Detection Rates Continue to Rise But Thyroid Cancer Deaths Stay the Same
The Takeaway
1. The number of papillary thyroid cancer cases treated has been going up in the US, Canada and Western Europe. In 2009 the incidence was three times what it had been in 1973, rising from 3.5 cases per 100,000 people to 12.5 cases per 100,000.
2. In a study published July 8th in the journal Thyroid, a team led by Luc Morris, MD MSc at Memorial Sloan-Kettering Cancer Center found a positive correlation between indicators of healthcare use and thyroid cancer diagnosis in the US. This looks like good news but it's actually a problem. The poor and those without access to care are getting fewer thyroid cancer diagnoses than those with access, even though both succumb to the disease at the same rate.
2. In a study published July 8th in the journal Thyroid, a team led by Luc Morris, MD MSc at Memorial Sloan-Kettering Cancer Center found a positive correlation between indicators of healthcare use and thyroid cancer diagnosis in the US. This looks like good news but it's actually a problem. The poor and those without access to care are getting fewer thyroid cancer diagnoses than those with access, even though both succumb to the disease at the same rate.
3. If more cases of a fatal disease are diagnosed and treated, but death rates don't decrease, the new cases being detected are likely part of a subclinical disease reservoir. These are cases that would not have gone on to cause harm if left alone. Treating subclinical cases is not only unnecessary, it is also harmful and costly. This is what is meant by the term overdiagnosis.
4. The authors speculate that the increase is due to the use of sensitive diagnostic tools such as ultrasonography, fine needle aspiration biopsy and the fact that small nodules sometimes show up "incidentally" when radiographic imaging is done for other reasons.
5. Census 2000 data was used to look at 9 socioeconomic variables across 443 US counties. SEER data provided patient demographic information, tumor and survival characteristics. An ecologic analysis and regression analysis were performed. Counties with higher income and education levels had more thyroid cancer cases than counties with more unemployment, non-English speakers, and poverty.
The One Minute Summary
Overdiagnosis is thought to occur when a reservoir of previously undetected, and non-lethal disease is revealed by new, more sensitive technologies. Papillary thyroid cancer fits this description because autopsies have revealed that between 8 and 35% percent of us are likely to go to our graves with detectable thyroid tumors, even if we have died from other causes. This latest study adds new evidence to the case for concluding that the rise in thyroid cancers over the last three decades is due to changes in the techniques of detection, rather than some change in the environment. It found that where there are more poor, non-English speaking, or unemployed adults, there is a lower rate of thyroid cancer diagnosis. And, crucially, that lower rate of diagnosis doesn't change life expectancy.
Read the Study: The Increasing Incidence of Thyroid Cancer: The Influence of Access to Care
By Luc Morris, MD MSc; Andrew Sikora, MD PhD; Tor Tosteson, ScD; and Louis Davis, MD MS
5. Census 2000 data was used to look at 9 socioeconomic variables across 443 US counties. SEER data provided patient demographic information, tumor and survival characteristics. An ecologic analysis and regression analysis were performed. Counties with higher income and education levels had more thyroid cancer cases than counties with more unemployment, non-English speakers, and poverty.
The One Minute Summary
Overdiagnosis is thought to occur when a reservoir of previously undetected, and non-lethal disease is revealed by new, more sensitive technologies. Papillary thyroid cancer fits this description because autopsies have revealed that between 8 and 35% percent of us are likely to go to our graves with detectable thyroid tumors, even if we have died from other causes. This latest study adds new evidence to the case for concluding that the rise in thyroid cancers over the last three decades is due to changes in the techniques of detection, rather than some change in the environment. It found that where there are more poor, non-English speaking, or unemployed adults, there is a lower rate of thyroid cancer diagnosis. And, crucially, that lower rate of diagnosis doesn't change life expectancy.
Read the Study: The Increasing Incidence of Thyroid Cancer: The Influence of Access to Care
By Luc Morris, MD MSc; Andrew Sikora, MD PhD; Tor Tosteson, ScD; and Louis Davis, MD MS
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