The effect of hormone replacement therapy on prognostic indices in women with breast cancer.

OBJECTIVE

To examine the effect of hormone replacement therapy (HRT) on breast cancer biology.

PATIENTS

Four hundred and sixty Western Australian women with breast cancer who were 40 years or over at the time of their breast cancer surgery.

DESIGN AND SETTING

A questionnaire was sent to women seeking information on the use of HRT before breast cancer surgery. To qualify as HRT users, HRT had to have been used continuously for six months or more up to within two weeks of surgery.

MAIN OUTCOME MEASURES

Biochemical indices of oestrogen receptor, progesterone receptor, cathepsin D and protein levels, and pathological indices of tumour size, tumour differentiation and lymph node involvement for users and nonusers of HRT.

RESULTS

Eighty-seven per cent of questionnaires were recovered and 39 HRT users and 258 non-users were analysed. Twenty-five HRT users used a combination of oestrogen and progestogen and 14 used oestrogen only. Twenty-six had used HRT for more than two years and 13 for two years or less at the time of breast cancer diagnosis. There were no significant differences in the tumour indices between these two groups. The mean level of oestrogen receptors appeared to be lower in oestrogen-only users than in combination HRT users and non-users. The mean cathepsin D level was significantly higher in oestrogen-only users than in non-users. The percentage of all HRT users with involved lymph nodes (23%) was significantly lower than the percentage of non-users (44%).

CONCLUSION

Oestrogen-only HRT may have a detrimental effect on tumour biology. The use of a progestogen in combination with oestrogen may offer some protection. On the other hand, HRT users had less lymph node involvement with tumour. This may reflect early detection with increased surveillance in women using HRT.