Regional Distribution of Fukushima Thyroid Cancer Cases (Confirmed and Suspected) Analyzed by Citizen Scientists

The first round of thyroid examination concluded in March 2014, and its results are nearly complete, except for some of the secondary examination results which were still not available as of August 24, 2014. Fukushima Medical University denies any regional difference in the incidence of thyroid cancer amongst Fukushima children and considers it unlikely that the current incidence of cancer is related to radiation exposure.  Although it might not be possible to epidemiologically assess the radiation health effects until the second round of thyroid examination is finished at the end of March 2016, the currently available data could still be analyzed in more detail.

As the nature of Japanese language allows significant amounts of information to be shared in a tweet using 140 letters, there has been an active discussion going on regarding the thyroid examination results on Twitter. When the results are released by Fukushima Medical University, citizen scientists--some professionals and some concerned citizens--would closely examine and analyze them.

Some say it is all due to the screening effect, having nothing to do with radiation exposure, and they claim the thyroid examination is causing more harm by unearthing cancer that might have laid dormant until much later in life. Some go to the other extreme to claim all the cancer cases could be due to radiation exposure. And there are those who are somewhere in-between, calling for a careful data collection and analysis so as not to miss any cases which might potentially be related to radiation exposure.

Two of the Twitter users actively involved in the discussion, @pririn and @iPatrioticmom, analyzed the latest Fukushima thyroid ultrasound examination results, released n August 24, 2014. Rather than claiming definite radiation health effects, which at this point is difficult to do, they simply want to point out the need for proper analyses of data from the first round of examination. They admit that this analysis is not by any means a final one and that the data is not age adjusted.

The translation was assisted by @sitesirius and @niigatamama.

Original analysis in an Excel file: Japanese and English.


Tab 1: Regional distribution of confirmed and suspected thyroid cancer cases in 
Fukushima Prefecture

Based on Table 8 of "Thyroid Examination (Initial Screening)" provisional results

	FY2011 target municipalities
	FY2012 target municipalities
	FY2013 target municipalities

No.	City, Town, Village		Number of primary examination participants	Number of confirmed or suspected cancer	Proportion of confirmed or suspected cancer	Incidence per 100,000
1	Minamisoma	南相馬市	10789	2	0.02%	19
2	Date	伊達市	10606	2	0.02%	19
3	Tamura	田村市	6327	3	0.05%	47
4	Kawamata	川俣町	2221	2	0.09%	90
5	Namie	浪江町	3249	2	0.06%	62
6	Hirono	広野町	838	0	0.00%	0
7	Naraha	楢葉町	1153	0	0.00%	0
8	Tomioka	富岡町	2302	1	0.04%	43
9	Okuma	大熊町	1973	1	0.05%	51
10	Futaba	双葉町	949	0	0.00%	0
11	Iitate	飯舘村	943	0	0.00%	0
12	Kawauchi	川内村	280	1	0.36%	357
13	Katsurao	葛尾村	183	0	0.00%	0
	Subtotal	計	41813	14	0.03%	33.5
14	Fukushima	福島市	47336	12	0.03%	25
15	Koori	桑折町	1857	0	0.00%	0
16	Kunimi	国見町	1429	0	0.00%	0
	Subtotal	計	50622	12	0.02%	23.7
17	Nihonmatsu	二本松市	8846	5	0.06%	57
18	Motomiya	本宮市	5233	3	0.06%	57
19	Koriyama	郡山市	53962	23	0.04%	43
20	Shirakawa	白河市	10805	6	0.06%	56
21	Miharu	三春町	2717	1	0.04%	37
22	Otama	大玉村	1372	2	0.15%	146
23	Ten-ei	天栄村	878	0	0.00%	0
24	Nishigo	西郷村	3618	1	0.03%	28
25	Izumizaki	泉崎村	1156	1	0.09%	87
	Subtotal	計	88587	42	0.05%	47.4
26	Soma	相馬市	5046	0	0.00%	0
27	Shinchi	新地町	1105	0	0.00%	0
	Subtotal	計	6151	0	0.00%	0
28	Iwaki	いわき市	47759	19	0.04%	40
	Subtotal	計	47759	19	0.04%	39.8
29	Sukagawa	須賀川市	11532	4	0.04%	35
30	Kagamiishi	鏡石町	1947	0	0.00%	0
31	Yabuki	矢吹町	2452	0	0.00%	0
32	Ishikawa	石川町	2078	1	0.05%	48
33	Yamatsuri	矢祭町	774	0	0.00%	0
34	Asakawa	浅川町	1067	0	0.00%	0
35	Tanagura	棚倉町	2256	1	0.04%	44
36	Hanawa	塙町	1210	0	0.00%	0
37	Ono	小野町	1317	0	0.00%	0
38	Furudono	古殿町	790	0	0.00%	0
39	Nakajima	中島村	801	0	0.00%	0
40	Hirata	平田村	824	1	0.12%	121
41	Samegawa	鮫川村	503	0	0.00%	0
42	Tamakawa	玉川村	984	0	0.00%	0
	Subtotal	計	28535	7	0.03%	24.5
43	Kitakata	喜多方市	5710	0	0.00%	0
44	Aizuwakamatsu	会津若松市	14632	5	0.03%	34
45	Minamiaizu	南会津町	1803	0	0.00%	0
46	Kaneyama	金山町	136	0	0.00%	0
47	Mishima	三島町	129	0	0.00%	0
48	Shimogo	下郷町	688	1	0.15%	145
49	Nishiaizu	西会津町	638	0	0.00%	0
50	Tadami	只見町	492	0	0.00%	0
51	Inawashiro	猪苗代町	1871	1	0.05%	53
52	Bandai	磐梯町	413	0	0.00%	0
53	Aizumisato	会津美里町	2547	0	0.00%	0
54	Aizubange	会津坂下町	2074	1	0.05%	48
55	Yanaizu	柳津町	375	0	0.00%	0
56	Hinoemata	檜枝岐村	61	0	0.00%	0
57	Showa	昭和村	101	0	0.00%	0
58	Kitashiobara	北塩原村	382	0	0.00%	0
59	Yugawa	湯川村	507	1	0.20%	197
	Subtotal	計	32559	9	0.03%	27.6

■ Incidence rate in adjacent municipalities, grouped together so each group consists of about 10,000 to 20,000 primary examination participants (age group is not controlled)

(Groups are shown in gradations of the color--blue, yellow, or green--assigned to each fiscal year's target municipalities in the table above).

■ Regional differences--up to 5 times between the FY2012 and FY2013 target municipality groups as shown below:

FY2012 Nihonmatsu, Motomiya and Otama, 64.7 per 100,000 (shown in red)

FY2013 Northern Hamadori and Southern Nakadori, 13.0 per 100,000 (shown in green--top and bottom of the map)

*****

Shown below is the same table as above, except with each fiscal year's target municipalities color-coded according to the map immediately below. Names of the municipalities are shown in English and numbers are assigned corresponding to the numbers shown in the leftmost column.

	FY2011 target municipalities
	FY2012 target municipalities
	FY2013 target municipalities

No.	City, Town, Village		Number of primary examination participants	Number of confirmed or suspected cancer	Proportion of confirmed or suspected cancer	Incidence per 100,000
1	Minamisoma	南相馬市	10789	2	0.02%	19
2	Date	伊達市	10606	2	0.02%	19
3	Tamura	田村市	6327	3	0.05%	47
4	Kawamata	川俣町	2221	2	0.09%	90
5	Namie	浪江町	3249	2	0.06%	62
6	Hirono	広野町	838	0	0.00%	0
7	Naraha	楢葉町	1153	0	0.00%	0
8	Tomioka	富岡町	2302	1	0.04%	43
9	Okuma	大熊町	1973	1	0.05%	51
10	Futaba	双葉町	949	0	0.00%	0
11	Iitate	飯舘村	943	0	0.00%	0
12	Kawauchi	川内村	280	1	0.36%	357
13	Katsurao	葛尾村	183	0	0.00%	0
	Subtotal	計	41813	14	0.03%	33.5
14	Fukushima	福島市	47336	12	0.03%	25
15	Koori	桑折町	1857	0	0.00%	0
16	Kunimi	国見町	1429	0	0.00%	0
	Subtotal	計	50622	12	0.02%	23.7
17	Nihonmatsu	二本松市	8846	5	0.06%	57
18	Motomiya	本宮市	5233	3	0.06%	57
19	Koriyama	郡山市	53962	23	0.04%	43
20	Shirakawa	白河市	10805	6	0.06%	56
21	Miharu	三春町	2717	1	0.04%	37
22	Otama	大玉村	1372	2	0.15%	146
23	Ten-ei	天栄村	878	0	0.00%	0
24	Nishigo	西郷村	3618	1	0.03%	28
25	Izumizaki	泉崎村	1156	1	0.09%	87
	Subtotal	計	88587	42	0.05%	47.4
26	Soma	相馬市	5046	0	0.00%	0
27	Shinchi	新地町	1105	0	0.00%	0
	Subtotal	計	6151	0	0.00%	0
28	Iwaki	いわき市	47759	19	0.04%	40
	Subtotal	計	47759	19	0.04%	39.8
29	Sukagawa	須賀川市	11532	4	0.04%	35
30	Kagamiishi	鏡石町	1947	0	0.00%	0
31	Yabuki	矢吹町	2452	0	0.00%	0
32	Ishikawa	石川町	2078	1	0.05%	48
33	Yamatsuri	矢祭町	774	0	0.00%	0
34	Asakawa	浅川町	1067	0	0.00%	0
35	Tanagura	棚倉町	2256	1	0.04%	44
36	Hanawa	塙町	1210	0	0.00%	0
37	Ono	小野町	1317	0	0.00%	0
38	Furudono	古殿町	790	0	0.00%	0
39	Nakajima	中島村	801	0	0.00%	0
40	Hirata	平田村	824	1	0.12%	121
41	Samegawa	鮫川村	503	0	0.00%	0
42	Tamakawa	玉川村	984	0	0.00%	0
	Subtotal	計	28535	7	0.03%	24.5
43	Kitakata	喜多方市	5710	0	0.00%	0
44	Aizuwakamatsu	会津若松市	14632	5	0.03%	34
45	Minamiaizu	南会津町	1803	0	0.00%	0
46	Kaneyama	金山町	136	0	0.00%	0
47	Mishima	三島町	129	0	0.00%	0
48	Shimogo	下郷町	688	1	0.15%	145
49	Nishiaizu	西会津町	638	0	0.00%	0
50	Tadami	只見町	492	0	0.00%	0
51	Inawashiro	猪苗代町	1871	1	0.05%	53
52	Bandai	磐梯町	413	0	0.00%	0
53	Aizumisato	会津美里町	2547	0	0.00%	0
54	Aizubange	会津坂下町	2074	1	0.05%	48
55	Yanaizu	柳津町	375	0	0.00%	0
56	Hinoemata	檜枝岐村	61	0	0.00%	0
57	Showa	昭和村	101	0	0.00%	0
58	Kitashiobara	北塩原村	382	0	0.00%	0
59	Yugawa	湯川村	507	1	0.20%	197
	Subtotal	計	32559	9	0.03%	27.6

Tab 2: Incidence by municipality and March 15th plume

■ Incidence rate of each municipality and plume flow on March 15, 2011 analyzed by JAEA

Incidence rate per 100,000 (in red) in municipalities with more than 1,000 primary examination participants, superimposed on maps showing contaminated regions due to the March 15-16 radioactive plume, analyzed by JAEA

Sources: 

① Table 8 of "Thyroid Examination (Initial Screening) provisional results"

② "Formation of contaminated areas from the morning of March 15 to the afternoon of March 16" on page 16 of "Diffusion of Radioactive Iodine in the Environment: Based on the Model Calculation Results" by Masamichi Kayano, JAEA"

<Plume flow 1: March 15, 2011 from 6:00 am to 3:00 pm>

<Plume flow 2: March 15, 2011 from 3:00 pm to 9:00 pm>

<Plume flow 3: From 9:00 pm on March 15 to 6.00 am on March 16>

<Plume flow 1 to 3>

Tab 3: Incidence by municipality and soil contamination

■ Incidence rate of each municipality and soil contamination

Incidence rate per 100,000 (in red) in municipalities with more than 1,000 primary examination participants, superimposed on a map of radioactive cesium concentration in agricultural land

Source: The Ministry of Health, Labour and Welfare document, based on the radionuclide concentration distribution map in the agricultural land by the Ministry of Agriculture, Forestry and Fisheries (in Japanese)

Source: Elaboration of Iodine 131 Soil Concentration Map Through Determination of Iodine 129 (in Japanese)