Table 1.
Age-adjusted incidence rates of, and numbers of women developing, invasive colorectal cancer in the WHI hormone trials and in corresponding observational study subcohorts, according to prior use of postmenopausal hormone therapy (HT) and hysterectomy status.
| Without Uterus at Enrollment | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Clinical Trial | Observational Study | ||||||||
| Prior HT* |
No |
Yes |
No |
Yes |
|||||
| Placebo |
CEE† |
Placebo |
CEE |
Non-User |
CEE |
Non-User |
CEE |
||
| Number of women | 2770 | 2769 | 2659 | 2541 | 6541 | 8677 | 4429 | 1905 | |
| Average age (yrs) | 63.8 | 63.6 | 63.4 | 63.6 | 65.1 | 63.4 | 65.7 | 64.2 | |
| Incidence rate† | 1.52 | 1.65 | 1.21 | 1.47 | 1.31 | 0.73 | 0.86 | 1.66 | |
| Number of cases | 30 | 32 | 23 | 26 | 65 | 46 | 33 | 24 | |
| With Uterus at Enrollment | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Clinical Trial | Observational Study | ||||||||
| Prior HT* | No |
Yes |
No |
Yes |
|||||
| Placebo |
CEE/MPA† |
Placebo |
CEE/MPA |
Non-User |
CEE/MPA |
Non-User |
CEE/MPA |
||
| Number of women | 6020 | 6277 | 2082 | 2229 | 19668 | 5710 | 5660 | 1046 | |
| Average age (yrs) | 63.4 | 63.4 | 63.0 | 62.6 | 64.7 | 61.0 | 64.8 | 64.3 | |
| Incidence rate‡ | 1.64 | 1.00 | 1.53 | 0.70 | 0.97 | 1.08 | 1.06 | 0.72 | |
| Number of cases | 55 | 35 | 17 | 8 | 109 | 27 | 35 | 4 | |
*
Prior HT is defined relative to WHI enrollment in the clinical trial and non-user group in the OS, and defined relative to the beginning of the ongoing hormone therapy episode at enrollment in the OS user groups.
†
CEE, conjugated equine estrogens; CEE/MPA, conjugated equine estrogens plus medroxyprogesterone acetate.
‡
Incidence rate per 1000 person years, adjusted to the 5-year age distribution in the respective clinical trials.