Table 2.
Median (interquartile range), characteristics of participants and adjusted RRs (95% CIs) for thyroid cancer according to minimum absorbed doses in thyroid glands, as estimated by UNSCEAR
| Lowest quartile | Low middle | High middle | Highest quartile | Total | |
|---|---|---|---|---|---|
| Age 6–14 years | |||||
| Absorbed dose (mGy), range | 12.00–18.81 | 18.82–22.61 | 22.82–28.73 | 29.00–58.00 | |
| No. at risk | 38 262 | 23 037 | 57 547 | 26 661 | 145 507 |
| Sex (female), % | 49.3 | 49.7 | 49.1 | 49.7 | 49.4 |
| Age at NPP accident (years), median (25–75%) | 10 (8–12) | 10 (8–12) | 10 (8–12) | 10 (8–12) | 10 (8–12) |
| Age at baseline thyroid examination (years), median (25–75%) | 14 (12–16) | 13 (11–16) | 14 (11–16) | 14 (12–16) | 14 (12–16) |
| Participants needing confirmatory testing, n (%) | 380 (0.99) | 251 (1.09) | 551 (0.96) | 255 (0.96) | 1,437 (0.99) |
| Participants completing confirmatory testing, n (%) | 302 (0.79) | 213 (0.92) | 444 (0.77) | 211 (0.79) | 1,170 (0.80) |
| Participants getting FNAC, n (%)a | 25 (8.3) | 23 (10.8) | 69 (15.5) | 23 (10.9) | 140 (12.0) |
| Examination year | |||||
| 2014 (%) | 10 728 (28.0) | 16 876 (73.3) | 57 501 (99.9) | 2359 (8.8) | 87 464 (60.1) |
| 2015–17 (%) | 27 534 (72.0) | 6161 (26.7) | 46 (0.1) | 24 302 (91.2) | 58 043 (39.9) |
| Interval from baseline to follow-up examination (years), median (25–75%) | 2.0 (1.9–2.1) | 2.1 (2.0–2.4) | 2.1 (2.0–2.2) | 2.2 (2.1–2.5) | 2.1 (2.0–2.3) |
| No. of cases | 8 | 8 | 20 | 9 | 45 |
| Detection rate per 100 000 person-years | 10.4 | 15.9 | 16.4 | 14.8 | 14.5 |
| Age- and sex-adjusted RR (95% CI) | Ref. | 1.62 (0.61–4.32) | 1.68 (0.74–3.83) | 1.35 (0.52–3.50) | (Trend P = 0.54) |
| Age-, sex- and examination year-adjusted RR (95% CI) | 1.22 (0.43–3.49) | 1.12 (0.43–2.95) | 1.60 (0.59–4.33) | (Trend P = 0.43) | |
| Age ≥15 years | |||||
| Absorbed dose (mGy), range | 7.20–11.12 | 11.28–12.62 | 13.31–16.30 | 17.35–34.00 | |
| No. at risk | 4604 | 5160 | 4989 | 4039 | 18 792 |
| Sex (female), % | 58.1 | 54.8 | 57.2 | 56.3 | 56.6 |
| Age at NPP accident (years), median (25–75%) | 16 (15–17) | 16 (15–17) | 16 (15–17) | 16 (15–17) | 16 (15–17) |
| Age at baseline thyroid examination (years), median (25–75%) | 21 (20–22) | 20 (19–21) | 20 (19–21) | 21 (20–22) | 20 (19–21) |
| Participants needing confirmatory testing, n (%) | 124 (2.69) | 144 (2.79) | 128 (2.57) | 118 (2.92) | 514 (2.74) |
| Participants completing confirmatory testing, n (%) | 103 (2.24) | 120 (2.33) | 104 (2.08) | 93 (2.30) | 420 (2.23) |
| Participants getting FNAC, n (%)a | 7 (6.8) | 23 (19.2) | 15 (14.4) | 1 (1.1) | 46 (11.0) |
| Examination year | |||||
| 2014 (%) | 1784 (38.7) | 5156 (99.9) | 4985 (99.9) | 453 (11.2) | 12 378 (65.9) |
| 2015–17 (%) | 2820 (61.3) | 4 (0.1) | 4 (0.1) | 3586 (88.8) | 6414 (34.1) |
| Interval from baseline to follow-up examination (years), median (25–75%) | 2.1 (2.0–2.4) | 2.1 (2.0–2.6) | 2.1 (2.0–2.3) | 2.1 (2.0–2.5) | 2.1 (2.0–2.5) |
| No. of cases | 5 | 13 | 4 | 1 | 23 |
| Detection rate per 100 000 person-years | 50.1 | 107.6 | 36.0 | 11.5 | 54.9 |
| Age- and sex-adjusted RR (95% CI) | Ref. | 2.03 (0.72–5.74) | 0.66 (0.17–2.51) | 0.23 (0.03–1.97) | (Trend P = 0.09) |
| Age-, sex- and examination year-adjusted RR (95% CI) | 1.66 (0.47–5.86) | 0.54 (0.12–2.45) | 0.26 (0.03–2.42) | (Trend P = 0.08) | |
aParticipants who underwent FNAC/participants who completed confirmatory testing.