Table 4.
Incidences and multiplicities of thyroid preneoplastic and neoplastic lesions in goitrogen‐treated rats after DHPN initiation
| Group | Treatments | Week | No. animals | Focal hyperplasias | Adenomas | Adenocarcinomas invasive to capsules |
|---|---|---|---|---|---|---|
| 1 | DHPN + PTU | 4 | 10 | 10 † (5.1 ± 1.7 ‡ ) | 2 (0.2 ± 0.4) | 0 |
| 10 | 10 | 10 (12.5 ± 2.9) | 9 (7.0 ± 3.1) | 0 | ||
| 3 | DHPN + SDM | 4 | 9 | 9 (7.7 ± 2.7) | 3 (0.3 ± 0.5) | 0 |
| 10 | 10 | 10 (15.6 ± 5.3) | 10 (5.0 ± 2.0) | 7* (1.0 ± 0.9) |
DHPN, N‐bis(2‐hydroxypropyl)nitrosamine; PTU, 6‐propyl‐2‐thiouracil; SDM, sulfadimethoxine; †incidence; ‡multiplicity; *P < 0.01 compared with group 2 (Fisher's exact probability test).