GEOGRAPHIC VARIATION IN U.S THYROID CANCER INCIDENCE, AND A CLUSTER NEAR NUCLEAR REACTORS IN NEW JERSEY, NEW YORK, AND PENNSYLVANIA Joseph J Mangano Thyroid cancer incidence is increasing more rapidly than any other malignancy in the U.S (along with liver cancer), rising nearly threefold from 1980 to 2006 Improved diagnosis has been proposed as the major reason for this change by some, while others contend that other factors also account for the increase Among U.S states, 2001-2005 age-adjusted thyroid cancer incidence rates vary from 5.4 to 12.8 per 100,000 Countyspecific incidence data available for the first time document that most U.S counties with the highest thyroid cancer incidence are in a contiguous area of eastern Pennsylvania, New Jersey, and southern New York Exposure to radioactive iodine emissions from 16 nuclear power reactors within a 90 mile radius in this area as a potential etiological factor of thyroid cancer is explored; these emissions are likely a cause of rising incidence rates From 1980 to 2006, annual U.S thyroid cancer incidence rose nearly threefold, from 4.33 to 11.03 cases per 100,000 (age adjusted to the 2000 U.S standard population) This increase has been steady, rising in 22 of 26 years, and has been most pronounced since the early 1990s (1) Along with liver/bile duct cancer, incidence of thyroid cancer has experienced the greatest increase of any type of malignancy (Appendix 1) Temporal trends during this period were consistent (between +137% and +181%) for males, females, blacks, and whites Rates have risen markedly for all age groups except for children and the very old (Appendix 2) The expected annual number of newly diagnosed U.S thyroid cancer cases has reached 37,340 Improvements in treatment have raised survival rates; by 2006, the prevalence of U.S thyroid cancer survivors was 410,404, and is increasing by more than 20,000 each year (1) This significant and largely unexpected rise in U.S thyroid cancer incidence is consistent with reports of similar increases in many other developed nations, including Scotland, France, Italy, the Netherlands, Poland, the Czech Republic, Switzerland, Australia, England, Wales, and Canada (2-11) A recent study concluded that the rise in U.S thyroid cancer incidence is a function of improved diagnostic techniques, especially for papillary malignancies, which account for the large majority of thyroid cancer cases (12) Another report contradicts this conclusion, contending that improved detection only accounts for a portion of the increase, and other factors should be explored (13) A frequently-employed means of understanding reasons for disease patterns is that of geographic variation Studies of U.S cancer incidence and mortality at the state, county, congressional district, and state economic area levels have been made (14-17) “Cancer mapping” techniques can be useful in generating etiological hypotheses (18) While variations in cancer rates are often due to risk factors, screening rates, and effectiveness of treatments, some conclude that cancer is often caused by environmental factors (19) The first national U.S cancer incidence data base can be particularly helpful in studying low-incidence cancers with relatively low mortality rates (20-21) Thyroid cancer is relatively uncommon (2-3% of incident cases in the U.S.) and has one of the highest survival rates of any cancer, making mortality data of little use There have been few attempts to assess geographic differences in thyroid cancer incidence However, at least two reports have documented a wide variation between nations (22-23) One of these (23) cited the many studies that document sensitivity of the thyroid gland to radiation-induced oncogenesis from exposure to radioiodine isotopes Affected populations include survivors of the Hiroshima and Nagasaki atomic bombs and Nevada, Semlja, and Marshall Island bomb tests, along with the Chernobyl accident The purpose of this report is to compare thyroid cancer incidence rates across U.S states and counties, to identify any potential causes of rapid rises in the past several decades MATERIALS AND METHODS Collection of U.S cancer cases has been a function historically performed by state governments Until the 1990s, most of the 50 states had either no established registry or voluntary reporting that failed to produce useful data But the emergence of comprehensive registries in all 50 states, plus efforts by the U.S government to establish a unified data base makes geographic analysis possible Recently, the U.S Centers for Disease Control and Prevention compiled state-based cancer incidence data for all states plus the District of Columbia from 2001-2005, excluding only Maryland, Mississippi, Tennessee, Virginia, and Wisconsin The data base also includes county-specific data for all states, excluding the five mentioned above plus Illinois, Minnesota, North Dakota, and the Colorado counties of Adams, Boulder, Broomfield, Jefferson, and Weld Incidence rates are published only for those counties with at least 15 thyroid cancer cases diagnosed in 2001-2005, as rates in less-populated counties are based on small numbers of cases which are often not reliable This report will utilize the following data: State thyroid cancer incidence for 45 states plus the District of Columbia, representing about 276 million Americans (90.7% of the 2008 U.S population of 304 million) County-specific thyroid cancer incidence for 42 states plus the District of Columbia for the one-fifth (628) of the 3139 U.S counties with a 2008 population over 88,000, with a total of 241 million Americans (79.4%) are analyzed In states with county-specific data, 500 of these counties, with 202 million (66.6% of the U.S.) are analyzed (Appendix 3) Rates are calculated as the annual number of thyroid cancer cases per 100,000 persons, adjusted to the 2000 U.S standard population for 2001-2005 The number of cases diagnosed in this period, plus confidence intervals (to the 95% level), are also provided RESULTS For 2001-2005, the U.S thyroid cancer rate was 8.9 per 100,000, adjusted to the 2000 U.S standard population Each state had at least 250 cases in the five-year period Rates ranged from 5.4 in Arkansas (n = 755, CI = 5.0-5.8) to 12.8 in Pennsylvania (n = 8330, CI = 12.6-13.1) (Table 1) Of the seven states with the highest rates, five are in the northeast U.S (Pennsylvania, Massachusetts, New Jersey, Connecticut, and Rhode Island) Of the five states with the lowest rates, four are in the southeast U.S (Arkansas, North Carolina, Alabama, and South Carolina) Table Thyroid Cancer Incidence, by State, U.S., 2001-2005 (U.S Rate = 8.9, CI = 8.9-9.0) Cases per State 100000 (n), CI Pennsylvania 12.8 (8330) 12.6-13.1 New Mexico 12.1 (1125) 11.4-12.9 Massachusetts 12.0 (4000) 11.6-12.4 Utah 11.9 (1215) 11.2-12.6 New Jersey 11.8 (5260) 11.5-12.1 Connecticut 11.7 (2110) 11.2-12.2 Rhode Island 11.3 ( 625) 10.5-12.3 Montana 10.9 ( 515) 10.0-11.9 Delaware 10.8 ( 450) 9.8-11.8 Nevada 10.8 (1245) 10.2-11.5 Wyoming 10.8 ( 275) 9.6-12.2 9.8-11.4 12 Hawaii 10.6 ( 680) 13 Idaho 10.4 ( 690) 9.6- 11.2 13 New York 10.4 (10255) 10.2-10.6 15 Kansas 9.9 (1340) 9.4-10.5 9.4- 10.1 16 Arizona 9.8 (2685) 17 Colorado 9.7 (2200) 9.3-10.1 18 Iowa 9.4 (1405) 8.9-10.0 18 Nebraska 9.4 ( 815) 8.8- 10.1 20 Vermont 9.3 ( 300) 8.2- 10.4 20 Washington 9.3 (2905) 9.0- 9.7 22 Alaska 9.2 ( 295) 8.1-10.4 23 Dist of Columbia 9.0 ( 270) 8.0-10.2 24 Illinois 9.0 (5650) 8.3- 9.2 25 Maine 9.0 ( 615) 8.3- 9.8 Cases per State 100000 (n), CI 26 Florida 8.6 (7825) 8.4- 8.8 26 Missouri 8.6 (2485) 8.2- 8.9 26 New Hampshire 8.6 ( 575) 7.9- 9.3 29 Kentucky 8.4 (1780) 8.1- 8.9 29 South Dakota 8.4 ( 320) 7.5- 9.4 29 West Virginia 8.4 ( 825) 7.8- 9.0 32 Michigan 8.3 (4205) 8.0- 8.5 32 Texas 8.3 ( - ) 8.1- 8.5 34 Minnesota 8.2 (2095) 7.9- 8.6 35 California 8.0 (13645) 7.8- 8.1 35 North Dakota 8.0 ( 255) 7.1- 9.1 37 Indiana 7.8 (2420) 7.5- 8.1 37 Oregon 7.8 (1425) 7.4- 8.2 39 Ohio 7.6 (4440) 7.4- 7.8 40 Louisiana 7.5 ( - ) 7.1- 7.9 41 Georgia 7.3 (3135) 7.1- 7.6 42 North Carolina 6.7 (2865) 6.4- 6.9 42 South Carolina 6.7 (1415) 6.3- 7.0 44 Alabama 6.4 ( - ) 6.1- 6.8 45 Oklahoma 5.9 (1035) 5.5- 6.3 46 Arkansas 5.4 ( 755) 5.0- 5.8 Maryland No data available Mississippi No data available Tennessee No data available Virginia No data available Wisconsin No data available Source: U.S Centers for Disease Control and Prevention, http://statecancerprofiles.cancer.gov, Rates adjusted to 2000 U.S standard population Cases calculated from annual cases in 2001-2005 The 45 states plus District of Columbia with computed rates account for 90.7% of U.S population Rates, but not case numbers, given for Alabama, Louisiana, and Texas No obvious demographic factors explain these variations For example, Pennsylvania has the highest state rate for all races and genders (12.8 cases per 100,000 population, or 44% above the U.S.) However, its rates exceed the U.S for whites (+40%), blacks (+63%), Asian/Pacific Islanders (+26%), males (+28%) and females (+47%) Table lists the 18 U.S counties with the highest 2001-2005 thyroid cancer incidence, of the 500 U.S counties with over 88,000 residents Rankings for all races and whites, which account for nearly 90% of U.S thyroid cancer cases, are given Table Counties with Highest Thyroid Cancer Incidence Rate 500 U.S Counties with Population > 88,000, 43 States, All Races, 2001-2005 U.S Rank All White 1 2 4 5 6 8 10 15 11 11 12 13 13 16 14 19 14 18 16 11 17 16 18 21 County 2008 Pop *Lehigh PA 339,989 Cache UT 112,616 *Northampton PA 294,787 *Rockland NY 298,545 *Putnam NY 99,244 *Luzerne PA 311,893 *York PA 424,583 *Orange NY 379,647 Lubbock TX 264,418 Lawrence PA 90,272 Bonneville ID 99,135 Delaware IN 114,685 Yellowstone MT 142,348 Mercer PA 116,652 *Bucks PA 621,643 *Camden NJ 517,234 *Burlington NJ 445,475 *Lancaster PA 502,370 Cases 360 65 275 265 95 300 360 295 80 65 98 110 100 515 410 360 370 Cases per 100,000 Pop 95% CI 21.4 19.2- 23.7 19.0 14.6 – 24.4 18.8 16.6 – 21.2 18.3 16.1 – 20.6 18.0 14.4 – 22.1 17.6 15.6 – 19.7 15.4 – 19.0 17.1 16.6 14.7 – 18.6 16.6 14.1 - 19.2 16.5 13.0 – 20.6 16.4 12.6 – 20.9 13.1 - 20.0 16.3 16.1 13.2 – 19.4 15.8 12.8 – 19.3 15.8 14.4 – 17.2 14.2 – 17.3 15.7 15.5 13.9 – 17.2 15.3 13.8 – 17.0 * Within 90 miles of 40o 20’ north latitude, 75o 20’ west longitude Source: U.S Centers for Disease Control and Prevention, http://statecancerprofiles.cancer.gov Rates adjusted to 2000 U.S standard population Cases calculated from annual cases in 2001-2005 The 500 counties represent 66.6% of U.S population Excluded are IL, MD, MN, MS, ND, TN, VA, and WI plus Adams CO, Boulder CO, Jefferson CO, and Weld CO Rate, but not case numbers, given for Alabama, Louisiana, and Texas Thirteen (13) of the 18 counties with the highest rates for all races combined are from the contiguous states of New Jersey, New York, and Pennsylvania Moreover, 11 of these counties lie within 90 miles of 40o 20’ north latitude, 75o 20’ west longitude (Figure 1) This area has 16 nuclear power reactors, 13 of which are still operating, at seven plants (Appendix 4) No area of the U.S has as great a concentration of reactors The medical literature contains few studies of thyroid cancer incidence near U.S nuclear installations The National Cancer Institute examined cancer mortality near 62 plants, but included incidence data for only four sites The NCI typically selected the counties completely or mostly within 20 miles of a nuclear plant for study Incidence ratios for thyroid cancer in these counties rose after startup for each of four areas (Table 3) Table Thyroid Cancer Incidence Rate in Counties Closest to Nuclear Plants Before and After Reactor Startup, Connecticut and Iowa, 1950-1984 Nuclear Plant Haddam Neck CT Millstone CT Duane Arnold IA Ft Calhoun IA TOTAL Bef/Aft Startup 1950-67 1968-84 1950-70 1971-84 1969-74 1975-84 1969-73 1974-84 Standard Incidence Ratio (Cases) Before Startup After Startup 0.94 ( 36) 1.03 ( 76) 0.69 ( 64) 0.79 ( 90) 0.92 ( 23) 1.13 ( 77) 0.52 ( 1) 0.92 ( 6) 0.785 (124) 0.950 (249) Change + +10 +21 +40 +16.5 p88,000) No Counties 2008 Population 3139 304,059,724 % of U.S Pop 100.0 628 241,467,475 79.4 Most populated 20% of 500 U.S Counties, 43 States with available cancer data 202,358,687 66.6 Excluded are IL, MD, MN, MS, ND, TN, VA, plus Adams CO, Boulder CO, Jefferson CO, and Weld CO Source: U.S Centers for Disease Control and Prevention, http://statecancerprofiles.cancer.gov, 15 Appendix Nuclear Power Reactors Within 100 Mile Radius New Jersey, Southern New York, and Eastern Pennsylvania Reactor Location Indian Point Buchanan NY Indian Point Buchanan NY Indian Point Buchanan NY Limerick Limerick PA Limerick Limerick PA Peach Bottom Delta PA Peach Bottom Delta PA Peach Bottom Delta PA Salem Salem NJ 10 Salem Salem NJ 11 Hope Creek Salem NJ 12 Susquehanna Berwick PA 13 Susquehanna Berwick PA 14 Three Mile Island Londonderry PA 15 Three Mile Island Londonderry PA 16 Oyster Creek Forked River NJ Megawatts Electrical 257 951 965 1105 1105 40 1093 1035 1106 1106 1031 1090 1094 786 906 619 Startup 8/ 2/62 5/22/73 4/ 6/76 12/22/84 8/ 1/89 3/ 3/66 9/16/73 8/ 7/74 12/11/76 8/ 8/80 6/28/86 9/10/82 5/ 8/84 6/ 5/74 3/27/78 5/ 3/69 Closed 10/31/74 10/31/74 3/28/79 Source: U.S Nuclear Regulatory Commission, www.nrc.gov 16 ... (1035) 5.5- 6.3 46 Arkansas 5.4 ( 755) 5.0- 5.8 Maryland No data available Mississippi No data available Tennessee No data available Virginia No data available Wisconsin No data available Source: U.S.. . Rhode Island) Of the five states with the lowest rates, four are in the southeast U.S (Arkansas, North Carolina, Alabama, and South Carolina) Table Thyroid Cancer Incidence, by State, U.S., 2001-2005... 100 Mile Radius New Jersey, Southern New York, and Eastern Pennsylvania Reactor Location Indian Point Buchanan NY Indian Point Buchanan NY Indian Point Buchanan NY Limerick Limerick PA Limerick