population-based trend study in Switzerland from 1998 to 2012. Cases of invasive prostate cancer, deaths from prostate cancer, and prostatectomies were analysed. We calculated changes in age-standardised prostate cancer incidence rates, stratified by tumor stage (early, advanced), prostate cancer-specific mortality, and prostatectomy rates. RESULTS:The age-standardised incidence rate of prostate cancer increased greatly in men aged 50-69 years (absolute mean annual change +4.6/100,000, 95% CI: +2.9 to +6.2) between 1998 and 2002, and stabilised afterwards. In men aged ≥ 70 years, the incidence decreased slightly between 1998 and 2002, and more substantially since 2003. The incidence of early tumor stages increased between 1998 and 2002 only in men aged 50-69 years, and then stabilised, while the incidence of advanced stages remained stable across both age strata. The rate of prostatectomy increased markedly until 2002, more so in the 50 to 69 age range than among men aged ≥ 70 years; it leveled off after 2002 in both age strata. Trends in surgery were driven by radical prostatectomy. Since 1998, the annual age-standardised mortality rate of prostate cancer slightly declined in men aged 50-69 years (absolute mean annual change -0.1/100,000, 95% CI: -0.2 to -0.1) and ≥ 70 years (absolute mean annual change -0.5/100,000, 95% CI: -0.7 to -0.3). CONCLUSIONS:The increases in the incidence of early stage prostate cancer and prostatectomy observed in Switzerland among men younger than 70 years have concomitantly leveled off around 2002/2003. Given the decreasing mortality, these trends may reflect recent changes in screening and clinical workup practices, with a possible attenuation of overdiagnosis and overtreatment.

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Project description:BackgroundIncidence rates of thyroid cancer in Ontario have increased more rapidly than those of any other cancer, whereas mortality rates have remained relatively stable. We evaluated the extent to which incidental detection of differentiated thyroid cancer during unrelated prediagnostic imaging procedures contributed to Ontario's incidence rates.MethodsWe conducted a retrospective cohort study involving Ontarians who received a diagnosis of differentiated thyroid cancer from 1998 to 2017 using linked health care administrative databases. We classified cases as incidentally detected if a nonthyroid diagnostic imaging test (e.g., computed tomography [CT]) preceded an index event (e.g., prediagnostic fine-needle aspiration biopsy); all other cases were nonincidentally detected cases. We used Joinpoint and negative binomial regressions to characterize sex-specific rates of differentiated thyroid cancer by incidentally detected status and to quantify potential age, diagnosis period and birth cohort effects.ResultsThe study included 36 531 patients with differentiated thyroid cancer, of which 78.7% were female. Incidentally detected cases increased from 7.0% to 11.0% of female patients and from 13.5% to 18.2% of male patients over the study period. Age-standardized incidence rates increased more rapidly for incidentally detected cases (4.2-fold for female and 3.7-fold for male patients) than for nonincidentally detected cases (2.6-fold for female and 3.0-fold for male patients; p < 0.001). Diagnosis period was the primary factor associated with increased incidence rates of differentiated thyroid cancer, adjusting for other factors. Within each period, incidentally detected rates increased faster than nonincidentally detected rates, adjusting for age. Our results showed that CT was the most common imaging procedure preceding incidentally detected diagnoses.InterpretationIncidentally detected cases represent a large and increasing component of the observed increases in differentiated thyroid cancer in Ontario over the past 20 years, and CT scans are primarily associated with these cases despite the modality having similar, increasing rates of use compared with magnetic resonance imaging (1993-2004). Recent increases in rates of differentiated thyroid cancer among males and incidentally detected cases among females in Ontario appear to be unrelated to birth cohort effects.

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Dataset Information

Overdiagnosis and overtreatment of thyroid cancer: A population-based temporal trend study.

Background

Methods

Results

Conclusions

Impact

Publications

Overdiagnosis and overtreatment of thyroid cancer: A population-based temporal trend study.

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