Table 3.
Breast cancer risk associated with therapeutic I-131 stratified by the number of administered activities and the maximum activity in a single administration to the breast.
| I-131 cumulative activity (mCi) | 10-year latency | |
|---|---|---|
| BC cases | RR (95% CI) | |
| No I-131 treatment | 234 | 1 |
| Number of administered activity | ||
| 1 | ||
| <40 | 4 | 0.51 (0.16–1.20) |
| 40–100 | 16 | 0.80 (0.46–1.30) |
| 100–200 | 49 | 1.09 (0.79–1.48) |
| 200–400 | 8 | 2.45 (1.10–4.67) |
| ≥400 | 0 | – |
| >1 | ||
| <40 | 0 | – |
| 40–100 | 0 | – |
| 100–200 | 4 | 1.10 (0.34–2.62) |
| 200–400 | 11 | 1.22 (0.62–2.15) |
| ≥400 | 9 | 2.57 (1.20–4.84) |
| The maximum activity in a single administration (mCi) | ||
| Maximum activity <200 mCi | ||
| <40 | 4 | 0.49 (0.15–1.15) |
| 40–100 | 16 | 0.77 (0.44–1.25) |
| 100–200 | 53 | 1.10 (0.80–1.47) |
| 200–400 | 8 | 1.10 (0.49–2.11) |
| ≥400 | 2 | 3.23 (0.53–10.37) |
| Maximum activity ≥200 mCi | ||
| 200–400 | 11 | 2.18 (1.11–3.83) |
| ≥400 | 7 | 2.24 (0.94–4.48) |
BC breast cancer, CI confidence interval, RR relative risk.