Cancer Stat Fact Sheets

Cancer of the Thyroid

It is estimated that 37,340 men and women (8,930 men and 28,410 women) will be diagnosed with and 1,590 men and women will die of cancer of the thyroid in 20081.

The following information is based on NCI’s SEER Cancer Statistics Review2.

Incidence & Mortality

SEER Incidence

From 2001-2005, the median age at diagnosis for cancer of the thyroid was 48 years of age3. Approximately 1.9% were diagnosed under age 20; 17.4% between 20 and 34; 22.6% between 35 and 44; 23.4% between 45 and 54; 16.3% between 55 and 64; 10.9% between 65 and 74; 6.2% between 75 and 84; and 1.3% 85+ years of age.

The age-adjusted incidence rate was 9.1 per 100,000 men and women per year. These rates are based on cases diagnosed in 2001-2005 from 17 SEER geographic areas.

US Mortality

From 2001-2005, the median age at death for cancer of the thyroid was 73 years of age4. Approximately 0.1% died under age 20; 0.9% between 20 and 34; 2.6% between 35 and 44; 8.7% between 45 and 54; 16.9% between 55 and 64; 24.0% between 65 and 74; 30.5% between 75 and 84; and 16.2% 85+ years of age.

The age-adjusted death rate was 0.5 per 100,000 men and women per year. These rates are based on patients who died in 2001-2005 in the US.

Trends in Rates

Trends in rates can be described in many ways. Information for trends over a fixed period of time, for example 1995-2005, can be evaluated by the annual percentage change (APC). If there is a negative sign before the number, the trend is a decrease; otherwise it is an increase. If there is an asterisk after the APC then the trend was significant, that is, one believes that it is beyond chance, i.e. 95% sure, that the increase or decrease is real over the period 1995-2005. If the trend is not significant, the trend is usually reported as stable or level. Joinpoint analyses can be used over a long period of time to evaluate when changes in the trend have occurred along with the APC which shows how much the trend has changed between each of the joinpoints.

Survival & Stage

Survival rates can be calculated by different methods for different purposes. The survival rates presented here are based on the relative survival rate, which measures the survival of the cancer patients in comparison to the general population to estimate the effect of cancer. The overall 5-year relative survival rate for 1996-2004 from 17 SEER geographic areas was 96.9%. Five-year relative survival rates by race and sex were: 94.3% for white men; 98.0% for white women; 90.7% for black men; 95.6% for black women.

The stage distribution based on historic stage shows that 59% of thyroid cancer cases are diagnosed while the cancer is still confined to the primary site (localized stage); 34% are diagnosed after the cancer has spread to regional lymphnodes or directly beyond the primary site; 5% are diagnosed after the cancer has already metastasized (distant stage) and for the remaining 3% the staging information was unknown. The corresponding 5-year relative survival rates were: 99.7% for localized; 96.9% for regional; 57.8% for distant; and 89.5% for unstaged.

Lifetime Risk

Based on rates from 2003-2005, 0.79% of men and women born today will be diagnosed with cancer of the thyroid at some time during their lifetime. This number can also be expressed as 1 in 127 men and women will be diagnosed with cancer of the thyroid during their lifetime. These statistics are called the lifetime risk of developing cancer. Sometimes it is more useful to look at the probability of developing cancer of the thyroid between two age groups. For example, 0.19% of men will develop cancer of the thyroid between their 50th and 70th birthdays compared to 0.44% for women.

Prevalence

On January 1, 2005, in the United States there were approximately 388,386 men and women alive who had a history of cancer of the thyroid -- 86,920 men and 301,466 women. This includes any person alive on January 1, 2005 who had been diagnosed with cancer of the thyroid at any point prior to January 1, 2005 and includes persons with active disease and those who are cured of their disease. Prevalence can also be expressed as a percentage and it can also be calculated for a specific amount of time prior to January 1, 2005 such as diagnosed within 5 years of January 1, 2005.

References

All statistics in this report are based on SEER incidence and NCHS mortality statistics. Most can be found within:

Ries LAG, Melbert D, Krapcho M, Stinchcomb DG, Howlader N, Horner MJ, Mariotto A, Miller BA, Feuer EJ, Altekruse SF, Lewis DR, Clegg L, Eisner MP, Reichman M, Edwards BK (eds). SEER Cancer Statistics Review, 1975-2005, National Cancer Institute. Bethesda, MD, http://seer.cancer.gov/csr/1975_2005/, based on November 2007 SEER data submission, posted to the SEER web site, 2008.

Footnotes

1 Table I-1 (http://seer.cancer.gov/csr/1975_2005/results_single/sect_01_table.01.pdf)
2Thyroid Section (http://seer.cancer.gov/csr/1975_2005/results_merged/sect_26_thyroid.pdf)
3 Table I-11 (http://seer.cancer.gov/csr/1975_2005/results_single/sect_01_table.11_2pgs.pdf)
4 Table I-13 (http://seer.cancer.gov/csr/1975_2005/results_single/sect_01_table.13_2pgs.pdf)
^Statistic not shown. Rate based on less than 16 cases for the time interval.
*The APC is significantly different from zero (p<.05).
aIncidence data for Hispanics is based on NHIA and excludes cases from Alaska Native Registry and Kentucky. Hispanic death rates exclude deaths from Minnesota, New Hampshire and North Dakota.
bIncidence and mortality data for American Indians/Alaska Natives is based on the CHSDA (Contract Health Service Delivery Area) counties.

Definitions

Annual percent change (APC)

The average annual percent change over several years. The APC is used to measure trends or the change in rates over time. For information on how this is calculated, go to Trend Algortihms in the SEER*Stat Help system. The calculation involves fitting a straight line to the natural logarithm of the data when it is displayed by calendar year.

Joinpoint analyses

A statistical model for characterizing cancer trends which uses statistical criteria to determine how many times and when the trends in incidence or mortality rates have changed. The results of joinpoint are given as calendar year ranges, and the annual percent change (APC) in the rates over each period.

Survival rates

Survival examines how long after diagnosis people live. Cancer survival is measured in a number of different ways depending on the intended purpose.

Relative survival rate

A measure of net survival that is calculated by comparing observed (overall) survival with expected survival from a comparable set of people that do not have cancer to measure the excess mortality that is associated with a cancer diagnosis.

Stage distribution

Stage provides a measure of disease progression, detailing the degree to which the cancer has advanced. Two methods commonly used to determine stage are AJCC and SEER historic. The AJCC method (see Collaborative Staging Method) is more commonly used in the clinical settings, while SEER has standardized and simplified staging to ensure consistent definitions over time.

Lifetime risk

The probability of developing cancer in the course of one's lifespan. Lifetime risk may also be discussed in terms of the probability of developing or of dying from cancer. Based on cancer rates from 2003 to 2005, it was estimated that men had about a 44 percent chance of developing cancer in their lifetimes, while women had about a 37 percent chance.

Probability of developing cancer

The chance that a person will develop cancer in his/her lifetime.

Prevalence

The number of people who have received a diagnosis of cancer during a defined time period, and who are alive on the last day of that period. Most prevalence data in SEER is for limited duration because information on cases diagnosed before 1973 is not generally available.