OBJECTIVE:

Some healthcare providers recommend hormone therapy (HT) cessation before mammography to improve performance. Our objective was to evaluate characteristics of women willing to consider HT cessation before screening mammography.

METHODS:

We performed a randomized clinical trial, the Radiological Evaluation and Breast Density study, within an integrated health plan (2004-2007). Women aged 45 to 80 years who used HT at their most recent screening (index) mammogram, who were due for a screening (study) mammogram, and who were still using HT were invited to participate. Randomization groups were: (1) no, (2) 1-month, or (3) 2-month cessation. Women's willingness to participate was evaluated by age, race, ethnicity, education, hysterectomy, type of HT (unopposed estrogen and estrogen plus progestin), duration of HT use, body mass index, breast cancer risk, and breast density.

RESULTS:

A total of 5,861 women were invited to participate; 2,999 refused. An additional 169 women agreed to participate but withdrew before data collection. Compared with women who participated (n = 1,535), nonparticipants (n = 3,168; 2,999 + 169; 54%) were older, were less educated, and had lower body mass index (all P < 0.05). Among nonparticipants, 1,876 (59.2%) were unwilling to stop HT. Among estrogen-plus-progestin users, women with a first-degree relative with a history of breast cancer had lower odds of refusal than women without a family history of breast cancer (adjusted odds ratio, 0.71; 95% CI, 0.54-0.93).

CONCLUSIONS:

Most women were unwilling to stop HT, even for a short period, when the intent was to improve mammographic accuracy, and even when informed that they could restart HT at any time during the 2-month study. Some factors predicted willingness to stop HT; the magnitude of the differences may not be clinically meaningful.