Overdiagnosis: epidemiologic concepts and estimation
19
Citation
92
Reference
10
Related Paper
Citation Trend
Abstract:
Overdiagnosis of thyroid cancer was propounded regarding the rapidly increasing incidence in South Korea. Overdiagnosis is defined as 'the detection of cancers that would never have been found were it not for the screening test', and may be an extreme form of lead bias due to indolent cancers, as is inevitable when conducting a cancer screening programme. Because it is solely an epidemiological concept, it can be estimated indirectly by phenomena such as a lack of compensatory drop in post-screening periods, or discrepancies between incidence and mortality. The erstwhile trials for quantifying the overdiagnosis in screening mammography were reviewed in order to secure the data needed to establish its prevalence in South Korea.Keywords:
Overdiagnosis
Cancer screening
Overdiagnosis
Cancer screening
Cite
Citations (0)
In 2011, the rate of thyroid-cancer diagnoses in the Republic of Korea was 15 times that observed in 1993, yet thyroid-cancer mortality remains stable — a combination that suggests that the problem is overdiagnosis attributable to widespread thyroid-cancer screening.
Overdiagnosis
Cite
Citations (1,115)
There is a consensus that Chernobyl accident has induced thyroid cancer increase in children and adolescents. The UNSCEAR report concluded that no somatic disorders other than thyroid cancer were caused by radiation exposure due to the accident except for acute radiation sickness occurred to the people within the Power Plant at the time of the accident. A hypothesis is discussed in this paper that the increase of thyroid cancer was caused predominantly by the screening, overdiagnosis, and registration of nonirradiated persons as Chernobyl victims. A mechanism of thyroid cancer overdiagnosis is described that can be active even today, causing hypertherapy. Older neglected tumors found by the screening shortly after the Chernobyl accident or brought from noncontaminated areas were misclassified as aggressive radiation-induced cancers. Therefore, supposed markers of the radiation-induced thyroid cancer, such as the RET rearrangements, are probably associated with disease duration and tumor progression. The screening effect is obviously dependent on the basis level of medical surveillance: the higher the level, the smaller the screening effect. Absence of any significant increase of thyroid cancer after the Fukushima accident in spite of the vigorous screening would certify the high level of health care in Japan especially for children.
Overdiagnosis
Chernobyl Nuclear Accident
Cite
Citations (10)
Overdiagnosis
Cite
Citations (38)
Overdiagnosis
Digital Mammography
Breast Cancer Screening
Cite
Citations (55)
The incidence of thyroid cancer in South Korea increased 15 times over the past twenty years, that made South Korea became a country of the highest reported incidence in thyroid cancer all over the world. But the mortality of thyroid cancer was stable and unchanged. The incidence of thyroid cancer in our country was growing at an annual percentage change of 20.1%. It is a generally accepted that the sharply increased incidence is attributed to overdiagnosis . Here we introduced the definition of overdiagnosis of cancer and the current understanding in tumor field. The corresponding strategy in our country was proposed. (Chin J Endocrinol Metab, 2016, 32: 443-447)
Key words:
Thyroid cancer; Incidence; Overdiagnosis; Overtreatment
Overdiagnosis
Cite
Citations (0)
To examine the secular trends of thyroid cancer incidence and mortality and to estimate the proportion of thyroid cancer cases potentially attributable to overdiagnosis.Data on thyroid cancer cases from 1973 to 2015 were obtained from the Shanghai Cancer Registry. The average annual percent change (AAPC) was evaluated using the joinpoint regression analysis. The age, period, and birth cohort effects were assessed using an age-period-cohort model. The overdiagnosis of thyroid cancer cases was estimated based on the difference between observed and expected incidences using the rates of Nordic countries as reference.From 1973 to 2015, the number of thyroid cancer cases was 23 117, and 75% of the patients were women. The age-standardized rates were seven- to eightfold higher from 2013 to 2015 than from 1973 to 1977. Compared with relatively stable mortality, thyroid cancer incidence was dramatically increased from 2002 to 2015 in both sexes, with significant trends (men: AAPC = 21.84%, 95% CI: 18.77%-24.98%, P < .001; women: AAPC = 18.55%, 95% CI: 16.49%-20.64%, P < .001). The proportion of overdiagnosis has gradually increased over time, rising from 68% between 2003 and 2007 to more than 90% between 2013 and 2015. This increasing trend appeared to be similar between men and women.An increasing gap between thyroid cancer incidence and mortality was observed in Shanghai, and overdiagnosis has contributed substantially to the rise of incidence, which calls for an urgent update on the practice of thyroid examination.
Overdiagnosis
Secular Variation
Cite
Citations (14)
Overdiagnosis is the main «driver» of the growing epidemic of thyroid cancer in the world. More than half of cases of thyroid cancer in women are the result of overdiagnosis, i.e. diagnosis of a tumor, the probability of progression and metastasis of which is extremely low. Our analysis showed that the incidence of thyroid cancer in Russia and most of its administrative regions is growing. At the same time, we observe pronounced interregional variability in the incidence rate. A very highage adjusted incidence rate, especially among women, is registered in the Bryansk region and other high-risk regions. The main cause of the increase in the incidence of thyroid cancer in the regions adjacent to the Chernobyl nuclear power plant is exposure to radioactive iodine (131I ) in childhood and adolescence. However, an increase in the incidence of thyroid cancer in this region at least partly is a consequence of ultrasonography (US) screening and the identification of clinically insignificant lesions. Only 40% of cases of thyroid cancer detected as a result, of screening could be the attributed to radiation. Accordingly, 60% are latent tumors that would never have clinically shown themselves if they had not been identified as a result, of screening.Altai region is also considered a high-risk region because it borders with the Semipalatinsk region of Kazakhstan the region where the former Soviet nuclear test site was located. Inthe Altai region, the introduction of US screening led to an increase in the detection of thyroid cancer from 8,7% in 1992 to 20,3% in 1999. A marked increase in incidence in Russia, the increase in incidence in middle age and as a result the change in expected exponential pattern of age-specific curve into inverted «U», a very high incidence to mortality ratio, a very high cancer survival rate, which statistically significantly correlates with incidence, a statistically significant correlation between the proportion of tumors detected at the first stage and the incidence of thyroid cancer, a statistically significant correlation between prevalence of thyroid cancer and the incidence is a clear evidence of overdiagnosis. We estimate that the number of overdiagnosed thyroid cancer in Russia over 27 years ranges from 99000 to 138000 cases. We do not have sufficient retrospective data to estimate more accurately the size of thyroid cancer overdiagnosis in Russia. Thyroid cancer incidence data for Russia overall is available only from 1989.
Overdiagnosis
Cite
Citations (4)
Overdiagnosis
Cite
Citations (4)
Thyroid cancer is the most common endocrine cancer, of which the incidence has dramatically increased worldwide in the past few decades. The reasons for the observed rapid increase still are not fully understood, but evidence suggests that overdiagnosis, with the advancement in detection methods and screening policies, is not the sole driver of the substantial increase of the incidence. However, the effect of environmental/lifestyle factors remains speculative other than that of radiation exposure at a young age. This review tries to give a balanced view of debated factors leading to the thyroid cancer epidemic, to offer some alternatives in understanding the controversies, and to suggest potential directions in the search of modifiable risk factors to help reduce thyroid cancer.
Overdiagnosis
Cite
Citations (107)